Jiangsu University

Huawei Zhou

Guohai Liu

Long Chen

Wenxiang Zhao

Jinghua Ji

Qian Chen

Cheng Zhou

Zhen Lu

Duo Zhang

In the fault-tolerant direct thrust-force control (FT-DTC) method, the generalized Clarke transform matrix and its inverse matrix are derived according to the fault-tolerant phase currents. The stator fluxes in &#x3b1;-&#x3b2; plane are deduced based on these. Based on the requirement of circular stator flux trajectory, virtual stator fluxes are defined, and then compensatory voltages in the &#x3b1;-&#x3b2; plane are obtained. Actual stator voltages in the &#x3b1;-&#x3b2; plane are calculated by modulation function of voltage source inverter. Combining with the compensatory voltages, the actual stator voltages and the stator currents, the virtual stator fluxes and the thrust-force are estimated by the flux and thrust-force observers. The thrust-force reference, the stator flux amplitude reference, the observed thrust-force and virtual stator flux are applied to predict virtual stator voltage references. The actual stator voltage references is calculated according to virtual voltage references and compensatory voltages, and are fed to voltage source inverter.

Fault-tolerant direct thrust-force control method for five-phase permanent-magnet linear motor with one open-circuit phase fault

The invention proposes a fault-tolerant field-oriented control method of five-phase interior permanent-magnet fault-tolerant linear motor (IPM-FTLM) with two nonadjacent short-circuit phase faults. Firstly, the extended Clark transformation matrix can be obtained according to the principle that magnetic motive force (MMF) keeps constant before and after the two-phase open-circuit faults, the constraint that the sum of healthy phase currents is zero and the adjacent two-phase current amplitude is equal. The back electric motive force (EMF) can be estimated by the transposed matrix. The nonlinear strong coupling system becomes the first-order inertia system when using the internal mode controller, the first-order inertia feed-forward voltage compensator and back-EMF observer, as the motor is with fault. Then, according to the principle that the sum of MMF of the healthy phase short-circuit compensation currents and two phases short-circuit fault currents is zero, the short-circuit compensation voltage can be obtained, and then these voltages add vector-controller output voltages, respectively. The invention not only restrains the thrust force fluctuation caused by two nonadjacent short-circuit phase faults, but also more importantly keeps the same dynamic and steady performance as the normal conditions, and also it has the constant switching frequency of voltage source inverter.

Fault-tolerant field-oriented control method of five-phase interior permanent-magnet linear motor under two nonadjacent short-circuit phase faults

Disclosed are fault-tolerant permanent-magnet vernier cylindrical electric motors with an electromagnetic suspension and a fault-tolerant vector control method for a short circuit of two adjacent phases. The fault-tolerant permanent-magnet vernier cylindrical electric motor with an electromagnetic suspension and the fault-tolerant vector control method for a short circuit of two adjacent phases suppress motor thrust ripples caused by a fault of two adjacent phases of an electric motor. The dynamic performance and the steady-state performance thereof are consistent with those under a normal state, and the switching frequency of a voltage source inverter is constant.

Fault-tolerant permanent-magnet Vernier cylindrical electric motor with electromagnetic suspension and fault-tolerant vector control method for short circuit of two adjacent phases

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Jiangsu, China

Huawei Zhou