Control circuit and servo motor driver

Abstract

The utility model relates to the technical field of motor safety, and further relates to a control circuit and a servo motor driver. The circuit comprises a bus filter capacitor used for filtering bus current; the regenerative braking circuit is connected in series between the positive end of the bus and the negative end of the bus and is used for discharging the energy of the bus; one end of the power-on soft start circuit is connected with the positive end of the bus, and the other end of the power-on soft start circuit is connected with the negative end of the bus through the bus filter capacitor; when the regenerative braking circuit is short-circuited and the servo motor driver is powered on, the power-on soft start circuit is used for limiting the impact current of the bus filter capacitor, and power-on protection of the servo motor driver is achieved. According to the circuit, the situation that key devices such as a rectifier bridge are burnt out due to impact current under the short-circuit condition is avoided, and the safety and stability of the servo motor driver are improved.

Description

Technical Field

[0001] This application relates to the field of motor safety technology, and further to a control circuit and a servo motor driver. Background Technology

[0002] Traditional servo motor drivers typically connect a soft-start resistor directly in series with the positive or negative terminal of the bus. This design effectively limits inrush current during normal power-up, protecting the servo motor driver from damage. However, when the regenerative braking circuit is short-circuited and the servo motor driver is powered on, the inrush current bypasses the soft-start resistor and flows directly through the rectifier bridge and related circuits, causing critical components such as the rectifier bridge to burn out, thus jeopardizing the safety and stability of the entire servo motor driver. Utility Model Content

[0003] To address the aforementioned technical issues, this application provides a control circuit and a servo motor driver that avoids the burnout of critical components such as the rectifier bridge due to inrush current under short-circuit conditions, thereby improving the safety and stability of the servo motor driver.

[0004] In a first aspect, this application provides a control circuit for a servo motor driver, comprising: a bus filter capacitor for filtering the bus current; a regenerative braking circuit connected in series between the positive and negative ends of the bus for dissipating bus energy; and a power-on soft-start circuit, one end of which is connected to the positive end of the bus, and the other end of which is connected to the negative end of the bus through the bus filter capacitor. When the regenerative braking circuit is short-circuited and the servo motor driver is powered on, the power-on soft-start circuit is used to limit the inrush current of the bus filter capacitor, thereby achieving power-on protection for the servo motor driver.

[0005] The above control circuit, by connecting the power-on soft-start circuit in series between the positive terminal of the bus and the bus filter capacitor, ensures that when the regenerative braking circuit is short-circuited and the servo motor is powered on, the power-on soft-start circuit can effectively limit the inrush current of the bus filter capacitor, thereby achieving power-on protection for the servo motor driver. This avoids the inrush current from flowing directly through the rectifier bridge and related circuits, which could lead to the burnout of key components such as the rectifier bridge, thus improving the safety and stability of the servo motor driver.

[0006] In one implementation, the power-on soft-start circuit includes: a relay, one end of which is connected to the positive terminal of the bus, and the other end of which is connected to the bus filter capacitor; and a first resistor, one end of which is connected to the positive terminal of the bus, and the other end of which is connected to the bus filter capacitor.

[0007] In one implementation, the regenerative braking circuit includes: a first insulated-gate bipolar transistor (IGBT), the collector of which is connected to the positive terminal of the bus via a first diode, and the emitter of which is connected to the negative terminal of the bus; and a second resistor, one end of which is connected to the positive terminal of the bus and the other end of which is connected to the collector of the first IGBT.

[0008] In one implementation, it further includes: an inverter circuit connected in series between the positive and negative terminals of the busbar, and the inverter circuit is also connected to an external servo motor to output three-phase current to the servo motor; when the output of the inverter circuit is short-circuited to ground and the servo motor driver is powered on, the power-on soft-start circuit is used to limit the inrush current of the busbar filter capacitor to realize the power-on protection of the servo motor driver.

[0009] The above control circuit, by connecting the power-on soft-start circuit in series between the positive terminal of the bus and the bus filter capacitor, ensures that when the inverter circuit output is short-circuited to ground and the servo motor is powered on, the power-on soft-start circuit can effectively limit the inrush current of the bus filter capacitor, thus achieving power-on protection for the servo motor driver. This prevents the inrush current from directly flowing through the rectifier bridge and related circuits, which could lead to the burnout of critical components such as the rectifier bridge, thereby improving the safety and stability of the servo motor driver.

[0010] In one implementation, the inverter circuit includes a first insulated-gate bipolar transistor (IGBT) group, a second IGBT group, and a third IGBT group, wherein each IGBT group includes a second IGBT and a third IGBT; the collector of the second IGBT is connected to the positive terminal of the bus, and the emitter of the second IGBT is connected to the collector of the third IGBT; the emitter of the third IGBT is connected to the negative terminal of the bus; wherein each IGBT is connected in parallel with a corresponding freewheeling diode.

[0011] In one implementation, it also includes: a bus overcurrent protection circuit, which is connected to the negative terminal of the bus via a third resistor, and is used to shut down the servo motor driver after the power-on protection of the servo motor driver is completed.

[0012] In one implementation, it further includes: a phase current overcurrent protection circuit, which is connected to the inverter circuit and is used to shut down the servo motor driver after the power-on protection of the servo motor driver is completed.

[0013] In one implementation, the phase current overcurrent protection circuit includes a single-phase phase current overcurrent protection circuit; the single-phase phase current overcurrent protection circuit is any one of the U-phase overcurrent protection circuit, the V-phase overcurrent protection circuit, and the W-phase overcurrent protection circuit.

[0014] In one implementation, the phase current overcurrent protection circuit includes a three-phase phase current overcurrent protection circuit; the three-phase phase current overcurrent protection circuit includes: a U-phase overcurrent protection circuit, which is connected to the inverter circuit through a fourth resistor; a V-phase current detection circuit, which is connected to the inverter circuit through a fifth resistor; and a W-phase current detection circuit, which is connected to the inverter circuit through a sixth resistor.

[0015] Secondly, this application also provides an electronic device including any of the control circuits implemented above.

[0016] Thirdly, this application also provides a servo motor driver, including any of the control circuits implemented above.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] By connecting the power-on soft-start circuit in series between the positive terminal of the bus and the bus filter capacitor, it is ensured that when the regenerative braking circuit is short-circuited and the servo motor is powered on, the power-on soft-start circuit can effectively limit the inrush current of the bus filter capacitor, thereby achieving power-on protection for the servo motor driver. This avoids the inrush current from flowing directly through the rectifier bridge and related circuits, which could lead to the burnout of key components such as the rectifier bridge, thus improving the safety and stability of the servo motor driver. Attached Figure Description

[0019] The preferred embodiments will be described below in a clear and easy-to-understand manner, in conjunction with the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages and implementation methods of this utility model.

[0020] Figure 1 A schematic diagram of the topology of a control circuit provided in an embodiment of this application is shown;

[0021] Figure 2 A circuit structure diagram of a control circuit provided in an embodiment of this application is shown. Detailed Implementation

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the specific implementation methods of this utility model will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of this utility model. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0023] To keep the drawings concise, each figure only schematically shows the parts relevant to the utility model, and these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some figures, only one of the components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0024] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0025] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] It should be noted that the above embodiments can be freely combined as needed. The above are merely preferred embodiments of this utility model. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

[0028] A servo motor driver typically includes a rectifier circuit, a power-on soft-start circuit, a bus filter capacitor, a regenerative braking circuit, and an inverter circuit. The rectifier circuit converts externally input AC power into DC power. The bus filter capacitor filters this DC power and transmits the filtered DC power to the inverter circuit, which then converts the filtered DC power back into three-phase AC power and outputs it to the servo motor. The regenerative braking circuit discharges bus energy and prevents excessive bus voltage rise when the motor stops under negative torque.

[0029] When the servo motor driver is initially powered on, the bus filter capacitor is essentially short-circuited, generating a very large inrush current at the moment of power-on. This excessive inrush current can easily damage the internal circuitry and components of the driver. Therefore, a power-on soft-start circuit needs to be incorporated into the circuit to limit the inrush current of the bus filter capacitor, thus achieving power-on protection for the servo motor driver. In this embodiment, by connecting the power-on soft-start circuit in series between the positive terminal of the bus and the bus filter capacitor, and simultaneously setting a bus overcurrent protection circuit and a U-phase overcurrent protection circuit at the negative terminal of the bus and the output terminal of the inverter circuit, respectively, at least one of the following beneficial effects can be achieved: when the regenerative braking circuit is short-circuited and the servo motor driver is powered on, the inrush current is prevented from directly flowing through the rectifier bridge and related circuits, thus avoiding the burnout of critical components such as the rectifier bridge, improving the safety and stability of the servo motor driver; or, it provides comprehensive and timely protection response for the servo motor driver, extending the service life of the equipment and enhancing the reliability of the servo motor driver.

[0030] The following explanation is based on the accompanying diagram:

[0031] Reference Appendix Figure 1 This illustrates a topological diagram of a control circuit provided in an embodiment of this application. For example... Figure 1 As shown, it includes: a bus filter capacitor, a regenerative braking circuit, and a power-on soft start circuit. The bus filter capacitor is used to filter the bus current; the regenerative braking circuit is connected in series between the positive and negative terminals of the bus to discharge bus energy; one end of the power-on soft start circuit is connected to the positive terminal of the bus (see attached diagram). Figure 1 The positive terminal is connected to the negative terminal of the bus via a bus filter capacitor (see attached diagram). Figure 1 The -) connection is used in the circuit. When the regenerative braking circuit is short-circuited and the servo motor driver is powered on, the power-on soft-start circuit is used to limit the inrush current of the bus filter capacitor, thereby achieving power-on protection for the servo motor driver.

[0032] When the servo motor driver is powered on normally, the externally input AC power passes through the rectifier circuit (see attached diagram). Figure 1 After rectification, the current flows into the power-on soft-start circuit, and then through the soft-start circuit to charge the bus filter capacitor, thereby limiting the inrush current of the bus filter capacitor. Once the bus voltage reaches the preset voltage, the switch inside the power-on soft-start circuit closes, short-circuiting the soft-start resistor inside the circuit, thus not affecting the normal operation of the circuit. (Refer to the attached diagram for the inverter circuit.) Figure 1 Normally, three-phase current is provided to the servo motor to drive it.

[0033] When a short circuit occurs in the regenerative braking circuit, the servo motor driver powers on. Since the power-on soft-start circuit is connected in series between the positive terminal of the bus and the bus filter capacitor, while the regenerative braking circuit is connected in series between the positive and negative terminals of the bus, even with a short circuit in the regenerative braking circuit, the rectified current can still charge the bus filter capacitor through the power-on soft-start circuit, thus limiting the inrush current to the bus filter capacitor. Similarly, after the bus voltage reaches the preset voltage, the switch inside the power-on soft-start circuit closes, short-circuiting the soft-start resistor inside the circuit, thus not affecting the normal operation of the circuit. The inverter circuit then normally provides three-phase current to the servo motor to drive it.

[0034] This embodiment of the application connects the power-on soft-start circuit in series between the positive terminal of the bus and the bus filter capacitor. This ensures that when the regenerative braking circuit is short-circuited and the servo motor is powered on, the power-on soft-start circuit can effectively limit the inrush current of the bus filter capacitor, thus achieving power-on protection for the servo motor driver. This prevents the inrush current from directly flowing through the rectifier bridge and related circuits, which could lead to the burnout of critical components such as the rectifier bridge, thereby improving the safety and stability of the servo motor driver.

[0035] In one embodiment of this application, reference is made to the appendix. Figure 1 It also includes: bus overcurrent protection circuit (see attached document). Figure 1 (Bus negative overcurrent protection). The bus overcurrent protection circuit is connected to the negative terminal of the bus and is used to shut down the servo motor driver after the power-on protection of the servo motor driver is completed.

[0036] After the power-on soft start circuit completes the power-on protection of the servo motor driver, when the regenerative braking circuit needs to discharge the bus energy, since the regenerative braking resistor in the regenerative braking circuit is in a short-circuit state, once the regenerative braking tube in the regenerative braking circuit is turned on, it will cause a short circuit between the positive and negative terminals of the bus. At this time, the bus overcurrent protection circuit will shut down the servo motor driver for protection.

[0037] In one embodiment of this application, reference is made to the appendix. Figure 1 The inverter circuit is connected in series between the positive and negative terminals of the busbar, and is also connected to an external servo motor to output three-phase current to the servo motor. When the output of the inverter circuit is short-circuited to ground and the servo motor driver is powered on, the power-on soft-start circuit is used to limit the inrush current of the busbar filter capacitor to realize the power-on protection of the servo motor driver.

[0038] When the inverter circuit output is short-circuited to ground and the servo motor driver is powered on, if the ground potential is higher than the phase potential of the external AC input, the charging path for the bus filter capacitor is: inverter circuit → bus positive terminal → power-on soft start circuit → bus filter capacitor → bus negative terminal. If the ground potential is lower than the input phase potential, the charging path for the bus filter capacitor is: bus positive terminal → power-on soft start circuit → bus filter capacitor → bus negative terminal → inverter circuit. Similarly, after the bus voltage reaches the preset voltage, the switch inside the power-on soft start circuit closes, short-circuiting the soft start resistor inside the power-on soft start circuit, thus not affecting the normal operation of the circuit. The inverter circuit normally provides three-phase current to the servo motor to drive it.

[0039] This embodiment of the application connects the power-on soft-start circuit in series between the positive terminal of the bus and the bus filter capacitor. This ensures that when the inverter circuit output is short-circuited to ground and the servo motor is powered on, the power-on soft-start circuit can effectively limit the inrush current of the bus filter capacitor, thus achieving power-on protection for the servo motor driver. This prevents the inrush current from directly flowing through the rectifier bridge and related circuits, which could lead to the burnout of critical components such as the rectifier bridge, thereby improving the safety and stability of the servo motor driver.

[0040] In one embodiment of this application, a phase current overcurrent protection circuit is further included. The phase current overcurrent protection circuit is connected to the inverter circuit and is used to perform a shutdown protection on the servo motor driver after the power-on protection of the servo motor driver is completed.

[0041] After the power-on soft start circuit completes the power-on protection of the servo motor driver, it triggers the phase current overcurrent protection circuit and the bus overcurrent protection circuit to shut down the servo motor driver. The specific protection threshold and action delay time of the phase current overcurrent protection circuit and the bus overcurrent protection circuit depend on their respective protection thresholds and action delay times.

[0042] Reference Appendix Figure 2 This illustrates a circuit structure diagram of a control circuit provided in an embodiment of this application. Figure 2 As shown, the power-on soft-start circuit includes a relay K1 and a first resistor R1 (or soft-start resistor R1); the regenerative braking circuit includes a first insulated-gate bipolar transistor G7, a first diode D7, and a second resistor R2 (or regenerative braking resistor R2). One end of the relay K1 is connected to the positive terminal of the bus, and the other end is connected to the bus filter capacitor C1; one end of the first resistor R1 is connected to the positive terminal of the bus, and the other end is connected to the bus filter capacitor C1; the collector of the first insulated-gate bipolar transistor G7 is connected to the positive terminal of the bus through the first diode D7, the emitter of the first insulated-gate bipolar transistor G7 is connected to the negative terminal of the bus, and a freewheeling diode is connected in parallel with the first insulated-gate bipolar transistor G7; one end of the second resistor R2 is connected to the positive terminal of the bus, and the other end is connected to the collector of the first insulated-gate bipolar transistor G7.

[0043] When the servo motor driver is powered on normally, the coil of relay K1 has no voltage, and relay K1 is in the normally open position. At this time, the rectified current flows sequentially through the positive terminal of the bus, the first resistor R1, DC+ (DC+ is the network name), and the bus filter capacitor C1, finally flowing into the negative terminal of the bus. The current charging the bus filter capacitor C1 flows through the first resistor R1, limiting the excessive inrush current of the bus filter capacitor when the servo motor driver is powered on. When the bus voltage reaches the set value, the 24V control power supply voltage supplies power to the coil of relay K1, the coil contacts of relay K1 close, shorting the first resistor R1, and the circuit begins to operate normally.

[0044] When the regenerative braking resistor R2 is short-circuited, the servo motor driver is powered on. Since the first resistor R1 is connected in series between the positive terminal of the bus and the bus filter capacitor C1 at this time, the rectified current does not flow through the second resistor R2 when the servo motor driver is powered on. Instead, it charges the bus filter capacitor C1 according to the current path: positive terminal of the bus → first resistor R1 → DC+ → bus filter capacitor C1 → negative terminal of the bus. Similarly, when the bus voltage reaches the set value, the 24V control power supply voltage powers the coil of relay K1, causing the relay K1 coil contacts to close, short-circuiting the first resistor R1, and the circuit begins normal operation.

[0045] Furthermore, when the servo motor decelerates rapidly, causing the bus voltage to rise and requiring the first insulated gate bipolar transistor G7 (or switching transistor G7) to perform regenerative braking, since the second resistor R2 is short-circuited at this time, the short-circuit current between the positive and negative terminals of the bus flows through the third resistor R3 (or the bus negative sampling resistor R3). If the current flowing through the third resistor R3 exceeds the protection threshold corresponding to the bus overcurrent protection circuit, then the bus overcurrent protection circuit will perform a shutdown protection operation on the servo motor driver.

[0046] In this embodiment, during normal power-on, the normally open position of the relay, in conjunction with the first resistor, effectively limits the inrush current of the bus filter capacitor, protecting the servo motor driver from damage. When the second resistor short-circuits, the current bypasses the second resistor and continues to charge the bus filter capacitor through the first resistor, ensuring the stability of the power-on process. Furthermore, when the servo motor rapidly decelerates, causing a surge in bus voltage and requiring the activation of the first insulated-gate bipolar transistor for regenerative braking, the bus overcurrent protection circuit responds promptly, shutting down the servo motor driver to prevent equipment damage due to excessive current. This design not only optimizes the response time and protection efficiency of the servo motor driver through precise current path control but also extends the equipment's lifespan and enhances the reliability of the servo motor driver.

[0047] In one embodiment of this application, reference is made to the appendix. Figure 2The inverter circuit includes a first insulated-gate bipolar transistor (IGBT) group, a second IGBT group, and a third IGBT group. The first IGBT group generates the U-phase current, the second IGBT group generates the V-phase current, and the third IGBT group generates the W-phase current. Each IGBT group includes both a second IGBT and a third IGBT. The collector of the second IGBT is connected to the positive terminal of the bus, and the emitter of the second IGBT is connected to the collector of the third IGBT. The emitter of the third IGBT is connected to the negative terminal of the bus. Each IGBT is connected in parallel with a corresponding freewheeling diode. The control circuit also includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. Among them, one end of the third resistor R3 is connected to the negative terminal of the bus, and the other end is connected to the emitter of the first insulated gate bipolar transistor G7; one end of the fourth resistor R4 is connected to the first insulated gate bipolar transistor group, and the other end is connected to the servo motor; one end of the fifth resistor R5 is connected to the second insulated gate bipolar transistor group, and the other end is connected to the servo motor; one end of the sixth resistor R6 is connected to the third insulated gate bipolar transistor group, and the other end is connected to the servo motor.

[0048] The first, second, and third insulated-gate bipolar transistor groups each include both second and third insulated-gate bipolar transistors. For example, refer to the appendix... Figure 2 The second insulated-gate bipolar transistor (IGBT) G1 and the third IGBT G4 together constitute the first IGBT group; the second IGBT G2 and the third IGBT G5 together constitute the second IGBT group. Similarly, the third IGBT group is composed of the second IGBT G3 and the third IGBT G6. Furthermore, each IGBT is connected in parallel with a corresponding freewheeling diode. For example, the second IGBT G1 corresponds to the freewheeling diode D1, and the third IGBT G4 corresponds to the freewheeling diode D4, etc.

[0049] When the output of the inverter circuit is short-circuited to ground, there are multiple power-on charging paths in the control circuit. Taking the U-phase short-circuit to ground as an example, if the ground potential is higher than the input phase potential, the charging path for the bus filter capacitor C1 is: U-phase → fourth resistor R4 → freewheeling diode D1 → bus positive terminal → first resistor R1 → (DC+) → bus filter capacitor C1 → bus negative terminal; if the ground potential is lower than the input phase potential, the charging path for the bus filter capacitor C1 is: bus positive terminal → first resistor R1 → (DC+) → bus filter capacitor C1 → bus negative terminal → third resistor R3 → freewheeling diode D4 → fourth resistor R4 → U-phase.

[0050] Taking a phase V short circuit to ground as an example, if the ground potential is higher than the input phase potential, the charging path for the bus filter capacitor C1 is: V phase → fifth resistor R5 → freewheeling diode D2 → bus positive terminal → first resistor R1 → (DC+) → bus filter capacitor C1 → bus negative terminal; if the ground potential is lower than the input phase potential, the charging path for the bus filter capacitor C1 is: bus positive terminal → first resistor R1 → (DC+) → bus filter capacitor C1 → bus negative terminal → third resistor R3 → freewheeling diode D5 → fifth resistor R5 → V phase.

[0051] Taking a short circuit between phase W and ground as an example, if the ground potential is higher than the input phase potential, the charging path for the bus filter capacitor C1 is: phase W → sixth resistor R6 → freewheeling diode D3 → positive terminal of the bus → first resistor R1 → (DC+) → bus filter capacitor C1 → negative terminal of the bus; if the ground potential is lower than the input phase potential, the charging path for the bus filter capacitor C1 is: positive terminal of the bus → first resistor R1 → (DC+) → bus filter capacitor C1 → negative terminal of the bus → third resistor R3 → freewheeling diode D6 → sixth resistor R6 → phase W.

[0052] Using the U, V, and W three-phase example, when the inverter circuit output is short-circuited to ground and the servo motor driver is powered on, the rectified current can charge the bus filter capacitor C1 through the first resistor R1 in the power-on soft-start circuit, thus limiting the inrush current of the bus filter capacitor. Similarly, when the bus voltage reaches the set value, the 24V control power supply voltage supplies power to the coil of relay K1, the relay K1 coil contacts close, short-circuiting the first resistor R1, and the circuit begins normal operation.

[0053] This embodiment utilizes first, second, and third insulated-gate bipolar transistor groups to generate three-phase current for the servo motor driver. The placement of the third, fourth, fifth, and sixth resistors, along with the use of freewheeling diodes in each transistor group, ensures that even in abnormal conditions such as a short circuit to ground at the inverter output, current can charge the bus filter capacitor through the soft-start resistor. This also limits inrush current, protecting the servo motor driver from damage and improving its safety and stability.

[0054] In one embodiment of this application, the phase current overcurrent protection circuit includes a single-phase phase current overcurrent protection circuit or a three-phase phase current overcurrent protection circuit. The single-phase phase current overcurrent protection circuit can be any one of a U-phase overcurrent protection circuit, a V-phase overcurrent protection circuit, and a W-phase overcurrent protection circuit; the three-phase phase current overcurrent protection circuit can include a U-phase overcurrent protection circuit, a V-phase current detection circuit, and a W-phase current detection circuit.

[0055] When the phase current overcurrent protection circuit is a three-phase phase current overcurrent protection circuit, in one embodiment of this application, refer to the appendix. Figure 2 The control circuit also includes: a U-phase overcurrent protection circuit, a V-phase current detection circuit, and a W-phase current detection circuit. Specifically, the U-phase overcurrent protection circuit is connected to the inverter circuit via a fourth resistor R4; the V-phase current detection circuit is connected to the inverter circuit via a fifth resistor R5; the W-phase current detection circuit is connected to the inverter circuit via a sixth resistor R6; and the bus overcurrent protection circuit is connected to the negative terminal of the bus via a third resistor R3.

[0056] After power-on, relay K1 energizes and shorts the first resistor R1. At this time, the short-circuit current will flow through the inverter circuit through the fourth resistor R4, the fifth resistor R5, the sixth resistor R6 (the fourth, fifth, and sixth resistors can all be called phase sampling resistors) and the third resistor R3. The bus overcurrent protection circuit can obtain the current on the third resistor R3 and compare it with the corresponding protection threshold to achieve shutdown protection for the servo motor driver. Similarly, the U-phase overcurrent protection circuit can obtain the current on the fourth resistor R4 and compare it with the corresponding protection threshold to achieve shutdown protection for the servo motor driver. The V-phase current detection circuit and the W-phase current detection circuit can obtain the current on the corresponding resistors respectively. When the current exceeds the corresponding protection threshold, the servo motor driver is triggered to alarm and stop.

[0057] In one embodiment of this application, the bus overcurrent protection circuit and the U-phase overcurrent protection circuit can be implemented by a comparator chip, which saves layout space while ensuring economy, and improves product protection performance in the trend of miniaturization and cost reduction of servo motor drivers.

[0058] In one embodiment of this application, reference is made to the appendix. Figure 2 The rectifier circuit includes a first diode group, a second diode group, and a third diode group, where each diode group includes a second diode and a third diode. The cathode of the second diode is connected to the positive terminal of the bus, and the anode of the second diode is connected to the cathode of the third diode; the anode of the third diode is connected to the negative terminal of the bus. For example, second diode D8 and second diode D11 constitute the first diode group, second diode D9 and second diode D12 constitute the second diode group, and second diode D10 and second diode D13 constitute the third diode group. The diodes in the rectifier circuit work together to convert externally input alternating current (AC) into direct current (DC).

[0059] This application also provides an electronic device, including the control circuit described in any of the above embodiments.

[0060] In one embodiment of this application, the electronic device may be a servo motor driver.

[0061] It should be noted that the above embodiments can be freely combined as needed. The above are merely preferred embodiments of this utility model. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A control circuit applied to a servo motor driver, characterized in that, include: Bus filter capacitors are used to filter bus current. A regenerative braking circuit, which is connected in series between the positive and negative ends of the busbar, is used to discharge the energy of the busbar. A power-on soft start circuit, one end of which is connected to the positive terminal of the bus, and the other end of which is connected to the negative terminal of the bus through the bus filter capacitor; When the regenerative braking circuit is short-circuited and the servo motor driver is powered on, the power-on soft-start circuit is used to limit the inrush current of the bus filter capacitor, thereby achieving power-on protection for the servo motor driver.

2. The control circuit according to claim 1, characterized in that, The power-on soft-start circuit includes: A relay, one end of which is connected to the positive terminal of the busbar, and the other end of which is connected to the busbar filter capacitor; The first resistor has one end connected to the positive terminal of the bus and the other end connected to the bus filter capacitor.

3. The control circuit according to claim 1, characterized in that, The regenerative braking circuit includes: A first insulated-gate bipolar transistor, wherein the collector of the first insulated-gate bipolar transistor is connected to the positive terminal of the bus via a first diode, and the emitter of the first insulated-gate bipolar transistor is connected to the negative terminal of the bus; The second resistor has one end connected to the positive terminal of the busbar and the other end connected to the collector of the first insulated gate bipolar transistor.

4. The control circuit according to claim 1, characterized in that, Also includes: An inverter circuit is connected in series between the positive terminal and the negative terminal of the busbar, and the inverter circuit is also connected to an external servo motor to output three-phase current to the servo motor. When the output of the inverter circuit is short-circuited to ground and the servo motor driver is powered on, the power-on soft-start circuit is used to limit the inrush current of the bus filter capacitor, thereby achieving power-on protection for the servo motor driver.

5. The control circuit according to claim 4, characterized in that, The inverter circuit includes a first insulated-gate bipolar transistor group, a second insulated-gate bipolar transistor group, and a third insulated-gate bipolar transistor group, wherein each insulated-gate bipolar transistor group includes a second insulated-gate bipolar transistor and a third insulated-gate bipolar transistor. The collector of the second insulated gate bipolar transistor is connected to the positive terminal of the bus, and the emitter of the second insulated gate bipolar transistor is connected to the collector of the third insulated gate bipolar transistor. The emitter of the third insulated gate bipolar transistor is connected to the negative terminal of the busbar; Each insulated gate bipolar transistor is connected in parallel with a corresponding freewheeling diode.

6. The control circuit according to claim 1, characterized in that, Also includes: A bus overcurrent protection circuit is provided, which is connected to the negative terminal of the bus via a third resistor. It is used to shut down the servo motor driver after the power-on protection of the servo motor driver is completed.

7. The control circuit according to claim 4, characterized in that, Also includes: A phase current overcurrent protection circuit is connected to the inverter circuit and is used to shut down the servo motor driver after the power-on protection of the servo motor driver is completed.

8. The control circuit according to claim 7, characterized in that, The phase current overcurrent protection circuit includes a single-phase phase current overcurrent protection circuit; the single-phase phase current overcurrent protection circuit is any one of the U-phase overcurrent protection circuit, the V-phase overcurrent protection circuit, and the W-phase overcurrent protection circuit.

9. The control circuit according to claim 7, characterized in that, The phase current overcurrent protection circuit includes a three-phase phase current overcurrent protection circuit; the three-phase phase current overcurrent protection circuit includes: U-phase overcurrent protection circuit, wherein the U-phase overcurrent protection circuit is connected to the inverter circuit through a fourth resistor; V-phase current detection circuit, which is connected to the inverter circuit through a fifth resistor; The W-phase current detection circuit is connected to the inverter circuit through a sixth resistor.

10. A servo motor driver, characterized in that, Includes the control circuit described in any one of claims 1-9.

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