Pitch control system in low voltage through process

Abstract

The invention relates to a pitch control system in a low voltage through process. The pitch control system comprises a PLC (programmable logic controller) control circuit, a power grid voltage monitoring control circuit, a motor brake power supply control circuit and a standby power supply control circuit. The PLC control circuit processes the received PLC control signal and then outputs the same to the motor brake power supply control circuit. The power grid voltage monitoring control circuit processes the monitored voltage drop or power failure signal and then outputs the same to the standby power supply control circuit. The standby power supply control circuit processes the voltage drop or power failure signal and outputs the same to the motor brake power supply control circuit. The standby power supply control circuit further receives a processing signal from the PLC control circuit. By using the PLC signal of the PLC control circuit to simultaneously control the motor brake power supply control circuit and the standby power supply control circuit, vane angle of the pitch control system is enabled to be consistent, emergency stop is avoided, and low voltage through in 3S is guaranteed under power grid voltage drop or power failure.

Description

technical field [0001] The invention relates to a pitch control system during low voltage ride through, in particular to a pitch control system during low voltage ride through. Background technique [0002] In the pitch control system, when the grid voltage monitoring relay detects that the grid voltage drops or loses power, it outputs a fault signal, and the brake power supply is switched from the grid voltage supply to the backup battery power supply, but in this backup battery power supply control loop , not controlled by PLC, so that the brakes are in the release state. In the field application environment of the wind field, the blades are blown by the influence of the wind, so that there is a following error between the blades, which causes the pitch control system to retract the pitch to a safe position in an emergency. Therefore, in the case of grid voltage drop or power failure, low voltage ride through within 3S is not possible. In the process of low voltage ride t...

AI Technical Summary

Problems solved by technology

[0002] In the pitch control system, when the grid voltage monitoring relay detects that the grid voltage drops or loses power, it outputs a fault signal, and the brake power supply is switched from the grid voltage supply to the backup battery power supply, but in this backup battery power supply control loop , not controlled by PLC, so that the brakes are in the release state. In the field application environment of the wind field, the blades are blown by the influence of the wind, so that there is a following error between the blades, which causes the pitch control system to retract the pitch to a safe position in an emergency. Therefore, in the case of grid voltage drop or power failure, low voltage ride through within 3S

In the process of low voltage ride through, the pitch control system needs to be controlled by PLC, so that the brake of the pitch motor also needs to be controlled. However, in the existing design, due to switching to battery power supply, the brake of the pitch motor is always released , cannot be controlled by the PLC, resulting in inconsistent blade angle failure of the pitch control system, and urgent propeller retraction

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