Parallel inverter power balance control method based on common-mode voltage injection

Abstract

The invention discloses a parallel inverter power balance control method based on common-mode voltage injection. According to the method, intrinsic and additional common-mode voltage components are injected into a main inverter reference output voltage, wherein the additional common-mode voltage component comprises a main inverter reference output current signal. N inverters on the slave inverter side are connected in parallel, and the nth slave inverter is controlled as follows: proportional-integral-multimode resonance control is performed on a zero-sequence component of output current to obtain an additional common-mode voltage component of the slave inverter, and meanwhile, a reference output current signal of the main inverter is extracted from a zero-sequence current controller to obtain an additional common-mode voltage component of the slave inverter; the current is used as a reference output current of the slave inverter. Communication lines required by traditional master-slave control can be eliminated, the structural complexity of a parallel inverter system is reduced, meanwhile, it can be guaranteed that the system automatically achieves power balance, good dynamic and steady-state performance is achieved, and the operation performance of the parallel inverter is improved.

Description

technical field [0001] The invention belongs to the technical field of power electronics, in particular to a control method for parallel inverters based on common-mode voltage injection. Background technique [0002] With the rapid development of various new energy power generation technologies such as photovoltaic power generation and wind power generation, renewable energy will gradually become the main force in the field of power generation. Most of the current renewable energy generates DC power, which needs to be integrated into the grid through an inverter link. Therefore, the inverter plays an irreplaceable role. [0003] At present, the power required by electrical equipment is increasing, and a single inverter can no longer meet the requirements. Simply increasing the power of a single inverter will not only bring about problems such as increased manufacturing costs and increased volume, but also a single inverter. The impact of device failure on the continuous ope...

AI Technical Summary

Problems solved by technology

The principle of traditional master-slave control is as follows: figure 2 As shown, the control signal generated by the master inverter is used as the given signal of the slave inverter to achieve load balancing. This control method can make the parallel inverter system obtain better dynamic and steady-state performance, but the communication line Existence makes the structure of the whole system more complicated, and there is also equipment coupling phenomenon, which is not conducive to the development of parallel inverters

Although there is no communication line in the traditional droop control method, the automatic power balance effect is poor, and the dynamic and steady-state performance is poor

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