Power supply system of servomotor

Abstract

The power supply system includes: a servo amplifier; the power supply can be switched to output at least two voltages; the servo amplifier control circuit is connected with the power supply and controls the servo amplifier; a switch that opens and closes a circuit between the power source and the servo amplifier; a voltage comparison circuit that compares the voltage output by the power supply with a predetermined threshold value; and a switch control circuit for controlling the switch to open and close the circuit between the power supply and the servo amplifier according to the comparison result of the voltage comparison circuit.

Description

Technical Field

[0001] The present disclosure relates to a power supply system for a servo motor. Background Art

[0002] In a servo amplifier that drives a servo motor in a machine such as an industrial robot or a machine tool, a power supply for supplying power for driving the servo motor and a control power supply for supplying power for controlling the circuit of the servo amplifier are provided.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-162193

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2012-135164 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In order to ensure the safety of a machine driven by a servo amplifier, a power supply system is desired in which, when the servo motor is not driven, the energization of the drive power supply is cut off, and on the other hand, the energization of the control power supply is ensured in order to monitor the state of the servo motor.

[0009] Means for Solving the Problems

[0010] According to one aspect of the present disclosure, a power supply system includes: a servo amplifier; a power supply capable of switching and outputting at least two voltages of different magnitudes; a servo amplifier control circuit connected to the power supply for controlling the servo amplifier; a switch for opening and closing a circuit between the power supply and the servo amplifier; a voltage comparison circuit for comparing the voltage output from the power supply with a preset threshold value; and a switch control circuit for controlling the opening and closing of the circuit between the power supply and the servo amplifier by the switch according to the comparison result of the voltage comparison circuit. Brief Description of the Drawings

[0011] Figure 1 is a circuit diagram showing a power supply system according to an embodiment of the present disclosure.

[0012] Figure 2 is a circuit diagram showing a buck chopper circuit provided in a servo amplifier control circuit in a power supply system according to an embodiment of the present disclosure;

[0013] Figure 3 is a flowchart showing operations related to the opening and closing of a switch in a power supply system according to an embodiment of the present disclosure.

[0014] Figure 4It is a circuit diagram of a power supply system showing an existing example in which a power supply for power and a power supply for control are separately provided. Detailed Implementation Manner

[0015] Hereinafter, the power supply system of the servo motor according to the embodiment will be described with reference to the accompanying drawings. In addition, in the following description, structures having the same or similar functions are denoted by the same reference numerals. Also, repeated descriptions of these structures are sometimes omitted. Here, "connection" means "electrical connection". In addition, "turning on" of a switch means closing of the circuit in which the switch is provided, that is, by performing a turning-on operation of the switch, the circuit in which the switch is provided is connected and becomes a closed state. In addition, "turning off" of a switch means opening of the circuit in which the switch is provided, that is, by performing a turning-off operation of the switch, the circuit in which the switch is provided is cut off and becomes an open state.

[0016] <Configuration of the Power Supply System According to the Embodiment of the Present Disclosure>

[0017] Figure 1 It is a circuit diagram showing the power supply system according to the embodiment of the present disclosure.

[0018] As an example, a case where a three-phase AC motor 2 is driven by the power supplied from the power supply system 1 is shown. The motor 2 is a servo motor. The motor 2 can be, for example, a synchronous motor or an induction motor. Machines provided with the motor 2 include, for example, industrial robots, machine tools, and the like.

[0019] According to the first embodiment of the present disclosure, the power supply system 1 includes a servo amplifier 11, a power supply 12, a servo amplifier control circuit 13, a positive-side switch 14P, a negative-side switch 14N, a voltage comparison circuit 15, a switch control circuit 16, a positive-side potential detection unit 17P, a negative-side potential detection unit 17N, and a capacitor 18.

[0020] The power supply 12 can switch and output at least two magnitudes of DC voltages. Examples of the power supply 12 include, for example: a variable voltage source having a battery and an output switching switch, a variable voltage source having a battery and a variable resistor, and a PWM rectifier that converts AC power supplied from an AC power supply into DC power and outputs it. For example, when the power supply 12 is constituted by a PWM rectifier, the power supply 12 is constituted by a bridge circuit of a switching element and a diode reversely connected in parallel with the switching element, and outputs various magnitudes of DC voltages by performing on-off control of each switching element according to a received command. Examples of the switching element include unipolar transistors such as FETs, bipolar transistors, IGBTs, thyristors, GTOs, and the like. However, the type of the switching element itself does not limit this embodiment, and other switching elements may also be used.

[0021] For example, when the power supply 12 is configured to be able to switch between outputting two DC voltages of high voltage (e.g., 48V) and low voltage (e.g., 24V), the high voltage output by the power supply 12 is used as the driving voltage of the motor 2 and the driving voltage of the servo amplifier control circuit 13 when the motor 2 is driven by the servo amplifier 11. In addition, the low voltage output by the power supply 12 is used as the driving voltage of the servo amplifier control circuit 13 when the motor 2 is not driven by the servo amplifier 11. In addition, the switching between the high voltage and the low voltage output by the power supply 12 is performed in conjunction with whether the motor 2 is driven or not. Regarding the switching of whether the motor 2 is driven or not, sometimes the operator manually performs the command operation using the control operation panel, etc., and sometimes the motor control unit (not shown) performs the command according to the operation program of the motor 2. In addition, the power supply 12 may also be configured to output two or more voltages such as 100V, 48V, and 24V. In addition, the numerical value indicating the magnitude of the output voltage of the power supply 12 cited here is only an example, and other values ​​may also be used.

[0022] A capacitor 18 is connected between a positive DC power line 19P extending from a positive output terminal of the power source 12 and a negative DC power line 19N extending from a negative output terminal. The capacitor 18 has a function of suppressing the pulsation amount of the DC output of the power source 12 and a function of accumulating DC power. Examples of the capacitor 18 include an electrolytic capacitor, a film capacitor, and the like.

[0023] The servo amplifier 11 has an inverter composed of a bridge circuit of switching elements. Examples of switching elements include unipolar transistors such as FET, bipolar transistors, IGBTs, thyristors, GTOs, etc. However, the type of switching element itself is not limited to this embodiment, and other switching elements may also be used. Figure 1In the example shown, the switching element of the upper arm of the U phase is designated as Su1, and the switching element of the lower arm of the U phase is designated as Su2. In addition, the switching element of the upper arm of the V phase is designated as Sv1, and the switching element of the lower arm of the V phase is designated as Sv2. The switching element of the upper arm of the W phase is designated as Sw1, and the switching element of the lower arm of the W phase is designated as Sw2. Hereinafter, as an example, the case where the switching element is composed of a MOSFET will be described, but the embodiments of the present disclosure can also be applied to IGBTs, thyristors, GTOs, or transistors. In addition, in the case where the switching element is composed of an IGBT, the "drain" as the current inflow terminal is read as "collector", and the "source" as the current outflow terminal is read as "emitter", so as to apply the embodiments of the present disclosure. In addition, in the case where the switching element is composed of a transistor, the "gate" as the control terminal is read as "base", the "drain" as the current inflow terminal is read as "collector", and the "source" as the current outflow terminal is read as "emitter", so as to apply the embodiments of the present disclosure. In addition. In the case where the switching element is composed of a thyristor or a GTO, the "drain" as the current inflow terminal is read as "anode", and the "source" as the current outflow terminal is read as "cathode", so as to apply the embodiments of the present disclosure.

[0024] The servo amplifier 11 drives each switching element to be turned on and off based on the PWM control method according to the switching instruction received from the servo amplifier control circuit 13, thereby performing power conversion between the DC power and the AC power as the driving power or the regenerative power of the motor 2. More specifically, the servo amplifier 11 causes the internal switching element to perform a switching operation according to the switching instruction received from the servo amplifier control circuit 13, and converts the DC power supplied from the power supply 12 when the switches 14P and 14N are turned on into AC power having a desired frequency for driving the motor 2. Thus, the motor 2 operates based on, for example, the frequency-variable AC power. In addition, sometimes regenerative power is generated when the motor 2 decelerates, and the internal switching element is caused to perform a switching operation based on the switching instruction received from the servo amplifier control circuit 13, so as to convert the AC regenerative power generated in the motor 2 into DC power and return it to the DC side.

[0025] The servo amplifier control circuit 13 generates a switching instruction for controlling the on / off of each switching element and applies it to the gate terminal of each switching element. The servo amplifier control circuit 13 controls the power conversion of the inverter in the servo amplifier 11 according to a preset operation program, thereby performing control so that the motor 2 operates according to a predetermined operation mode. In addition, the structure of the servo amplifier control circuit 13 defined here is merely an example, and for example, it may also include terms such as a position command generation unit, a torque command generation unit, and a switching command generation unit to define the structure of the servo amplifier control circuit 13.

[0026] Power is supplied from the power supply 12 to the servo amplifier control circuit 13 via the positive-side DC power line 19P and the negative-side DC power line 19N. As described above, the power supply 12 can switch the output of at least two magnitudes of DC voltage. Thus, at least two magnitudes of DC voltage are input to the servo amplifier control circuit 13. On the other hand, the driving voltage of each circuit in the servo amplifier control circuit 13 is always constant regardless of the magnitude of the output voltage of the power supply 12. Therefore, a voltage conversion circuit for converting the voltage input from the power supply 12 into a driving voltage for driving the servo amplifier control circuit is provided in the servo amplifier control circuit 13.

[0027] For example, when the power supply 12 is configured to be able to switch the output of a high voltage of 48V and a low voltage of 24V, either 48V or 24V is input to the servo amplifier control circuit 13. The voltage conversion circuit in the servo amplifier control circuit 13 converts the input voltage of 48V or 24V from the power supply 12 into a driving voltage (such as 5V or 10V, etc.) for driving the servo amplifier control circuit. As an example of the voltage conversion circuit in the servo amplifier control circuit 13, for example, there are a buck chopper circuit, a boost chopper circuit, a buck-boost chopper circuit, and a combined circuit of a switching element and a voltage-dividing resistor, etc.

[0028] As an example, an example in which the voltage conversion circuit in the servo amplifier control circuit 13 is constituted by a buck chopper circuit will be described. Figure 2 It is a circuit diagram showing a buck chopper circuit provided in the servo amplifier control circuit in the power supply system of the embodiment of the present disclosure. As Figure 2 shown, in the servo amplifier control circuit 13, for example, a buck chopper circuit including a switching element 31, a diode 32, and an inductor 33 is provided as the voltage conversion circuit 21. As an example of the switching element 31, there are unipolar transistors such as FETs, bipolar transistors, IGBTs, thyristors, GTOs, etc. However, the type of the switching element 31 itself does not limit this embodiment, and other switching elements may also be used.

[0029] In Figure 2 the impedance of the circuit 40 located at the subsequent stage compared with the voltage conversion circuit 21 in the servo amplifier control circuit 13 is set to Z in . The input voltage E of the voltage conversion circuit 21 inis a DC voltage of, for example, 48V or 24V supplied from the power supply 12. In the voltage conversion circuit 21, energy is stored in the inductor 33 when the switching element 31 is turned on, and the energy stored in the inductor 33 is released when the switching element 31 is turned off. The longer the on-time of the switching element 31, the higher the output voltage of the voltage conversion circuit 21, and the shorter the on-time of the switching element 31, the lower the output voltage of the voltage conversion circuit 21. By controlling the duty ratio of the switching element 31, an output voltage (for example, 5V, 10V, etc.) for driving the servo amplifier control circuit is output from the voltage conversion circuit 21.

[0030] Return Figure 1 An explanation will be given. As switches for opening and closing the circuit between the power supply 12 and the servo amplifier 11, a positive-side switch 14P and a negative-side switch 14N are provided. That is, in the circuit between the positive-side DC power line 19P extending from the positive-side output terminal of the power supply 12 and the positive-side input terminal of the servo amplifier 11, a positive-side switch 14P for opening and closing this circuit is provided. In addition, in the circuit between the negative-side DC power line 19N extending from the negative-side output terminal of the power supply 12 and the negative-side input terminal of the servo amplifier 11, a negative-side switch 14N for opening and closing this circuit is provided. The positive-side switch 14P and the negative-side switch 14N perform a closing operation when receiving an on command from the switch control circuit 16, closing the circuit between the power supply 12 and the servo amplifier 11. In addition, the positive-side switch 14P and the negative-side switch 14N perform an opening operation when receiving an off command from the switch control circuit 16, opening the circuit between the power supply 12 and the servo amplifier 11.

[0031] The positive-side potential detection unit 17P detects the positive-side potential in the positive-side DC power line 19P extending from the positive-side output terminal of the power supply 12. The negative-side potential detection unit 17N detects the negative-side potential in the negative-side DC power line 19N extending from the negative-side output terminal of the power supply 12. The potential difference between the positive-side potential in the positive-side DC power line 19P and the negative-side potential in the negative-side DC power line 19N becomes the magnitude of the voltage output from the power supply 12. The detection results of the positive-side potential detection unit 17P and the negative-side potential detection unit 17N are sent to the voltage comparison circuit 15.

[0032] The voltage comparison circuit 15 compares the voltage output by the power supply 12 with a preset threshold value. As described above, the power supply 12 can switch to output at least two DC voltages of different magnitudes. The voltage comparison circuit 15 uses the threshold value to determine which value of voltage is output from the power supply 12. The comparison result of the voltage comparison circuit 15 is sent to the switch control circuit 16. For example, when the power supply 12 is configured to be able to switch and output 48V as the high voltage and 24V as the low voltage, either 48V or 24V is output from the power supply 12. In this case, the threshold value is set to, for example, 36V, and the threshold value of 36V is compared with the voltage output by the power supply 12 in the voltage comparison circuit 15, whereby it is possible to determine which of 48V and 24V is output from the power supply 12. That is, the voltage comparison circuit 15 determines that the power supply 12 outputs 24V voltage when the voltage output by the power supply 12 is below the threshold value of 36V, and determines that the power supply 12 outputs 48V voltage when the voltage output by the power supply 12 is greater than the threshold value of 36V. The numerical example shown here is just an example, and other values may also be used. In addition, regarding the threshold value, it can be stored in a rewritable storage unit (not shown) and can be rewritten by an external device. Thus, even after the threshold value is temporarily set, it can be changed to an appropriate value as needed.

[0033] The switch control circuit 16 controls the opening and closing of the circuit between the power supply 12 and the servo amplifier 11 by the positive side switch 14P and the negative side switch 14N according to the comparison result of the voltage comparison circuit 15. The more detailed content is described below.

[0034] When the voltage comparison circuit 15 determines that the voltage output by the power supply 12 is below the threshold value, the switch control circuit 16 sends a disconnection instruction to the positive side switch 14P and the negative side switch 14N. The positive side switch 14P and the negative side switch 14N that receive the disconnection instruction perform an opening operation, opening the circuit between the power supply 12 and the servo amplifier 11. When it is determined that the voltage output by the power supply 12 is below the threshold value, corresponding to not driving the motor 2, a low voltage (for example, 24V) is output from the power supply 12. Since the positive side switch 14P and the negative side switch 14N are in the open state, the voltage output from the power supply 12 is not input to the servo amplifier 11 but is input to the servo amplifier control circuit 13. Therefore, the motor 2 is not driven, but the servo amplifier control circuit 13 itself operates, so various processes including the state monitoring process of the motor 2 can be executed, ensuring the safety of the machine.

[0035] In addition, when the voltage comparison circuit 15 determines that the voltage output from the power supply 12 is greater than the threshold value, the switch control circuit 16 sends a turn-on command to the positive-side switch 14P and the negative-side switch 14N. The positive-side switch 14P and the negative-side switch 14N that receive the turn-on command perform a closing operation, closing the circuit between the power supply 12 and the servo amplifier 11. When it is determined that the voltage output from the power supply 12 is greater than the threshold value, corresponding to driving the motor 2, a high voltage (e.g., 48V) is output from the power supply 12. Since the positive-side switch 14P and the negative-side switch 14N are in the closed state, the voltage output from the power supply 12 is input to the servo amplifier 11 and the servo amplifier control circuit 13, enabling the servo amplifier 11 to drive the motor 3.

[0036] The above voltage comparison circuit 15 may have a comparator circuit. In this case, the switch control unit 16 controls the positive-side switch 14P and the negative-side switch 14N based on the output of the comparator circuit. Alternatively, the above voltage comparison circuit 15 may also have a circuit structure formed by combining an arithmetic processing device, a memory, and an analog-to-digital converter.

[0037] In addition, at least one processor serving as an arithmetic processing device is provided in the power supply system 1. Examples of the arithmetic processing device include an IC, an LSI, a CPU, an MPU, a DSP, etc. The arithmetic processing device may have a voltage comparison circuit 15, a switch control circuit 16, a motor control unit (not shown), and other processing circuits. Each of these units included in the arithmetic processing device may be, for example, a functional module implemented by a program executed on the processor. For example, when the voltage comparison circuit 15, the switch control circuit 16, the motor control unit, and other processing circuits are constructed in the form of a program, by causing the arithmetic processing device to operate according to this program, the functions of each unit can be realized. The programs for executing the respective processes of the voltage comparison circuit 15, the switch control circuit 16, the motor control unit, and other processing circuits may be provided in the form of being recorded on a computer-readable recording medium such as a semiconductor memory, a magnetic recording medium, or an optical recording medium. Alternatively, the voltage comparison circuit 15, the switch control circuit 16, the motor control unit, and other processing circuits may be implemented as a semiconductor integrated circuit in which a program for realizing the functions of each unit is written.

[0038] In addition, at least one memory as a storage device is provided in the power supply system 1. As the memory, for example, there is a non-volatile memory such as an EEPROM (registered trademark) that can be electrically erased / recorded, or a random access memory such as a DRAM or SRAM that can perform high-speed reading and writing. In addition, the storage device may have a structure such as an HDD or an SSD. Programs for operating the voltage comparison circuit 15, the switch control circuit 16, the motor control unit, and other processing circuits can be stored in the memory. In addition, the potential detection results obtained by the positive-side potential detection unit 17P and the negative-side potential detection unit 17N can be stored in the memory. In addition, the comparison result of the voltage comparison circuit 15 can be stored in the memory. In addition, various data required for motor driving can be stored in the memory.

[0039] <Operation of the power supply system according to the embodiment of the present disclosure>

[0040] Figure 3 It is a flowchart showing the operation related to the opening and closing of the switch in the power supply system according to the embodiment of the present disclosure.

[0041] The power supply 12 outputs a voltage of any magnitude among at least two magnitudes of DC voltages. In step S101, the positive-side potential detection unit 17P detects the positive-side potential in the positive-side DC power line 19P extending from the positive-side output terminal of the power supply 12. The negative-side potential detection unit 17N detects the negative-side potential in the negative-side DC power line 19N extending from the negative-side output terminal of the power supply 12. Thereby, the magnitude of the voltage output by the power supply 12 is detected. The detection results of the positive-side potential detection unit 17P and the negative-side potential detection unit 17N are sent to the voltage comparison circuit 15.

[0042] In step S102, the voltage comparison circuit 15 compares the voltage output by the power supply 12 with a preset threshold value. When it is determined by the voltage comparison circuit 15 in step S102 that the voltage output by the power supply 12 is equal to or less than the threshold value, the process proceeds to step S103. When it is not determined by the voltage comparison circuit 15 in step S102 that the voltage output by the power supply 12 is equal to or less than the threshold value (that is, when it is determined that the voltage output by the power supply 12 is greater than the threshold value), the process proceeds to step S104.

[0043] In step S103, the switch control circuit 16 sends a disconnection command to the positive-side switch 14P and the negative-side switch 14N. The positive-side switch 14P and the negative-side switch 14N that receive the disconnection command perform an opening operation, opening the circuit between the power supply 12 and the servo amplifier 11. Since the positive-side switch 14P and the negative-side switch 14N are in the open state, the voltage output from the power supply 12 is not input to the servo amplifier 11 but is input to the servo amplifier control circuit 13. Therefore, the motor 2 does not operate, but the servo amplifier control circuit 13 itself operates, so various processes including the state monitoring process of the motor 2 can be executed, ensuring the safety of the machine.

[0044] In step S104, the switch control circuit 16 sends a connection command to the positive-side switch 14P and the negative-side switch 14N. The positive-side switch 14P and the negative-side switch 14N that receive the connection command perform a closing operation, closing the circuit between the power supply 12 and the servo amplifier 11. Since the positive-side switch 14P and the negative-side switch 14N are in the closed state, the voltage output from the power supply 12 is input to the servo amplifier 11 and the servo amplifier control circuit 13, and the servo amplifier 11 can drive the motor 3.

[0045] Figure 4 is a circuit diagram of a power supply system showing an existing example in which a power supply for power and a power supply for control are separately provided.

[0046] In the power supply system 100 of an existing example in which a power supply for power 112-1 and a power supply for control 112-2 are separately provided, in order not to supply power from the power supply for power 112-1 to the servo amplifier 111 when the motor 2 is not driven, a positive-side power supply switch 114P and a negative-side power supply switch 114N are provided on the output side of the power supply for power 112-1. The positive-side power supply switch 114P is connected to the positive-side input terminal of the servo amplifier 111 via the positive-side power line for power 116P-1. The negative-side power supply switch 114N is connected to the negative-side input terminal of the servo amplifier 111 via the negative-side power line for power 116N-1. In addition, the positive-side terminal and the negative-side terminal of the power supply for control 112-2 are respectively connected to the servo amplifier control circuit 113 via the positive-side control power line 116P-2 and the negative-side control power line 116N-2. Thus, according to the existing example, between the power supply for power 112-1 and the power supply for control 112-2 and the servo amplifier 111 and the servo amplifier control circuit 113, a total of four power lines such as the positive-side power line for power 116P-1, the negative-side power line for power 116N-1, the positive-side control power line 116P-2, and the negative-side control power line 116N-2 are required.

[0047] In contrast, according to the embodiment of the present disclosure, as Figure 1As shown, only two power lines, namely the positive-side DC power line 19P and the negative-side DC power line 19N, are required between the power supply 12, the servo amplifier 11, and the servo amplifier control circuit 13. Therefore, according to the embodiment of the present disclosure, not only can the mechanical safety during the driving and stopping of the motor 2 be ensured, but also the power wiring can be reduced. For example, when the servo amplifier 11 is arranged near the motor 2 in an industrial robot and daisy-chain connected, the effect of reducing the power wiring is greater.

[0048] The present disclosure has been described in detail above, but the present disclosure is not limited to the above-described respective embodiments. These embodiments can be subjected to various additions, replacements, changes, partial deletions, etc. within the scope not departing from the gist of the present disclosure, or within the scope not departing from the gist of the present disclosure derived from the content described in the patent protection scope and its equivalents. In addition, these embodiments can also be implemented in combination. For example, in the above embodiments, the order of each operation and the order of each process are shown as an example and are not limited thereto. The same applies to the cases where numerical values or mathematical formulas are used in the description of the above embodiments.

[0049] <Supplementary Note>

[0050] Regarding the above embodiments and modification examples, the following supplementary notes are further disclosed.

[0051] (Supplementary Note 1)

[0052] A power supply system having:

[0053] A servo amplifier 11;

[0054] A power supply 12 that can switch and output voltages of at least two magnitudes;

[0055] A servo amplifier control circuit 13 that is connected to the power supply 12 and controls the servo amplifier 11;

[0056] Switches 14P and 14N that open and close the circuit between the power supply 12 and the servo amplifier 11;

[0057] A voltage comparison circuit 15 that compares the voltage output by the power supply 12 with a preset threshold value; and

[0058] A switch control circuit 16 that controls the opening and closing of the circuit between the power supply 12 and the servo amplifier 11 by the switches 14P and 14N according to the comparison result of the voltage comparison circuit 15.

[0059] (Supplementary Note 2)

[0060] The power supply system according to Note 1, wherein the switch control circuit 16 controls the switches 14P and 14N to open the circuit between the power supply 12 and the servo amplifier 11 when the voltage output from the power supply 12 is determined by the voltage comparison circuit 15 to be below the threshold value, and controls the switches 14P and 14N to close the circuit between the power supply 12 and the servo amplifier 11 when the voltage output from the power supply 12 is determined by the voltage comparison circuit 15 to be greater than the threshold value.

[0061] (Note 3)

[0062] The power supply system according to Note 1 or 2, wherein the servo amplifier control circuit 13 has a voltage conversion circuit 21 that converts the voltage input from the power supply 12 into a driving voltage for driving the servo amplifier control circuit 13.

[0063] Description of reference numerals

[0064] 1 Power supply system

[0065] 2 Motor

[0066] 11 Servo amplifier

[0067] 12 Power supply

[0068] 13 Servo amplifier control circuit

[0069] 14P Positive side switch

[0070] 14N Negative side switch

[0071] 15 Voltage comparison circuit

[0072] 16 Switch control circuit

[0073] 17P Positive side potential detection unit

[0074] 17N Negative side potential detection unit

[0075] 18 Capacitor

[0076] 19P Positive side DC power line

[0077] 19N Negative side DC power line

[0078] 21 Voltage conversion circuit

[0079] 31 Switch element

[0080] 32 Diode

[0081] 33 Inductor

[0082] Su1, Su2, Sv1, Sv2, Sw1, Sw2 Switch elements.

Claims

1. A power supply system, characterized in that, it has: a servo amplifier; a power supply that can switch and output voltages of at least two magnitudes; a servo amplifier control circuit connected to the power supply to control the servo amplifier; a switch that opens and closes the circuit between the power supply and the servo amplifier; a voltage comparison circuit that compares the voltage output by the power supply with a preset threshold; and a switch control circuit that controls the opening and closing of the circuit between the power supply and the servo amplifier by the switch according to the comparison result of the voltage comparison circuit.

2. The power supply system according to claim 1, characterized in that, when the voltage comparison circuit determines that the voltage output by the power supply is below the threshold, the switch control circuit controls the switch to open the circuit between the power supply and the servo amplifier, and when the voltage comparison circuit determines that the voltage output by the power supply is greater than the threshold, the switch control circuit controls the switch to close the circuit between the power supply and the servo amplifier.

3. The power supply system according to claim 1 or 2, characterized in that, the servo amplifier control circuit has a voltage conversion circuit that converts the voltage input from the power supply into a driving voltage for driving the servo amplifier control circuit.

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