Voltage balance control method between multiple task loads and bus

Abstract

The invention discloses a voltage balance control method between a plurality of task loads and a bus in the field of voltage balance control. The voltage balance control method comprises the following steps: 1, judging whether each load is in a power-on state or a standby state; 2, in the power-on state, enabling a high-voltage direct-current bus to be powered on, enabling each bidirectional pre-charging module to pre-charge a load capacitor, and when the voltage is balanced and consistent, completing pre-charging work; and 3, in the standby state, enabling the relay switch of each load to be switched off, collecting the voltage of the high-voltage direct-current bus and the voltage of each load end and judging, and if the voltage difference value is larger than a threshold value, enabling the two-way pre-charging module corresponding to the load to be switched on so that the load is discharged or charged. According to the invention, the slow start between each load and the high-voltage bus is realized, the current impact when the load and the high-voltage direct current bus are in hard connection is eliminated, the potential risk of overcurrent and abnormal current protection is effectively avoided or eliminated, the characteristics of a power grid and the power supply quality of the power grid are improved, and the power utilization environment is purified.

Description

technical field [0001] The invention relates to the field of bus voltage balance, in particular to a voltage balance control method between multiple task loads and the bus. Background technique [0002] Electric new energy vehicles generally adopt a mixed-voltage system power supply system, which generally has a high-voltage DC bus, a low-voltage DC bus, or even two high-voltage DC buses of different voltage levels. The equipment on the high-voltage DC bus is mainly electric equipment, such as drive motors, air conditioners, cooling fans, pumps, etc., and the equipment on the low-voltage DC bus is mainly electronic equipment. [0003] Motor loads are mostly used in vehicle power equipment, and the motor loads are basically equipped with controllers. The input terminals of the controllers are equipped with filter capacitors and support capacitors with different capacitances. The characteristics of the capacitor determine that the voltage across the capacitor cannot change su...

AI Technical Summary

Problems solved by technology

[0006] In this case, the high-voltage DC bus voltage will be directly added to the load side with a lower voltage, and an instantaneous overshoot large current will appear at the load end, which will cause impact damage and damage to the power grid and equipment, and the stability of the power grid will be affected.

It may even cause the safety threshold protection of the road to malfunction, the active protection of the load line will be cut off, and the load will not work normally.

[0007] 2. Individual load terminal voltage is higher than high voltage DC bus voltage

[0009] a) The reverse current is uncontrolled and often not monitored, which will cause "concealed" damage;

[0010] b) The reverse impact current is harmful to the contacts of the high-voltage relay, and causes the high-voltage relay to be unable to extinguish the arc electromagnetically, affecting the contact resistance and life of the contact;

[0011] c) The reverse current will cause current collision in two directions in the high-voltage DC network, and crosstalk the high-voltage DC network;

[0012] d) Unexpected results such as false alarms and malfunctions will occur in the network with reverse current detection and early warning

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