A three-phase bridge half-controlled rectifier trigger circuit with protection function

Abstract

Provided is a three-phase bridge-type half-control rectification trigger circuit with the protection function. By means of the three-phase bridge-type half-control rectification trigger circuit with the protection function, pre-charging of a three-phase bridge-type half-control rectification circuit and regulation of a busbar voltage can be achieved. The three-phase bridge-type half-control rectification trigger circuit with the protection function mainly comprises a DSP controller, a Butterworth low-pass filtering circuit, a synchronous detection link device, a phase-shifting control chip and a drive circuit. It is achieved that the busbar voltage is regulated according to the duty ratio of PWM waves output by a DSP main control chip, and therefore the charging current of a capacitor is lowered during starting. Pre-charging of the three-phase bridge-type half-control rectification circuit is achieved, and the cost of a high-power inverter is lowered. Meanwhile, when the inverter operates, whether a three-phase incoming line current is an over-current and whether phase loss of a three-phase incoming line voltage occurs can be detected, a fault signal can be fed back to the DSP controller, and therefore safe operation of the inverter is guaranteed. The three-phase bridge-type half-control rectification trigger circuit with the protection function has the advantages of being flexible in control, good in charging effect, economical, practical, perfect in protection function and reliable in performance.

Description

technical field [0001] The invention relates to a three-phase bridge-type half-controlled rectification trigger circuit applied to the pre-charging of high-power inverters and the regulation of bus voltage, in particular to a three-phase bridge-type half-controlled rectifier trigger circuit with protection function. Background technique [0002] like figure 1 Shown is the control principle diagram of the traditional three-phase bridge half-controlled rectifier circuit. The three-phase bridge half-controlled rectifier trigger outputs the thyristor trigger pulse to control the thyristor of the rectifier circuit to output DC voltage. [0003] Pre-charging is the process of charging the DC bus capacitors in the inverter unit from the power supply. Because there is a large capacitor on the DC bus, when the power is turned on, the voltage across the capacitor will not change suddenly, but the current at both ends of the capacitor will change suddenly, and the two ends of the capa...

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Problems solved by technology

[0004] 1. In the occasion where the inverter needs to be started frequently, the contactor should also be closed and disconnected frequently. Long-term work will not only reduce the life of the contactor, but also affect the normal operation of the equipment due to contact oxidation, poor contact, mechanical wear, etc.

[0005] 2. The contactor is the main component of the pre-charging scheme. As the power of the inverter increases, the capacity also needs to increase accordingly, which increases the cost of the entire inverter equipment.

[0006] 3. The large-capacity contactor increases the volume and weight of the equipment

[0007] 4. The starting current is large, which has a certain impact on the device

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