Hybrid active discharge circuit and control method thereof

Abstract

The invention discloses a hybrid active discharge circuit and a control method thereof. The hybrid active discharge circuit comprises a controller and a high-voltage power battery, the high-voltage power battery is connected with a high-voltage inverter and a high-voltage DC / DC through a direct-current bus, the high-voltage DC / DC is connected with a low-voltage battery, and a high-voltage capacitor is connected between a positive bus and a negative bus of the direct-current bus; and the high-voltage inverter is connected with a high-voltage alternating-current load, the low-voltage battery isconnected with a low-voltage battery load, and a discharging branch is arranged at the input end, connected with the direct-current bus, of the high-voltage DC / DC. In the early stage of discharging, the high-voltage capacitor charges the low-voltage battery through the high-voltage DC / DC; in the later period of discharging, the high-voltage capacitor discharges through a discharging branch; and one part of discharge electric energy is transmitted to the low-voltage battery, one part of the discharge electric energy is consumed in the HVDCDC converter, and the other part of the discharge electric energy is consumed on a miniaturized power discharge resistor. The hybrid active discharge circuit has the advantages of being high in discharge speed, small in power discharge resistor size, low in cost, easy to control and high in reliability.

Description

Technical field[0001]The present invention relates to the field of electric vehicle high pressure power systems, and more particularly to a mixed active discharge circuit and a control method thereof.Background technique[0002]The inverter input voltage used in electric vehicles and hybrid vehicles is higher than 60VDC, which is required to protect personal safety, requiring discharge circuits in the inverter DC side capacitance to reduce the voltage of the DC side capacitance. Currently used active discharge method is an additional active discharge circuit, utilizing power resistance amplifier, but additionally increases constant power control circuit, increase cost, high power discharge resistance, and power discharge resistance may be damaged after multiple discharges.[0003]Therefore, it is a technical issue that saves energy, small, long-lived, and reliable work.Inventive content[0004]In order to solve the above defects present in the prior art, the present invention proposes a m...

AI Technical Summary

Problems solved by technology

At present, the commonly used active discharge method is to add an active discharge circuit and use a power resistor to discharge, but it needs to add a constant power control circuit, which increases the cost. The power discharge resistor is large in size, and the power discharge resistor may be damaged after multiple discharges.

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