High-voltage synchronous motor soft starting equipment and starting method thereof

Abstract

The invention provides high-voltage synchronous motor soft starting equipment and a starting method thereof. The high-voltage synchronous motor soft starting equipment comprises a step-down transformer, a step-up transformer, a plurality of rectifier bridges, a plurality of inverter bridges, an analog signal acquisition unit, a zero-crossing detection unit, an FPGA and an MCU. The step-down transformer reduces a voltage of a high-voltage power grid and then uses the reduced voltage as an input voltage of the rectifier bridge. The rectifier bridge rectifies the input voltage and outputs a direct-current voltage; each inverter bridge inverts the input direct-current voltage into an alternating-current signal and sends the alternating-current signal to the low-voltage end of the step-up transformer; the step-up transformer boosts the voltage input by the inverter bridge and then selectively outputs the boosted voltage to the high-voltage power grid as a starting signal of the synchronousmotor; the analog signal acquisition unit is used for acquiring a voltage signal of the low-voltage side of the step-down transformer, an output current signal of the rectifier bridge and an output voltage signal of an inverter, and sending the acquired signals to the MCU; and the MCU generates a control signal to drive the synchronous motor to switch from intermittent commutation to automatic commutation.

Description

technical field [0001] The invention relates to the technical field of starting equipment for synchronous motors, in particular to a soft starting equipment for high-voltage synchronous motors and a starting method thereof. Background technique [0002] The synchronous motor, like the asynchronous motor, is a commonly used AC motor. The synchronous motor is the core of the power system. When the stator is fed with three-phase alternating current, a rotating magnetic field will be generated in the air gap, and a direct current will be fed into the rotor excitation winding. When the current is flowing, a static magnetic field with constant polarity will be generated. The rotor magnetic field will rotate synchronously with the stator rotating magnetic field due to the magnetic pulling force of the stator magnetic field, and the speed of the rotor is equal to the speed and direction of the rotating magnetic field. The synchronous speed and the size of the load Nothing to do; the...

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Problems solved by technology

[0003] In the process of variable frequency soft start of high-voltage synchronous motors, the traditional method is to set up a mechanical position sensor to obtain the motor rotor position and then control the opening state of the inverter bridge arm. The commutation control of the inverter bridge determines the output torque of the synchronous motor. Mechanical rotor position sensors not only require a certain space, but also increase system cost and complexity, and reduce system reliability and anti-interference ability

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