Control device and method of servo driver and motor

Abstract

The invention discloses a control device and method of a servo driver and a motor, and the device comprises a first sampling unit which samples the voltage on a bus capacitor unit, and records the voltage as the first voltage of the first side of a contact of a switch module; the second sampling unit is used for sampling the direct-current voltage of the output end of the rectifying unit and recording the direct-current voltage as second voltage of the second side of the contact of the switch module; and the control unit is used for dynamically adjusting a preset bus voltage threshold value when the contact of the switch module acts according to the second voltage of the second side of the contact of the switch module and the first voltage of the first side of the contact of the switch module, so that the voltage difference value of the first side and the second side of the contact of the switch module after adjustment is within a set voltage range. According to the scheme, the bus voltage threshold value when the relay is closed or opened is dynamically adjusted according to the voltage difference between the voltages at the two ends of the contact of the relay, so that the voltage difference between the voltages at the two ends of the contact of the relay is within the set voltage range, and the working reliability of the relay and the working reliability of the servo driver are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of servo drives, and specifically relates to a control device of a servo drive, a motor and a control method of the servo drive, and more particularly to a control device of a pre-charging circuit of a bus electrolytic capacitor in a servo drive, a motor having the control device of the pre-charging circuit of the bus electrolytic capacitor in the servo drive, and a control method of the pre-charging circuit of the bus electrolytic capacitor in the servo drive of the motor. Background Art

[0002] Servo drive is a controller used to control servo motors. Servo drives are divided into AC servo drives and DC servo drives. AC servo drives use a voltage-type AC-DC-AC topology. AC servo drives first convert the industrial frequency AC power supply into DC through a rectifier, and then convert the DC into variable frequency AC with controllable frequency and voltage through an inverter to transmit it to the motor. The intermediate DC link between the industrial frequency AC power supply input and the variable frequency AC output is called the DC bus. The DC bus is usually connected in parallel with many large electrolytic capacitors for energy storage to provide energy for the back-end inverter to control the rotation of the servo motor.

[0003] The AC servo drive adopts a voltage-type AC-DC-AC topology structure, which consists of a rectifier unit, a pre-charging circuit unit, an energy storage unit, a regenerative braking unit, and a power inverter unit. The rectifier unit mainly adopts a three-phase rectifier bridge U1 module. In order to prevent the extremely large impact current at the moment of power-on from damaging the bus electrolytic capacitor and the switch module (such as a relay) or causing an impact on the power grid, a pre-charging circuit needs to be set; the unit where the pre-charging circuit is located is the pre-charging circuit unit, which is mainly composed of a positive temperature coefficient (PTC) resistor and a switch module (such as a relay) in parallel. The energy storage unit is mainly composed of a bus electrolytic capacitor array with multiple electrolytic capacitors connected in parallel or in series. A large amount of electrical energy is stored on the bus electrolytic capacitor array to provide energy for the rear-end power inverter unit to control the rotation of the servo motor. The regenerative braking unit is mainly composed of a braking resistor, an insulated gate bipolar transistor (IGBT) and a corresponding control circuit. The power inverter unit mainly consists of an intelligent power module (IPM) or an IGBT module (insulated gate bipolar transistor module) and its drive circuit.

[0004] Among them, when the switch module (such as a relay) in the pre-charging circuit of the servo drive (such as an AC servo drive) is closed, the bus voltage threshold is too low or too high, affecting the reliability of the switch module (such as a relay) and thus affecting the reliability of the servo drive.

[0005] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0006] The object of the present invention is to provide a control device of a servo drive, a motor and a control method of the servo drive thereof, so as to solve the problem that when a switch module (such as a relay) in a pre-charging circuit in a servo drive (especially an AC servo drive) is closed, the bus voltage threshold is too low or too high, which affects the reliability of the switch module (such as a relay) and further affects the reliability of the servo drive. The bus voltage threshold when the switch module (such as a relay) is closed or disconnected is dynamically adjusted according to the voltage difference across the contacts of the switch module (such as a relay) in the pre-charging circuit of the bus capacitor unit in the servo drive, so that the voltage difference across the contacts of the switch module (such as a relay) is within a set voltage range, which is conducive to improving the reliability of the switch module (such as a relay) and the reliability of the servo drive.

[0007] The present invention provides a control device for a servo driver, wherein the servo driver is arranged between an access end of an external AC power supply and a power supply end of a motor; the servo driver at least comprises a rectifier unit, a pre-charging circuit, a bus capacitor unit and an inverter unit which are arranged in sequence; the pre-charging circuit comprises: a pre-charging resistor module and a switch module, wherein the pre-charging resistor module is arranged between an output end of the rectifier unit and the bus capacitor unit, and a contact of the switch module is connected in parallel with the pre-charging resistor module; the control device for the servo driver comprises: a first sampling unit, a second sampling unit and a control unit; wherein the The first sampling unit is used to sample the voltage on the bus capacitor unit, which is recorded as the first voltage on the first side of the contact of the switch module; the second sampling unit is used to sample the DC voltage at the output end of the rectifier unit, which is recorded as the second voltage on the second side of the contact of the switch module; the control unit is used to dynamically adjust the preset bus voltage threshold when the contact of the switch module is actuated according to the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range.

[0008] In some embodiments, the switch module includes: a relay module; the contacts of the relay module serve as the contacts of the switch module; the control end of the coil of the relay module serves as the control end of the switch module; wherein the contact action of the switch module refers to the closing or opening of the contacts of the relay module; and / or, in the servo drive, a regenerative braking circuit is also arranged between the bus capacitor unit and the inverter unit; the regenerative braking circuit includes: a diode module, a discharge resistor module and a brake switch tube module; wherein the diode module is connected in parallel with the discharge resistor module, and the cathode of the diode module is connected to the positive end of the bus capacitor unit; the anode of the diode module is connected to the first connection end of the brake switch tube module, and the second connection end of the brake switch tube module is connected to the negative end of the bus capacitor unit.

[0009] In some embodiments, the control unit dynamically adjusts a preset bus voltage threshold when the contact of the switch module is actuated according to a second voltage on the second side of the contact of the switch module and a first voltage on the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after the adjustment is within a set voltage range, including: determining a magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, and determining a difference between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module; and dynamically adjusting a preset bus voltage threshold when the contact of the switch module is actuated according to the magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after the adjustment is within the set voltage range.

[0010] In some embodiments, the control unit dynamically adjusts a preset bus voltage threshold when the contact of the switch module is actuated according to a magnitude relationship between a second voltage on the second side of the contact of the switch module and a first voltage on the first side of the contact of the switch module, and a voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range, including: if the second voltage on the second side of the contact of the switch module is greater than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the first voltage on the first side of the contact of the switch module, If the value is greater than the upper limit of the set voltage range, the preset bus voltage threshold when the contact of the switch module is actuated is adjusted higher, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range; if the second voltage on the second side of the contact of the switch module is less than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the preset bus voltage threshold when the contact of the switch module is actuated is adjusted lower, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range.

[0011] In some embodiments, the control unit increases the bus voltage threshold preset when the contacts of the switch module are actuated, including: determining the difference between the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module and the upper limit of the set voltage range or the lower limit of the set voltage range, recording it as a first difference; increasing the bus voltage threshold preset when the contacts of the switch module are actuated by the first difference, to obtain a new bus voltage threshold preset when the contacts of the switch module are actuated; and / or, the control unit lowers the bus voltage threshold preset when the contacts of the switch module are actuated, including: determining the difference between the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module and the upper limit of the set voltage range or the lower limit of the set voltage range, recording it as a second difference; lowering the bus voltage threshold preset when the contacts of the switch module are actuated by the second difference, to obtain a new bus voltage threshold preset when the contacts of the switch module are actuated.

[0012] Matching the above device, the present invention further provides a motor, comprising: a control device of the servo drive described above.

[0013] To match the above-mentioned motor, the present invention provides a control method for a servo driver of a motor on another aspect, comprising: sampling the voltage on the bus capacitor unit, recorded as the first voltage on the first side of the contact of the switch module; sampling the DC voltage at the output end of the rectifier unit, recorded as the second voltage on the second side of the contact of the switch module; and dynamically adjusting a preset bus voltage threshold when the contact of the switch module is actuated according to the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range.

[0014] In some embodiments, dynamically adjusting a preset bus voltage threshold when the contact of the switch module is actuated according to a second voltage on the second side of the contact of the switch module and a first voltage on the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after the adjustment is within a set voltage range, includes: determining a magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, and determining a difference between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module; and dynamically adjusting a preset bus voltage threshold when the contact of the switch module is actuated according to the magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after the adjustment is within the set voltage range.

[0015] In some embodiments, according to the magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module, the preset bus voltage threshold value when the contact of the switch module is actuated is dynamically adjusted so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range, including: if the second voltage on the second side of the contact of the switch module is greater than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the set voltage range; If the upper limit of the set voltage range is exceeded, the preset bus voltage threshold when the contact of the switch module is actuated is adjusted higher, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range; if the second voltage on the second side of the contact of the switch module is less than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the preset bus voltage threshold when the contact of the switch module is actuated is adjusted lower, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range.

[0016] In some embodiments, the bus voltage threshold preset when the contacts of the switch module are actuated is adjusted higher, including: determining the difference between the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module and the upper limit of the set voltage range or the lower limit of the set voltage range, recorded as the first difference; adjusting the bus voltage threshold preset when the contacts of the switch module are actuated higher by the first difference to obtain a new bus voltage threshold preset when the contacts of the switch module are actuated; and / or, the bus voltage threshold preset when the contacts of the switch module are actuated is adjusted lower, including: determining the difference between the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module and the upper limit of the set voltage range or the lower limit of the set voltage range, recorded as the second difference; adjusting the bus voltage threshold preset when the contacts of the switch module are actuated lower by the second difference to obtain a new bus voltage threshold preset when the contacts of the switch module are actuated.

[0017] Therefore, the scheme of the present invention is for a servo driver composed of at least a rectifier unit, a bus capacitor unit and an inverter unit, a pre-charging circuit of the bus capacitor unit is arranged between the rectifier unit and the bus capacitor unit, the pre-charging circuit is composed of a pre-charging resistor and a relay, the pre-charging resistor is arranged between the output end of the rectifier unit and the input end of the bus capacitor unit, the normally open contact of the relay is connected in parallel with the pre-charging resistor, and the control end of the coil of the relay is controlled by the control unit; a first sampling unit is arranged at one end of the relay where the normally open contact is connected to the bus capacitor unit, which is used to detect the bus voltage of the bus capacitor unit as the first voltage, and a second sampling unit is arranged at one end of the relay where the normally open contact is connected to the rectifier unit, which is used to detect the DC at the output end of the rectifier unit. The voltage is recorded as the second voltage; after the servo drive is powered on, the bus voltage threshold when the normally open contact of the relay is closed or disconnected is dynamically adjusted according to the difference between the second voltage and the first voltage, so that the voltage difference across the normally open contact of the relay is within the set voltage range; thereby, the bus voltage threshold when the relay is closed or disconnected is dynamically adjusted according to the voltage difference across the contacts of the relay in the pre-charging circuit of the bus capacitor unit in the servo drive, so that the voltage difference across the contacts of the relay is within the set voltage range, thereby avoiding the bus voltage threshold being too low or too high when the relay is closed, affecting the reliability of the relay and then affecting the reliability of the servo drive, which is beneficial to improving the reliability of the relay and the reliability of the servo drive.

[0018] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram of an embodiment of a control device for a servo drive of the present invention;

[0021] Figure 2 It is a structural schematic diagram of an embodiment of a pre-charging control circuit of a busbar electrolytic capacitor in a servo drive in a related solution;

[0022] Figure 3 It is a structural schematic diagram of an embodiment of a pre-charging control circuit of a busbar electrolytic capacitor in a servo drive of the present invention;

[0023] Figure 4 A schematic flow chart of an embodiment of a method for controlling a servo driver of a motor of the present invention;

[0024] Figure 5A schematic flow chart of an embodiment of dynamically adjusting a preset bus voltage threshold value when the contact of the switch module is actuated in the method of the present invention;

[0025] Figure 6 A flow chart of an embodiment of increasing a preset bus voltage threshold when the contacts of the switch module are actuated in the method of the present invention;

[0026] Figure 7 The present invention is a flow chart of an embodiment of lowering a preset bus voltage threshold when the contacts of the switch module are actuated in the method of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] In the relevant scheme, the pre-charging circuit is that the three-phase AC power is rectified by the rectifier bridge, and the DC power first charges the bus electrolytic capacitor array on the DC bus through the PTC resistor. When the voltage on the bus electrolytic capacitor array reaches a certain threshold, the closed relay continues to charge the bus electrolytic capacitor array. At the moment the relay is closed, there is a certain voltage difference between the two ends of the relay contact. The greater the voltage difference, the greater the impact current at the moment the relay is closed. The greater the impact current, the greater the damage to the relay, resulting in reduced durability of the relay, and may cause the relay contacts to stick for a long time. At the moment the AC servo drive is powered on, the bus electrolytic capacitor array is charged directly through the relay contacts, making the instantaneous impact current of the relay powered on larger. The larger impact current will cause the circuit breaker connected to the AC servo drive to trip, and the AC servo drive cannot work normally. At the same time, the adhesion of the relay contacts will make it impossible to disconnect the relay contacts when they need to be disconnected, causing the AC servo drive to fail to work normally. Therefore, it is necessary to control the bus voltage threshold when the relay is closed, control the voltage difference across the relay contacts, and reduce the impact current passing through the relay contacts at the moment the relay is closed to make it as small as possible, so that the durability of the relay is increased and the failure rate is reduced. The failure rate of the AC servo drive is reduced and the service life will also increase. However, if the bus voltage threshold when the relay is closed is too high and the voltage difference across the relay contacts is too small, the bus electrolytic capacitor array charging time is relatively long when the AC servo drive is initially powered on or restarted after power failure, and the time required to wait for the relay to close is relatively long. Repeated restarting of the AC servo drive will cause the PTC resistor temperature to be too high, and the AC servo drive will charge more slowly and take longer to charge; too long charging time will cause the AC servo drive to start up too long, and the boot waiting time will be relatively long, which seriously affects the customer's experience and reduces production efficiency. At the same time, if the bus voltage threshold when the relay is closed is too high, when the power supply to the AC servo drive fluctuates within a reasonable range, when the power supply fluctuates to the lowest voltage limit of the power supply, the closing threshold of the relay is higher than the lowest voltage limit, the relay will never be closed, and the AC servo drive will not work properly.

[0029] Therefore, it is more important to select a reasonable bus voltage threshold when the relay is closed. Therefore, the solution of the present invention proposes a control scheme for a servo driver, specifically a control scheme for a pre-charging circuit of a bus electrolytic capacitor that dynamically adjusts the bus voltage threshold when the relay is closed according to the voltage of the AC servo driver power supply. The voltage of the bus electrolytic capacitor is monitored to determine whether the voltage on the bus electrolytic capacitor reaches the relay contact closing or disconnecting threshold condition; at the same time, the voltage of the servo driver three-phase power supply is monitored, and according to the voltage change of the servo driver three-phase power supply, the bus voltage threshold when the relay contact in the pre-charging circuit of the servo driver is closed or disconnected is dynamically adjusted to avoid the problem that the bus voltage threshold is too low or too high when the relay in the pre-charging circuit of the servo driver (especially the AC servo driver) is closed, which affects the reliability of the relay operation, and then affects the reliability of the servo driver operation, which is beneficial to improving the reliability of the relay operation and the reliability of the servo driver operation.

[0030] According to an embodiment of the present invention, a control device for a servo drive is provided. Figure 1 The structure diagram of an embodiment of the device of the present invention is shown. The servo drive is arranged between the access end of the external AC power supply and the power supply end of the motor; the servo drive has at least a rectifier unit, a pre-charging circuit, a bus capacitor unit and an inverter unit arranged in sequence, that is, between the output end of the rectifier unit and the bus capacitor unit, a pre-charging circuit of the bus capacitor unit is arranged; the pre-charging circuit includes: a pre-charging resistor module and a switch module, the pre-charging resistor module is such as a pre-charging resistor R1, the switch module is such as a relay RLY1, the pre-charging resistor module is arranged between the output end of the rectifier unit and the bus capacitor unit, the contacts of the switch module are connected in parallel with the pre-charging resistor module, preferably the normally open contacts of the switch module are connected in parallel with the pre-charging resistor module; in the scheme of the present invention, Figure 1 As shown, the control device of the servo drive includes: a first sampling unit, a second sampling unit and a control unit. The first sampling unit is such as a voltage sampling circuit 1, the second sampling unit is such as a voltage sampling circuit 2, and the control unit is such as a main control chip CPU. Figure 2 is a structural schematic diagram of an embodiment of a pre-charging control circuit of a busbar electrolytic capacitor in a servo drive in a related solution, Figure 3 FIG. 1 is a schematic diagram of a pre-charging control circuit for a busbar electrolytic capacitor in a servo drive of the present invention. Figure 3 The pre-charging control circuit of the bus electrolytic capacitor in the servo drive shown in the figure is Figure 2In the scheme shown, the voltage sampling circuit 1 monitors the voltage V1 on the busbar electrolytic capacitor array in real time, and a voltage sampling circuit 2 is added; the resistor R3 is the voltage dividing resistor of the voltage sampling circuit 1, and the resistor R4 is the voltage dividing resistor of the voltage sampling circuit 2. The voltage sampling circuit 2 is used to monitor the DC voltage V2 of the rear end DC+ of the rectifier bridge in real time.

[0031] Among them, the first sampling unit is arranged at one end of the contact of the switch module connected to the input end of the bus capacitor unit, specifically, between the contact of the switch module and the bus capacitor unit, and is used to sample the voltage on the bus capacitor unit, which is recorded as the first voltage on the first side of the contact of the switch module, such as voltage V1.

[0032] The second sampling unit is arranged at an end connected to the output end of the rectifier unit and the contact of the switch module, specifically between the output end of the rectifier unit and the contact of the switch module, and is used to sample the DC voltage at the output end of the rectifier unit, which is recorded as the second voltage on the second side of the contact of the switch module, such as voltage V2.

[0033] The control unit is connected to the control end of the switch module, and is used to dynamically adjust a preset bus voltage threshold when the contacts of the switch module are actuated according to a second voltage on the second side of the contacts of the switch module and a first voltage on the first side of the contacts of the switch module, so that the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module after adjustment is within a set voltage range.

[0034] The scheme of the present invention proposes a control scheme for a bus electrolytic capacitor pre-charging circuit that dynamically adjusts the bus voltage threshold when the relay is closed according to the voltage of the servo drive power supply. The bus electrolytic capacitor charging voltage is monitored in real time to determine whether the voltage on the bus electrolytic capacitor reaches the relay contact closing or disconnecting threshold condition; at the same time, a monitoring circuit for real-time monitoring the voltage of the servo drive three-phase power supply is added, and the bus voltage threshold when the relay contact in the pre-charging circuit of the servo drive is closed or disconnected is dynamically adjusted according to the voltage change of the servo drive three-phase power supply, so as to avoid the problem that the bus voltage threshold is too low or too high when the relay in the pre-charging circuit of the servo drive (especially the AC servo drive) is closed, which affects the reliability of the relay operation, and then affects the reliability of the servo drive operation, which is conducive to improving the reliability of the relay operation and the reliability of the servo drive operation.

[0035] In some embodiments, the switch module includes: a relay module, such as a normally open contact large relay RLY1; the contacts of the relay module are used as the contacts of the switch module; the control end of the coil of the relay module is used as the control end of the switch module; wherein the contact action of the switch module refers to the closing or opening of the contacts of the relay module. In the solution of the present invention, the relay module is used as the switch module, which makes the control simpler and more reliable.

[0036] In some embodiments, in the servo drive, a regenerative braking circuit is also provided between the bus capacitor unit and the inverter unit; the regenerative braking circuit includes: a diode module, a discharge resistor module and a brake switch tube module, the diode module is such as a reverse diode D1, the discharge resistor module is such as a regenerative discharge resistor R2, and the brake switch tube module is such as a regenerative braking IGBT switch tube K1.

[0037] The diode module is connected in parallel with the discharge resistor module, and the cathode of the diode module is connected to the positive end of the bus capacitor unit; the anode of the diode module is connected to the first connection end of the brake switch module, and the second connection end of the brake switch module is connected to the negative end of the bus capacitor unit. The first connection end of the brake switch module is such as the anode of the diode module and the collector of the regenerative brake IGBT switch K1; the second connection end of the brake switch module is such as the anode of the diode module and the emitter of the regenerative brake IGBT switch K1.

[0038] The solution of the present invention provides a pre-charging control circuit for a busbar electrolytic capacitor in a servo drive. Figure 2 The pre-charging control circuit of the bus electrolytic capacitor in the servo drive shown in FIG. 1 includes: a three-phase rectifier bridge U1, a normally open contact large relay RLY1, a PTC resistor R1, a bus voltage sampling circuit (such as Figure 2The voltage sampling circuit 1), bus electrolytic capacitor array, regenerative discharge resistor R2, regenerative braking IGBT switch K1, inverter power module U2, servo motor and other devices. Among them, the three-phase rectifier bridge U1 is connected to a three-phase input power supply (such as a three-phase AC input power supply input from L1, L2, and L3) and is used to rectify the three-phase AC input power supply into a DC bus power supply. The rectified voltage is DC+ (i.e., the voltage at the rear end of the three-phase rectifier bridge U1). The PTC resistor R1 and the normally open contact large relay RLY1 form a pre-charge circuit, which is used to prevent the components at the rear end of the three-phase rectifier bridge U1 from being damaged by excessive inrush current when the servo driver is powered on. The energy storage electrolytic capacitors C1, C2, C3, C4, C5, and C6 form a bus electrolytic capacitor array. The rectified voltage DC+ charges the bus electrolytic capacitor array through the PTC resistor R1; DCP is the positive terminal of the bus voltage on the bus electrolytic capacitor array, and PGND is the negative terminal of the bus voltage.

[0039] The voltage sampling circuit 1 monitors the voltage V1 on the bus electrolytic capacitor array in real time. The resistor R3 is the voltage dividing resistor of the voltage sampling circuit 1. When the voltage V1 on the bus electrolytic capacitor array rises to a certain voltage but is less than the rectified voltage DC+ (V1 < DC+), the normally open contact large relay RLY1 closes, and the rectified voltage DC+ at the rear end of the rectifier bridge charges the bus electrolytic capacitor through the normally open contact large relay RLY1 and provides continuous current for the inverter power module U2 and the servo motor at the rear end. A regenerative braking circuit is provided between the bus electrolytic capacitor array and the inverter power module U2. The regenerative braking circuit includes a regenerative braking resistor R2, a regenerative braking IGBT switch K1, and a reverse diode D1. The reverse diode D1 serves as a freewheeling diode for the regenerative discharge circuit; the regenerative braking resistor R2 is connected in parallel with the reverse diode D1. The cathode of the reverse diode D1 is connected to the positive terminal DCP of the bus voltage on the bus electrolytic capacitor array, the anode of the reverse diode D1 is connected to the collector of the regenerative braking IGBT switch K1, and the emitter of the regenerative braking IGBT switch K1 is connected to the negative terminal PGND of the bus voltage on the bus electrolytic capacitor array. There are 6 IGBT tubes with freewheeling diodes in the inverter power module U2, such as IGBT tube T1, IGBT tube T2, IGBT tube T3, IGBT tube T4, IGBT tube T5, and IGBT tube T6. U, V, and W are the input leads of the three-phase servo motor. When the servo motor decelerates and stops, the energy on the servo motor charges the bus electrolytic capacitor array through the freewheeling diodes in the inverter power module U2. When the voltage on the bus electrolytic capacitor array is higher than a certain threshold, it discharges through the regenerative braking resistor R2 and the regenerative braking IGBT switch K1.

[0040] Because the servo drive needs to operate under the condition of ±15% fluctuation of the rated power supply, for example, for a servo drive powered by three-phase 380VAC (i.e. 380V three-phase AC voltage), the normal value of the bus voltage is 537VDC (i.e. 537V DC voltage), and the servo drive can operate under the condition of ±15% fluctuation of the three-phase power supply 380VAC, that is, the bus voltage operates in the range of 459VDC to 618VDC. In order to enable the servo drive to operate normally under -15% power supply voltage, the bus voltage V1 when the large relay RLY1 is closed cannot exceed 457VDC. Because the bus voltage threshold when the relay contact in the pre-charging circuit of the servo drive is set too high when it is closed or disconnected, when the grid voltage fluctuates, considering that the voltage sampling has a certain error fluctuation, if the bus voltage V1 when the normally open contact large relay RLY1 contact is closed is set to 450VDC, then when the power supply is normal, the bus voltage is 537VDC, and the voltage difference between the two ends of the normally open contact large relay RLY1 contact is 537VDC-450VDC=87VDC. When the bus voltage is +15% of 537VDC, the voltage difference across the contacts of the normally open large relay RLY1 is 618VDC-450VDC=168VDC. That is, when the normally open large relay RLY1 is closed, the voltage difference across the contacts of the normally open large relay RLY1 is within the range of 87VDC-168VDC. Such a large voltage difference will charge the bus electrolytic capacitor array, which will generate a large impact current. Excessive impact current will greatly reduce the durability of the normally open large relay RLY1; for a long time, the normally open large relay RLY1 will cause the contacts to stick, causing the circuit breaker inside the cabinet to trip as soon as the servo drive is powered on, causing the servo drive to fail to work properly. The voltage difference across the contacts of the relay (such as the normally open large relay RLY1) recommended by the manufacturer is below 60VDC when the relay contacts are closed, and the smaller the better. If the bus voltage V1 is set to be greater than 457VDC when the normally open contact large relay RLY1 contacts are closed, for example, when the bus voltage V1 is 465VDC, it is possible that when the voltage fluctuates at -15% of 380VAC, that is, at 457VDC, the bus voltage threshold when the normally open contact large relay RLY1 is closed is higher than the bus voltage corresponding to the lowest limit of the power supply voltage, and the normally open contact large relay RLY1 will never be closed, and the servo drive will not work properly.

[0041] In the solution of the present invention, a regenerative braking circuit is also provided between the bus capacitor unit and the inverter unit, which is used to discharge the bus electrolytic capacitor array through the regenerative braking circuit when the voltage on the bus electrolytic capacitor array exceeds a certain threshold value during the process of charging the bus electrolytic capacitor array with the energy on the servo motor through the freewheeling diode in the inverter power module U2 when the servo motor is decelerating or stopping, thereby ensuring safety.

[0042] In some embodiments, the control unit dynamically adjusts a preset bus voltage threshold when the contact of the switch module is actuated according to a second voltage on the second side of the contact of the switch module and a first voltage on the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range, including:

[0043] The control unit is further configured to determine the magnitude relationship between the second voltage on the second side of the switch module contact and the first voltage on the first side of the switch module contact, and determine the difference between the second voltage on the second side of the switch module contact and the first voltage on the first side of the switch module contact. And,

[0044] The control unit is further specifically used to dynamically adjust a preset bus voltage threshold when the contacts of the switch module are actuated according to a magnitude relationship between a second voltage on the second side of the contacts of the switch module and a first voltage on the first side of the contacts of the switch module, and a voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module, so that after adjustment, the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module is within a set voltage range.

[0045] In the scheme of the present invention, the bus voltage threshold preset when the contact of the switch module is actuated is dynamically adjusted according to the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range, thereby avoiding the problem that the bus voltage threshold is too low or too high when the relay in the pre-charging circuit of the servo drive (especially the AC servo drive) is closed, affecting the reliability of the relay operation, and then affecting the reliability of the servo drive operation, which is beneficial to improving the reliability of the relay operation and improving the reliability of the servo drive operation. For example: avoid the situation where the bus voltage threshold is too low when the relay in the pre-charging circuit of the servo drive is closed, the voltage difference across the relay contacts is too large, resulting in excessive impact current at the moment the relay is closed, reduced relay durability, adhesion damage to the relay contacts, and the servo drive cannot work properly; or avoid the situation where the bus voltage threshold is too high when the relay in the pre-charging circuit of the servo drive is closed, and the voltage of the servo drive power supply fluctuates within a reasonable range to the minimum voltage limit of the power supply. When the closing threshold of the relay is higher than the bus voltage corresponding to the minimum voltage limit of the power supply, the relay can never be closed, and the servo drive cannot work properly.

[0046] In some embodiments, the control unit dynamically adjusts the preset bus voltage threshold when the contact of the switch module is actuated according to the magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range, including any of the following adjustment situations:

[0047] The first adjustment scenario: the control unit is specifically used to increase the preset bus voltage threshold when the contacts of the switch module are actuated if the second voltage on the second side of the contacts of the switch module is greater than the first voltage on the first side of the contacts of the switch module, and the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module is greater than the upper limit of the set voltage range, so that the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module after adjustment is within the set voltage range.

[0048] The second adjustment scenario: the control unit is specifically used to lower the preset bus voltage threshold when the contacts of the switch module are actuated if the second voltage on the second side of the contacts of the switch module is less than the first voltage on the first side of the contacts of the switch module, and the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module is greater than the upper limit of the set voltage range, so that the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module after adjustment is within the set voltage range.

[0049] The solution of the present invention is to add a bus monitoring circuit (i.e., voltage sampling circuit 2) at the rear end of the three-phase rectifier bridge U1 to monitor the voltage of the three-phase power supply of the servo driver in real time, and dynamically adjust the bus voltage threshold when the relay contacts in the pre-charging circuit in the servo driver are closed or disconnected according to the voltage change of the power supply, so as to avoid the problem that the bus voltage threshold is too low when the relay in the pre-charging circuit in the servo driver is closed, the voltage difference across the relay contacts is too large, resulting in excessive impact current at the moment of relay closing, reduced relay durability, adhesion damage to the relay contacts, and the servo driver cannot work normally; or avoid the problem that the bus voltage threshold is too high when the relay in the pre-charging circuit in the servo driver is closed, the voltage of the servo driver power supply fluctuates to the lowest voltage limit of the power supply within a reasonable range, and the closing threshold of the relay is higher than the bus voltage corresponding to the lowest voltage limit of the power supply, the relay can never be closed, and the servo driver cannot work normally. Thus, the problem that when the relay in the pre-charging circuit in the servo drive is closed, the bus voltage threshold is too low, the voltage difference across the relay contacts is too large, the impact current flowing through the relay contacts at the moment the relay is closed is relatively large, the durability of the relay is reduced after long-term use, the relay contacts will stick, the relay will be damaged, and the servo drive cannot work properly is solved; the problem that when the relay in the pre-charging circuit in the servo drive is closed, the bus voltage threshold is too high, the voltage difference across the relay contacts is too small, the bus electrolytic capacitor array charging time is relatively long when the servo drive is initially powered on or restarted after power failure, and the waiting time for the relay to close is relatively long, which seriously affects the customer's user experience and reduces production efficiency at the same time is solved; the problem that when the relay in the pre-charging circuit in the servo drive is closed, the bus voltage threshold is too high, when the power supply to the servo drive fluctuates within a reasonable range, when the power supply fluctuates to the lowest voltage limit of the power supply, the closing threshold of the relay is higher than the bus voltage corresponding to the lowest voltage limit of the power supply, the relay can never be closed, and the servo drive cannot work properly is solved.

[0050] In some embodiments, the control unit increases the preset bus voltage threshold when the contact of the switch module is actuated, including:

[0051] The control unit is further specifically used to determine the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the upper limit of the set voltage range or the lower limit of the set voltage range, which is recorded as the first difference.

[0052] The control unit is further specifically used to increase the bus voltage threshold preset when the contacts of the switch module are actuated by the first difference value to obtain a new bus voltage threshold preset when the contacts of the switch module are actuated.

[0053] Specifically, the control unit, for the first adjustment situation, when the second voltage on the second side of the contact of the switch module is greater than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, adjusts the bus voltage threshold preset when the contacts of the switch module are actuated higher, including: determining the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the upper limit of the set voltage range, recorded as the first difference; and increasing the bus voltage threshold preset when the contacts of the switch module are actuated by the first difference to obtain a new bus voltage threshold preset when the contacts of the switch module are actuated.

[0054] Alternatively, the control unit, for the fourth adjustment scenario, when the second voltage on the second side of the contact of the switch module is less than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is less than the lower limit of the set voltage range, adjusts the bus voltage threshold preset when the contact of the switch module is actuated higher, including: determining the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the lower limit of the set voltage range, recorded as the first difference; and increasing the bus voltage threshold preset when the contact of the switch module is actuated by the first difference to obtain a new bus voltage threshold preset when the contact of the switch module is actuated.

[0055] And / or, the control unit lowers a preset bus voltage threshold when the contact of the switch module is actuated, comprising:

[0056] The control unit is further specifically used to determine the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the upper limit of the set voltage range or the lower limit of the set voltage range, which is recorded as the second difference.

[0057] The control unit is further specifically used to adjust the bus voltage threshold preset when the contacts of the switch module are actuated lower by the second difference value to obtain a new bus voltage threshold preset when the contacts of the switch module are actuated.

[0058] Specifically, for the second adjustment scenario, when the second voltage on the second side of the contact of the switch module is greater than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side and the first side of the contact of the switch module is less than the lower limit of the set voltage range, the control unit lowers the preset bus voltage threshold when the contact of the switch module operates, including: determining the difference between the voltage difference between the second side and the first side of the contact of the switch module and the lower limit of the set voltage range, denoted as the second difference; lowering the preset bus voltage threshold when the contact of the switch module operates by the second difference to obtain the new preset bus voltage threshold when the contact of the switch module operates.

[0059] Alternatively, for the second adjustment scenario, when the second voltage on the second side of the contact of the switch module is less than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the control unit lowers the preset bus voltage threshold when the contact of the switch module operates, including: determining the difference between the voltage difference between the second side and the first side of the contact of the switch module and the upper limit of the set voltage range, denoted as the second difference; lowering the preset bus voltage threshold when the contact of the switch module operates by the second difference to obtain the new preset bus voltage threshold when the contact of the switch module operates.

[0060] In the Figure 3 pre-charge control circuit of the bus electrolytic capacitor in the servo drive shown, the voltage sampling circuit 2 is used to monitor the DC voltage V2 of DC+ at the back end of the rectifier bridge in real time. Before the normally open contact of the large relay RLY1 closes, V1 < V2. Dynamically adjust the bus voltage threshold when the normally open contact of the large relay RLY1 closes or opens. According to the manufacturer's suggestion of the relay (such as the large relay RLY1 with normally open contacts), the voltage difference across the relay contacts when the relay contacts close is below 60 VDC, and the smaller the better. Set V1 = V2 - 10V, that is, when the voltage V1 for charging the electrolytic capacitor through the PTC resistor R1 rises to V2 - 10V, control the main chip (such as the CPU chip) to make the normally open contact of the large relay RLY1 close. At this time, the voltage difference across the normally open contact of the large relay RLY1 is 10V, which is relatively small, and the current flowing through the normally open contact of the large relay RLY1 is relatively small, so the normally open contact of the large relay RLY1 will not stick. Compared with Figure 2 the control scheme of the normally open contact of the large relay RLY1 in the scheme shown, the servo drive has higher reliability and more stable operation. Among them, the normally open contact of the large relay RLY1 is made of metal material, such as silver-nickel alloy AgNi, and the contacts will stick when the current is too large.

[0061] In the scheme of the present invention, the preset bus voltage threshold value when the contact of the switch module is actuated is adjusted up or down according to the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the upper limit of the set voltage range or the lower limit of the set voltage range, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range, thereby avoiding the problem that when the relay in the pre-charging circuit in the servo drive is closed, the bus voltage threshold value is too low, the voltage difference across the relay contact is too large, resulting in excessive impact current at the moment of relay closing, reduced relay durability, adhesion damage to the relay contact, and the servo drive cannot work normally; or avoiding the problem that when the relay in the pre-charging circuit in the servo drive is closed, the bus voltage threshold value is too high, the voltage of the servo drive power supply fluctuates to the lowest voltage limit of the power supply within a reasonable range, and the closing threshold of the relay is higher than the bus voltage corresponding to the lowest voltage limit of the power supply, the relay can never be closed, and the servo drive cannot work normally.

[0062] According to the technical solution of the present invention, a pre-charging circuit of the bus capacitor unit is provided between the rectifier unit and the bus capacitor unit for a servo driver composed of at least a rectifier unit, a bus capacitor unit and an inverter unit. The pre-charging circuit is composed of a pre-charging resistor and a relay. The pre-charging resistor is provided between the output end of the rectifier unit and the input end of the bus capacitor unit. The normally open contact of the relay is connected in parallel with the pre-charging resistor. The control end of the coil of the relay is controlled by the control unit. A first sampling unit is provided at one end of the relay normally open contact connected to the bus capacitor unit for detecting the bus voltage of the bus capacitor unit as the first voltage. A second sampling unit is provided at one end of the relay normally open contact connected to the rectifier unit for detecting the direct current at the output end of the rectifier unit. The flow voltage is recorded as the second voltage; after the servo drive is powered on, the bus voltage threshold when the normally open contact of the relay is closed or disconnected is dynamically adjusted according to the difference between the second voltage and the first voltage, so that the voltage difference across the normally open contact of the relay is within the set voltage range; thereby, the bus voltage threshold when the relay is closed or disconnected is dynamically adjusted according to the voltage difference across the contacts of the relay in the pre-charging circuit of the bus capacitor unit in the servo drive, so that the voltage difference across the contacts of the relay is within the set voltage range, thereby avoiding the bus voltage threshold being too low or too high when the relay is closed, which affects the reliability of the relay and then affects the reliability of the servo drive, which is beneficial to improving the reliability of the relay and the reliability of the servo drive.

[0063] According to an embodiment of the present invention, a motor corresponding to a control device of a servo drive is also provided. The motor may include: the control device of the servo drive described above.

[0064] Since the processing and functions implemented by the motor of this embodiment basically correspond to the embodiments, principles and examples of the device, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0065] According to an embodiment of the present invention, a control method for a servo driver of a motor corresponding to the motor is also provided. Figure 4 The control method of the servo driver of the motor may include: steps S110 to S130.

[0066] In step S110, the voltage on the bus capacitor unit is sampled and recorded as a first voltage on a first side of the contact of the switch module, such as voltage V1.

[0067] In step S120, the DC voltage at the output end of the rectifier unit is sampled and recorded as a second voltage on the second side of the contact of the switch module, such as voltage V2.

[0068] At step S130, a preset bus voltage threshold when the contacts of the switch module are actuated is dynamically adjusted according to a second voltage on the second side of the contacts of the switch module and a first voltage on the first side of the contacts of the switch module, so that the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module after adjustment is within a set voltage range.

[0069] The scheme of the present invention proposes a control scheme for a bus electrolytic capacitor pre-charging circuit that dynamically adjusts the bus voltage threshold when the relay is closed according to the voltage of the servo drive power supply. The bus electrolytic capacitor charging voltage is monitored in real time to determine whether the voltage on the bus electrolytic capacitor reaches the relay contact closing or disconnecting threshold condition; at the same time, a monitoring circuit for real-time monitoring the voltage of the servo drive three-phase power supply is added, and the bus voltage threshold when the relay contact in the pre-charging circuit of the servo drive is closed or disconnected is dynamically adjusted according to the voltage change of the servo drive three-phase power supply, so as to avoid the problem that the bus voltage threshold is too low or too high when the relay in the pre-charging circuit of the servo drive (especially the AC servo drive) is closed, which affects the reliability of the relay operation, and then affects the reliability of the servo drive operation, which is conducive to improving the reliability of the relay operation and the reliability of the servo drive operation.

[0070] In some embodiments, in step S130, a preset bus voltage threshold is dynamically adjusted when the contacts of the switch module are actuated according to a second voltage on the second side of the contacts of the switch module and a first voltage on the first side of the contacts of the switch module, so that the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module after adjustment is within a set voltage range. For the specific process, see the following exemplary description.

[0071] Combine the following Figure 5 The flowchart of an embodiment of the method of the present invention for dynamically adjusting the preset bus voltage threshold when the contact of the switch module is actuated is shown, which further illustrates the specific process of dynamically adjusting the preset bus voltage threshold when the contact of the switch module is actuated in step S130, including: step S210 to step S220.

[0072] Step S210, determining the magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, and determining the difference between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module. And,

[0073] Step S220, dynamically adjusting a preset bus voltage threshold when the contacts of the switch module are actuated according to a magnitude relationship between a second voltage on the second side of the contacts of the switch module and a first voltage on the first side of the contacts of the switch module, and a voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module, so that after adjustment, the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module is within a set voltage range.

[0074] In the scheme of the present invention, the bus voltage threshold preset when the contact of the switch module is actuated is dynamically adjusted according to the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range, thereby avoiding the problem that the bus voltage threshold is too low or too high when the relay in the pre-charging circuit of the servo drive (especially the AC servo drive) is closed, affecting the reliability of the relay operation, and then affecting the reliability of the servo drive operation, which is beneficial to improving the reliability of the relay operation and improving the reliability of the servo drive operation. For example: avoid the situation where the bus voltage threshold is too low when the relay in the pre-charging circuit of the servo drive is closed, the voltage difference across the relay contacts is too large, resulting in excessive impact current at the moment the relay is closed, reduced relay durability, adhesion damage to the relay contacts, and the servo drive cannot work properly; or avoid the situation where the bus voltage threshold is too high when the relay in the pre-charging circuit of the servo drive is closed, and the voltage of the servo drive power supply fluctuates within a reasonable range to the minimum voltage limit of the power supply. When the closing threshold of the relay is higher than the bus voltage corresponding to the minimum voltage limit of the power supply, the relay can never be closed, and the servo drive cannot work properly.

[0075] In some embodiments, in step S220, according to the magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module, the preset bus voltage threshold value when the contact of the switch module is actuated is dynamically adjusted so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range, including any of the following adjustment situations:

[0076] The first adjustment scenario: if the second voltage on the second side of the contact of the switch module is greater than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the preset bus voltage threshold when the contact of the switch module is actuated is adjusted higher so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range.

[0077] The second adjustment situation: if the second voltage on the second side of the contact of the switch module is less than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the preset bus voltage threshold when the contact of the switch module is actuated is adjusted lower, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range. Among them, the corresponding voltage difference values ​​are all directional voltage differences.

[0078] The solution of the present invention is to add a bus monitoring circuit (i.e., voltage sampling circuit 2) at the rear end of the three-phase rectifier bridge U1 to monitor the voltage of the three-phase power supply of the servo driver in real time, and dynamically adjust the bus voltage threshold when the relay contacts in the pre-charging circuit in the servo driver are closed or disconnected according to the voltage change of the power supply, so as to avoid the problem that the bus voltage threshold is too low when the relay in the pre-charging circuit in the servo driver is closed, the voltage difference across the relay contacts is too large, resulting in excessive impact current at the moment of relay closing, reduced relay durability, adhesion damage to the relay contacts, and the servo driver cannot work normally; or avoid the problem that the bus voltage threshold is too high when the relay in the pre-charging circuit in the servo driver is closed, the voltage of the servo driver power supply fluctuates to the lowest voltage limit of the power supply within a reasonable range, and the closing threshold of the relay is higher than the bus voltage corresponding to the lowest voltage limit of the power supply, the relay can never be closed, and the servo driver cannot work normally. Thus, the problem that when the relay in the pre-charging circuit in the servo drive is closed, the bus voltage threshold is too low, the voltage difference across the relay contacts is too large, the impact current flowing through the relay contacts at the moment the relay is closed is relatively large, the durability of the relay is reduced after long-term use, the relay contacts will stick, the relay will be damaged, and the servo drive cannot work properly is solved; the problem that when the relay in the pre-charging circuit in the servo drive is closed, the bus voltage threshold is too high, the voltage difference across the relay contacts is too small, the bus electrolytic capacitor array charging time is relatively long when the servo drive is initially powered on or restarted after power failure, and the waiting time for the relay to close is relatively long, which seriously affects the customer's user experience and reduces production efficiency at the same time is solved; the problem that when the relay in the pre-charging circuit in the servo drive is closed, the bus voltage threshold is too high, when the power supply to the servo drive fluctuates within a reasonable range, when the power supply fluctuates to the lowest voltage limit of the power supply, the closing threshold of the relay is higher than the bus voltage corresponding to the lowest voltage limit of the power supply, the relay can never be closed, and the servo drive cannot work properly is solved.

[0079] In some embodiments, the specific process of increasing the preset bus voltage threshold when the contacts of the switch module are actuated in step S220 is described in the following exemplary embodiments.

[0080] Combine the following Figure 6 The flowchart of an embodiment of the method of the present invention for raising the preset bus voltage threshold when the contacts of the switch module are actuated is shown, further illustrating the specific process of raising the preset bus voltage threshold when the contacts of the switch module are actuated, including: step S310 to step S320.

[0081] Step S310: Determine the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the upper limit of the set voltage range or the lower limit of the set voltage range, and record it as the first difference.

[0082] Step S320: increasing the bus voltage threshold preset when the contacts of the switch module are actuated by the first difference value to obtain a new bus voltage threshold preset when the contacts of the switch module are actuated.

[0083] Specifically, in step S310 and step S320, for the first adjustment situation, when the second voltage on the second side of the contact of the switch module is greater than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the bus voltage threshold preset when the contact of the switch module is actuated is adjusted higher, including: determining the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the upper limit of the set voltage range, recorded as the first difference; and increasing the bus voltage threshold preset when the contact of the switch module is actuated by the first difference to obtain a new bus voltage threshold preset when the contact of the switch module is actuated.

[0084] Alternatively, in step S310 and step S320, for the fourth adjustment scenario, when the second voltage on the second side of the contact of the switch module is less than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is less than the lower limit of the set voltage range, the bus voltage threshold preset when the contact of the switch module is actuated is adjusted higher, including: determining the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the lower limit of the set voltage range, recorded as the first difference; raising the bus voltage threshold preset when the contact of the switch module is actuated by the first difference to obtain a new bus voltage threshold preset when the contact of the switch module is actuated

[0085] And / or, the specific process of lowering the preset bus voltage threshold when the contacts of the switch module are actuated in step S220 is described in the following exemplary description.

[0086] Combine the following Figure 7 The flowchart of an embodiment of lowering the preset bus voltage threshold when the contacts of the switch module are actuated in the method of the present invention is shown, further illustrating the specific process of lowering the preset bus voltage threshold when the contacts of the switch module are actuated, including: step S410 to step S420.

[0087] Step S410: Determine the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the upper limit of the set voltage range or the lower limit of the set voltage range, and record it as the second difference.

[0088] Step S420, lowering the bus voltage threshold preset when the contact of the switch module is actuated by the second difference to obtain a new bus voltage threshold preset when the contact of the switch module is actuated.

[0089] Specifically, in step S410 and step S420, for the second adjustment scenario, when the second voltage on the second side of the contact of the switch module is greater than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is less than the lower limit of the set voltage range, the bus voltage threshold preset when the contact of the switch module is actuated is lowered, including: determining the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the lower limit of the set voltage range, recorded as the second difference; lowering the bus voltage threshold preset when the contact of the switch module is actuated by the second difference, to obtain a new bus voltage threshold preset when the contact of the switch module is actuated.

[0090] Alternatively, in step S410 and step S420, for the second adjustment scenario, when the second voltage on the second side of the contact of the switch module is less than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the bus voltage threshold preset when the contact of the switch module is actuated is lowered, including: determining the difference between the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and the upper limit of the set voltage range, recorded as the second difference; lowering the bus voltage threshold preset when the contact of the switch module is actuated by the second difference, to obtain a new bus voltage threshold preset when the contact of the switch module is actuated.

[0091] In such Figure 3In the pre-charge control circuit of the DC link electrolytic capacitor of the servo drive shown, the voltage sampling circuit 2 is used to monitor the DC voltage V2 of DC+ at the back end of the rectifier bridge in real time. Before the normally open contact of the large relay RLY1 closes, the voltage V1 < V2. Dynamically adjust the bus voltage threshold when the normally open contact of the large relay RLY1 closes or opens. According to the recommendations of the relay manufacturer (such as the large relay RLY1 with normally open contacts), the voltage difference across the relay contacts is below 60 VDC when the relay contacts close, and the smaller the better. Set V1 = V2 - 10V. That is, when the voltage V1 for charging the electrolytic capacitor through the PTC resistor R1 rises to V2 - 10V, control the main chip (such as the CPU chip) to make the normally open contact of the large relay RLY1 close. At this time, the voltage difference across the normally open contact of the large relay RLY1 is 10V, which is relatively small, and the current flowing through the normally open contact of the large relay RLY1 is relatively small, so the normally open contact of the large relay RLY1 will not stick. Compared with Figure 2 the control scheme of the large relay RLY1 with normally open contacts in the scheme shown, the servo drive has higher reliability and more stable operation. Among them, the normally open contact of the large relay RLY1 is made of a metal material, such as silver-nickel alloy AgNi, and it will stick when the current is too large.

[0092] In the solution of the present invention, by adjusting the preset bus voltage threshold when the contact of the switch module operates according to the difference between the voltage difference between the second side and the first side of the contact of the switch module and the upper limit or the lower limit of the set voltage range, so that after adjustment, the voltage difference between the second side and the first side of the contact of the switch module is within the set voltage range, avoiding the problem that when the relay in the pre-charge circuit of the servo drive closes, the bus voltage threshold is too low, the voltage difference across the relay contacts is too large, resulting in too large an impact current when the relay closes, reduced durability of the relay, sticking and damage of the relay contacts, and the servo drive cannot work properly; or avoiding the problem that when the relay in the pre-charge circuit of the servo drive closes, the bus voltage threshold is too high, and when the voltage of the power supply of the servo drive fluctuates within a reasonable range to the lowest limit of the power supply voltage, and the closing threshold of the relay is higher than the bus voltage corresponding to the lowest limit of the power supply voltage, the relay can never close and the servo drive cannot work properly.

[0093] Since the processing and functions implemented by the method of this embodiment are basically corresponding to the foregoing embodiments, principles and examples of the motor, for the details not described in the description of this embodiment, reference can be made to the relevant descriptions in the foregoing embodiments and will not be elaborated here.

[0094] In summary, it is easy for those skilled in the art to understand that, on the premise of no conflict, the above-mentioned advantageous ways can be freely combined and superimposed.

[0095] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A control device for a servo drive, characterized in that: The servo driver is arranged between the input terminal of the external AC power supply and the power supply terminal of the motor; The servo driver at least comprises a rectifier unit, a pre-charging circuit, a bus capacitor unit and an inverter unit which are arranged in sequence; The pre-charging circuit comprises: a pre-charging resistor module and a switch module, wherein the pre-charging resistor module is arranged between the output end of the rectifier unit and the bus capacitor unit, and the contact of the switch module is connected in parallel with the pre-charging resistor module; the control device of the servo drive comprises: a first sampling unit, a second sampling unit and a control unit; wherein, The first sampling unit is used to sample the voltage on the bus capacitor unit, which is recorded as the first voltage on the first side of the contact of the switch module; The second sampling unit is used to sample the DC voltage at the output end of the rectifying unit, which is recorded as the second voltage on the second side of the contact of the switch module; The control unit is used to dynamically adjust a preset bus voltage threshold when the contacts of the switch module are actuated according to a second voltage on the second side of the contacts of the switch module and a first voltage on the first side of the contacts of the switch module, so that the voltage difference between the second side of the contacts of the switch module and the first side of the contacts of the switch module after adjustment is within a set voltage range.

2. The control device of the servo drive according to claim 1, characterized in that: in, The switch module comprises: a relay module; a contact of the relay module, serving as a contact of the switch module; a control end of a coil of the relay module, serving as a control end of the switch module; wherein the contact action of the switch module refers to the closing or opening of the contact of the relay module; and / or, In the servo drive, a regenerative braking circuit is further provided between the bus capacitor unit and the inverter unit; the regenerative braking circuit comprises: a diode module, a discharge resistor module and a brake switch tube module; wherein, The diode module is connected in parallel with the discharge resistor module, and the cathode of the diode module is connected to the positive end of the bus capacitor unit; the anode of the diode module is connected to the first connection end of the brake switch tube module, and the second connection end of the brake switch tube module is connected to the negative end of the bus capacitor unit.

3. The control device of the servo drive according to claim 1 or 2, characterized in that: The control unit dynamically adjusts a preset bus voltage threshold when the contact of the switch module is actuated according to a second voltage on the second side of the contact of the switch module and a first voltage on the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range, including: Determine the magnitude relationship between a second voltage on the second side of the contact of the switch module and a first voltage on the first side of the contact of the switch module, and determine the difference between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module; and, According to the magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module, the bus voltage threshold preset when the contact of the switch module is actuated is dynamically adjusted so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range.

4. The control device of the servo drive according to claim 3, characterized in that: The control unit dynamically adjusts a preset bus voltage threshold when the contact of the switch module is actuated according to a magnitude relationship between a second voltage on the second side of the contact of the switch module and a first voltage on the first side of the contact of the switch module, and a voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range, including: If the second voltage on the second side of the contact of the switch module is greater than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the preset bus voltage threshold when the contact of the switch module is actuated is adjusted higher, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range; If the second voltage on the second side of the contact of the switch module is less than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the preset bus voltage threshold when the contact of the switch module is actuated is adjusted lower so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range.

5. The control device of the servo drive according to claim 4, characterized in that: in, The control unit adjusts the preset bus voltage threshold value when the contact of the switch module is actuated to increase, including: Determine a difference between a voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and an upper limit of a set voltage range or a lower limit of the set voltage range, and record it as a first difference; The bus voltage threshold preset when the contact of the switch module is actuated is increased by the first difference to obtain a new bus voltage threshold preset when the contact of the switch module is actuated; and / or, The control unit adjusts the preset bus voltage threshold value when the contact of the switch module is actuated to lower the bus voltage threshold value, including: Determine a difference between a voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and an upper limit of a set voltage range or a lower limit of the set voltage range, and record it as a second difference; The bus voltage threshold preset when the contact of the switch module is actuated is adjusted lower by the second difference to obtain a new bus voltage threshold preset when the contact of the switch module is actuated.

6. A motor, characterized in that: include: A control device for a servo drive according to any one of claims 1 to 5.

7. A control method for a servo driver of a motor as claimed in claim 6, characterized in that: include: Sampling the voltage on the bus capacitor unit and recording it as a first voltage on a first side of a contact of the switch module; Sampling a DC voltage at an output end of the rectifying unit, and recording the DC voltage as a second voltage at a second side of a contact of the switch module; According to the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, the preset bus voltage threshold when the contact of the switch module is actuated is dynamically adjusted so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range.

8. The control method of the servo driver of the motor according to claim 7, characterized in that: According to the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, dynamically adjusting the preset bus voltage threshold when the contact of the switch module is actuated, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range, including: Determine the magnitude relationship between a second voltage on the second side of the contact of the switch module and a first voltage on the first side of the contact of the switch module, and determine the difference between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module; and, According to the magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module, the bus voltage threshold preset when the contact of the switch module is actuated is dynamically adjusted so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range.

9. The control method of the servo driver of the motor according to claim 8, characterized in that: According to the magnitude relationship between the second voltage on the second side of the contact of the switch module and the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module, dynamically adjusting the preset bus voltage threshold when the contact of the switch module is actuated, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within a set voltage range, including: If the second voltage on the second side of the contact of the switch module is greater than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the preset bus voltage threshold when the contact of the switch module is actuated is adjusted higher, so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range; If the second voltage on the second side of the contact of the switch module is less than the first voltage on the first side of the contact of the switch module, and the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module is greater than the upper limit of the set voltage range, the preset bus voltage threshold when the contact of the switch module is actuated is adjusted lower so that the voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module after adjustment is within the set voltage range.

10. The control method of the servo driver of the motor according to claim 9, characterized in that: in, The preset bus voltage threshold value when the contact of the switch module is actuated is adjusted higher, including: Determine a difference between a voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and an upper limit of a set voltage range or a lower limit of the set voltage range, and record it as a first difference; The bus voltage threshold preset when the contact of the switch module is actuated is increased by the first difference to obtain a new bus voltage threshold preset when the contact of the switch module is actuated; and / or, Lowering the preset bus voltage threshold when the contact of the switch module is actuated, including: Determine a difference between a voltage difference between the second side of the contact of the switch module and the first side of the contact of the switch module and an upper limit of a set voltage range or a lower limit of the set voltage range, and record it as a second difference; The bus voltage threshold preset when the contact of the switch module is actuated is adjusted lower by the second difference to obtain a new bus voltage threshold preset when the contact of the switch module is actuated.

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