DC-link Voltage Control Method for High Speed Motors powered by Z-source Inverter

In order to widen the flux-weakening range of motors, this paper derived and proposed a DC-link voltage control strategy for high speed permanent magnet motor drive systems powered by Z-source inverter. In this control strategy, the DC-link voltage varies with the output voltage and remains optimal at all times, not only in steady state, but also in dynamic state. And shoot-through duty ratio and modulation index, the two main control variables in the Z-source inverter, are under unified control to ensure the stability of the system, while achieving fast rising and reducing the loss. In addition, due to the versatility of the control methods, an optimal output control realized during motor starts can be achieved. Besides, various of conventional voltage Z-source inverter space vector pulse width modulation strategies can be applied to this technology. Simulations and experiments verified the effectiveness of the proposed strategy.