Bus voltage stabilization control device

Abstract

The invention discloses a bus voltage stabilization control device. Firstly, high-end bus voltage and low-end bus voltage are respectively sampled by two bus voltage sensors; then, the sampling values are respectively transferred into a high-end bus voltage controller and a low-end bus voltage controller and are compared with the expected values; when the voltage sampling values are less than theexpected voltage values of the buses, the duty ratio of pulse width modulation signals is correspondingly reduced so that the output power of a half-bridge inverter circuit is reduced, and the storedenergy of a bus capacitor is increased, thus the voltage sampling values are increased until the voltage sampling values are equal to the expected voltage values of the buses; and the reverse is alsotrue. In the invention, by controlling corresponding output current values by the high-end bus voltage controller and the low-end bus voltage controller, the regulation of the bus voltage is realizedto enable the bus voltage to be in a stabilized state. Meanwhile, because the expected voltage values (Uref) of the buses in the high-end bus voltage controller and the low-end bus voltage controllerare same, the bus voltage is stabilized, and simultaneously, the balance of the high-end voltage and the low-end voltage of the buses is also realized.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic inverter grid-connected power generation systems, and more specifically relates to a bus voltage stabilization control device for controlling the bus voltage of a photovoltaic inverter. Background technique [0002] At present, the solar photovoltaic inverter power generation system has been paid attention to by many countries in the world, and the photovoltaic inverter, as a key part of the photovoltaic inverter grid-connected power generation system, has also been greatly developed. Usually, as figure 1 As shown, the photovoltaic inverter grid-connected power generation system is composed of a solar panel array 1 and a photovoltaic inverter 2 . Among them, the photovoltaic inverter 2 includes a maximum power point tracking (MPPT) module 201 , a bus circuit 202 , an inverter bridge circuit 203 and a control circuit 204 , and its function is to convert solar energy into electrical energy and...

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Problems solved by technology

[0005] In addition, the deviation of the capacitor voltage can be reduced by increasing the value of the voltage-dividing capacitor, or a large power resistor can be connected in parallel to the voltage-dividing capacitor to reduce the voltage deviation of the voltage-dividing capacitor, but these methods cannot completely eliminate the capacitor voltage. Bias voltage, and all increase circuit complexity or reduce system efficiency to varying degrees

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