Bidirectional dcdc converter and slow-start control method

Abstract

The present invention provides a bidirectional DCDC converter and a slow-start control method. First, only the slow-start relay on the first side of the bidirectional DCDC converter is closed, and after the corresponding positive and negative half-bus capacitors are charged, close the relay on the first side bus. All relays; then by controlling the conversion branch action on the first side of the bidirectional DCDC converter, charge the positive and negative half bus capacitors on the second side of the bidirectional DCDC converter until the voltage of the positive and negative half bus capacitors on the second side of the bidirectional DCDC converter and Charge to the preset voltage; finally control all the relays on the second side bus of the bidirectional DCDC converter to close, which can ensure that the bidirectional DCDC converter enters the normal operating state reliably, thereby avoiding the failure caused by the low external insulation resistance in the prior art During the slow-start process, there is a problem of half-bus capacitor bias voltage.

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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