三相电压型PWM变流器自然坐标准直接功率控制

Quasi direct power control for three-phase voltage-source pwm converter under natural coordinate

为降低三相电压型PWM变流器直接功率控制系统复杂度,提出一种自然坐标(abc坐标)系下的准直接功率控制策略。该策略采用直接电流控制方式,根据自然坐标系下的瞬时功率理论,由功率给定值计算电流环的参考值,通过控制电流来间接控制功率。相比传统方法,所提控制策略在实现功率解耦控制的同时省去了电网相位检测和坐标变换,功率解耦各变量物理意义清晰明确、易于理解且PWM为定频调制方式。实验结果表明,所提策略可实现三相电压型PWM变流器功率解耦控制,并具有较好的鲁棒性能。

To reduce the complexity of direct power control （ DPC） system for three-phase voltage-source pulse width modulation （ PWM ） converter, a quasi-DPC strategy under natural coordinate （ abc coordinate） is presented. This strategy is based on instantaneous power theory under natural coordinate. So the current references are worked out with the instantaneous power references then we the instantaneous power can be controlled indirectly by the direct current controlling. Compare with the conventional DPC strategy, the quasi-DPC has good performance on the power decoupling control and saving phase detection of grid and coordinate transformation. The variables under the natural co-ordinate are clear to understand while the switching frequency of the PWM converter is fixed. The experimental results show that the proposed strategy can realize the power decoupling control of three-phase voltage-source PWM converter while robustness of system is obtained.