Active Damping Control Strategy for Five-phase Permanent Magnet Synchronous Motor Drive System without Electrolytic Capacitors

The electrolytic capacitor-less motor drive system has the advantages of small size, long life and high reliability. However, the motor drive system using film capacitors may have the problem of DC-link voltage instability, which is mainly manifested in the over-voltage phenomenon of DC-link voltage caused by LC resonance between film capacitors and grid-side inductors, and the existing resonance suppression strategy is widely used in the three-phase motors, while the five-phase permanent magnet synchronous motors without electrolytic capacitors resonance suppression strategy is applied to a lesser extent. For this reason, an active damping resonance suppression strategy for five-phase permanent magnet synchronous motors is proposed. Firstly, the instability and LC resonance of the system are analyzed based on the transfer function of the simplified driving circuit and the mathematical model of the five-phase permanent magnet synchronous motor is constructed. Secondly, the specific implementation of the damping current is introduced. Finally, the damping current is converted into a voltage command to construct a feedback loop to achieve the resonance suppression of the bus voltage, and the validity of the method is verified in the simulation.