Processing equipment

Abstract

To mitigate, as much as possible, an adverse effect due to electric charge stored in a capacitor which a processing device has when the processing device, to which DC power is supplied, is removed from a DC bus.SOLUTION: A processing device that is connected to a DC bus to which DC power is output from a converter, and to which DC power is supplied through the DC bus comprises: a capacitor that stores DC power in the DC bus; a discharge circuit that discharges DC power stored in the capacitor to be consumed by discharge resistance; a detection section that detects a connection state of the DC bus of the processing device on the basis of a result of a predetermined processing which is performed between the processing device and any upstream side device of devices which are connected at an upstream side of the processing device in the DC bus including the converter; and a control section that drives the discharge circuit using power stored in the capacitor when it is detected that the processing device is removed from the DC bus by the detection section.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a processing device that is connected to a DC bus and receives DC power. [Background technology]

[0002] Systems with DC buses are widely used as power supply systems for driving electric motors and other electrical devices. Connecting various devices that use DC power to these DC buses ensures a stable supply of power. However, due to an event on the device side, for example, if the processing device includes an inverter, the operation of the motor or other device driven by the inverter may cause the voltage of the DC bus to fluctuate. If this voltage fluctuation exceeds the allowable range, it may affect the various devices connected to the DC bus. Therefore, a capacitor may be provided on the DC bus to suppress the fluctuation range or to absorb the regenerative energy of the motor.

[0003] While a capacitor installed in a DC bus can stabilize the DC bus, from a safety standpoint, when a device (processing device) including the capacitor is removed from the DC bus, the charge stored in the capacitor must be appropriately disposed of. For example, Patent Document 1 discloses a configuration in which the positive terminal of a circuit is connected to the high-voltage side of a capacitor so that the charge of the capacitor is directly supplied to the capacitor's discharge control circuit as driving power. This technology uses the stored energy of the capacitor as energy for discharging the stored charge. Patent Document 2 also discloses a configuration in which the power of the DC bus is used to control the driving of a discharge circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-236451 [Patent Document 2] Japanese Patent Publication No. 2020-22259 Summary of the Invention [Problem to be solved by the invention]

[0005] When a processing device that is connected to a DC bus and configured to receive DC power to perform a predetermined process (for example, drive an electric motor) is removed from the DC bus for maintenance or other purposes, sufficient consideration must be given to how to handle the charge stored in the capacitor included in the processing device, taking into account that the processing device had previously received power from the DC bus. In particular, it is necessary to accurately avoid electric shock due to the charge stored in the capacitor even if a user attempts to remove the processing device without realizing that the processing device had been receiving DC power from the DC bus.

[0006] The present invention has been made in consideration of such problems, and aims to provide a technology that reduces as much as possible the adverse effects of electric charges stored in a capacitor of a processing device when the processing device that has been receiving DC power supply is removed from the DC bus. [Means for solving the problem]

[0007] A processing device according to one aspect of the present disclosure is a processing device connected to a DC bus through which DC power is output from a converter and to which DC power is supplied via the DC bus, the processing device including a capacitor that stores the DC power in the DC bus, a discharge circuit that discharges the DC power stored in the capacitor and consumes it through a discharge resistor, and a predetermined processing operation performed between any one of upstream devices that includes the converter and is connected on the DC bus upstream of the processing device. The device further comprises a detection unit that detects the connection state of the processing device to the DC bus based on the result of the processing, and a control unit that drives the discharge circuit using the power stored in the capacitor when the detection unit detects that the processing device has been removed from the DC bus.

[0008] The processing device disclosed herein is a device connected to a DC bus through which DC power is output from a converter and configured to receive DC power via the DC bus. The processing device includes the capacitor, which can store part or all of the supplied power and return part or all of the stored power to the DC bus. The processing device supplies DC power for various purposes, including for any processing in the processing device, or as described above, may be configured to exchange power between the capacitor and the DC bus. An example of a processing device may be a driver unit including an inverter that receives DC power from the DC bus and generates a drive current for driving an electric motor. The driver unit, which is a processing device, may include an inverter capable of driving one or more electric motors. Alternatively, the processing device may be a capacitor unit that adjusts voltage fluctuations on the DC bus using the capacitor. The processing device may also have a configuration other than those described above.

[0009] In this processing device, since the capacitor is configured to be able to exchange DC power with the DC bus, it is undesirable from a safety standpoint if the capacitor remains charged when the processing device is removed from the DC bus. Therefore, the processing device is provided with a discharge circuit, and by operating the discharge circuit, the DC power stored in the capacitor can be consumed by the discharge resistor, thereby reducing the amount of charge on the capacitor. On the other hand, given that the capacitor is configured to receive power from the DC bus while the DC bus and the processing device are still connected, in order to operate the discharge circuit appropriately, it is necessary to appropriately determine the timing of operating the discharge circuit, i.e., the timing when the processing device is removed from the DC bus, and operate the discharge circuit according to that timing.

[0010] Therefore, in the processing device, a detection unit detects removal of the processing device from the DC bus by utilizing the results of a predetermined process performed between the processing device and the upstream device. The converter is a device that outputs DC power to the DC bus, and the upstream devices excluding the converter are devices that receive DC power from the DC bus and are connected to the DC bus upstream of the processing device. Note that, in this application, "upstream" refers to a device that is closer to the converter that outputs DC power. Therefore, an upstream device is a device that is always located upstream of the processing device, based on the connection position of the processing device on the DC bus. Even if the processing device is removed from the DC bus, the device remains connected to the DC bus and continues to receive power. Therefore, even if the processing device is removed from the DC bus, the upstream device maintains an environment in which electrical processing is possible.

[0011] Therefore, a detection unit provided in the processing device can stably detect that the processing device has been removed from the DC bus by utilizing the results of a predetermined process performed between the processing device and an upstream device to which power supply is maintained. When the detection unit detects that the processing device has been removed, the discharge circuit is driven to discharge the power stored in the capacitor. At this time, since the processing device is in a state where it has been removed from the DC bus (or in a state immediately after being removed), no DC power is supplied from the DC bus. Therefore, in the processing device of the present application, the discharge circuit is driven using the power stored in the capacitor of the discharge circuit.

[0012] According to the processing device configured in this way, when the processing device is removed from the DC bus, particularly when the processing device is removed by a user operation or the like, Even if the user forgets that the capacitor is in the processing device, the detection unit will detect the removal and the discharge circuit will be driven appropriately based on the detection results, making it possible to reduce as much as possible the adverse effects of the charge stored in the capacitor.

[0013] Here, the processing device may further include a voltage conversion unit that converts and outputs the voltage between the terminals of the capacitor, and at least one of the detection unit and the control unit may be configured to be driven by the output voltage of the voltage conversion unit. By providing a voltage conversion unit in the processing device in this manner, the energy stored in the capacitor can be effectively used when removing the processing device, from the perspective of driving the detection unit and the control unit.

[0014] As an example of the predetermined processing by the detection unit, a predetermined signal corresponding to the output voltage of the voltage conversion unit may be transmitted to the upstream device, and then a response signal in response to the received predetermined signal may be transmitted from the upstream device. The detection unit may then compare the predetermined signal with the response signal to detect the connection status of the processing device with the DC bus. By using the voltage conversion unit, which outputs drive power for the detection unit and the control unit, for the predetermined processing and the detection processing by the detection unit, the configuration of the processing device can be simplified while effectively reducing the adverse effects of capacitor charge caused by removing the processing device. As an alternative to the predetermined processing, any processing performed between the upstream device and the voltage conversion unit may be performed using a signal generated by a functional unit other than the voltage conversion unit.

[0015] Furthermore, in the processing device described above, when the output of DC power from the converter to the DC bus is stopped, the control unit may drive the discharge circuit using the power stored in the capacitor. When the output of DC power from the converter to the DC bus is stopped, the processing device is still connected to the DC bus but is effectively unable to receive DC power. Even in such a case, the discharge circuit can be driven using the power stored in the capacitor to eliminate unexpected adverse effects caused by the charge in the capacitor. [Effects of the Invention]

[0016] It is possible to provide a technology that reduces as much as possible the adverse effects of electric charges stored in the capacitors of a processing device that has been receiving DC power supply when the processing device is removed from the DC bus. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a power supply system. [Figure 2] 2 is a diagram schematically showing the circuit configuration of a driver unit and a capacitor unit included in the power supply system shown in FIG. 1. FIG. [Figure 3] 3 is a flowchart showing the flow of a process for discharging a capacitor when a driver unit is removed in the power supply system shown in FIG. 2. [Figure 4] 4 is a diagram showing the transition of each parameter related to the terminal voltage of the capacitor when the discharge process shown in FIG. 3 is performed. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that identical or corresponding parts in the drawings are designated by the same reference numerals, and their description will not be repeated. In the present disclosure, a driver unit and a capacitor unit for supplying drive power to drive a motor are shown as an exemplary embodiment of a processing device, but the technical concept of the processing device disclosed herein can also be applied to devices other than these devices.

[0019] FIG. 1 is a diagram showing a schematic configuration of a power supply system that supplies drive power to a motor. The power supply system is composed of a converter 10, a capacitor unit 15, and a driver unit 20. The converter 10 receives AC power from an AC power source 7 via a cable 7a and outputs DC power. The output DC power is supplied to the capacitor unit 15 and the driver unit 20, which are arranged adjacent to the converter 10, via a DC bus 11 (see FIG. 2 described below). This DC bus 11 is a DC power conduction path that is formed between the converter 10, the capacitor unit 15, and the driver unit 20. The capacitor unit 15 and the driver unit 20 each correspond to a processing device disclosed in the present application.

[0020] The driver unit 20 is controlled by a programmable logic controller (PLC) (not shown) or the like. The control unit 230 of the driver unit 20 (see FIG. 2 described later) receives an operation command signal related to the operation (motion) of the motor 2 from a higher-level device via the network and a detection signal from an encoder mounted on the motor 2, and calculates a command value related to servo control related to the drive of the motor 2. The driver unit 20 then supplies drive power for driving the corresponding motor to the motor 2 via the power line 2a in accordance with the calculated command value. The control unit 230 is also configured to execute control related to the discharge process of the capacitor 25 built into the driver unit 20 when the driver unit 20 is removed from the DC bus 11, the details of which will be described later. Furthermore, the control unit 230 may be configured to perform control other than these controls regarding the motor 2.

[0021] Furthermore, the capacitor unit 15 is a unit that has a capacitor 155 therein that can store regenerative power from the motor 2. Storing the regenerative power in the capacitor 155 makes it possible to prevent the voltage of the DC bus 11 from rising excessively during regeneration of the motor 2, and also makes it possible to use the stored power to drive the motor 2. When constructing a power supply system, the capacitor unit 15 is not an essential component, and it is sufficient to determine whether to use the capacitor unit 15 and the capacity of the capacitor 155 built into the capacitor unit 15, taking into account the operating conditions and load conditions of the motor 2, etc.

[0022] The motor 2 is controlled by a driver unit 20 to drive a specific facility device. The driver unit 20 has a built-in inverter 26, which generates a drive current for the motor 2. As an example of the facility device, various mechanical devices (e.g., an arm of an industrial robot or a conveying device) can be exemplified, and the motor 2 is incorporated into the device as an actuator that drives the facility device. The motor 2 is an AC servo motor. Alternatively, the motor 2 may be an induction motor or a DC motor. The motor 2 has a detection disk that rotates in conjunction with the rotation of each rotor and is equipped with an encoder that can detect the rotation state of the rotor. Furthermore, the motor 2 may be a linear motor, in which case a linear encoder is used to detect the position of the mover.

[0023] Here, the configurations of driver unit 20 and capacitor unit 15, which correspond to power supply devices, in the power supply system shown in Fig. 1 will be described with reference to Fig. 2. In this power supply system, AC power supplied from AC power source 7 is converted into DC power by converter 10 and output to DC bus 11. Driver unit 20 and capacitor unit 15 are configured to be detachable from DC bus 11. Therefore, a user can remove or attach devices connected to DC bus 11 as needed for maintenance or other purposes.

[0024] The following describes the internal circuit of the driver unit 20, in particular the configuration of the input section 200 to which DC power supplied from the DC bus 11 is input. The input section 200 is a portion to which DC power from the outside is input within the driver unit 20. The power is supplied to the inverter 26 located downstream. The inverter 26 itself is based on known technology, and therefore a detailed description thereof will be omitted.

[0025] In the input unit 200, a resistor 22 and a relay 23 are provided in the positive side path of the power supply line 21. These resistors 22 and relay 23 constitute a prevention circuit for preventing an inrush current from flowing from the DC bus 11 to the input unit 200 when DC power begins to be supplied from the converter 10 to the DC bus 11 to which the driver unit 20 is connected. In the prevention circuit, the resistor 22 and the relay 23 are connected in parallel. When the relay 23 is in an off state, the current flowing through the positive side path passes through the resistor 22. When the relay 23 is in an on state, the current bypasses the resistor 22. More specifically, when DC power begins to be supplied from the converter 10, the relay 23 is in an off state, and the current flows through the resistor 22 in the positive side path, thereby suppressing the peak value of the inrush current. Then, when a predetermined time has elapsed since the inrush current was detected, the relay 23 is turned on. This prevents the power supplied from the DC bus 11 from being consumed by the resistor 22. Alternatively, a PTC (Positive Temperature Coefficient) can be used in place of the resistor 22, and a semiconductor switch element can be used in place of the relay 23. This also applies to a resistor 152 and a relay 153, which will be described later.

[0026] In addition, a capacitor 25 is disposed between the positive path and the negative path of the input section 200. The capacitor 25 is disposed so as to keep voltage fluctuations in the power supply path 28 within an allowable range. The capacitor 25 is also capable of storing regenerative power from the motor 2 driven by the driver unit 20. A discharge circuit 24 for discharging the power stored in the capacitor 25 is connected between the positive path and the negative path. The discharge circuit 24 has a resistor for consuming power and a switch circuit for controlling the application of voltage to the resistor, and the drive of the switch circuit is configured to be controlled by the control section 230 described below.

[0027] Furthermore, in input unit 200, voltage conversion unit 27, which is a DC-DC converter, is provided between the positive path and the negative path. Voltage conversion unit 27 is configured to perform voltage conversion using the voltage between the terminals of capacitor 25 as input and outputting a drive voltage required to drive detection unit 220 and control unit 230. The operation of voltage conversion unit 27 will be described later.

[0028] Next, we will explain capacitor unit 15. Capacitor unit 15 is not a unit for driving a motor, and therefore does not have a built-in inverter 26 like driver unit 20, but its input section 150 has an electrical configuration that is generally equivalent to that of input section 200 of driver unit 20. That is, input section 150 has resistor 152 and relay 153 that constitute an inrush current prevention circuit provided in the positive path of power supply path 21, and capacitor 155, discharge circuit 154, and voltage conversion section 157 that are provided between the positive path and negative path of power supply path 21.

[0029] In this way, the power supply system constituted by the driver unit 20 and the capacitor unit 15 realizes the supply of drive power for driving and controlling the motor 2, the recovery of regenerative power from the motor 2, and the like. Here, the driver unit 20 may be removed from the DC bus 11 for purposes such as maintenance, and in such cases, sufficient care must be taken when handling the capacitor 25 built into the removed driver unit 20. That is, if the driver unit 20 has been used to drive and control the motor 2, there is a possibility that a considerable amount of charge will be stored in the capacitor 25. Therefore, before removing the driver unit 20, the charge in the capacitor 25 must be discharged by the discharge circuit 24. However, if the driver unit 20 is removed from the DC bus 11 without sufficient discharge processing by the discharge circuit 24 due to carelessness on the part of the user, the charge will remain stored in the capacitor 25, which is undesirable from a safety standpoint. Therefore, even in such a case, the driver unit 20 and the capacitor unit 15 have a configuration that allows the driver unit 20 to be safely removed.

[0030] In detail, the driver unit 20 uses its own communication unit 210, detection unit 220, and control unit 230 in cooperation with the communication unit 160 and response unit 170 of the capacitor unit 15 to realize the discharge process of the capacitor 25 when the driver unit 20 is removed from the DC bus 11. In this way, the driver unit 20 cooperates with the capacitor unit 15 connected to the DC bus 11 at the time of its removal, thereby being able to appropriately detect the removal and to accurately perform the discharge process of the capacitor 25.

[0031] The communication unit 210 is a functional unit that functions as an interface for exchanging signals with devices electrically connected to the DC bus 11, such as the capacitor unit 15 and the converter 10, which are located upstream of the driver unit 20. The communication unit 160 is a functional unit on the capacitor unit 15 side that corresponds to the communication unit 210 of the driver unit 20. The converter 10, the capacitor unit 15, and the driver unit 20 are sequentially connected by control signal lines. The control signal lines connect the devices when the capacitor unit 15 or the driver unit 20 is connected to the DC bus 11, and are also removed when the capacitor unit 15 or the driver unit 20 is removed from the DC bus 11. The communication units 210 and 160 enable the exchange of signals between the devices via these control communication lines. Specifically, the communication unit 210 receives a predetermined signal corresponding to the output voltage of the voltage conversion unit 27 from the voltage conversion unit 27 and transmits the predetermined signal to the communication unit 160 on the capacitor unit 15 side. The predetermined signal is a signal that goes to a high state when the voltage conversion unit 27 configured to output the drive voltage of the detection unit 220 and the control unit 230 as described above is able to generate the drive voltage, and goes to a low state when the voltage conversion unit 27 is unable to generate the drive voltage. is passed to the detection unit 220 as well as the communication unit 210.

[0032] The communication unit 160 of the capacitor unit 15 receives a predetermined signal from the communication unit 210 of the driver unit 20 and passes the predetermined signal to the response unit 170 of the capacitor unit 15. The response unit 170 returns the predetermined signal passed from the communication unit 160 to the communication unit 160 as a response signal. Note that the communication unit 160 may perform some processing on the predetermined signal, for example, to perform processing so that another device (for example, the driver unit 20) can recognize that the capacitor unit 15 has received the predetermined signal, and return the result to the communication unit 160 as a response signal. The communication unit 160 receives the response signal from the response unit 170 and transmits it to the communication unit 210 on the driver unit 20 side. The communication unit 210 receives the response signal and passes it to the detection unit 220.

[0033] The detection unit 220 is a functional unit that compares a predetermined signal received from the voltage conversion unit 27 with a response signal transmitted from the response unit 170 and received via the communication unit 210 to detect whether the driver unit 20 has been removed from the DC bus 11, i.e., the connection state of the driver unit 20 to the DC bus 11. That is, the response signal is a signal corresponding to a predetermined signal generated due to the output voltage of the voltage conversion unit 27, and therefore the response signal reflects the connection state of the driver unit 20 with the DC bus 11. If the driver unit 20 is removed from the DC bus 11, the predetermined signal will no longer be input to the response unit 170, and the response signal will no longer be able to be generated as before. Therefore, the detection unit 220 can detect a change in the connection state of the driver unit 20 with the DC bus 11 by comparing the predetermined signal with the response signal.

[0034] Then, the detection unit 220 passes the detection result to the control unit 230. The control unit 230 controls the driving of the discharge circuit 24 based on the detection result passed thereto. When it is detected that the driver unit 20 has been removed from the DC bus 11, the control unit 230 drives the switch circuit of the discharge circuit 24 based on the result, and the charge stored in the capacitor 25 is consumed by the resistor in the discharge circuit 24, thereby reducing the voltage between the terminals of the capacitor 25.

[0035] Here, even if an attempt is made to remove the driver unit 20 from the DC bus 11, if a certain amount of charge is stored in the capacitor 25, the necessary drive voltage is supplied to the communication unit 210, the detection unit 220, and the control unit 230 by the voltage conversion unit 27 based on that charge. Therefore, even if a discharge process of the capacitor 25 is required, the drive voltage of the communication unit 210, the detection unit 220, and the control unit 230 is sufficiently ensured, and on the other hand, if these drive voltages cannot be ensured, the voltage stored in the capacitor 25 is correspondingly low, so no safety problem occurs.

[0036] Next, the flow of the discharge process of the capacitor 25 executed by the above-mentioned functional unit and the transition of each parameter at that time will be described with reference to Figures 3 and 4. Figure 3 is a flowchart showing the flow of the discharge process of the capacitor 25. The discharge process is repeatedly executed by the driver unit 20 at predetermined intervals. Figure 4 is a diagram showing the transition of each parameter related to the terminal voltage of the capacitor 25 when the discharge process shown in Figure 3 is performed. Of the parameters shown in Figure 4, (a) represents the on / off state of the power supply of the DC bus 11, (b) represents the DC voltage on the DC bus 11, (c) represents the state of a predetermined signal, (d) represents the state of a response signal, (e) represents the lighting state of an LED (not shown) provided in the driver unit 20 that indicates the charge state of the capacitor 25, and (f) represents the driving state of the discharge circuit 24. In relation to (e), the LED is used to notify the user of the danger when a certain amount of charge remains in the capacitor 25, and in the present disclosure, it is configured to light up (become in a High state) when the DC voltage of the DC bus 11, which can be equated with the terminal voltage of the capacitor 25, reaches 50 V or more.

[0037] Before the discharge process is performed, the converter 10 starts driving at timing t1, and starts supplying DC power to the DC bus 11. When the converter 10 is driving, the voltage of the DC bus 11 is basically set to about 280 V (equivalent to AC 200 V). In this state, the voltage conversion unit 27 of the driver unit 20 outputs drive voltages for the communication unit 210, the detection unit 220, and the control unit 230. In the capacitor unit 15, the voltage conversion unit 157 built in the capacitor unit 15 also outputs voltages required for driving the communication unit 160 and the response unit 170.

[0038] First, in S101, it is determined whether the power supply is off. That is, it is determined whether the supply of DC power by the converter 10 has been stopped. Signals related to the on / off of the converter 10 are transmitted via a control signal line connecting the converter 10, the capacitor unit 15, and the driver unit 20. When the control unit 230 determines that the converter 10 is off via the control signal line, it makes a positive determination in S101, and when it does not determine that the converter 10 is off, it makes a negative determination in S101. If a positive determination is made in S101, the process proceeds to S105, and if a negative determination is made, the process proceeds to S102.

[0039] Next, in S102, the detection unit 220 receives a predetermined signal output from the voltage conversion unit 27, and in S103, the detection unit 220 receives a response signal output from the response unit 170 of the capacitor unit 15. Then, in S104, the detection unit 220 compares the received predetermined signal with the response signal to determine whether the driver unit 20 has been removed from the DC bus 11. Specifically, when the driver unit 20 is connected to the DC bus 11, both the predetermined signal and the response signal are in a High state, as shown in the period between timing t1 and t2 in FIG. 4. This is because, by being connected to the DC bus 11, the driver unit 20 and the This is because the exchange of the predetermined signal and the response signal between the capacitor unit 15 and the driver unit 20 is maintained. On the other hand, if the driver unit 20 is removed from the DC bus 11 at timing t2, the detection unit 220 can receive the predetermined signal from the voltage conversion unit 27, but the capacitor unit 15 cannot send the expected response signal to the driver unit 20, and the detection unit 220 cannot receive the response signal. Therefore, as shown after timing t2 in Figure 4, the predetermined signal received by the detection unit 220 is in a High state, but the response signal is in a Low state, resulting in a discrepancy between the two signals. The detection unit 220 detects this discrepancy between the two signals. This makes it possible to detect that the driver unit 20 has been removed from the DC bus 11. If removal is detected in S104, the process proceeds to S105, and if removal is not detected, the discharge process ends.

[0040] Then, if a positive determination is made in S101 or removal of the driver unit 20 is detected in S104, the control unit 230 drives the discharge circuit 24 in S105. In FIG. 4, removal of the driver unit 20 is detected at timing t4, and the discharge circuit 24 is immediately driven. Therefore, at timing t4, the drive state of the discharge circuit 24 shown in (f) becomes a High state. When the discharge circuit 24 is driven in this manner, the DC voltage on the DC bus 11 begins to drop, as shown in (b). Then, when the DC voltage falls below 50 V at timing t3, the LED provided in the driver unit 20 becomes a Low state (off state), as shown in (e), and the user is notified of the discharge of the capacitor 25. The discharge circuit 24 continues to be driven until the DC voltage in the DC bus reaches a voltage sufficiently lower than 50V, for example, 30V. Therefore, at timing t4, the discharge circuit 24 is stopped from being driven. When the discharge circuit 24 is stopped from being driven, the discharge process shown in FIG. 3 ends.

[0041] Although FIG. 4 shows the driving of the discharge circuit 24 when the driver unit 20 is removed, the discharge circuit 24 is also driven in the same manner when a positive determination is made in S101.

[0042] In this way, in the power supply system disclosed in the present application, even if the driver unit 20 is inadvertently removed from the DC bus 11, the power stored in the capacitor 25 of the driver unit 20 is suitably utilized, and the removal is detected and the discharge process of the capacitor 25 is executed appropriately. Therefore, it is possible to sufficiently ensure the safety of the user.

[0043] <Variation 1> In the above embodiment, the driver unit 20 detects removal of the driver unit 20 by exchanging a predetermined signal and a response signal with the capacitor unit 15 located immediately upstream on the DC bus 11. However, instead of this configuration, the driver unit 20 may be configured to exchange a predetermined signal and a response signal with the converter 10 located most upstream on the DC bus 11. In this case, the converter 10 will have functional units equivalent to the communication unit 160 and response unit 170 that the capacitor unit 15 has.

[0044] <Variation 2> In the above embodiment, the removal of the driver unit 20 has been mentioned, but considering that the capacitor unit 15 also includes the capacitor 155, the discharge process shown in Fig. 3 may be performed similarly when the capacitor unit 15 is removed from the DC bus 11. In this case, the capacitor unit 15 has functional units corresponding to the communication unit 210, detection unit 220, and control unit 230 of the driver unit 20, and the converter 10 has functional units corresponding to the communication unit 160 and response unit 170 of the capacitor unit 15. In the capacitor unit 15, the DC voltage output by the voltage conversion unit 157 is supplied to drive each functional unit.

[0045] <Appendix 1> A processing device (20) connected to a DC bus (11) through which DC power is output from a converter (10) and to which DC power is supplied via the DC bus (11), a capacitor (25) for storing DC power in the DC bus (11); a discharge circuit (24) that discharges the DC power stored in the capacitor (25) and consumes it through a discharge resistor; a detection unit (220) that detects a connection state of the processing device (20) to the DC bus (11) by performing a predetermined process between the processing device (20) and any one of upstream devices (15) among devices that include the converter (10) and are connected to the DC bus (11) on the upstream side of the processing device (20); a control unit (230) that drives the discharge circuit using the power stored in the capacitor (25) when the detection unit (220) detects that the processing device (20) has been removed from the DC bus (11); and A processing device comprising: [Explanation of symbols]

[0046] 2 motors 7 AC power supply 10 Converter 11 DC bus 15 Capacitor Unit 20 driver units 24 Discharge circuit 25 capacitors 26 inverter 27 Voltage conversion section 150 Input section 154 Discharge circuit 155 capacitor 157 Voltage conversion unit 170 Response Section 200 Input section 220 Detector 230 Control Unit

Claims

1. A processing device connected to a DC bus through which DC power is output from a converter and to which DC power is supplied via the DC bus, a capacitor for storing DC power in the DC bus; a discharge circuit that discharges the DC power stored in the capacitor and consumes it through a discharge resistor; a detection unit that detects a connection state of the DC bus of the processing device based on a result of a predetermined process performed between the processing device and any one of upstream devices that includes the converter and is connected to the DC bus on the upstream side of the processing device; a control unit that drives the discharge circuit using the power stored in the capacitor when the detection unit detects that the processing device has been removed from the DC bus; A processing device comprising:

2. a voltage conversion unit that converts and outputs a voltage between the terminals of the capacitor; At least one of the detection unit and the control unit is driven by the output voltage of the voltage conversion unit. The processing device of claim 1 .

3. the predetermined process is configured to transmit a predetermined signal corresponding to an output voltage of the voltage conversion unit to the upstream device, and then transmit a response signal in response to the received predetermined signal from the upstream device; the detection unit compares the predetermined signal with the response signal to detect a connection state of the processing device with the DC bus; The processing device of claim 2 .

4. Furthermore, when the output of DC power from the converter to the DC bus is stopped, the control unit drives the discharge circuit using the power stored in the capacitor. The processing device according to any one of claims 1 to 3.

5. the processing device is a driver unit including an inverter that receives DC power from the DC bus and generates a drive current for driving an electric motor, or a capacitor unit that adjusts voltage fluctuations of the DC bus using the capacitor. The processing device according to any one of claims 1 to 4.

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