Pumping voltage detection and discharge circuit

Abstract

The invention discloses a pumping voltage detection and discharge circuit. The invention changes the conventional pumping voltage detection and discharge circuit and designs a novel pumping voltage detection and discharge circuit. The circuit can detect the power supply voltage stably and quickly and can filter out the unstable interference in the power supply. The pumping voltage detection and discharge circuit transmits a voltage signal to a single-chip microcomputer through an AD conversion chip and controls the single-chip microcomputer to output a PWM signal to control the interruption ofan MOS transistor, thereby quickly discharging the pumping voltage, and greatly enhancing the stability of the traditional pumping voltage detection and discharge circuit. The pumping voltage detection and discharge circuit disclosed by the invention comprises a single-chip microcomputer U4, a voltage sampling circuit, an optical coupler isolation circuit and a voltage discharge circuit. The circuit has the characteristics of high voltage sampling accuracy, long-time working stability, simple circuit structure, isolation function and simple circuit maintenance.

Description

technical field [0001] The invention relates to a pump-up voltage detection and discharge circuit, which is mainly used for detection and discharge of the pump-up voltage generated by the motor of an electric forklift powered by a storage battery due to emergency stop or reverse rotation. Background technique [0002] In the frequency conversion speed control system, when the motor suddenly stops or reverses suddenly, the motor is in the state of regenerative braking, and the electric energy regenerated by the motor is fed back to the DC circuit after full-wave rectification by the freewheeling diode. The electric energy cannot be fed back to the grid, resulting in filtering The increase of the DC voltage across the capacitor, that is, the generation of a pumped voltage, will seriously threaten the safe operation of the motor and cause permanent damage to the power device. [0003] The generation of pump voltage is inevitable during the braking process of the motor. The trad...

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Problems solved by technology

[0002] In the frequency conversion speed control system, when the motor suddenly stops or reverses suddenly, the motor is in the state of regenerative braking, and the electric energy regenerated by the motor is fed back to the DC circuit after full-wave rectification by the freewheeling diode. The electric energy cannot be fed back to the grid, resulting in filtering The DC voltage at both ends of the capacitor increases, that is, the pump voltage is generated, which will seriously threaten the safe operation of the motor and cause permanent damage to the power device

[0003] The generation of pump voltage is inevitable during the braking process of the motor. The traditional processing method is composed of a voltage sampling circuit, a Schmitt comparator and a driving circuit. The disadvantages are: 1. The Schmitt comparator circuit is too complicated , It is necessary to obtain the upper and lower threshold voltages through tedious calculations; 2. No isolation is used between the overall circuit and the pumping voltage, which may cause the pumping voltage to interfere with the overall circuit; 3. The driving circuit can only control the MOS tube The complete turn-on and turn-off of the MOS cannot control the partial turn-on and turn-off of the MOS

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