High-power wind power converter energy storage capacitor charging circuit

Abstract

The invention belongs to wind power generation equipment, and relates to a charging circuit for an energy storage capacitor of a high-power wind power converter. The circuit includes a machine-side rectifier circuit and a grid-side inverter circuit connected between the generator and the power grid; the machine-side rectifier circuit is composed of an IGBT power unit, and is connected to the generator through a machine-side switch; the grid-side inverter circuit consists of It is composed of IGBT power unit, and connected to the power grid through LCL filter circuit and grid-side switch in sequence; its feature is that the charging resistor is connected in parallel at the grid-side switch, and the charging resistor is controlled by the charging switch connected in series. The invention can ensure that the DC bus voltage reaches a capacitor safety voltage range in advance before the converter starts to work, and prolongs the service life of the capacitor; it not only has a simple circuit structure and low cost, but also has fast charging speed, high charging voltage and harmonic suppression effect it is good.

Description

technical field [0001] The invention belongs to wind power generation equipment, and relates to a charging circuit for an energy storage capacitor of a high-power wind power converter. Background technique [0002] In the main circuit of the voltage-type PWM high-power rectifier (VSR) of the wind power generation system, as attached figure 1 As shown, the DC side includes a machine-side rectifier circuit 01 composed of IGBT power units, and the machine-side rectifier circuit is connected to the generator 02 through a machine-side switch. The inverter circuit is connected to the grid 05 through the LCL filter circuit 04 and the grid side switch. On the DC side, the energy storage capacitor 06 is usually used for DC energy storage. The energy storage capacitor can not only buffer the energy conversion between the AC side and the DC side load, stabilize the VSR DC side voltage, but also suppress the DC side harmonic voltage. However, in high-power MW-level wind power converte...

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Problems solved by technology

This circuit and method is currently the mainstream charging method for MW-level converters. Its defects are: 1. The charging time is long; 2. The harmonic current component in the charging current is very large. Although it will not affect the performance of the energy storage capacitor, it will produce The additional harmonic loss reduces the efficiency of the equipment, and may cause inaccurate measurement of the voltage and current sensors at both ends of the energy storage capacitor; 3. Due to the setting of a separate rectifier module, the cost of its charging circuit is relatively high

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