A current sharing method for a charger

Abstract

The invention provides a charger current sharing method. A microprocessor DSP, an FPGA module and at least two choppers are included, the microprocessor DSP is used for respectively detecting the actual output voltage of all the choppers in parallel connection and the output current of each chopper, and is used for driving a benchmark chopper through a PWM port, the rest of the choppers are correction choppers and are driven by the FPGA module, the microprocessor DSP is used for is used for comparing the actual output voltage and a preset charging voltage value to obtain the benchmark duty ratio of the benchmark chopper at the moment, and correcting values of all the correction choppers are obtained through current parameters of the benchmark chopper and current parameters of the correction choppers. According to the charger current sharing method, only one PSW port of the microprocessor DSP is used for driving the benchmark chopper, the rest of the correction choppers are driven by an FPGA, current sharing control among the choppers is easy, the calculated amount is small, and the effect is stable and reliable.

Description

technical field [0001] The invention relates to a current sharing method, in particular to a current sharing method of a charger. Background technique [0002] In power electronic equipment such as high-voltage DC power supplies, electric vehicle charging piles, and UPS, DC-DC voltage conversion circuits called choppers or switching power supplies are required to supply power to DC loads; when the load power is large, more Two DC conversion circuits are connected in parallel to output power to realize a low-cost and high-efficiency power supply solution. However, in UPS and other equipment, the PWM wave generating unit of DSP is occupied by other power electronic circuits such as rectification. In the parallel connection of multiple choppers In this case, there may be insufficient PWM resources. [0003] In the case of supplying power to a high-power DC load, a single chopper or multiple choppers are usually used for power supply. The former needs to use large-capacity pow...

AI Technical Summary

Problems solved by technology

The former needs to use large-capacity power devices such as IGBT, and the cost of the device itself and the radiator is relatively high, so the latter is often used in general products, that is, multiple choppers are used for power supply; when multiple choppers are running, Even if the power devices of each chopper receive the same switching signal, the output current between the choppers will be unbalanced due to the different internal resistances of the choppers; when the load power is large, the uneven current may It will cause the chopper with a large current to heat up or the stress will exceed the standard, and then damage the power device of the chopper

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