Inverter control method and system

Abstract

The invention provides an inverter control method and system. The method is used for the inverter control process of a current inner-ring controller. The current inner-ring controller comprises an active current controller and a reactive current controller. The method comprises the steps that a k1-multiple output value of a voltage outer-ring controller is used as a reference value of the active current controller; a k2-multiple grid connection current active component is used as a feedback value of the active current controller; the ratio of the k2 to the k1 is a per unit value of the network voltage; according to the output value of the active current controller and the output value of the reactive current controller, a driving signal for the inverter is generated; the driving signal is output to the inverter to control an inverter to work. According to the inverter control method and system, the ratio of the k2 to the k1is the per unit value of the network voltage, so that the phenomenon that direct-current power output power is not matched with output power of the inverter is avoided, the fluctuation range of direct-current bus voltage is reduced, and the oscillation amplitude of the output current of the inverter is reduced.

Description

technical field [0001] The invention relates to the field of grid-connected inverters, in particular to an inverter control method and system. Background technique [0002] The inverter is used to convert the DC voltage output by the DC power supply into an AC voltage and then output it to the load circuit. It is widely used in photovoltaic, wind power generation and other fields. [0003] Under the condition that the grid voltage is stable, the output power of the DC power supply and the output power of the inverter basically match, that is, the difference between the two output powers is within a preset range. However, under some weak grid conditions, the grid voltage changes frequently, especially when the bus capacitor capacity is small and the control bandwidth of the voltage outer loop is narrow, which will cause a mismatch between the output power of the DC power supply and the output power of the inverter, thus This causes the DC bus voltage to rise or drop suddenly...

AI Technical Summary

Problems solved by technology

However, under some weak grid conditions, the grid voltage changes frequently, especially when the bus capacitor capacity is small and the control bandwidth of the voltage outer loop is narrow, which will cause a mismatch between the output power of the DC power supply and the output power of the inverter, thus This causes the DC bus voltage to rise or drop suddenly, causing the inverter output current to oscillate, and even causing the inverter to fail and go off-grid.

[0004] However, the prior art does not take the above problems into consideration when controlling the inverter.

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