A method for implementing a safe torque off

Abstract

The application discloses a kind of safety torque off implementation methods, including controller, drive board, buffer, power conversion module and motor, drive board is powered to motor, and the power output end of power conversion module is powered to buffer;Controller issues drive signal to drive board through buffer, when the control end of power conversion module receives protection signal, power conversion module closes power output end, and buffer loses power and cuts off drive signal from controller to drive board, and drive board stops power supply to motor.The application is based on hardware STO protection mode, simple and effective, improve the reliability of STO protection function when CPU fails, exclude the direct participation of CPU from hardware, so as to use two channels in safety function implementation, realize double-loop protection, effectively improve work safety.

Description

TECHNICAL FIELD

[0001] The present application relates to motor control, in particular to a method for implementing safe torque off. BACKGROUND

[0002] The safe torque off (STO) function can be used to build safety or monitoring circuits, which can make the drive stop (for example, emergency stop circuit) in dangerous situations. Another application is the anti-misoperation switch, which makes the drive not need to be powered off for short-term maintenance operations, such as cleaning or non-electrical component operations. When the safe torque off function is activated, the control voltage of the power semiconductor of the drive output stage is disabled, so that the drive is prevented from generating the torque of the rotating motor. If the motor is running when the safe torque off is activated, the motor is free to stop.

[0003] The STO protection on the market at present is based on software, which is complex to operate and has the possibility of software misjudgment. For example: the <STO control circuit and system> of Inovance, when the STO is triggered, the CPU needs to trigger identification before protection. If the CPU fails, the STO trigger will also exist the situation that the system does not respond. Or when the system is in the STO protection process, the CPU suddenly fails, which may also cause the failure of the STO system protection function. SUMMARY

[0004] The technical problem solved by the present application is to provide a method for implementing safe torque off with good reliability.

[0005] In order to solve the above technical problems, the technical scheme adopted by the present application is a method for implementing safe torque off, including a controller, a drive board, a buffer, a power conversion module and a motor. The drive board supplies power to the motor, and the power output end of the power conversion module supplies power to the buffer. The controller sends a drive signal to the drive board through the buffer. When the control end of the power conversion module receives a protection signal, the power conversion module closes the power output end, the buffer loses power, the controller sends a drive signal to the drive board, and the drive board stops supplying power to the motor.

[0006] The above-mentioned method for implementing safe torque off, the protection signal is obtained by the first protection signal and the second protection signal through the line and circuit processing.

[0007] The implementation method of the safety torque off, the line and the circuit include an NPN triode and two optical coupling isolation circuits, the optical coupling isolation circuit includes a protection signal input end, an optical coupling and a diode; the first protection signal input end is connected with the anode of the optical coupling light emitting diode, the collector of the optical coupling photosensitive triode is connected with the anode of the diode, and the diode is connected with the low-voltage direct-current power supply through the pull-up resistor; the cathode of the diode is connected with the base of the NPN triode, the emitter of the NPN triode is connected with the ground, and the collector is used as the output end of the line and the circuit; the protection signal input end of the first optical coupling isolation circuit is connected with the first protection signal, the protection signal input end of the second optical coupling isolation circuit is connected with the second protection signal, and the output end of the line and the circuit outputs the protection signal.

[0008] The implementation method of the safety torque off, the emitters of the photosensitive triodes of the two optical coupling isolation circuits are respectively connected with the two protection notification signal input ends of the controller; and the power supply input end of the controller is connected with the power supply output end of the power supply conversion module.

[0009] The implementation method of the safety torque off, the emitters of the photosensitive triodes of the two optical coupling isolation circuits are respectively connected with the two protection notification signal input ends of the controller; and the power supply input end of the controller is connected with the power supply output end of the power supply conversion module.

[0010] The present application is a hardware-based STO protection mode, simple and effective, improves the reliability of the STO protection function when the CPU fails, and excludes the direct participation of the CPU from the hardware, so as to use two channels in the implementation of the safety function, realize double-loop protection, and effectively improve the operation safety. BRIEF DESCRIPTION OF DRAWINGS

[0011] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0012] Figure 1 is the function block diagram of the implementation circuit of the safety torque off of the embodiment of the present application.

[0013] Figure 2 is the main control logic schematic diagram of the implementation method of the safety torque off of the embodiment of the present application.

[0014] Figure 3 is the principle diagram of the line and the circuit of the embodiment of the present application.

[0015] Figure 4 is the principle diagram of the power supply conversion module of the embodiment of the present application.

[0016] Figure 5 is the wiring diagram of the controller of the embodiment of the present application. DETAILED DESCRIPTION

[0017] The principle of the implementation of the safety torque off of the embodiment of the application is as follows Figures 1 to 5 As shown in Table 1, the implementation circuit of the safety torque off comprises a DSP controller, a driving board, a buffer, a power conversion module (a power conversion chip TPS54340DDAR) and a motor. The driving board supplies power to the motor, and a power output end STO_5V of the power conversion module supplies power to the buffer and the DSP controller. The DSP controller sends a driving signal to the driving board through the buffer. When the control end of the power conversion module receives a protection signal SN_STO, the power conversion module closes the power output end STO_5V, the buffer cuts off the driving signal sent by the DSP controller to the driving board, and the driving board stops supplying power to the motor, thereby realizing the STO protection.

[0018] The protection signal SN_STO is obtained by processing the first protection signal S_IN1 and the second protection signal S_IN2 through a line and circuit. The line and circuit comprises an NPN transistor and two optical coupling isolation circuits.

[0019] The first optical coupling isolation circuit comprises an input end of the first protection signal S_IN1, an optical coupling U25 and a diode D6. The input end of the first protection signal S_IN1 is connected to the anode of the light emitting diode of the optical coupling U25, the cathode of the light emitting diode of the optical coupling U25 is connected to STO_COM, the collector of the optical coupling U25 photosensitive transistor is connected to the anode of the diode D6 and connected to the positive pole +3.3V of the low-voltage direct-current power supply through a pull-up resistor R172, and the emitter of the optical coupling U25 photosensitive transistor is connected to the ground.

[0020] The second optical coupling isolation circuit comprises an input end of the second protection signal S_IN2, an optical coupling U30 and a diode D7. The input end of the second protection signal S_IN2 is connected to the anode of the light emitting diode of the optical coupling U30, the cathode of the light emitting diode of the optical coupling U30 is connected to STO_COM, the collector of the optical coupling U30 photosensitive transistor is connected to the anode of the diode D7 and connected to the positive pole +3.3V of the low-voltage direct-current power supply through a pull-up resistor R170, and the emitter of the optical coupling U30 photosensitive transistor is connected to the ground.

[0021] The cathodes of the diode D6 and the diode D7 are connected to the base of the NPN transistor Q16 through a resistor R205, the emitter of the NPN transistor Q16 is connected to the ground, and the collector thereof is used as the output end of the line and circuit to output the protection signal SN_STO.

[0022] The first protection enable signal STO_EN1 output by the emitter of the photosensitive transistor of the first optical coupling isolation circuit is connected to the protection notification signal input pin STO_EN1 of the DSP controller. The second protection enable signal STO_EN2 output by the emitter of the photosensitive transistor of the second optical coupling isolation circuit is connected to the protection notification signal input pin STO_EN2 (not shown in the figure) of the DSP controller.

[0023] The power input pin of the SP controller is connected to the power output end STO_5V of the power conversion module.

[0024] The realization circuit of the safety torque off includes two buffers, and the DSP controller sends the driving signal to the driving board through the two buffers in series. The first protection enable signal STO_EN1 output by the emitter of the light-sensitive triode of the first optical coupling isolation circuit is connected to the enable signal input end of the first buffer, and the first protection enable signal STO_EN2 output by the emitter of the light-sensitive triode of the second optical coupling isolation circuit is connected to the enable signal input end of the second buffer.

[0025] As shown in Figure 4 When the protection signal SN_STO received by the SS pin of the power conversion chip U15 (TPS54340DDAR) is low, the U15 will stop output. The output of the STO_5V output pin is 0V.

[0026] Table 1: Protection logic relationship table of the application

[0027]

[0028] From Table 1, it can be seen that:

[0029] When the first protection signal S_IN1 and the second protection signal S_IN2 are both high, the motor runs normally.

[0030] When the first protection signal S_IN1 and the second protection signal S_IN2 are both low, the protection signal SN_STO is low, the power conversion module closes the power output end STO_5V, the buffer is closed, the driving signal sent by the DSP controller to the driving board is cut off, the driving board stops supplying power to the motor, the STO protection is realized, and the motor stops running. When the user needs to use the STO function, the first protection signal S_IN1 and the second protection signal S_IN2 can be manually disconnected to convert to low, so as to realize the enable effect.

[0031] When one of the first protection signal S_IN1 and the second protection signal S_IN2 is low, the protection signal SN_STO is low, the power conversion module closes the power output end STO_5V, the buffer is closed, the driving signal sent by the DSP controller to the driving board is cut off, the driving board stops supplying power to the motor, the STO protection is realized, and the motor stops running.

[0032] In addition, when the first protection signal S_IN1 and the second protection signal S_IN2 are both low or one of them is low, the first protection enable signal STO_EN1 and the second protection enable signal STO_EN2 are all high or one of them is high, the first buffer and / or the second buffer 2 are locked, at this time, the driving board stops working, the purpose of stopping the motor running is achieved. At the same time, the fault signal is transmitted to the DSP controller, and the DSP controller informs the user of the system state,

[0033] The above embodiment of the application is a hardware-based STO protection mode, which is simple and effective, improves the reliability of the STO protection function when the CPU fails, excludes the direct participation of the CPU from the hardware, uses two channels in the implementation of the safety function, realizes double-loop protection, and effectively improves the operation safety.

Claims

1. A method for implementing safe torque shutdown, comprising a controller, a drive board, and a motor, wherein the controller sends a drive signal to the drive board, and the drive board supplies power to the motor, characterized in that, The system includes a buffer and a power conversion module. The power output of the power conversion module supplies power to the buffer. The controller sends a drive signal to the drive board through the buffer. When the control terminal of the power conversion module receives a protection signal, the power conversion module shuts off its power output, the buffer loses power, and the controller cuts off the drive signal sent to the drive board, causing the drive board to stop supplying power to the motor. The protection signal is obtained by processing the first protection signal and the second protection signal through a wired-AND circuit. The wired-AND circuit includes an NPN transistor and two optocoupler isolation circuits. The optocoupler isolation circuit includes a protection signal input terminal, an optocoupler, and a diode. The first protection signal input terminal is connected to the anode of the optocoupler's LED, the collector of the optocoupler's phototransistor is connected to the anode of the diode, and both are connected to a low-voltage DC power supply through a pull-up resistor. The cathode of the diode is connected to the base of the NPN transistor, the emitter of the NPN transistor is grounded, and the collector serves as the output terminal of the wired-AND circuit. The protection signal input terminal of the first optocoupler isolation circuit is connected to the first protection signal, the protection signal input terminal of the second optocoupler isolation circuit is connected to the second protection signal, and the output terminal of the wired-AND circuit outputs the protection signal.

2. The method for implementing safe torque shutdown according to claim 1, characterized in that, The emitters of the phototransistors in the two optocoupler isolation circuits are connected to the two protection notification signal input terminals of the controller, respectively; the power input terminal of the controller is connected to the power output terminal of the power conversion module.

3. The method for implementing safe torque shutdown according to claim 1, characterized in that, The system includes two buffers, and the controller sends a drive signal to the driver board through the two buffers connected in series. The emitter of the phototransistor in the first optocoupler isolation circuit is connected to the enable signal input terminal of the first buffer as the first enable signal output terminal, and the emitter of the phototransistor in the second optocoupler isolation circuit is connected to the enable signal input terminal of the second buffer as the second enable signal output terminal.

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