Automatic master-slave parallel control method for sine pulse width modulation inverter power supply

Abstract

This invention discloses a SPWM inversion supply automatic master-slave parallel control method applying transient reactive power theory and parallel inversion supply output power performance, that is to control the output active power by converting frequency of its output voltage to control the output reactive power by converting its amplitude so as to uncouple the output active power P and reactive power Q to control the invented power source frequency / phase and amplitude. Although the system exists interlink signal line, the signal transferred by it is DC which can conveniently suppress interference of long distance transmission, so, the automatic master-slave control way is available in the distributed generation and UPS systems.

Description

1. Technical field [0001] The invention belongs to the field of electrical technology, and relates to a multi-machine parallel operation control method of a sinusoidal pulse width modulation inverter power supply in distributed power generation systems, UPS and other systems. 2. Background technology [0002] The parallel operation of multiple sinusoidal pulse width modulation inverters can expand the capacity of the system, and can also form a parallel redundant system to improve the reliability and maintainability of the system. However, parallel operation of sinusoidal PWM inverters is relatively difficult, because the frequencies, phases and amplitudes of all sinusoidal PWM inverters operating in parallel must be the same, otherwise, there will be a lot of problems between the inverters. Large circulating current, excessive circulating current will increase the burden on the inverter, and divergent circulating current will cause the system to collapse and cause power sup...

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Problems solved by technology

However, the master-slave control method also has some shortcomings: the existence of the master module makes it not a redundant system. Once the master module fails, the entire system will be paralyzed; the stability of the system depends on the number of parallel slave modules; There is a current command signal line between them, which should not be laid for a long distance, otherwise the signal will be greatly attenuated, the interference will be serious, and the phase will be seriously lagged

This method is especially suitable for distributed power generation systems. However, the equal distribution of reactive power is seriously affected by the line impedance. If the line impedance is not well matched, the reactive power required by the load will not be well divided. Therefore, this method has high requirements for system detection and control accuracy; and this method will sacrifice the voltage frequency and amplitude stability indicators of the system output due to the droop characteristic

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