Bidirectional DCDC converter and slow start control method

Abstract

The invention provides a bidirectional DCDC converter and a slow start control method, and the method comprises the steps: firstly only closing a slow start relay at a first side of the bidirectionalDCDC converter, and closing all relays on a bus at the first side after the charging of positive and negative half-bus capacitors corresponding to the slow start relay is finished; then, charging thepositive and negative half-bus capacitors on the second side of the bidirectional DCDC converter by controlling the action of a conversion branch on the first side of the bidirectional DCDC converteruntil the voltage of the positive and negative half-bus capacitors on the second side of the bidirectional DCDC converter is equal to a preset voltage; and finally, controlling all relays on the bus on the second side of the bidirectional DCDC converter to be closed, so that the bidirectional DCDC converter can reliably enter a normal operation state, and the problem of half-bus capacitor bias ina slow start process caused by low external insulation impedance in the prior art is avoided.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a bidirectional DC-DC converter and a slow-start control method. Background technique [0002] In the prior art, the topology of the bidirectional DCDC converter is as follows figure 1 As shown, during slow-start charging, usually, the slow-start relays on both sides are closed first, and the slow-start resistors (such as figure 1 shown in R1 and R2) to the half-bus capacitors on both sides (such as figure 1 shown in C1-C4) to charge. For example, close the auxiliary relays on both sides, that is, the negative bus relay (such as figure 1 Q10, Q12 in ), at this time, the charging current charges the corresponding half-bus capacitance through the slow-start resistor respectively, and charges the half-bus capacitor voltage on each side until it is equal to the total bus capacitor voltage, that is, capacitor C1 and capacitor When the sum of the voltages of C2 is equal t...

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Problems solved by technology

[0004] In view of this, embodiments of the present invention provide a bidirectional DCDC converter and its slow-start control method, which can solve the problem of half-bus capacitance bias in the slow-start process caused by low external insulation resistance in the prior art

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