Motor control system

Abstract

A motor control system includes a first STO circuit including a first filter circuit, a first STO switch, a first optical coupling switch circuit and a second optical coupling switch circuit, the first optical coupling switch circuit and the second optical coupling switch circuit are connected in series, the first STO switch is electrically connected with the first optical coupling switch circuit, and the first filter circuit is electrically connected with the first optical coupling switch circuit; the second STO circuit comprises a second filter circuit, a second STO switch, a third optical coupling switch circuit and a fourth optical coupling switch circuit, the third optical coupling switch circuit and the fourth optical coupling switch circuit are connected in series, the second STO switch is electrically connected to the third optical coupling switch circuit, and the second filter circuit is electrically connected to the third optical coupling switch circuit; and the pulse control module is used for sending a pulse signal to the second optical coupling switch circuit and the fourth optical coupling switch circuit and detecting whether the first STO circuit and the second STO circuit are abnormal or not.

Description

Technical Field

[0001] This case pertains to the field of motor technology, specifically a motor control system. Background Technology

[0002] Safe torque off (STO) circuits can be applied in motor control systems. When the motor control system needs to be stopped for maintenance or emergency braking is required due to danger, this STO function allows the motor control system to safely stop without cutting off the main power supply. When the motor control system restarts, it does not require re-energizing, thus greatly improving production efficiency. Currently, motor control systems often employ a dual-channel design for STO circuits to achieve redundant control.

[0003] Because the safety torque shutdown circuit and motor control system are prone to component failure due to prolonged operation, leading to the malfunction of safety functions, some current motor control systems also include a self-test circuit to prevent this. To achieve a timing synchronization control mechanism, the self-test circuit requires two switches to coordinate with the timing synchronization control. Each switch is electrically connected to the corresponding safety torque shutdown circuit in the dual-channel design. When the self-test circuit does not receive an external trigger signal, both switches are on, and the motor control system and safety torque shutdown circuit operate normally. Conversely, when the self-test circuit receives an external trigger signal, it performs a self-test on the motor control system and simultaneously controls the two switches to turn off, thereby avoiding electrical short circuits and misjudgments in the self-test mechanism caused by timing asynchrony with the external trigger signal.

[0004] However, the self-testing circuit of the aforementioned motor control system requires the use of two switches and the design of a timing synchronization mechanism, resulting in a high production cost for the motor control system.

[0005] Therefore, how to develop a motor control system that overcomes the above-mentioned shortcomings is the most urgent issue to be addressed at present. Summary of the Invention

[0006] The purpose of this project is to provide a motor control system that solves the problem of high production costs associated with traditional motor control systems.

[0007] To achieve the aforementioned objectives, a preferred embodiment of this invention provides a motor control system for driving a motor, comprising: a frequency converter electrically connected to the motor, and including a first drive unit and a second drive unit, wherein the first drive unit and the second drive unit operate to enable the frequency converter to provide AC power to the motor; a first STO circuit, including a first filter circuit, a first STO switch, a first optocoupler switch circuit, and a second optocoupler switch circuit, wherein the first filter circuit is electrically connected to the first optocoupler switch circuit, the first STO switch is electrically connected between the first drive unit and the optotransistor of the first optocoupler switch circuit, and the photodiode of the first optocoupler switch circuit is connected in series with the optotransistor of the second optocoupler switch circuit; a second STO circuit, including a second filter circuit, a second STO switch, a third optocoupler switch circuit, and a fourth optocoupler switch circuit, wherein the second filter circuit is electrically connected to the third optocoupler switch circuit, and the second STO switch is electrically connected to the first drive unit and the second optocoupler switch circuit. Between the phototransistors of the second drive unit and the third optocoupler switch circuit, the photodiode of the third optocoupler switch circuit and the phototransistor of the fourth optocoupler switch circuit are connected in series; and the pulse control module is electrically connected to the photodiodes of the second optocoupler switch circuit and the fourth optocoupler switch circuit to send pulse signals to the photodiodes of the second optocoupler switch circuit and the fourth optocoupler switch circuit, and to detect whether the first STO circuit and the second STO circuit are abnormal, wherein the pulse signal switches between a high level voltage and a low level voltage; wherein, when the pulse control module sends a pulse signal at a high level voltage, the second optocoupler switch circuit and the fourth optocoupler switch circuit are turned on, and the motor control system enters the STO trigger mode; and when the pulse control module sends a pulse signal at a low level voltage, the second optocoupler switch circuit and the fourth optocoupler switch circuit are turned off, and the motor control system enters the STO self-test mode.

[0008] In summary, the motor control system provided in this case has a first optocoupler switch circuit in the first STO circuit with a photodiode connected in series with a second optocoupler switch circuit with a phototransistor connected in series with a third optocoupler switch circuit in the second STO circuit. In this way, the pulse control module can issue corresponding pulse signals based on entering the STO trigger mode or the STO self-test mode to directly control the second and fourth optocoupler switch circuits to turn on or off. Therefore, the motor control system does not require an additional timing synchronization mechanism or the addition of two switches similar to those in a traditional motor control system. As a result, the production cost of the motor control system in this case is lower. At the same time, the motor control system can avoid electrical short circuits and misjudgments when the motor control system performs the safe torque shutdown function without considering the state of the first and second STO control signals. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the system structure of the motor control system according to a preferred embodiment of this invention;

[0010] Figure 2 for Figure 1 The diagram shows a block illustration of the motor control system when the second and fourth optocoupler switch circuits are turned on.

[0011] Figure 3 for Figure 1 The diagram shows a block illustration of the motor control system when the second and fourth optocoupler circuits are turned off; and

[0012] Figure 4 for Figure 1 This is a detailed circuit diagram of a portion of the circuitry of the motor control system shown.

[0013] Explanation of reference numerals in the attached figures

[0014] 1: Motor control system

[0015] 2: Motor

[0016] 3: Frequency converter

[0017] 4: First STO circuit

[0018] 5: Second STO circuit

[0019] 6: Pulse Control Module

[0020] 30: First drive unit

[0021] 31: Second drive unit

[0022] 32: Switching circuit

[0023] 33: Control and drive unit

[0024] 40: First filter circuit

[0025] 41: First STO switch

[0026] 42: First Optocoupler Switch Circuit

[0027] 43: Second Optocoupler Switch Circuit

[0028] 50: Second filter circuit

[0029] 51: Second STO switch

[0030] 52: Third Optocoupler Switch Circuit

[0031] 53: Fourth Optocoupler Switch Circuit

[0032] TP: Pulse signal

[0033] 7: STO end

[0034] 8: Safety transmission equipment

[0035] 100: First detection circuit

[0036] 101: Second detection circuit

[0037] FB1: First detection signal

[0038] FB2: Second detection signal

[0039] 60: NPN transistor switch

[0040] R1: First resistor

[0041] R2: Second resistor

[0042] 61: Second Optical Coupler Switch

[0043] G: Reference end

[0044] S1: First voltage source

[0045] C1: First capacitor

[0046] 70: First Optocoupler Switch

[0047] R3: Third resistor

[0048] R4: Fourth resistor

[0049] R5: Fifth resistor

[0050] R6: Sixth resistor

[0051] C2: Second capacitor

[0052] 80: Control chip

[0053] C3: Third capacitor

[0054] R7: Seventh resistor

[0055] S2: Second voltage source Detailed Implementation

[0056] Some typical embodiments embodying the features and advantages of this invention will be described in detail in the following description. It should be understood that this invention can have various variations in different implementations, all of which do not depart from the scope of this invention, and the descriptions and illustrations herein are for illustrative purposes only and are not intended to limit this invention.

[0057] Please see Figure 1 , Figure 2 , Figure 3 and Figure 4 ,in Figure 1 This is a schematic diagram of the system structure of the motor control system according to a preferred embodiment of this invention. Figure 2 for Figure 1 The diagram shows a block illustration of the motor control system when the second and fourth optocoupler circuits are turned on. Figure 3 for Figure 1 The diagram shows a block illustration of the motor control system when the second and fourth optocoupler switch circuits are turned off. Figure 4 for Figure 1 The diagram shows a detailed circuit structure of a portion of the motor control system. In this embodiment, the motor control system 1 is used to drive the motor 2 and includes a frequency converter 3, a first safe torque off circuit (hereinafter referred to as the first STO (safe torque off) circuit) 4, a second safe torque off circuit (hereinafter referred to as the second STO circuit) 5, and a pulse control module 6.

[0058] The frequency converter 3 includes a first drive unit 30, a second drive unit 31, and a switching circuit 32. The switching circuit 32 includes multiple switching elements (not shown). When the first drive unit 30 operates, it drives the switching elements in the switching circuit 32. When the second drive unit 31 operates, it drives the switching elements in the switching circuit 32. The switching circuit 32 is then connected to the motor 2, thereby enabling the frequency converter 3 to convert the received input electrical energy into AC electrical energy and supply it to the motor 2. In some embodiments, the aforementioned first drive unit 30 is applied to drive the high-voltage side of the switching circuit 32, and the second drive unit 31 is applied to drive the low-voltage side of the switching circuit 32, but this is not intended to limit the invention. In some embodiments, the frequency converter 3 includes a control drive unit 33, which can detect the operating state of the frequency converter 3 and control the frequency converter 3 accordingly based on the detection result. In addition, the control drive unit 33 also includes the first drive unit 30 and the second drive unit 31. It should be noted that the aforementioned first drive unit 30 and second drive unit 31 may be selected from high-voltage side drive unit, low-voltage side drive unit, power control drive unit and control signal drive unit, etc., and may be integrated into the aforementioned control drive unit 33, but this is not intended to limit the present invention.

[0059] The first STO circuit 4 includes a first filter circuit 40, a first STO switch 41, a first optocoupler switch circuit 42, and a second optocoupler switch circuit 43. The photodiode of the first optocoupler switch circuit 42 and the phototransistor of the second optocoupler switch circuit 43 are connected in series. The first STO switch 41 is electrically connected between the first driving unit 30 and the phototransistor of the first optocoupler switch circuit 42. The first filter circuit 40 is electrically connected to the phototransistor of the first optocoupler switch circuit 42. In some embodiments, the first driving unit 30 may be selected from a high-voltage driving unit, a low-voltage driving unit, a power control driving unit, and a control signal driving unit, but this is not intended to limit the invention.

[0060] The second STO circuit 5 includes a second filter circuit 50, a second STO switch 51, a third optocoupler switch circuit 52, and a fourth optocoupler switch circuit 53. The photodiode of the third optocoupler switch circuit 52 and the phototransistor of the fourth optocoupler switch circuit 53 are connected in series. The second STO switch 51 is electrically connected between the second driving unit 31 and the phototransistor of the third optocoupler switch circuit 52. The second filter circuit 50 is electrically connected to the phototransistor of the third optocoupler switch circuit 52. In some embodiments, the second driving unit 31 may be selected from a high-voltage driving unit, a low-voltage driving unit, a power control driving unit, and a control signal driving unit, but this is not intended to limit the invention.

[0061] In some embodiments, the first drive unit 30 and the second drive unit 31 may be selected from different control units. In some embodiments, the first drive unit 30 is, for example, a high-voltage drive unit, and the second drive unit 31 is, for example, a low-voltage drive unit, but this is not intended to limit the invention.

[0062] The pulse control module 6 is electrically connected to the photodiodes of the second optocoupler switch circuit 43 and the fourth optocoupler switch circuit 53 to send a pulse signal TP to the photodiodes of the second optocoupler switch circuit 43 and the fourth optocoupler switch circuit 53, and to detect whether the first STO circuit 4 and the second STO circuit 5 are abnormal. The pulse signal TP switches between high-level voltage and low-level voltage.

[0063] In some embodiments, the motor control system 1 further includes an STO terminal 7, which is electrically connected to the photodiode of the first optocoupler switch circuit 42 of the first STO circuit 4 and the photodiode of the third optocoupler switch circuit 52 of the second STO circuit 5. The STO terminal 7 provides a first STO control signal to the first STO circuit 4 and a second STO control signal to the second STO circuit 5. The first and second STO control signals are used to control the shutdown of the first drive unit 30 and the shutdown of the second drive unit 31, respectively. In some embodiments, the STO terminal 7 further provides an input power supply, such as a 24V power supply, to a safety power transmission device 8 inside the motor control system 1, so that the safety power transmission device 8 supplies the input power provided by the STO terminal 7 to the relevant circuit components inside the motor control system 1.

[0064] In this embodiment, the motor control system 1 can enter either the STO trigger mode or the STO self-test mode. Specifically, when the motor control system 1 enters the STO trigger mode and the pulse control module 6 sends a high-level voltage pulse signal TP, the second optocoupler switch circuit 43 and the fourth optocoupler switch circuit 53 are turned on (e.g., ...). Figure 2 As shown), at this time, the first STO circuit 4 and the second STO circuit 5 will respectively control the shutdown of the first drive unit 30 and the second drive unit 31 according to the first STO control signal and the second STO control signal, so that the motor control system 1 starts the safety torque shutdown function. On the other hand, when the motor control system 1 enters the STO self-test mode and the pulse control module 6 sends a pulse signal TP at a low voltage, the second optocoupler switch circuit 43 and the fourth optocoupler switch circuit 53 are turned off. At this time, the first filter circuit 40 and the second filter circuit 50 will respectively filter out the pulse signal TP output by the pulse control module 6 on the first optocoupler switch circuit 42 and the third optocoupler switch circuit 52, thereby avoiding the first STO circuit 4 and the second STO circuit 5 from being falsely triggered. This setting does not need to consider the state of the first STO control signal and the second STO signal received by the first STO circuit 4 and the second STO circuit 5. In addition, after the motor control system 1 enters the STO self-test mode, the pulse control module 6 will detect whether the first STO circuit 4 and the second STO circuit 5 are abnormal.

[0065] In this embodiment, the photodiode of the first optocoupler switch circuit 42 of the first STO circuit 4 of the motor control system 1 is connected in series with the phototransistor of the second optocoupler switch circuit 43, and the photodiode of the third optocoupler switch circuit 52 of the second STO circuit 5 is connected in series with the phototransistor of the fourth optocoupler switch circuit 53. In this way, the pulse control module 6 can issue a corresponding pulse signal TP according to entering the STO trigger mode or the STO self-test mode to directly control the second optocoupler switch circuit 43 and the fourth optocoupler switch circuit 53 to be turned on or off. Therefore, the motor control system 1 does not need an additional timing synchronization mechanism or two switches similar to those in a traditional motor control system. As a result, the production cost of the motor control system 1 in this case is lower. At the same time, the motor control system 1 does not need to consider the state of the first STO control signal and the second STO signal, which can avoid electrical short circuits of the signal and misjudgments when the motor control system 1 performs the safe torque shutdown function. Furthermore, the motor control system 1 in this case filters out the pulse signals TP on the first optocoupler switch circuit 42 and the third optocoupler switch circuit 52 respectively through the first filter circuit 40 and the second filter circuit 50. This prevents the first STO circuit 4 and the second STO circuit 5 from being falsely triggered and significantly increases their response time, thereby improving the safety of the motor control system 1. In addition, the first filter circuit 40 and the second filter circuit 50 help decoupling the circuits within the motor control system 1, allowing the transition of the sampled signal from the control drive unit 33 to be instantaneous. Furthermore, the motor control system 1 in this case adopts a dual-channel architecture of the first STO circuit 4 and the second STO circuit 5, and the photodiode of the first optocoupler switch circuit 42 of the first STO circuit 4 and the phototransistor of the second optocoupler switch circuit 43 are connected in series. The photodiode of the third optocoupler switch circuit 52 of the second STO circuit 5 and the phototransistor of the fourth optocoupler switch circuit 53 are connected in series. Therefore, the motor control system 1 satisfies the design of circuit independence (the first STO circuit 4 and the second STO circuit 5 are completely independent) and time independence (in the STO self-test mode, the test timing of the first STO circuit 4 and the second STO circuit 5 is staggered).

[0066] In some embodiments, the motor control system 1 further includes a first detection circuit 100 and a second detection circuit 101. The first detection circuit 100 is electrically connected to the phototransistor of the first optocoupler switch circuit 42, and is used to detect whether the signal on the phototransistor of the first optocoupler switch circuit 42 changes synchronously with the change of the pulse signal TP when the motor control system 1 enters the STO self-test mode, and outputs a first detection signal FB1 to the pulse control module 6 according to the detection result. The second detection circuit 101 is electrically connected to the phototransistor of the third optocoupler switch circuit 52, and is used to detect whether the signal on the phototransistor of the third optocoupler switch circuit 52 changes synchronously with the change of the pulse signal TP when the motor control system 1 enters the STO self-test mode, and outputs a second detection signal FB2 to the pulse control module 6 according to the detection result. When the pulse control module 6 detects, based on the first detection signal FB1, that the signal on the phototransistor of the first optical coupling switch circuit 42 does not change synchronously with the change in the pulse signal TP, or detects, based on the second detection signal FB2, that the signal on the phototransistor of the third optical coupling switch circuit 52 does not change synchronously with the change in the pulse signal TP, it indicates that there is an abnormality in the first STO circuit 4 or the second STO circuit 5. Therefore, the pulse control module 6 drives the motor control system 1 to shut down, ensuring the safe operation of the motor control system 1.

[0067] In this case, the circuit structures and connections of the first optocoupler switch circuit 42 and the third optocoupler switch circuit 52 are similar; the circuit structures and connections of the second optocoupler switch circuit 43 and the fourth optocoupler switch circuit 53 are similar; the circuit structures and connections of the first filter circuit 40 and the second filter circuit 50 are similar; and the circuit structures and connections of the first detection circuit 100 and the second detection circuit 101 are similar. Therefore... Figure 4Only the first optocoupler switch circuit 42, the second optocoupler switch circuit 43, the first filter circuit 40, the first detection circuit 100, and the control drive unit 33 are shown, and the third optocoupler switch circuit 52, the fourth optocoupler switch circuit 53, the second filter circuit 50, and the second detection circuit 101 are not described in detail. In some embodiments, the second optocoupler switch circuit 43 includes an NPN transistor switch 60, a first resistor R1, a second resistor R2, and a second optocoupler switch 61. The base of the NPN transistor switch 60 is electrically connected to the pulse control module 6 to receive the pulse signal TP, the emitter of the NPN transistor switch 60 is electrically connected to the reference terminal G, and the collector of the NPN transistor switch 60 is electrically connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is electrically connected to the first voltage source S1. The anode of the second optocoupler switch 61 is electrically connected to the first terminal of the first resistor R1, and the cathode of the second optocoupler switch 61 is electrically connected to the reference terminal G. The anode of the second optocoupler 61 is electrically connected to the cathode of the first optocoupler 70. The phototransistor of the second optocoupler 61 is electrically connected between the first terminal of the second resistor R2 and the first optocoupler circuit 42. The second terminal of the second resistor R2 is electrically connected to the reference terminal G.

[0068] The first optocoupler switch circuit 42 includes a first capacitor C1, a first optocoupler switch 70, a third resistor R3, and a fourth resistor R4. The first terminal of the third resistor R3 is electrically connected to the STO terminal 7 to receive the first STO control signal. The first terminal of the fourth resistor R4 is electrically connected to the second terminal of the third resistor R3. The cathode of the photodiode of the first optocoupler switch 70 is electrically connected to the first terminal of the fourth resistor R4 and the second terminal of the third resistor R3. The anode of the photodiode of the first optocoupler switch 70 is electrically connected to the second terminal of the fourth resistor R4 and the phototransistor of the second optocoupler switch 61. The anode of the photodiode of the first optocoupler switch 70 is electrically connected to the cathode of the photodiode of the first optocoupler switch 70, and the cathode of the first optocoupler switch 70 is electrically connected to the anode of the second optocoupler switch 61. The emitter of the phototransistor of the first optocoupler switch 70 is electrically connected to the first detection circuit 100, and the collector of the phototransistor of the first optocoupler switch 70 is electrically connected to the first voltage source S1. The first terminal of the first capacitor C1 is electrically connected to the collector of the optotransistor of the first voltage source S1 and the first optocoupler switch 70, and the second terminal of the first capacitor C1 is electrically connected to the reference terminal G.

[0069] The first filter circuit 40 is electrically connected to the emitter of the phototransistor of the first optocoupler switch 70, and includes a fifth resistor R5, a sixth resistor R6, and a second capacitor C2. The first terminal of the fifth resistor R5 is electrically connected to the emitter of the phototransistor of the first optocoupler switch 70, and the second terminal of the fifth resistor R5 is electrically connected to the reference terminal G. The first terminal of the sixth resistor R6 is electrically connected to the first terminal of the fifth resistor R5, and the second terminal of the sixth resistor R6 is electrically connected to the control drive unit 33. The second capacitor C2 is electrically connected between the second terminal of the sixth resistor R6 and the reference terminal G.

[0070] The first detection circuit 100 includes a control chip 80, a third capacitor C3, and a seventh resistor R7. The first terminal of the seventh resistor R7 is electrically connected to the emitter of the phototransistor of the first optocoupler switch 70. The control chip 80 is electrically connected to the second terminal of the seventh resistor R7, the reference terminal G, and the first voltage source S1. The control chip 80 detects whether the signal on the phototransistor of the first optocoupler switch 70 in the first optocoupler switch circuit 42 changes synchronously with the change of the pulse signal TP, and outputs a first detection signal FB1 at the output terminal of the control chip 80 according to the detection result. The first terminal of the third capacitor C3 is electrically connected to the first voltage source S1 and the control chip 80, and the second terminal of the third capacitor C3 is electrically connected to the reference terminal G. The first terminal of the eighth resistor R8 is electrically connected to the second voltage source S2, and the second terminal of the eighth resistor R8 is electrically connected to the output terminal of the control chip 80.

[0071] In summary, this invention provides a motor control system in which the photodiode of the first optocoupler switch circuit of the first STO circuit of the motor control system is connected in series with the phototransistor of the second optocoupler switch circuit, and the photodiode of the third optocoupler switch circuit of the second STO circuit is connected in series with the phototransistor of the fourth optocoupler switch circuit. In this way, the pulse control module can issue corresponding pulse signals according to entering the STO trigger mode or the STO self-test mode to directly control the second optocoupler switch circuit and the fourth optocoupler switch circuit to be turned on or off. Therefore, the motor control system does not require an additional timing synchronization mechanism or the addition of two switches similar to those in a traditional motor control system. As a result, the production cost of the motor control system in this invention is lower. At the same time, the motor control system does not need to consider the state of the first STO control signal and the second STO control signal to avoid electrical short circuits of the signals and misjudgments when the motor control system 1 performs the safe torque shutdown function. Furthermore, the motor control system in this case filters out pulse signals from the first and third optocoupler switch circuits using a first and a second filter circuit, respectively. This prevents accidental activation of the first and second STO circuits and significantly increases their response time, thereby improving the safety of the motor control system. In addition, the first and second filter circuits help decouple the circuits within the motor control system, allowing for real-time changes in the sampling signals of the control drive unit. Moreover, the motor control system employs a dual-channel architecture of the first and second STO circuits, with the photodiode of the first optocoupler switch circuit of the first STO circuit connected in series with the phototransistor of the second optocoupler switch circuit, and the photodiode of the third optocoupler switch circuit of the second STO circuit connected in series with the phototransistor of the fourth optocoupler switch circuit. Therefore, the motor control system achieves both circuit independence and time independence.

Claims

1. A motor control system for driving a motor, comprising: A frequency converter is electrically connected to the motor and includes a first drive unit and a second drive unit, wherein the first drive unit or the second drive unit operates to enable the frequency converter to provide AC power to the motor. The first STO circuit includes a first filter circuit, a first STO switch, a first optical coupling switch circuit, and a second optical coupling switch circuit. The first filter circuit is electrically connected to the first optical coupling switch circuit, the first STO switch is electrically connected between the first driving unit and the phototransistor of the first optical coupling switch circuit, and the photodiode of the first optical coupling switch circuit is connected in series with the phototransistor of the second optical coupling switch circuit. The second STO circuit includes a second filter circuit, a second STO switch, a third optocoupler switch circuit, and a fourth optocoupler switch circuit. The second filter circuit is electrically connected to the third optocoupler switch circuit. The second STO switch is electrically connected between the second driving unit and the optotransistor of the third optocoupler switch circuit. The photodiode of the third optocoupler switch circuit is connected in series with the optotransistor of the fourth optocoupler switch circuit. as well as A pulse control module is electrically connected to the photodiodes of the second and fourth optocoupler circuits to send pulse signals to the photodiodes of the second and fourth optocoupler circuits and to detect whether the first and second STO circuits are abnormal, wherein the pulse signal switches between a high-level voltage and a low-level voltage. When the pulse control module sends the pulse signal at the high-level voltage, the second and fourth optocoupler switch circuits are turned on, entering the STO trigger mode. When the pulse control module sends the pulse signal at the low voltage level, the second and fourth optical coupling switch circuits are turned off, and the system enters the STO self-test mode.

2. The motor control system according to claim 1 further includes a first detection circuit electrically connected to the phototransistor of the first optical coupling switch circuit, for detecting whether the signal on the phototransistor of the first optical coupling switch circuit changes synchronously with the change of the pulse signal when entering the STO self-test mode, and outputting a first detection signal to the pulse control module according to the result of detecting the signal on the phototransistor of the first optical coupling switch circuit.

3. The motor control system according to claim 2 further includes a second detection circuit electrically connected to the phototransistor of the third optical coupling switch circuit, for detecting whether the signal on the phototransistor of the third optical coupling switch circuit changes synchronously with the change of the pulse signal when entering the STO self-test mode, and outputting a second detection signal to the pulse control module according to the result of detecting the signal on the phototransistor of the third optical coupling switch circuit.

4. The motor control system according to claim 1, wherein the second optocoupler switch circuit includes an NPN transistor switch, a first resistor, a second resistor, and a second optocoupler switch; the base of the NPN transistor switch is electrically connected to the pulse control module to receive the pulse signal; the emitter of the NPN transistor switch is electrically connected to a reference terminal; the collector of the NPN transistor switch is electrically connected to a first terminal of the first resistor; the second terminal of the first resistor is electrically connected to a first voltage source; the anode of the second optocoupler switch is electrically connected to the first terminal of the first resistor; the cathode of the second optocoupler switch is electrically connected to the reference terminal; wherein the second optocoupler switch includes the photodiode and the phototransistor of the second optocoupler switch circuit; the phototransistor of the second optocoupler switch is electrically connected between the first terminal of the second resistor and the first optocoupler switch circuit; and the second terminal of the second resistor is electrically connected to the reference terminal.

5. The motor control system according to claim 4 further includes a first detection circuit electrically connected to the phototransistor of the first optocoupler switch circuit, wherein the first optocoupler switch circuit includes a first capacitor, a first optocoupler switch, a third resistor, and a fourth resistor; a first terminal of the third resistor electrically receives the first STO control signal; a second terminal of the third resistor is electrically connected to the first terminal of the fourth resistor; the first optocoupler switch is electrically connected to the second optocoupler switch and includes the photodiode and the phototransistor of the first optocoupler switch circuit; the cathode of the photodiode of the first optocoupler switch is electrically connected to the first terminal of the fourth resistor and the second terminal of the third resistor; and the photodiode of the first optocoupler switch... The anode of the tube is electrically connected to the second terminal of the fourth resistor and the phototransistor of the second optocoupler switch. The anode of the photodiode of the second optocoupler switch is electrically connected to the cathode of the photodiode of the first optocoupler switch. The cathode of the photodiode of the second optocoupler switch is electrically connected to the anode of the photodiode of the first optocoupler switch. The emitter of the phototransistor of the first optocoupler switch is electrically connected to the first detection circuit. The collector of the phototransistor of the first optocoupler switch is electrically connected to the first voltage source. The first terminal of the first capacitor is electrically connected to the first voltage source and the collector of the phototransistor of the first optocoupler switch. The second terminal of the first capacitor is electrically connected to the reference terminal.

6. The motor control system according to claim 5, wherein the first filter circuit is electrically connected to the emitter of the phototransistor of the first optocoupler switch, and includes a fifth resistor, a sixth resistor and a second capacitor, wherein a first end of the fifth resistor is electrically connected to the emitter of the phototransistor of the first optocoupler switch, a second end of the fifth resistor is electrically connected to the reference end, a first end of the sixth resistor is electrically connected to the first end of the fifth resistor, a second end of the sixth resistor is electrically connected to the control drive unit, and the second capacitor is electrically connected between the second end of the fifth resistor and the reference end.

7. The motor control system according to claim 6, wherein the first detection circuit includes a control chip, a third capacitor, a seventh resistor, and an eighth resistor, the first end of the seventh resistor is electrically connected to the emitter of the phototransistor of the first optocoupler switch, the control chip is electrically connected to the second end of the seventh resistor, the reference end, and the first voltage source, and the control chip detects whether the signal on the phototransistor of the first optocoupler switch changes synchronously with the change of the pulse signal, and outputs the first detection signal at the output end of the control chip according to the result of detecting the signal on the phototransistor of the first optocoupler switch, the first end of the third capacitor is electrically connected to the first voltage source and the control chip, the second end of the third capacitor is electrically connected to the reference end, the first end of the eighth resistor is electrically connected to the second voltage source, and the second end of the eighth resistor is electrically connected to the output end of the control chip.

8. The motor control system according to claim 3, wherein the frequency converter includes a control drive unit electrically connected to the first filter circuit and the second filter circuit, for detecting the operating state of the frequency converter and controlling the frequency converter accordingly based on the detection result.

9. The motor control system according to claim 8, wherein the control drive unit comprises the first drive unit and the second drive unit.

10. The motor control system according to claim 1, wherein the first drive unit and the second drive unit are selected from two of the following combinations: a high-voltage side drive unit, a low-voltage side drive unit, a power control drive unit, and a control signal drive unit.

11. The motor control system according to claim 3, wherein when the pulse control module learns, based on the first detection signal, that the signal on the phototransistor of the first optical coupling switch circuit does not change synchronously in response to the change in the pulse signal, or learns, based on the second detection signal, that the signal on the phototransistor of the third optical coupling switch circuit does not change synchronously in response to the change in the pulse signal, the pulse control module drives the motor control system to shut down.

12. The motor control system according to claim 1, wherein when entering the STO trigger mode, the first STO circuit and the second STO circuit respectively control the shutdown of the first drive unit and the shutdown of the second drive unit according to the first STO control signal and the second STO signal.

13. The motor control system according to claim 1, wherein when entering the STO self-test mode, the first filter circuit and the second filter circuit respectively filter out the pulse signals on the first optical coupling switch circuit and the third optical coupling switch circuit, and the pulse control module detects whether the first STO circuit and the second STO circuit are abnormal.

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