Marine current turbine system post-fault behavior under an open circuit fault

POWER ENGINEERING AND ELECTRICAL ENGINEERING VOLUME: 16 |NUMBER: 3 |2018 |SEPTEMBER Marine Current Turbine System Post-Fault Behavior under an Open Circuit Fault Sana TOUMI 1,2, Elhoussin ELBOUCHIKHI 3, Yassine AMIRAT 3, Mohamed TRABELSI 1, Mohamed BENBOUZID 2,4, Mohamed Faouzi MIMOUNI 5 1Department of Electrical Engineering, National Engineering School of Sousse, University of Sousse, Sahloul 4, BP 526 Sousse, Tunisia 2Department of Electrical Engineering, UMR CNRS 6027 IRDL, University of Brest, Rue de Kergoat-CS 93837, 29238 Brest, France 3Department of Electrical Engineering, ISEN Yncrea Ouest Brest, UMR CNRS 6027 IRDL, University of Brest, Rue Cuirasse Bretagne, 29200 Brest, France 4Department of Electrical Engineering, Shanghai Maritime University, Shanghai Maritime University, 201306 Shanghai, China 5Department of Electrical Engineering, National Engineering School of Monastir, UR ESIER, University of Monastir, Rue Ibn El Jazzar, 5000 Monastir, Tunisia [email protected], Mohamed.Benb[email protected], elhoussin.elbouc[email protected], y[email protected], [email protected]u.tn DOI: 10.15598/aeee.v16i3.2839 Abstract. This paper describes the modeling and simulation of a Permanent Magnet Synchronous Generator (PMSG) based Marine Current Turbine (MCT) under converter faulty conditions. The modeling of the generator is represented in the d-q reference frame. The Proportional Integral (PI) controllers are used for the direct current, the quadratic current, and the speed Control. The faulty mode describes an open-circuit fault in the generator-side converter. Simulations results show that the dynamic performances and the power generation of the MCT are highly degraded due to the fault. Keywords Generator-side converter, marine current turbine, MPPT, open-circuit fault, permanent magnet synchronous generator, PI control. 1. Introduction Nowadays, new renewable resources are developed such as wave energy, thermal energy, and marine tidal energy. In fact, the production of electric power from marine tidal energy is interesting; 48 % is in the UK, 8 % in Ireland, and 42 % in France [1]. However, marine current turbine systems are exposed to ecological constraints because of the severe weather conditions (immersed systems). Due to these constraints, the performance of the MCT system can be degraded [2] and [3]. That leads to several faults, which can be related to the PMSG, to the blades, and to the converters [4] and [5]. Indeed, industrial surveys have shown that 70 % of converter faults are related to the switches. This paper describes the modeling of the MCT system under switchs fault conditions (open circuit fault). The control of the MCT system is achieved by using the Maximum Power Point Tracking (MPPT) to extract the optimal power and the PI controllers are designed to control the dq-axis currents and the speed. This paper is composed as follows: in Sec. 2. , the MCT system modeling is given. In Sec. 3. , MCT system control is developed. In Sec. 4. , post-fault behavior of the generator-side converter and performance evaluation are analyzed. Section 5. gives the conclusion. 2. Marine Current Turbine Modeling Figure 1 represents the MCT basic structure. It contains the turbine, the PMSG, the three-phase converter and the DC-bus. c 2018 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 279 POWER ENGINEERING AND ELECTRICAL ENGINEERING VOLUME: 16 |NUMBER: 3 |2018 |SEPTEMBER 2.1. Resource Description The gravitational interaction of Moon, Earth, and Sun creates the marine currents [6]. Marine currents are resulted about 32 % from the Sun and 68 % from the Moon. PMSG Marine turbine PWM DC bus vtide R Fig. 1: Marine current turbine basic structure. In fact, this interaction makes the ocean swell on different places. This fact makes an increase of the altitude of the water in the aligned places with the moon and a decrease in the level of the water between those two places. A horizontal movement is resulted from the increase in water level; this movement is called tidal current. 2.2. Marine Turbine Model A marine turbine mechanical power is given by Eq. (1) [7]. Pm=1 2Cp(λ, β)ρπr2v3 t,(1) where ρis the fluid density in (kg·m−3), ris the turbine radius in (m), vtis the tidal velocity in (m·s−1), Cp represents the rate of mechanical power extracted by the turbine from the fluid, λis the tip speed ratio, and βis the blade pitch angle in (◦). For typical MCTs and under normal operation, the maximum value of Cpis in the range of 0.35–0.5. In fact, for a given turbine, the power coefficient is represented using λ(Eq. (2)) and β[8]. λ=rΩ vt ,(2) where Ωis the mechanical turbine speed in (rpm). 2.3. Generator Model The PMSG was chosen for the system [9] thanks to its high efficiency, its compactness, and the possibility to remove gearbox in case of a direct-drive system. This reduces maintenance and makes the PMSG as a candidate of choice for immersed systems. The modeling of PMSG in the d-q reference is given by Eq. (3) as follows:                    disd dt=vsd Ls − Rs Ls isd +pΩisq, disq dt=vsq Ls − Rs Ls isq −pΩisd −pΦa Ls , Tem =3 2pΦaisq, Jt dΩ dt=Tm−Tem −fΩ, (3) where Jtis the total inertia in (kg·m−2), Tmis the mechanical torque in (N·m), Tem is the electromagnetic torque in (N·m), fis the viscosity coefficient in (N·m·s−1) tidal velocity in (m·s−1), vsd and vsq are the d−qcomponents of the stator voltages respectively in (V), isd and isq are the d−qcomponents of the stator currents respectively in (A), Rsis the phase resistance of the stator winding in (Ω), Lsis the stator cyclic inductance in (H), Φais the permanent magnet flux in (Wb) and pis the pole pair number. 2.4. Converter Model The generator-side converter contains three legs (Fig. 2). Every leg is composed by two switches (Tk, Tk+ 3,k= 1,2,3) and two freewheeling diodes (Dk, Dk+ 3) called IGBT. These IGBTs are controlled by a block of a PWM using gate signals Sk(k= 1,2,3) [10]. The kth gate signal denoted Skswitch is defined by Eq. (4) as follows: Sk=1if Tkon and Tk+3 off, 0if Tk+3 on and Tkoff.(4) D1 T2 D4 T5 T1 D2 T3 T4 D5 T6 D3 D6 Vdc A B C PMSG Marine turbine vtide R Fig. 2: Generator-side converter topology. 3. Marine Current Turbine Control The marine current turbine control system is based on a PI controller, which is used in conventional fieldoriented control technique. It is illustrated by Fig. 3. c 2018 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 280 POWER ENGINEERING AND ELECTRICAL ENGINEERING VOLUME: 16 |NUMBER: 3 |2018 |SEPTEMBER vtide Ω Ωref Ω Fig. 3: The proposed control structure. 3.1. Maximum Power Point Tracking The control system is defined by Eq. (5) as follows:            isd =1 Rs+Lss(vsd +ωψsq) isq =1 Rs+Lss(vsq −ωψsd) Tem =3 2pΦaisq ,(5) where (ω=pΩ) is the electrical speed, ψsd and ψsq are the d−qcomponents of the stator flux, respectively, defined by Eq. (6) as follows: ψsd =Lsisd +Φa, ψsq =Lsisq.(6) The MPPT strategy is based on a variable speed [11]. Indeed, the rotor speed is controlled using a PI controller to obtain the value of λthat corresponds to the maximum value of the power coefficient Cpand finally achieve the expected maximum power by the MCT. The speed controller is given by Eq. (7) as follows: R(s) = b1+b0 s,(7) where b1is the controller proportional coefficient and b0is the controller integral. The placing poles technique is used to compute the parameters of this controller. The reference of the speed is expressed by Eq. (8). It is used in order to make the function of the turbine is around the maximum power for different current tidal velocities. Ωref =vtλopt r.(8) If the tidal velocity exceeds 2.3 m·s−1[12], the power is restricted to 7.5 kW. The power of the turbine for different tidal velocities is determined by Eq. (1). 3.2. Current PI Controller The PI currents controllers are given by Eq. (9) as follows: R(s) = kp1 + 1 kis,(9) where kpis the controller proportional coefficient and kiis the controller integral. The division compensation technique is used to complete the parameters of these controllers. To reduce resistive losses, the reference of the d-axis current is zero, so, the q-axis current is the only current which control the electromagnetic torque. c 2018 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 281 POWER ENGINEERING AND ELECTRICAL ENGINEERING VOLUME: 16 |NUMBER: 3 |2018 |SEPTEMBER The reference of the quadratic current is determined via the controller of the speed. The converter voltage vector is given by the two PI currents controllers. The control signal is generated by the PWM block to implement the vector control of the generator. Time (s) 0 2 4 6 8 10 12 14 16 18 20 Marine current speed (m/s) 0 0.5 1 1.5 2 2.5 Fig. 4: Marine current turbine basic structure. 4. Marine Current Turbine Post-Fault Behavior and Results Analysis In this section, the influence of an open-circuit fault on the PMSG phase currents and the MCT dynamic performances will be studied on a PMSG-based MCT whose parameters are given in the Appendix. Simulations are carried out using MATLAB/Simulink environment. Figure 4 represents an example of marine current velocity in the Raz de Sein (potential site for the MCT project of the coast of Brittany in France) during 20 s based on tidal current data given by the French Navy Hydrographic and Oceanographic Service (SHOM). The marine current velocity can reach 2.3 m·s−1. time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic (a) Current. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 (b) Current. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension UAB (V) -200 -100 0 100 200 (c) Line-to-line voltage. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 (d) Line-to-line voltage. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 (e) Load voltage. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 (f) Load voltage. Fig. 5: Simulation Results of (T1) open-circuit fault: (a, b) currents, (c, d) line-to-line voltage UAB, (e, f) load voltage VAN. c 2018 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 282 POWER ENGINEERING AND ELECTRICAL ENGINEERING VOLUME: 16 |NUMBER: 3 |2018 |SEPTEMBER Waveforms given by Fig. 5 and Fig. 6 shows the three phase currents, the line-to-line voltage UAB, and the load voltage VAN, respectively. In Fig. 6, a fault state is introduced at t= 1.02 s and applied to the switch (T1). It is observed that the phase current ia is no more negative (Fig. 5(a)). The lineto-line voltage UAB (Fig. 5(c)) and the load voltage VAN (Fig. 5(e)) exhibit a great drop from the positive level to the negative one. Figure 5(b), Fig. 5(d), and Fig. 5(f) shows that the Fault detection is accomplished time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic (a) Current. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 (b) Current. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 (c) Line-to-line voltage. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.0175 1.018 1.0185 1.019 1.0195 1.02 1.0205 1.021 1.0215 1.022 tension UAB (V) -200 -100 0 100 200 (d) Line-to-line voltage. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.0175 1.018 1.0185 1.019 1.0195 1.02 1.0205 1.021 1.0215 1.022 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 (e) Load voltage. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.0175 1.018 1.0185 1.019 1.0195 1.02 1.0205 1.021 1.0215 1.022 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.018 1.019 1.02 1.021 1.022 1.023 1.024 1.025 tension VAN (V) -150 -100 -50 0 50 100 150 (f) Load voltage. Fig. 6: Simulation Results of (T4) open-circuit fault: (a, b) currents, (c, d) line-to-line voltage UAB, (e, f) load voltage VAN. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.0175 1.018 1.0185 1.019 1.0195 1.02 1.0205 1.021 1.0215 1.022 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.018 1.019 1.02 1.021 1.022 1.023 1.024 1.025 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 0 2 4 6 8 10 12 14 16 18 20 Power (W) 0 2000 4000 6000 8000 (a) time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.0175 1.018 1.0185 1.019 1.0195 1.02 1.0205 1.021 1.0215 1.022 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.018 1.019 1.02 1.021 1.022 1.023 1.024 1.025 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 0 2 4 6 8 10 12 14 16 18 20 Power (W) 0 2000 4000 6000 8000 time (s) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Power (W) 0 2000 4000 6000 8000 (b) Fig. 7: PMSG generated power. c 2018 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 283 POWER ENGINEERING AND ELECTRICAL ENGINEERING VOLUME: 16 |NUMBER: 3 |2018 |SEPTEMBER time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension UAB (V) -200 -100 0 100 200 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.0175 1.018 1.0185 1.019 1.0195 1.02 1.0205 1.021 1.0215 1.022 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.018 1.019 1.02 1.021 1.022 1.023 1.024 1.025 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 0 2 4 6 8 10 12 14 16 18 20 Power (W) 0 2000 4000 6000 8000 time (s) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Power (W) 0 2000 4000 6000 8000 time (s) 0 2 4 6 8 10 12 14 16 18 20 Rotor speed (rpm) 0 500 1000 1500 2000 2500 3000 (a) time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension UAB (V) -200 -100 0 100 200 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.0175 1.018 1.0185 1.019 1.0195 1.02 1.0205 1.021 1.0215 1.022 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.018 1.019 1.02 1.021 1.022 1.023 1.024 1.025 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 0 2 4 6 8 10 12 14 16 18 20 Power (W) 0 2000 4000 6000 8000 time (s) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Power (W) 0 2000 4000 6000 8000 time (s) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Rotor speed (rpm) 0 500 1000 1500 2000 2500 3000 (b) Fig. 8: PMSG rotor speed. time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension UAB (V) -200 -100 0 100 200 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.0175 1.018 1.0185 1.019 1.0195 1.02 1.0205 1.021 1.0215 1.022 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.018 1.019 1.02 1.021 1.022 1.023 1.024 1.025 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 0 2 4 6 8 10 12 14 16 18 20 Power (W) 0 2000 4000 6000 8000 time (s) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Power (W) 0 2000 4000 6000 8000 0 2 4 6 8 10 12 14 16 18 20 Rotor speed (rpm) 0 500 1000 1500 2000 2500 3000 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Rotor speed (rpm) 0 500 1000 1500 2000 2500 3000 time (s) 0 2 4 6 8 10 12 14 16 18 20 Torque (N.m) 0 5 10 15 20 (a) time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension UAB (V) -200 -100 0 100 200 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.02 1.022 1.024 1.026 1.028 1.03 1.032 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 Currents (A) -30 -20 -10 0 10 20 30 ia ib ic time (s) 1.015 1.016 1.017 1.018 1.019 1.02 1.021 1.022 Current ia(A) -30 -20 -10 0 10 20 30 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.0175 1.018 1.0185 1.019 1.0195 1.02 1.0205 1.021 1.0215 1.022 tension UAB (V) -200 -100 0 100 200 time (s) 1 1.01 1.02 1.03 1.04 1.05 1.06 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 1.017 1.018 1.019 1.02 1.021 1.022 1.023 1.024 1.025 tension VAN (V) -150 -100 -50 0 50 100 150 time (s) 0 2 4 6 8 10 12 14 16 18 20 Power (W) 0 2000 4000 6000 8000 time (s) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Power (W) 0 2000 4000 6000 8000 time (s) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Rotor speed (rpm) 0 500 1000 1500 2000 2500 3000 0 2 4 6 8 10 12 14 16 18 20 Torque (N.m) 0 5 10 15 20 time (s) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Torque (N.m) 0 5 10 15 20 (b) Fig. 9: PMSG torque. at t= 1.0295 s, taking 9.5 ms as fault detection time. In Fig. 6, the fault is now applied to the switch (T4), the reverse effect is observed on the phase current ia (Fig. 6(a)), the line-to-line voltage UAB (Fig. 6(b)), and the load voltage VAN (Fig. 6(c)) exhibit a great drop from the negative level to the positive one. Figure 7, Fig. 8, and Fig. 9 represent the generated power, the rotor speed, and the torque with its version. It should be noticed that these results are achieved for an open-circuit in switch T1 occurring at t= 1 s, t= 4 s, t= 8 s and t= 17 s. As shown in these 0% 10% 20% 30% 40% 50% Power Rotor speed Torque Fig. 10: Range of variation in speed, torque and power in (%) at t= 1 s. figures, by using PI control, the power, the speed, and the torque have some ripples at the faults occurrence. Figure 10 gives a histogram which shows the range of variation in speed, torque, and power in (%) at t= 1 s. This proves that this technique is not useful and does not present any robustness against faults, therefore leading to the MCT system performances degradation. 5. Conclusion The paper described the simulation of a PMSG-based marine current turbine experiencing open-circuit fault in power switches of its generator-side converter. PI controllers have been adopted for the MCT control. These results evidently show that PI control is very sensitive to faulty conditions and does not present any robustness. Therefore a fault-tolerant rectifier with specific redundancy or an advanced robust control techniques such as a high order sliding mode control are required. References [1] BENELGHALI, S., M. E. H. BENBOUZID, T. AHMED-ALI and J. F. CHARPENTIER. c 2018 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 284 POWER ENGINEERING AND ELECTRICAL ENGINEERING VOLUME: 16 |NUMBER: 3 |2018 |SEPTEMBER High-order sliding mode control of a marine current turbine driven doubly-fed induction generator. IEEE Journal of Oceanic Engineering. 2010, vol. 35, iss. 2, pp. 402–411. ISSN 0364-9059. DOI: 11.1109/jae.2010.2040402. [2] AMIRAT, Y., M. E. H. BENBOUZID, E. ALAHMAR, B. BENSAKER and S. TURRI. A brief status on condition monitoring and fault diagnosis in wind energy conversion systems. Renewable and Sustainable Energy Reviews. 2009, vol. 3, iss. 9, pp. 2629–2636. ISSN 1364-0321. DOI: 10.1016/rser.2009.06.031. [3] TOUMI, S., S. BENELGHALI, M. TRABELSI, E. ELBOUCHIKHI, Y. AMIRAT, M. E. H. BENBOUZID and M. F. MIMOUNI. Modeling and simulation of a PMSG-based marine current turbine system under faulty rectifier conditions. Electric Power Components and Systems. 2017, vol. 45, iss. 7, pp. 715–725. ISSN 1532-5008. DOI: 10.1080/15325008.2017.1293197. [4] ELGENEDY, M. A., A. S. ABDEL-KHALIK, A. ELSEROUGI, S. AHMED and A. MASSOUD. Fault-tolerant control of five phase current source inverter for medium-voltage drives. In: 7th International Conference on Power Electronics, Machines and Drives. Manchester: IEEE, 2014, pp. 1–6. ISBN 978-184919-815-8. DOI: 10.1049/cp.2014.0329. [5] TOUMI, S., S. BENELGHALI, M. TRABELSI, E. ELBOUCHIKHI, M. E. H. BENBOUZID and M. F. MIMOUNI. Robustness analysis and evaluation of a PMSG-based marine current turbine system under faulty conditions. In: IEEE STA. Hammamet: IEEE, 2014, pp. 631–636. ISBN 9781-4799-5906-8. DOI: 10.1109/STA.2014.7086809. [6] TOUMI, S., Y. AMIRAT, E. ELBOUCHIKHI, M. TRABELSI, M. E. H. BENBOUZID and M. F. MIMOUNI. A comparison of fault-tolerant control strategies for a PMSG-based marine current turbine system under converter faulty conditions. Journal of Electrical Systems. 2017, vol. 13, iss. 3, pp. 472–488. ISSN 1949-3029. DOI: 10.1080/15325008.2017.1293197. [7] HAMMONS, T. J. Tidal power in the UK and worldwide to reduce greenhouse gas emissions. International Journal of Engineering Business. 2011, vol. 3, iss. 2, pp. 1–13. ISSN 1847-9790. DOI: 10.5772/50933. [8] ZHOU, Z., F. SCUILLER, J. F. CHARPENTIER, M. E. H. BENBOUZID and T. TANG. Power smoothing control in a grid-connected marine current turbine system for compensating swell effect. IEEE Transactions Sustainable Energy. 2013, vol. 4, iss. 3, pp. 816–826. ISSN 19493029. DOI: 10.1109/TSTE.2013.2251918. [9] TOUMI, S., Y. AMIRAT, E. ELBOUCHIKHI, M. TRABELSI, M. F. MIMOUNI and M. E. H. BENBOUZID. Second-order sliding mode for marine current turbine fault-tolerant control. In: 4th International Conference on Control Engineering and Information Technology. Hammamet: IEEE, 2016, pp. 1–6. ISBN 978-1-50901055-4. DOI: 10.1109/CEIT.2016.7929075. [10] TRABELSI, M., M. BOUSSAK and M. GOSSA. Multiple IGBTs open circuit faults diagnosis in voltage source inverter fed induction motor using modified slope method. In: The XIX International Conference on Electrical Machines. Marseille: IEEE, 2012, pp. 1–6. ISBN 978-1-4244-41747. DOI: 10.1109/ICELMACH.2010.5608044. [11] SUNG-YOON, J., C. C. MI and N. KWANGHEE. Torque control of IPMSM in the field-weakening region with improved DC-link voltage utilization. IEEE Transactions on Industrial Electronics. 2015, vol. 62, iss. 6, pp. 3380–3387. ISSN 02780046. DOI: 10.1109/TIE.2014.2369453. [12] TOUMI, S., Y. AMIRAT, E. ELBOUCHIKHI, M. TRABELSI, M. E. H. BENBOUZID and M. F. MIMOUNI. A simplified mathematical approach for magnet defects modeling in PMSGbased marine current turbine. In: 17th International Conference on Sciences and Techniques of Automatic Control and Computer Engineering. Sousse: IEEE, 2016, pp. 1–6. ISBN 978-1-50901055-4. DOI: 10.1109/STA.2016.7951996. About Authors Sana TOUMI received her B.Sc. and the M.Sc. degrees in electrical engineering from Ecole Nationale d’Ingenieurs de Monastir (ENIM), Monastir, Tunisia in 2012 and 2013, respectively. She received a Ph.D. degree in electrical engineering from l’Universite de Bretagne Occidentale (UBO), Brest, France and l’Ecole Nationale d’Ingenieurs de Sousse (ENISO), Sousse, Tunisia, in 2017. Currently, she is working with the Research Unit Industrial Systems Study and renewable Energy, University of Sousse, Sousse, Tunisia and the Institut de Recherche Dupuy de Lome, IRDL (UMR CNRS 6027), University of Brest, Brest, France. Her current research interests include marine current turbine systems, power electronics, faulty conditions, and fault-tolerant control. Elhoussin ELBOUCHIKHI received his Engineer Diploma degree in automatic and electrical c 2018 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 285 POWER ENGINEERING AND ELECTRICAL ENGINEERING VOLUME: 16 |NUMBER: 3 |2018 |SEPTEMBER engineering and the Research Master’s degree in automatic systems, computer science and decision from the National Polytechnic Institute of Toulouse, Toulouse, France, in 2010, and Ph.D. degree in electrical engineering from the University of Brest, Brest, France, in 2013. He has been a postdoctoral researcher at Institut Superieur de l’Electronique et du Numerique (ISEN), Brest, France, from October 2013 to September 2014. Since September 2014, he has been working as an associate professor at ISEN Brest, Yncrea Ouest, Brest, France, and is an affiliated member of the IRDL (UMR CNRS 6027). His current research interests include electrical machines’ fault detection and diagnosis, fault-tolerant control, and signal processing and statistics for power system monitoring. Yassine AMIRAT received his B.Sc. and M.Sc. degrees both in electrical engineering, from the University of Annaba, Algeria, in 1994 and 1997, respectively. In 2011, he received a Ph.D. degree in electrical engineering from the University of Brest, Brest, France. Dr. Amirat was a lecturer in the University of Annaba, Annaba, Algeria and then in Institut Superieur de l’Electronique et du Numerique (ISEN), Brest, France. Since January 2012, he has been an associate professor of electrical engineering at ISEN Brest, Yncrea Ouest, Brest, France, and is an affiliated member of the IRDL (UMR CNRS 6027). His current research interests are the condition monitoring and the control of electrical drives and power electronics. Mohamed TRABELSI received his B.Sc. and M.Sc. degrees in electrical engineering and industrial systems from Ecole Superieure des Sciences et Techniques de Tunis (ESSTT), Tunis, Tunisia, in 2005 and 2007, respectively. He received a Ph.D. degree in electrical engineering from Aix-Marseille III University, Marseille, France and the ESSTT, Tunis, Tunisia, in 2012. He has carried out independent professional activity in several industrial and research fields for seven years. In 2007, he was an Assistant Technologue at Institut Superieur des Etudes Technologiques (ISET) Sousse, Tunisia, and, in 2009, he moved to Aix-Marseille III University. From 2013 to 2014, he was an assistant professor at Ecole Nationale d’Ingenieurs de Sousse (ENISO), Sousse, Tunisia. Since then, he has been a postdoctoral affiliate with the L2EP Laboratory at the University of Lille, Lille, France. His research interests are focused on fault diagnosis in power converters, AC motor drives, and multi-phase drive systems. Mohamed BENBOUZID received the B.Sc. degree in electrical engineering from the University of Batna, Batna, Algeria, in 1990, the M.Sc. and Ph.D. degrees in electrical and computer engineering from the National Polytechnic Institute of Grenoble, Grenoble, France, in 1991 and 1994, respectively, and the Habilitation a Diriger des Recherches degree from the University of Picardie "Jules Verne," Amiens, France, in 2000. After receiving the Ph.D. degree, he joined the Professional Institute of Amiens, University of Picardie "Jules Verne," where he was an Associate Professor of electrical and computer engineering. Since September 2004, he has been with the Institut Universitaire de Technologie of Brest, University of Brest, Brest, France, where he is a Professor of electrical engineering. Prof. Benbouzid is also a Distinguished Professor at the Shanghai Maritime University, Shanghai, China. His main research interests and experience include analysis, design, and control of electric machines, variable-speed drives for traction, propulsion, and renewable energy applications, and fault diagnosis of electric machines. Profesor Benbouzid is an IEEE Senior Member. He is the Editor-in-Chief of the International Journal on Energy Conversion (IRECON). He is also an Associate Editor of the IEEE Transactions on Energy Conversion, the IEEE Transactions on Industrial Electronics, the IEEE Transactions on Sustainable Energy, the IEEE Transactions on Vehicular Technology. He is a Subject Editor for the IET Renewable Power Generation. Mohamed Faouzi MIMOUNI received his Ph.D. and University Habilitation degrees in Electrical Engineering from the University of Monastir, Monastir, Tunisia in 1997 and 2004, respectively. He is currently a Full Professor at Ecole Nationale d’Ingenieurs de Monastir (ENIM), Monastir, Tunisia. His specific research interests are in the area of power electronics; motor drives; solar and wind power generation. c 2018 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 286 POWER ENGINEERING AND ELECTRICAL ENGINEERING VOLUME: 16 |NUMBER: 3 |2018 |SEPTEMBER Appendix A PMSG-Based MCT Parameters MCT Parameters Turbine blade radius 0.87 m Number of blades 3 Fluid density 1027.68 kg·m−3 PMSG Parameters Rated Power 7.5 kW Rated Speed 3000 tr·mn−1 Rated Torque 17 N·m Stator resistance 0.173 mΩ Stator inductance 0.951 mH Permanent magnets flux 0.112 Wb System total inertia 1.3131 106 kg·m−2 Viscosity coefficient 8.5 10-3 Nm·s−1 Converter Parameters Turn-on time 0.13 µs Turn-off time 0.445 µs Dead-time 4 µs Duty-cycle frequency 5 kHz DC-bus voltage 600 V PI Controller parameter Turbine speed loop (b0, b1) (0.56, 1.7) Generator dq-axis current loop (kp, ki) (0.0173, 5.49) c 2018 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 287