A safety torque interruption circuit and an inverter using the safety torque interruption circuit

Abstract

The present invention discloses a frequency converter with a safety torque interruption circuit, which relates to the field of frequency converters. At present, in the industry, a digital circuit and a controller are mostly used to implement the safety torque interruption function, but the reliability depends on the controller, and the failure probability is relatively high. The safety torque interruption circuit of this frequency converter includes two independently controlled input signal terminals IN1 and IN2, a on-off control unit, a control logic unit, a power control unit, and a drive signal source. IN1 and IN2 are respectively connected to the control logic unit and the power control unit. The control logic unit is independently connected to n current amplification devices of the on-off control unit, the power control unit is independently connected to n current amplification devices, the drive signal source is independently connected to the current amplification devices, and the n current amplification devices are independently connected to the gates of n×m (m≥1) insulated gate bipolar transistors of the inverter unit to drive the closing and opening operations of the inverter unit. The safety torque interruption function is realized through a hardware circuit, which improves the reliability and reduces the failure probability.

Description

Technical Field

[0001] The present invention relates to the field of frequency converters, and particularly to a frequency converter with a safe torque interruption circuit. Background Art

[0002] A frequency converter is a control device for controlling the speed and current of an AC motor. The frequency converter mainly includes a rectification and filtering unit, an inversion unit, a drive circuit, a safe torque interruption circuit, a protection circuit, etc. The safe torque interruption function can be used to construct a safety or monitoring circuit, and can stop the drive in case of danger. Another functional application is an anti-misstart switch, which enables short-time maintenance operations such as cleaning or operating non-electrical components without powering off the drive.

[0003] Currently, the industry mostly uses digital circuits and controllers to implement the safe torque interruption function, but the reliability of the safe torque interruption function of this solution depends on the controller, and the probability of dangerous failures cannot be significantly reduced.

[0004] Therefore, to overcome the above defects, a safe torque interruption function implemented only by a hardware circuit and having a redundant structure is designed. Summary of the Invention

[0005] The technical problem to be solved and the technical task proposed by the present invention are to improve and refine the existing technical solution, and provide a frequency converter with a safe torque interruption circuit, aiming to improve the reliability of the safe torque interruption function. To this end, the present invention adopts the following technical solutions.

[0006] A safe torque interruption circuit includes two independently controlled input signal terminals IN1 and IN2, a turn-on and turn-off control unit, a control logic unit, and a power supply control unit. The input signal terminal IN1 is connected to the control logic unit, and the input signal terminal IN2 is connected to the power supply control unit. The control logic unit is connected to the enable terminal of the turn-on and turn-off control unit to control the enable signal, and the power supply control unit is connected to the power supply terminal of the turn-on and turn-off control unit to control the power supply of the turn-on and turn-off control unit. The input terminal of the turn-on and turn-off control unit is connected to a drive signal source to input a PWM pulse width modulation signal. The output terminal of the turn-on and turn-off control unit is connected to the inversion unit to drive the closing and opening operations of the inversion unit. By implementing the safe torque interruption function only by using a hardware circuit, compared with the traditional implementation of the safe torque interruption function using digital circuits and controllers, the reliability of the safe torque interruption function can be effectively improved, the probability of dangerous failures can be significantly reduced, and the safety is improved.

[0007] As a preferred technical means: The on-off control unit includes a plurality of current amplification devices. Each current amplification device is provided with an input end, an output end, and an enable end. The power control unit is provided with an output port corresponding to the power supply end of each current amplification device, and the control logic unit is independently connected to the enable end of each current amplification device. It can effectively control the power supply of each current amplification device and the enable signal of each current amplification device. On the premise of keeping the circuit structure basically unchanged, by using a plurality of current amplification devices to independently connect control signals, the required hardware fault margin can be provided, which has good flexibility.

[0008] As a preferred technical means: The input end of each current amplification device is connected to the drive signal source. An independent PWM pulse width modulation signal is provided for each current amplification device. After being amplified by the on-off control unit, it is used to drive the closing and opening operations of the insulated gate bipolar transistor, and provide the required voltage and current to the motor.

[0009] As a preferred technical means: The number of current amplification devices corresponds to the insulated gate bipolar transistors provided in the inverter unit. The output end of each current amplification device is connected to the gate of the corresponding insulated gate bipolar transistor. An independent control connection is provided, which is convenient for realizing independent closing and opening operation control.

[0010] As a preferred technical means, the on-off control unit includes n current amplification devices, and each of the current amplification devices corresponds to m insulated gate bipolar transistors in the inverter unit, where m≥1; The insulated gate bipolar transistors are correspondingly connected. It has the ability to have two turn-off drive signal paths, provides a simple redundant circuit design structure, has high circuit reliability and low cost. The n current amplification devices are independently connected to the gates of the n×m insulated gate bipolar transistors in the inverter unit to drive the closing and opening operations of the inverter unit.

[0011] As a preferred technical means: The current amplification device adopts an isolated opto-coupler circuit or an isolated magnetic-coupler circuit. Electrical isolation is achieved between the input end and the output end, and the electrical stability is good.

[0012] As a preferred technical means: The enable end signal and the power control input end signal of each current amplification device can be independently controlled. They do not affect each other and realize redundant control.

[0013] Another object of the present invention is to propose a frequency converter.

[0014] A frequency converter includes an inverter unit, a drive signal source, and also includes the aforementioned safety torque interruption circuit.

[0015] As a preferred technical means: when the control input signal terminal IN1 is turned on, the enable signal of the on-off control unit is pulled low, thereby blocking the driving signal path of the driving signal source and realizing the safety torque interruption function;

[0016] When the control input signal terminal IN2 is turned on, the power control unit is disconnected, cutting off the power supply of the on-off control unit, thereby blocking the driving signal path of the driving signal source and realizing the safety torque interruption function.

[0017] Beneficial effects: By implementing the safety torque interruption function only using hardware circuits, compared with the traditional implementation of the safety torque interruption function using digital circuits and controllers, the reliability of the safety torque interruption function can be effectively improved, the probability of dangerous failures can be significantly reduced, and the safety is enhanced; on the premise of keeping the circuit structure basically unchanged, by using multiple current amplification devices to independently connect control signals and realizing independent control to provide the required hardware fault tolerance, it has good flexibility. Brief Description of the Drawings

[0018] Figure 1 It is a block diagram of the circuit principle of the inverter of the present invention.

[0019] In the figure: 1 - control logic unit; 2 - power control unit; 3 - on-off control unit; 4 - inverter unit; 5 - driving signal source; 301 - current amplification device; 401 - insulated gate bipolar transistor. Detailed Embodiments

[0020] The technical solution of the present invention will be further described in detail below with reference to the drawings in the specification.

[0021] As shown in Figure 1 A safety torque interruption circuit includes two independently controlled input signal terminals IN1 and IN2, an on-off control unit 3, a control logic unit 1, and a power control unit 2. The input signal terminal IN1 is connected to the control logic unit 1, and the input signal terminal IN2 is connected to the power control unit 2. The control logic unit 1 is connected to the enable terminal of the on-off control unit 3 to control the enable signal, and the power control unit 2 is connected to the power supply terminal of the on-off control unit 3 to control the power supply of the on-off control unit 3. The input end of the on-off control unit 3 is connected to the driving signal source 5 to input a PWM pulse width modulation signal. The output end of the on-off control unit 3 is connected to the inverter unit 4 to drive the on-off operation of the inverter unit 4.

[0022] An inverter using the above safety torque interruption circuit includes a rectifier filter unit, an inverter unit 4, a drive circuit, a safety torque interruption circuit, and a protection circuit.

[0023] To achieve a hardware fault margin, the on-off control unit 3 includes n current amplification devices 301. Each current amplification device 301 is provided with an input terminal, an output terminal, and an enable terminal. The power control unit 2 has 1 output port corresponding to the power supply terminal of each current amplification device 301. The control logic unit 1 is independently connected to the enable terminal of each current amplification device 301. The enable terminal signal and the power input of each current amplification device 301 can be independently controlled. The inverter unit 4 has n×m, where m≥1; insulated gate bipolar transistors 401. The output terminal of each current amplification device 301 is connected to the gate of the corresponding m insulated gate bipolar transistors 401. The drive signal source 5 is independently connected to the drive signal terminal of each current amplification device 301, providing an independent PWM pulse width modulation signal for each current amplification device 301. After being amplified by the on-off control unit 3, it is used to drive the closing and opening operations of the insulated gate bipolar transistors 401, providing the required voltage and current to the motor. It can effectively supply power to each current amplification device 301 and control the enable signal of each current amplification device 301. On the premise of keeping the circuit structure basically unchanged, by using n current amplification devices 301 to independently connect control signals, the independent closing and opening operation control of each insulated gate bipolar transistor 401 is realized to provide the required hardware fault margin, with good flexibility.

[0024] When the control input signal terminal IN1 is turned on, the enable signal of the on-off control unit 3 is pulled low, thereby blocking the drive signal path of the drive signal source 5, realizing the safe torque interruption function.

[0025] When the control input signal terminal IN2 is turned on, the power control unit 2 is disconnected, cutting off the power supply to the on-off control unit 3, thereby blocking the drive signal path of the drive signal source 5, realizing the safe torque interruption function.

[0026] By only using a hardware circuit to realize the safe torque interruption function and having a redundant control hardware circuit structure, compared with the traditional method of using a digital circuit and a controller to realize the safe torque interruption function, the reliability of the safe torque interruption function can be effectively improved, the probability of dangerous failure can be significantly reduced, and the safety is improved.

[0027] In this embodiment, the current amplification device 301 uses an isolated opto-coupler circuit, and an isolated magnetic-coupler circuit can also be used instead.

[0028] The above Figure 1 A safe torque interruption circuit and an inverter using the safe torque interruption circuit shown above are specific embodiments of the present invention, which have already demonstrated the prominent substantive features and remarkable progress of the present invention. According to the actual usage needs, under the inspiration of the present invention, equivalent modifications can be made to its shape, structure, etc., which are all within the protection scope of this solution.

Claims

1. A safety torque interruption circuit, characterized in that: It includes two independently controlled input signal terminals IN1 and IN2, an on-off control unit (3), a control logic unit (1), and a power control unit (2). The input signal terminal IN1 is connected to the control logic unit (1), and the input signal terminal IN2 is connected to the power control unit (2). The control logic unit (1) is connected to the enable terminal of the on-off control unit (3) to control the enable signal, and the power control unit (2) is connected to the power supply terminal of the on-off control unit (3) to control the power supply of the on-off control unit (3); the input terminal of the on-off control unit (3) is connected to the drive signal source (5) to input a PWM pulse width modulation signal; the output terminal of the on-off control unit (3) is connected to the inverter unit (4) to drive the on-off operation of the inverter unit (4); The on-off control unit (3) includes a plurality of current amplification devices (301). Each current amplification device (301) is provided with an input terminal, an output terminal, and an enable terminal. The power control unit (2) is provided with an output port corresponding to the power supply terminal of each current amplification device (301), and the control logic unit (1) is independently connected to the enable terminal of each current amplification device (301).

2. A safety torque interruption circuit according to claim 1, characterized in that: The input terminal of each current amplification device (301) is connected to the drive signal source.

3. A safety torque interruption circuit according to claim 1, characterized in that: The number of the current amplification devices (301) corresponds to the insulated gate bipolar transistors (401) provided in the inverter unit (4). The output terminal of each current amplification device (301) is connected to the gate of the corresponding m insulated gate bipolar transistors (401).

4. A safety torque interruption circuit according to claim 1, characterized in that: The on-off control unit (3) includes n current amplification devices (301). Each current amplification device (301) is correspondingly connected to m insulated gate bipolar transistors (401) of the inverter unit (4), where m≥1.

5. A safety torque interruption circuit according to claim 1, characterized in that: The current amplification device (301) adopts an isolated opto-coupling circuit or an isolated magnetic coupling circuit.

6. A safety torque interruption circuit according to claim 1, characterized in that: The enable signal and the power input terminal of each current amplification device (301) can be independently controlled.

7. An inverter, including an inverter unit (4) and a drive signal source (5), characterized in that: It further includes the safety torque interruption circuit according to any one of claims 1-6.

8. An inverter according to claim 7, characterized in that: When the control input signal terminal IN1 is turned on, the enable signal of the on-off control unit (3) is pulled low, thereby blocking the drive signal path of the drive signal source (5) and realizing the safety torque interruption function; When the control input signal terminal IN2 is turned on, the power control unit (2) is disconnected, cutting off the power supply to the on-off control unit (3), thereby blocking the drive signal path of the drive signal source (5) and realizing the safety torque interruption function.

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