Drive power supply for mechanical switch, power supply device, and deterioration diagnosis method

Abstract

A mechanical switch (4) includes a mechanical contact (40) and coils (42, 44) that open and close the mechanical contact (40) by receiving supply of drive currents from a drive power supply (30). The drive power supply (30) comprises capacitors (C1, C2) and switches (320, 340) connected between the capacitors (C1, C2) and the coils (42, 44), respectively. The switches (320, 340) is temporarily turned on to turn on / off the mechanical switch (4) to supply the drive currents from the capacitors (C1, C2) to the coils (42, 44), respectively. The drive power supply (30) further comprises a charge circuit (36) that charges the capacitors (C1, C2) during an off-period of the switches (320, 340), detection circuits (52, 54) that detect the charge currents and voltages of the capacitors (C1, C2), respectively, and a diagnosis circuit (58) that diagnoses a deterioration state of each of the capacitors (C1, C2) from the detected charge current and voltage.

Description

Mechanical switch drive power supply, power supply device, and deterioration diagnosis method

[0001] The present disclosure relates to a drive power supply for a mechanical switch, a power supply device, and a method for diagnosing deterioration of a capacitor included in the drive power supply for a mechanical switch.

[0002] Japanese Patent Laid-Open Publication No. 2013-50351 (Patent Document 1) discloses a degradation diagnosis device for an electric double layer capacitor used in a power supply device such as a momentary sag compensator.

[0003] The degradation diagnosis device disclosed in Patent Document 1 includes a discharge circuit that connects a sine wave load circuit to a charged electric double layer capacitor and applies a sine wave load to discharge the electric double layer capacitor, a current detection circuit that detects the current flowing in the discharge circuit, a voltage detection circuit that measures the voltage of the electric double layer capacitor during discharge via the discharge circuit, and a calculation unit that calculates the impedance of the electric double layer capacitor using the current detected by the current detection circuit and the voltage detected by the voltage detection circuit.

[0004] JP 2013-50351 A

[0005] The degradation diagnosis device described above requires connecting a discharge circuit having a sine wave load circuit to the electric double layer capacitor. It also requires sensors for detecting the current flowing through the discharge circuit and the voltage of the electric double layer capacitor during discharge, as well as a computing unit for processing the values ​​detected by these sensors. Therefore, there is a concern that incorporating the degradation diagnosis device into a power supply unit will increase the size of the power supply unit. Furthermore, there is a concern that the increased size of the power supply unit will increase costs.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide a driving power supply for a mechanical switch, a power supply device, and a degradation diagnosis method that can diagnose the degradation state of a capacitor with a compact configuration.

[0007] A driving power supply according to one aspect of the present disclosure supplies a driving current to a mechanical switch. The mechanical switch includes a mechanical contact and a coil that receives the driving current and opens or closes the mechanical contact. The driving power supply includes a capacitor and a switch connected between the capacitor and the coil. The switch is configured to supply the driving current from the capacitor to the coil by being temporarily turned on to turn the mechanical switch on or off. The driving power supply further includes a charging circuit that charges the capacitor while the switch is off, a detection circuit that detects the charging current and voltage of the capacitor, and a diagnosis circuit that diagnoses the deterioration state of the capacitor from the charging current and voltage detected by the detection circuit.

[0008] A degradation diagnosis method according to one aspect of the present disclosure is a degradation diagnosis method for a capacitor included in a drive power supply that supplies a drive current to a mechanical switch. The mechanical switch includes a mechanical contact and a coil that receives the drive current and opens and closes the mechanical contact. The drive power supply includes a capacitor and a switch connected between the capacitor and the coil, and is configured to supply the drive current from the capacitor to the coil by temporarily turning on the switch to turn the mechanical switch on or off. The degradation diagnosis method includes the steps of charging the capacitor while the switch is off, detecting the charging current and voltage of the capacitor, and diagnosing the degradation state of the capacitor from the charging current and voltage.

[0009] According to the present disclosure, the deterioration state of a capacitor can be diagnosed from the capacitor's charging current and voltage using a capacitor charging circuit mounted on the drive power supply of a mechanical switch. This eliminates the need for a dedicated deterioration diagnosis device and enables the deterioration state of a capacitor to be diagnosed with a compact configuration.

[0010] 1 is a diagram showing the configuration of a power supply device to which a drive power supply for a mechanical switch according to embodiment 1 is applied; FIG. 2 is a diagram showing an example of the hardware configuration of a control device; FIG. 3 is a diagram showing an example of the configuration of a drive power supply according to embodiment 1; FIG. 4 is a circuit diagram showing an example of the circuit configuration of the drive circuit and charging circuit shown in FIG. 3; FIG. 5 is a diagram for explaining the operation of a drive power supply; FIG. 6 is a diagram for explaining a first example of a degradation diagnosis process for a capacitor in a diagnostic circuit; FIG. 7 is a flowchart showing a degradation diagnosis process for a capacitor in a drive power supply according to embodiment 1; FIG. 8 is a flowchart showing a degradation diagnosis process for a capacitor in a drive power supply according to embodiment 2; FIG. 9 is a diagram for explaining a second example of a degradation diagnosis process for a capacitor in a diagnostic circuit;

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and the description thereof will not be repeated.

[0012] [Embodiment 1] <Configuration of Power Supply Device> Fig. 1 is a diagram showing the configuration of a power supply device to which a drive power supply for a mechanical switch according to embodiment 1 is applied. In Fig. 1, a momentary sag compensator will be described as an example of the power supply device.

[0013] As shown in FIG. 1 , the instantaneous sag compensator includes an input terminal T1, an output terminal T2, a DC terminal T3, VCBs (Vacuum Circuit Breakers) 1, 5, 6, and 21, a high-speed switch 2, a power converter 7, a transformer 20, an operation unit 22, a control device 23, and a drive power supply 30.

[0014] The input terminal T1 receives a commercial frequency AC voltage VI supplied from a commercial AC power supply 71. The instantaneous value of the AC voltage VI is detected by the control device 23. When the AC voltage VI falls below a lower limit value, the control device 23 determines that a momentary voltage sag (momentary voltage drop) has occurred.

[0015] The output terminal T2 is connected to a load 72. The load 72 is driven by an AC voltage VO supplied from the output terminal T2. The instantaneous value of the AC voltage VO is detected by the control device 23.

[0016] The DC terminal T3 is connected to the power storage device 73. The power storage device 73 stores DC power. The power storage device 73 may be a battery or a capacitor. The DC voltage VDC at the DC terminal T3 is detected by the control device 23.

[0017] VCB1, high-speed switch 2, and VCB5 are connected in series between input terminal T1 and output terminal T2. VCB1 and VCB5 are turned on during normal operation of the instantaneous voltage sag compensator, and are turned off, for example, during maintenance of high-speed switch 2 or when bypass power is supplied.

[0018] The high-speed switch 2 includes a semiconductor switch 3 and a mechanical switch 4 connected in series. The semiconductor switch 3 is controlled by a control device 23, and is turned on when the AC voltage VI is normal, and is turned off when the AC voltage VI is abnormal (during a momentary drop).

[0019] The mechanical switch 4 is driven by a drive power supply 30. The drive power supply 30 is controlled by the control device 23, and drives the mechanical switch 4 to the ON state when the AC voltage VI is normal, and drives the mechanical switch 4 to the OFF state when the AC voltage VI is abnormal (during a momentary drop).

[0020] The semiconductor switch 3 has the characteristics of a faster operating speed and a lower withstand voltage than the mechanical switch 4. The mechanical switch 4 has the characteristics of a slower operating speed and a higher withstand voltage than the semiconductor switch 3. By connecting the semiconductor switch 3 and the mechanical switch 4 in series, a high-speed switch 2 that instantly turns off when a voltage drop occurs and has a high withstand voltage is formed.

[0021] The VCB 6 is connected between the input terminal T1 and the output terminal T2. The VCB 6 is turned off during normal operation of the instantaneous sag compensator and turned on during, for example, bypass power feeding. When the VCB 6 is turned on, an AC voltage VI is supplied from the commercial AC power supply 71 to the load 72 via the VCB 6, and the load 72 operates.

[0022] The power converter 7 includes a bidirectional converter 8, a fuse 9, a current detector 10, a reactor 11, and a capacitor 12. The DC terminal 8a of the bidirectional converter 8 is connected to the DC terminal T3, and the AC terminal 8b is connected to the primary winding 20a of the transformer 20 via the fuse 9 and the reactor 11. The secondary winding 20b of the transformer 20 is connected to a node N1 between the high-speed switch 2 and the VCB 5 via the VCB 21. The instantaneous value of the AC voltage VAC appearing in the primary winding 20a of the transformer 20 is detected by the control device 23.

[0023] The bidirectional converter 8 is a well-known device including a plurality of semiconductor switching elements and a plurality of diodes, and is controlled, for example, by PWM (Pulse Width Modulation) by the control device 23. By turning on and off each semiconductor switching element included in the bidirectional converter 8 at a predetermined frequency, it becomes possible to convert AC power to DC power, and conversely, to convert DC power to AC power.

[0024] When the AC voltage VI supplied from the commercial AC power supply 71 is normal, the bidirectional converter 8 converts the AC power supplied from the commercial AC power supply 71 via the VCB 1, the high-speed switch 2, the VCB 21, the transformer 20, the reactor 1N21, and the fuse 9 into DC power and stores it in the power storage device 73.

[0025] Furthermore, when the AC voltage VI is abnormal, the bidirectional converter 8 converts the DC power of the power storage device 73 into AC power and outputs it to the AC terminal 8b. This AC power is supplied to the load 72 via the fuse 9, the reactor 11, the transformer 20, and the VCBs 21 and 5.

[0026] The fuse 9 protects the bidirectional converter 8 from overcurrent. The current detector 10 detects a current IL flowing through the reactor 11, and provides the control device 23 with a signal ILf indicating the detected value.

[0027] The reactor 11 and the capacitor 12 constitute an AC filter. This AC filter is a low-pass filter that passes a current of the commercial frequency and blocks a current of the switching frequency generated by the bidirectional converter 8. In other words, the AC filter converts the output voltage of the bidirectional converter 8 into a sinusoidal AC voltage VAC.

[0028] The transformer 20 exchanges AC power between the node N1 and the power converter 7. The VCB 21 is turned on during normal operation of the instantaneous sag compensator, and is turned off, for example, during maintenance of the high-speed switch 2 or the power converter 7.

[0029] The operation unit 22 includes a plurality of buttons, a plurality of switches, a display, etc. By operating the operation unit 22, a user of the voltage sag compensator can instruct the voltage sag compensator to start, stop, operate automatically or manually, and set various conditions. The operation unit 22 sends signals indicating the user's instructions to the control device 23.

[0030] The control device 23 controls the entire instantaneous sag compensator based on signals from the operation unit 22, AC voltages VI, VO, VAC, DC voltage VDC, output signal ILf of the current detector 10, and the like.

[0031] When the AC voltage VI supplied from the commercial AC power supply 71 is normal, the control device 23 controls the bidirectional converter 8 based on the AC voltage VAC, the DC voltage VDC, and the output signal ILf of the current detector 10 so that the DC voltage VDC at the DC terminal T3 becomes a predetermined reference DC voltage VDCr.

[0032] When the AC voltage VI supplied from the commercial AC power supply 71 is abnormal, the control device 23 controls the bidirectional converter 8 so that the AC voltage VO at the output terminal T2 becomes a predetermined reference AC voltage VOr.

[0033] 2 is a diagram showing an example of the hardware configuration of the control device 23. Typically, the control device 23 can be configured by a microcomputer in which a predetermined program is stored in advance.

[0034] 2, the control device 23 includes a CPU (Central Processing Unit) 230, a memory 232, and an input / output (I / O) circuit 234. The CPU 230, the memory 232, and the I / O circuit 234 can exchange data with one another via a bus 236. Programs are pre-stored in a partial area of ​​the memory 232, and various functions can be realized by the CPU 230 executing the programs.

[0035] 2, at least a part of the control device 23 can be configured using a circuit such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).Furthermore, at least a part of the control device 23 can also be configured using an analog circuit.

[0036] 1 , the drive power supply 30 is controlled by the control device 23 and drives the mechanical switch 4. The drive power supply 30 is equipped with a capacitor that stores DC power, and uses the power stored in the capacitor to turn on the mechanical switch 4 when the AC voltage is VI, and to turn off the mechanical switch 4 when the AC voltage VI is abnormal.

[0037] High reliability is required of the capacitor in order to instantly turn off the mechanical switch 4 when a momentary drop occurs in the commercial AC power supply 71 and ensure the supply of power to the load 72. Therefore, the deterioration state of the capacitor must be diagnosed, and if it is determined that the deterioration state is progressing, measures such as replacing the capacitor must be taken.

[0038] In this embodiment, the drive power supply 30 is configured to diagnose the degradation state of the capacitor in parallel with driving the mechanical switch 4. More specifically, the drive power supply 30 has a charging circuit for charging the capacitor with DC power, and is configured to diagnose the degradation state of the capacitor while the capacitor is being charged by this charging circuit. Because the degradation diagnosis of the capacitor is performed using an existing charging circuit in this way, there is no need to mount a dedicated degradation diagnosis device on the instantaneous voltage sag compensator. Therefore, it is possible to diagnose the degradation state of the capacitor with a compact configuration.

[0039] <Configuration of Driving Power Supply> Fig. 3 is a diagram showing an example of the configuration of the driving power supply 30 according to embodiment 1. As shown in Fig. 3, the driving power supply 30 is configured to supply a driving current to the mechanical switch 4.

[0040] The mechanical switch 4 includes a mechanical contact 40 and coils 42 and 44 that open and close the mechanical contact 40. The mechanical contact 40 is formed using an elastic material such as a spring.

[0041] The coil 42 receives a drive current Id1 from the drive power supply 30 and converts electrical energy into mechanical energy to open the mechanical contact 40. When the mechanical contact 40 is opened, the mechanical switch 4 is turned off and the current to the mechanical switch 4 is stopped (opened). In the following description, the coil 42 is also referred to as an "open coil" for turning off the mechanical switch 4.

[0042] The coil 44 receives a drive current Id2 from the drive power supply 30 and converts electrical energy into mechanical energy to close the mechanical contact 40. Closing the mechanical contact 40 turns on the mechanical switch 4, and starts (closes) current to the mechanical switch 4. In the following description, the coil 42 is also referred to as a "closing coil" for turning on the mechanical switch 4.

[0043] The drive power supply 30 includes drive circuits 32 and 34 , a charging circuit 36 ​​, a current detector 50 , a charging current detection circuit 52 , a charging voltage detection circuit 54 , a charging control circuit 56 , and a power outage detection circuit 60 .

[0044] The drive circuit 32 is a circuit for supplying a drive current Id1 to the open coil 42. The drive circuit 32 includes a capacitor C1, a drive power switch unit 320, a current detector 322, a drive current detection circuit 324, and a drive power control circuit 326.

[0045] The capacitor C1 is configured by connecting a plurality of electrolytic capacitor elements in series and / or parallel, and has a positive terminal connected to the DC positive bus PL1 and a negative terminal connected to the DC negative bus NL1.

[0046] The drive power switch unit 320 uses the power stored in the capacitor C1 to supply a drive current Id1 to the open coil 42. The drive power switch unit 320 has a switch for controlling the supply and stop of the drive current Id1. The on / off of this switch is controlled by a drive power control circuit 326. When the switch is turned on, the drive current Id1 is supplied from the capacitor C1 to the open coil 42. When the switch is turned off, the supply of the drive current Id1 to the open coil 42 is stopped.

[0047] The current detector 322 is provided on the DC positive bus PL 1 or the DC negative bus NL 1 between the drive power supply switch unit 320 and the open coil 42 , and detects the drive current Id 1 flowing through the open coil 42 .

[0048] The drive current detection circuit 324 receives a signal Id1f indicating the detected value of the drive current Id1 from the current detector 322 and provides the received signal Id1f to the charge control circuit 56.

[0049] The drive power supply control circuit 326 controls the drive power supply switch unit 320 based on a power failure detection signal DET from the power failure detection circuit 60. The power failure detection circuit 60 generates the power failure detection signal DET based on the AC voltage VI at the input terminal T1. The power failure detection signal DET is set to an L (logical low) level when the AC voltage VI supplied from the commercial AC power supply 71 is normal, and is set to an H (logical high) level when the AC voltage VI is abnormal.

[0050] When the power failure detection signal DET is at an L level, that is, when the AC voltage VI supplied from the commercial AC power supply 71 is normal, the drive power supply control circuit 326 maintains the switch included in the drive power supply switch unit 320 in an OFF state. By maintaining the switch in an OFF state, the supply of the drive current Id1 to the open coil 42 is stopped.

[0051] When a momentary drop occurs in the commercial AC power supply 71 and the power failure detection signal DET transitions from L level to H level, the drive power supply control circuit 326 temporarily turns on a switch included in the drive power supply switch unit 320. While the switch is in the ON state, a drive current Id1 is supplied to the opening coil 42. The opening coil 42 converts electrical energy based on the drive current Id1 into mechanical energy, thereby opening the mechanical contact 40 of the mechanical switch 4. When the mechanical contact 40 is opened, the mechanical switch 4 is turned off. The ON period of the switch in the drive power supply switch unit 320 is set in advance based on the electrical energy required by the opening coil 42 to open the mechanical contact 40.

[0052] The drive circuit 34 is a circuit for supplying a drive current Id2 to the closing coil 44. The drive circuit 34 includes a capacitor C2, a drive power switch unit 340, a current detector 342, a drive current detection circuit 344, and a drive power control circuit 346.

[0053] Capacitor C2 is configured by connecting a plurality of electrolytic capacitor elements in series and / or parallel. The positive terminal of capacitor C2 is connected to DC positive bus PL2, and the negative terminal of capacitor C2 is connected to DC negative bus NL2. DC positive bus PL2 is electrically connected to DC positive bus PL1. DC negative bus NL2 is electrically connected to DC negative bus NL1.

[0054] The drive power switch unit 340 uses the power stored in the capacitor C2 to supply the drive current Id2 to the closing coil 44. The drive power switch unit 340 has a switch for controlling the supply and stop of the drive current Id2. The on / off of this switch is controlled by the drive power control circuit 346. When the switch is turned on, the drive current Id2 is supplied from the capacitor C2 to the closing coil 44. When the switch is turned off, the supply of the drive current Id2 to the closing coil 44 is stopped.

[0055] Current detector 342 is provided on DC positive bus PL2 or DC negative bus NL2 between drive power supply switch unit 340 and closing coil 44, and detects drive current Id2 flowing through closing coil 44.

[0056] The drive current detection circuit 344 receives a signal Id2f indicating the detected value of the drive current Id2 from the current detector 342 and provides the received signal Id2f to the charge control circuit 56.

[0057] The drive power supply control circuit 346 controls the drive power supply switch unit 340 based on the power failure detection signal DET from the power failure detection circuit 60 .

[0058] When the power failure detection signal DET is at H level, the drive power control circuit 346 maintains in the OFF state the switch included in the drive power switch unit 340. By maintaining the switch in the OFF state, the supply of the drive current Id2 to the closing coil 44 is stopped.

[0059] When the power failure detection signal DET transitions from H level to L level, the drive power supply control circuit 346 temporarily turns on a switch included in the drive power supply switch unit 340. While the switch is in the ON state, a drive current Id2 is supplied to the closing coil 44. The closing coil 44 converts electrical energy based on the drive current Id2 into mechanical energy, thereby closing the mechanical contact 40 of the mechanical switch 4. Closing the mechanical contact 40 turns on the mechanical switch 4. The ON period of the switch in the drive power supply switch unit 340 is set in advance based on the electrical energy required by the closing coil 44 to close the mechanical contact 40.

[0060] The charging circuit 36 ​​is a circuit for charging the capacitor C1 of the drive circuit 32 and the capacitor C2 of the drive circuit 34. By supplying a drive current Id1 from the drive circuit 32 to the opening coil 42 to turn off the mechanical switch 4, the amount of charge accumulated in the capacitor C1 decreases, and the voltage between the terminals of the capacitor C1 (hereinafter simply referred to as the "voltage of capacitor C1") drops. By supplying a drive current Id2 from the drive circuit 34 to the closing coil 44 to turn on the mechanical switch 4, the amount of charge accumulated in the capacitor C2 decreases, and the voltage between the terminals of the capacitor C2 (hereinafter simply referred to as the "voltage of capacitor C2") drops. The charging circuit 36 ​​is controlled by a charge control circuit 56 and supplies a charging current Ic to the capacitors C1 and C2. The charging current Ic is a constant current.

[0061] The charging circuit 36 ​​has a first charging mode in which a charging current Ic is supplied to the capacitor C1 to charge the capacitor C1, a second charging mode in which a charging current Ic is supplied to the capacitor C2 to charge the capacitor C2, and a third charging mode in which a charging current Ic is supplied to the capacitors C1 and C2 to charge the capacitors C1 and C2. The switching of the charging modes will be described in detail later.

[0062] The current detector 50 detects the charging current Ic flowing from the charging circuit 36 ​​to the corresponding capacitor in each of the first to third charging modes.

[0063] The charging current detection circuit 52 receives a signal Icf indicating the detected value of the charging current Ic from the current detector 50 , and provides the received signal Icf to the charging control circuit 56 .

[0064] Charge voltage detection circuit 54 detects instantaneous values ​​of DC voltage V1 of DC positive bus PL1 and DC voltage V2 of DC positive bus PL2, and provides signals V1f, V2f indicating the detected values ​​to charge control circuit 56. DC voltage V1 of DC positive bus PL1 corresponds to the voltage of capacitor C1. DC voltage V2 of DC positive bus PL2 corresponds to the voltage of capacitor C2.

[0065] The charging control circuit 56 controls the charging circuit 36 ​​based on the output signal Icf of the charging current detection circuit 52, the output signals V1f and V2f of the charging voltage detection circuit 54, the output signals Id1f and Idf of the drive current detection circuits 324 and 344, and the power outage detection signal DET.

[0066] In one aspect, the charge control circuit 56 controls the charging circuit 36 ​​to charge the capacitor C1 in response to the supply of the drive current Id1 to the open coil 42 being stopped, i.e., in response to the switch included in the drive power switch unit 320 being turned off. Specifically, the charge control circuit 56 controls the charging circuit 36 ​​to execute the first charging mode in response to the elapse of the switch on period from the time when the power failure detection signal DET transitions from low to high. When the charge current Ic is supplied to the capacitor C1 and the voltage V1 of the capacitor C1 reaches a predetermined upper limit VH, the charge control circuit 56 controls the charging circuit 36 ​​to stop the supply of the charge current Ic to the capacitor C1.

[0067] In another aspect, in response to the supply of drive current Id2 to closing coil 44 being stopped, i.e., in response to the switch included in drive power switch unit 340 being turned off, charge control circuit 56 controls charging circuit 36 ​​to execute the second charging mode in response to the elapse of the switch on period from the time point at which power failure detection signal DET transitions from H level to L level. When charge is accumulated in capacitor C2 upon receiving charging current Ic and voltage V2 of capacitor C2 reaches upper limit value VH, charge control circuit 56 controls charging circuit 36 ​​to stop supplying charging current Ic to capacitor C2.

[0068] If the voltage V1 of capacitor C1 and the voltage V2 of capacitor C2 have not yet reached the upper limit VH, the charging control circuit 56 controls the charging circuit 36 ​​to operate in the third charging mode. When the charging current Ic is supplied to the capacitors C1 and C2, charge is accumulated in the capacitors C1 and C2, and the voltages V1 and V2 of the capacitors C1 and C2 reach the upper limit VH, the charging control circuit 56 controls the charging circuit 36 ​​to stop supplying the charging current Ic to the capacitors C1 and C2.

[0069] The charging control circuit 56 includes a diagnostic circuit 58 for diagnosing the degradation state of the capacitors C1 and C2. The diagnostic circuit 58 diagnoses the degradation state of the capacitors C1 and C2 based on the output signal Icf of the charging current detection circuit 52 and the output signals V1f and V2f of the charging voltage detection circuit 54. The diagnostic circuit 58 will be described in detail later.

[0070] The functions of each block shown in Figure 3, namely, the drive current detection circuit 324 and drive power supply control circuit 326 in the drive circuit 32, the drive current detection circuit 344 and drive power supply control circuit 346 in the drive circuit 34, the charge current detection circuit 52, the charge voltage detection circuit 54, and the charge control circuit 56, can be realized by at least one of software processing and hardware processing by the control device 23 (Figure 1).

[0071] FIG. 4 is a circuit diagram showing an example of the circuit configuration of the drive circuits 32 and 34 and the charging circuit 36 ​​shown in FIG.

[0072] As shown in FIG. 4, the drive circuit 32 includes a positive input terminal 32a, a negative input terminal 32b, a positive output terminal 32c, a negative output terminal 32d, a diode D1, a capacitor C1, a discharge resistor R1, a freewheel circuit 320a, and a switch 320b.

[0073] The positive input terminal 32a is connected to the DC positive bus PL1, and the negative input terminal 32b is connected to the DC negative bus NL1. An open coil 42 is connected between the positive output terminal 32c and the negative output terminal 32d.

[0074] The diode D1 is connected between the positive input terminal 32a and the positive terminal of the capacitor C1 and is a diode for blocking reverse current.

[0075] The capacitor C1 can be represented by a series circuit of a capacitance C and a resistance component, ESR (Equivalent Series Resistance). Note that an electrolytic capacitor has the characteristic that as it deteriorates, the capacitance C decreases and the ESR increases.

[0076] The discharge resistor R1 is connected between the positive and negative terminals of the capacitor C1 and is provided to discharge the charge stored in the capacitor C1 when the drive circuit 32 is electrically disconnected from the open coil 42 and the charging circuit 36.

[0077] The freewheel circuit 320a and the switch 320b are connected in series between the positive and negative terminals of the capacitor C1. The freewheel circuit 320a and the switch 320b constitute the drive power switch unit 320 shown in Fig. 3. A node N2 between the freewheel circuit 320a and the switch 320b is connected to the negative output terminal 32d.

[0078] The switch 320b is a switch for controlling the supply and stop of the drive current Id1. The on and off of the switch 320b is controlled by the drive power supply control circuit 326. When the switch 320b is turned on, the drive current Id1 is supplied from the capacitor C1 to the open coil 42. The current detector 322 is inserted between the negative output terminal 32d and the node N2 and detects the drive current Id1. When the switch 320b is turned off, the supply of the drive current Id1 to the open coil 42 is stopped.

[0079] The freewheel circuit 320a is a circuit for protecting the drive circuit 32 from a surge voltage that occurs when the switch 320b is turned off to stop the supply of the drive current Id1 to the open coil 42. The freewheel circuit 320a is, for example, a diode whose cathode is electrically connected to the positive output terminal 32c and whose anode is electrically connected to the negative output terminal 32d.

[0080] The drive circuit 34 has a configuration similar to that of the drive circuit 32. Specifically, the drive circuit 34 includes a positive input terminal 34a, a negative input terminal 34b, a positive output terminal 34c, a negative output terminal 34d, a diode D2, a capacitor C2, a discharge resistor R2, a freewheel circuit 340a, and a switch 340b.

[0081] Positive input terminal 34a is connected to DC positive bus PL2, and negative input terminal 34b is connected to DC negative bus NL2. A closing coil 44 is connected between positive output terminal 34c and negative output terminal 34d.

[0082] The diode D2 is connected between the positive input terminal 34a and the positive terminal of the capacitor C2 and is a diode for blocking reverse current.

[0083] The discharge resistor R2 is connected between the positive and negative terminals of the capacitor C2 and is provided to discharge the charge stored in the capacitor C2 when the drive circuit 34 is electrically disconnected from the closing coil 44 and the charging circuit 36.

[0084] The freewheel circuit 340a and the switch 340b are connected in series between the positive and negative terminals of the capacitor C2. The freewheel circuit 340a and the switch 340b constitute the drive power switch unit 340 shown in Fig. 3. A node N3 between the freewheel circuit 340a and the switch 340b is connected to the negative output terminal 34d.

[0085] The switch 340b is a switch for controlling the supply and stop of the drive current Id2. The on and off of the switch 340b is controlled by a drive power supply control circuit 346. When the switch 340b is turned on, the drive current Id2 is supplied from the capacitor C2 to the closing coil 44. The current detector 342 is inserted between the negative output terminal 34d and a node N3 and detects the drive current Id2. When the switch 340b is turned off, the supply of the drive current Id2 to the closing coil 44 is stopped.

[0086] The return circuit 340a is a circuit for protecting the drive circuit 34 from a surge voltage that occurs when the switch 340b is turned off to stop the supply of the drive current Id2 to the closing coil 44. The return circuit 340a is, for example, a diode whose cathode is electrically connected to the positive output terminal 34c and whose anode is electrically connected to the negative output terminal 34d.

[0087] The charging circuit 36 ​​includes a battery 36a and a DC / DC converter 36b. The DC / DC converter 36b is controlled by the charging control circuit 56 and generates a charging current Ic based on the DC power of the battery 36a. The DC / DC converter 36b outputs an output voltage that matches the lower of the voltages V1 and V2. Because the drive circuits 32 and 34 are provided with backflow-blocking diodes D1 and D2, the charging current Ic is supplied only to the capacitor with the lower voltage. When the voltages V1 and V2 are equal, the charging current Ic is supplied to the capacitors C1 and C2. In this case, the charging current Ic supplied to each capacitor is approximately half the charging current Ic supplied to a single capacitor.

[0088] By controlling the output voltage in this way in the DC / DC converter 36b and by using the diodes D1 and D2 for blocking reverse current, the charging circuit 36 ​​can automatically switch between the first charging mode, the second charging mode, and the third charging mode according to the voltages V1 and V2.

[0089] DC reactor L1 is inserted in DC positive bus PL1 between DC / DC converter 36b and drive circuit 32, and smoothes the DC current supplied from DC / DC converter 36b.

[0090] <Operation of Driving Power Supply> Next, the operation of the driving power supply 30 according to the first embodiment will be described.

[0091] Fig. 5 is a diagram for explaining the operation of drive power supply 30. Fig. 5 shows waveforms representing the time changes of power failure detection signal DET, switches 320b and 340b, drive currents Id1 and Id2, voltages V1 and V2 of capacitors C1 and C2, and charging current Ic.

[0092] As shown in Fig. 5, at time t1, a momentary drop in the commercial AC power supply 71 causes the power failure detection signal DET to transition from L level to H level. In the drive circuit 32, the drive power supply control circuit 326 temporarily turns on the switch 320b in response to the transition of the power failure detection signal DET from L level to H level. In Fig. 5, the switch 320b is in the ON state during the period from time t1 to t2.

[0093] During the on period of this switch 320b, a drive current Id1 is supplied from the drive circuit 32 to the opening coil 42. The opening coil 42 converts electrical energy based on the drive current Id1 into mechanical energy, thereby opening the mechanical contact 40 of the mechanical switch 4. When the mechanical contact 40 is opened, the mechanical switch 4 is turned off.

[0094] Before time t1, the voltage V1 of the capacitor C1 is maintained at a predetermined upper limit VH. The voltage V1 of the capacitor C1 is proportional to the amount of charge stored in the capacitor C1. The upper limit VH is set based on the amount of charge required to supply the drive current Id1 to the open coil 42 during the ON period of the switch 320b.

[0095] Between times t1 and t2, the amount of charge stored in capacitor C1 decreases as drive current Id1 is supplied, causing voltage V1 across capacitor C1 to drop. At time t2, switch 320b is turned off, and in response, charge control circuit 56 controls charging circuit 36 ​​to charge capacitor C1. DC / DC converter 36b included in charging circuit 36 ​​outputs an output voltage that matches the lower voltage V1 of voltages V1 and V2, thereby supplying charging current Ic to capacitor C1. As a result, from time t2 onward, charge accumulates in capacitor C1, causing voltage V1 to gradually increase. Note that because charging current Ic is a constant current (current value I1), voltage V1 increases linearly.

[0096] At time t3, the commercial AC power supply 71 is restored, causing the power failure detection signal DET to transition from L level to H level. In the drive circuit 34, the drive power supply control circuit 346 temporarily turns on the switch 340b in response to the transition of the power failure detection signal DET from H level to L level. In FIG. 5, the switch 340b is in the ON state during the period from time t3 to t4. During the ON period of the switch 340b, a drive current Id2 is supplied from the drive circuit 34 to the closing coil 44. The closing coil 44 converts electrical energy based on the drive current Id2 into mechanical energy, thereby closing the mechanical contact 40 of the mechanical switch 4. Closing the mechanical contact 40 turns on the mechanical switch 4.

[0097] Before time t3, the voltage V2 of capacitor C2 is maintained at the upper limit value VH. Between times t3 and t4, the amount of charge stored in capacitor C2 decreases as drive current Id2 is supplied, causing the voltage V2 of capacitor C2 to drop. When switch 340b is turned off at time t4, charge control circuit 56 controls charging circuit 36 ​​to charge capacitor C2.

[0098] In the example of FIG. 5 , because neither voltage V1 nor V2 has reached the upper limit value VH at time t4, the charge control circuit 56 controls the charging circuit 36 ​​to charge the capacitors C1 and C2. Specifically, the DC / DC converter 36b included in the charging circuit 36 ​​outputs an output voltage that matches the lower of voltages V1 and V2. Because voltage V2 is lower than voltage V1, from time t4 onwards, a charging current Ic is supplied only to capacitor C2. As a result, charge is accumulated in capacitor C2, and voltage V2 increases linearly. Meanwhile, since the supply of charging current Ic to capacitor C1 is stopped from time t4 onwards, voltage V1 maintains the value it had at time t4.

[0099] When voltage V2 increases and becomes equal to voltage V1 (time t5), charging circuit 36 ​​supplies charging current Ic to capacitors C1 and C2. After time t5, charge accumulates in capacitors C1 and C2, causing voltages V1 and V2 to gradually increase. When voltages V1 and V2 reach upper limit VH, charging control circuit 56 stops charging circuit 36, thereby stopping the supply of charging current Ic.

[0100] As described above, the drive power supply 30 supplies drive currents Id1 and Id2 from the capacitors C1 and C2 to the coils 42 and 44, respectively, to open and close the mechanical contacts 40, thereby turning on or off the mechanical switch 4. After turning on or off the mechanical switch 4, the drive power supply 30 supplies a charging current Ic from the charging circuit 36 ​​to the capacitors C1 and C2 to charge the capacitors C1 and C2 so that the capacitors C1 and C2 store power for driving the mechanical switch 4 the next time.

[0101] While the capacitors C1 and C2 are being charged, the diagnostic circuit 58 diagnoses the deterioration state of the capacitors C1 and C2 based on the charging current Ic detected by the charging current detection circuit 52 and the voltages V1 and V2 of the capacitors C1 and C2 detected by the charging voltage detection circuit 54.

[0102] (Capacitor Deterioration Diagnosis) Fig. 6 is a diagram for explaining a first example of the capacitor deterioration diagnosis process in the diagnosis circuit 58. Fig. 6 shows extracted portions of the waveforms of the voltage V1 and charging current Ic of the capacitor C1 shown in Fig. 5. The deterioration diagnosis process for the capacitor C1 will be explained using Fig. 6.

[0103] 6, before time t2, the amount of charge stored in capacitor C1 decreases as drive current Id1 is supplied, causing voltage V1 of capacitor C1 to drop. At time t2, charging circuit 36 ​​starts supplying charging current Ic to capacitor C1. After time t2, charging circuit 36 ​​is controlled by charge control circuit 56 to supply charging current Ic having a constant value I1 to capacitor C1.

[0104] The voltage V1 of the capacitor C1 changes by ΔV2 at time t2 when the supply of the charging current Ic starts. This change ΔV2 occurs due to a change in the magnitude of the current flowing through the ESR of the capacitor C1.

[0105] During the period from time t2 to time t4, voltage V1 increases linearly. Based on the output signal V1f of the charging voltage detection circuit 54, the diagnostic circuit 58 detects the value VA of voltage V1 at time ta, which is after time t2. Time ta corresponds to the start point of measurement for diagnosis. VA corresponds to the voltage V1 of capacitor C1 at the start of measurement (hereinafter also referred to as the "measurement start voltage"). The time difference between time t2 and time ta is on the order of several milliseconds, which is set so that fluctuations in voltage V1 due to ESR are not included in the measurement results.

[0106] The diagnostic circuit 58 adds a predetermined amount ΔV1 to VA and sets the resultant voltage VB as the voltage V1 of the capacitor C1 at the end of the measurement (hereinafter also referred to as the "measurement end voltage") (VB = VA + ΔV1). The predetermined amount ΔV1 is set to, for example, about 1 / 2 to 1 / 3 of the rated voltage of the capacitor C1. This is to prevent fluctuations in the voltage V1 caused by the ESR when the supply of the charging current Ic is stopped from being included in the measurement result. The predetermined amount ΔV1 corresponds to one example of the "first amount."

[0107] The diagnostic circuit 58 detects the time tb at which the voltage V1 reaches the measurement end voltage VB based on the output signal V1f of the charging voltage detection circuit 54. This time tb corresponds to the measurement end point.

[0108] Next, based on the output signal Icf of the charging current detection circuit 52, the diagnostic circuit 58 detects the charging current Ic during the measurement period from the measurement start time ta to the measurement end time tb. The diagnostic circuit 58 then integrates the charging current Ic during the measurement period to calculate the amount of charge Q accumulated in the capacitor C1 during the measurement period. In the example of FIG. 6, since the charging current Ic is a constant value I1, the amount of charge Q is Q = I1 × (tb - ta). Note that this amount of charge Q corresponds to the area of ​​the portion of the waveform of the charging current Ic enclosed by times ta and tb.

[0109] The diagnostic circuit 58 calculates the capacitance C of the capacitor C1 by dividing the calculated charge Q by the change in the voltage V1 during the measurement period (a predetermined amount ΔV1) (C=Q / ΔV1). The diagnostic circuit 58 then diagnoses the degradation state of the capacitor C1 based on the calculated capacitance C. Electrolytic capacitors generally have the characteristic that the capacitance C decreases with degradation. The diagnostic circuit 58 diagnoses the degradation state of the capacitor C1 based on, for example, the amount of change in the current capacitance C compared to the capacitance C when the capacitor C1 is in its initial state.

[0110] Fig. 7 is a flowchart showing the deterioration diagnosis process for the capacitors in the driving power supply 30 according to the first embodiment. The flowchart in Fig. 7 is repeatedly executed at predetermined control intervals by the charge control circuit 56 in the control device 23 during operation of the driving power supply 30. Fig. 7 shows the procedure for the deterioration diagnosis process for the capacitor C1. The charge control circuit 56 also executes the deterioration diagnosis process for the capacitor C2 in parallel according to the same procedure as in Fig. 7.

[0111] 7, the charge control circuit 56 determines in step (hereinafter simply referred to as "S") 01 whether the switch 320b included in the drive power switch unit 320 of the drive circuit 32 has been turned off. In S01, if the ON period of the switch 320b has elapsed since the power failure detection signal DET transitioned from L level to H level, a YES determination is made in S01. If the power failure detection signal DET is at L level or H level, or if the ON period has not elapsed, a NO determination is made in S01.

[0112] If it is determined that switch 320b is turned off (YES in S01), the charging control circuit 56 proceeds to S02 and controls the charging circuit 36 ​​to charge capacitor C1. In S02, the DC / DC converter 36b included in the charging circuit 36 ​​outputs an output voltage that is equal to the lower voltage V1 of voltages V1 and V2, thereby supplying charging current Ic to capacitor C1.

[0113] During charging of the capacitor C1, the charge control circuit 56 detects the charge current Ic and the voltage V1 of the capacitor C1 based on the output signals of the charge current detection circuit 52 and the charge voltage detection circuit 54 in S03.

[0114] In step S04, the diagnostic circuit 58 detects the voltage V1 at the measurement start time ta, which is after the charging start time of the capacitor C1, and sets the detected value as the measurement start voltage VA. Subsequently, in step S05, the diagnostic circuit 58 sets the measurement end voltage VB by adding a predetermined amount ΔV1 to the measurement start voltage VA.

[0115] In step S06, the diagnostic circuit 58 detects the measurement end time tb at which the voltage V1 reaches the measurement end voltage V. In step S07, the diagnostic circuit 58 integrates the charging current Ic during the period from the measurement start time ta to the measurement end time tb to calculate the amount of charge Q stored in the capacitor C1 during that period.

[0116] In step S08, the diagnostic circuit 58 calculates the capacitance C of the capacitor C1 by dividing the calculated charge Q by a predetermined amount ΔV1 (C=Q / ΔV1). In step S09, the diagnostic circuit 58 diagnoses the deterioration state of the discharge of the capacitors C1 and C2 based on the capacitance C calculated in step S07.

[0117] In S10, the charge control circuit 56 determines whether the voltage V1 of the capacitor C1 is equal to or greater than the upper limit VH. If V1<VH (NO in S10), the charge control circuit 56 continues charging the capacitor C1.

[0118] If V1≧VH (YES in S10), the charging control circuit 56 controls the charging circuit 36 ​​to stop supplying the charging current Ic to the capacitor C1 in S11, thereby terminating the charging of the capacitor C1.

[0119] As described above, in the driving power supply 30 according to the first embodiment, while the capacitors C1 and C2 included in the driving power supply 30 of the mechanical switch 4 are being charged, the degradation state of the capacitors C1 and C2 is diagnosed from the charging current Ic detected by the charging current detection circuit 52 and the voltages V1 and V2 of the capacitors C1 and C2 detected by the charging voltage detection circuit 54. This makes it possible to diagnose the degradation state of the capacitors C1 and C2 using the charging circuit 36 ​​and the charging control circuit 56 already provided in the driving power supply 30, eliminating the need to mount a dedicated degradation diagnosis device on the instantaneous sag compensator. This makes it possible to diagnose the degradation state of the capacitors C1 and C2 with a compact configuration.

[0120] [Embodiment 2] In the above-described embodiment 1, a configuration was described in which the deterioration state of the capacitors C1 and C2 is diagnosed from the charging current Ic and voltages V1 and V2 of the capacitors C1 and C2 when the capacitors C1 and C2 are charged in preparation for the next driving of the mechanical switch 4 by the driving power supply 30.

[0121] In the above configuration, a relatively large charging current Ic is supplied to each capacitor, and the voltage of each capacitor changes significantly in response to this charging current Ic. This reduces the effect of detection errors by the charging current detection circuit 52 and the charging voltage detection circuit 54, and as a result, the capacitance of each capacitor can be calculated with high accuracy. Furthermore, because a deterioration diagnosis is performed each time capacitors C1 and C2 are charged, it is possible to detect rapid deterioration of capacitors C1 and C2 due to sparks that occur when capacitors C1 and C2 discharge.

[0122] However, on the other hand, when the frequency of voltage drops in the commercial AC power supply 71 is low, the drive power supply 30 drives the mechanical switch 4 less frequently. Therefore, in the configuration described in the first embodiment, the frequency of performing the deterioration diagnosis on the capacitors C1 and C2 is also low. In such a case, there is a concern that it may become difficult to detect the deterioration of the capacitors C1 and C2 over time. Even when the frequency of voltage drops in the commercial AC power supply 71 is low, it is necessary to periodically diagnose the deterioration state of the capacitors C1 and C2 in order to ensure the charge storage capacity of the capacitors C1 and C2 in preparation for the occurrence of a voltage drop.

[0123] Therefore, in the second embodiment, a configuration will be described in which the deterioration state of capacitors C1 and C2 is periodically diagnosed while driving power supply 30 is in a standby state. Note that the configuration of driving power supply 30 according to the second embodiment is the same as the configuration of driving power supply 30 shown in Figures 3 and 4 except for the configuration of diagnostic circuit 58, and therefore a description thereof will be omitted.

[0124] Fig. 8 is a flowchart showing the degradation diagnosis process for the capacitors in the drive power supply 30 according to embodiment 2. The flowchart of Fig. 8 is repeatedly executed at a predetermined control period by the charge control circuit 56 in the control device 23 during normal operation of the instantaneous sag compensator shown in Fig. 1. Fig. 8 shows the procedure for the degradation diagnosis process for capacitor C1. The charge control circuit 56 also executes the degradation diagnosis process for capacitor C2 in parallel according to the same procedure as Fig. 8.

[0125] As shown in FIG. 8, the charge control circuit 56 determines whether the switch 320b included in the drive power switch unit 320 of the drive circuit 32 has been turned off in S01, which is the same as in FIG.

[0126] If it is determined that switch 320b is turned off (YES in S01), the charge control circuit 56 proceeds to S02, the same as in Fig. 7, and controls the charging circuit 36 ​​to charge the capacitor C1. While the capacitor C1 is being charged, the charge control circuit 56 detects the charging current Ic and the voltage V1 of the capacitor C1 based on the output signals of the charging current detection circuit 52 and the charging voltage detection circuit 54 in S03, the same as in Fig. 7.

[0127] 7, the charge control circuit 56 determines whether the voltage V1 of the capacitor C1 is equal to or greater than the upper limit value VH. If V1<VH (NO in S10), the charge control circuit 56 continues charging the capacitor C1.

[0128] If V1≧VH (YES in S10), the charging control circuit 56 terminates charging of the capacitor C1 by controlling the charging circuit 36 ​​to stop supplying the charging current Ic to the capacitor C1 in S11, which is the same as in FIG. 7.

[0129] Returning to S01, if the switch 320b is not turned off (NO in S01), the charging control circuit 56 proceeds to S21 and determines whether the drive circuit 32 is in a standby state. In S21, if the voltage V1 of the capacitor C1 is equal to or greater than the upper limit value VH based on the output signal V1f of the charging voltage detection circuit 54, a YES determination is made in S21. If the voltage V1 is less than the upper limit value VH, a NO determination is made in S21.

[0130] When the drive circuit 32 is in a standby state (YES in S21), the charge control circuit 56 determines in S22 whether a predetermined period has elapsed since the last time the capacitor C1 was diagnosed for deterioration. In S22, the charge control circuit 56, which has a timing function, measures the elapsed time since the last time the deterioration diagnosis was performed. If the elapsed time has not reached the predetermined period (e.g., one month), the determination in S22 is NO. If the elapsed time has reached the predetermined period, the determination in S22 is YES.

[0131] If a predetermined period of time has elapsed since the last time the deterioration diagnosis of capacitor C1 was performed (YES in S22), the charge control circuit 56 proceeds to S23 and controls the charging circuit 36 ​​to charge capacitor C1. In S23, the charge control circuit 56 charges capacitor C1 so as to increase the voltage V1 of capacitor C1 by a predetermined amount ΔV3. When the drive circuit 32 is in a standby state, the voltage V1 of capacitor C1 is equal to or greater than the upper limit value VH. Therefore, the charging in S23 may cause capacitor C1 to become overcharged. If capacitor C1 becomes overcharged, an excessive drive current Id1 may be supplied to the open coil 42 during operation of the drive circuit 32, potentially causing the mechanical contact 40 to rebound. To avoid this situation, the predetermined amount ΔV3 is set to a small voltage that does not affect the operation of the drive circuit 32. The predetermined amount ΔV3 corresponds to an example of the "second amount."

[0132] While the capacitor C1 is being charged, the charge control circuit 56 detects the charge current Ic and the voltage V1 of the capacitor C1 based on the output signals of the charge current detection circuit 52 and the charge voltage detection circuit 54 in S24.

[0133] 7, diagnostic circuit 58 detects voltage V1 at measurement start time ta, which is after the charging start time of capacitor C1, and sets the detected value as measurement start voltage VA. Subsequently, in S05, also in FIG. 7, diagnostic circuit 58 sets measurement end voltage VB by adding a predetermined amount ΔV3 to measurement start voltage VA.

[0134] 7, diagnostic circuit 58 detects measurement end time tb at which voltage V1 reaches measurement end voltage V. In S07, diagnostic circuit 58 integrates charging current Ic during the period from measurement start time ta to measurement end time tb to calculate the amount of charge Q stored in capacitor C1 during that period.

[0135] 7, the diagnostic circuit 58 calculates the capacitance C of the capacitor C1 by dividing the calculated charge Q by a predetermined amount ΔV3 (C=Q / ΔV3). In S09, the diagnostic circuit 58 diagnoses the deterioration state of the discharge of the capacitors C1 and C2 based on the capacitance C calculated in S07.

[0136] The degradation diagnosis process for the capacitors C1 and C2 according to the second embodiment can be performed in combination with the degradation diagnosis process for the capacitors C1 and C2 according to the first embodiment. That is, when the driving power supply 30 is in an operating state for driving the mechanical switch 4, the degradation diagnosis process according to the first embodiment is performed during charging of the capacitors C1 and C2, and when the driving power supply 30 is in a standby state, the degradation diagnosis process according to the second embodiment can be performed.

[0137] In this way, it is possible to appropriately diagnose the deterioration state of the capacitors C1 and C2 regardless of the frequency of occurrence of momentary dips in the commercial AC power supply 71. That is, in a situation where the frequency of occurrence of momentary dips in the commercial AC power supply 71 is high, it is possible to detect rapid deterioration of the capacitors C1 and C2 due to repeated sparks during discharge. Also, in a situation where the frequency of occurrence of momentary dips in the commercial AC power supply 71 is low, it is possible to detect deterioration over time of the capacitors C1 and C2.

[0138] Third Embodiment In the first and second embodiments described above, the configuration for calculating the capacitance C of each capacitor in order to diagnose the degradation state of the capacitors C1 and C2 has been described. In a third embodiment, a configuration for calculating the ESR of each capacitor will be described.

[0139] Fig. 9 is a diagram for explaining a second example of the capacitor deterioration diagnosis process in the diagnosis circuit 58. Fig. 9 shows extracted portions of the waveforms of the voltage V1, drive current Id1, and charging current Ic of the capacitor C1 shown in Fig. 5. The deterioration diagnosis process for the capacitor C1 will be explained using Fig. 9.

[0140] 9, before time t2, the amount of charge stored in capacitor C1 decreases as drive current Id1 is supplied, causing voltage V1 across capacitor C1 to drop. At time t2, charging circuit 36 ​​begins supplying charging current Ic to capacitor C1. After time t2, charging circuit 36 ​​is controlled by charge control circuit 56 to supply charging current Ic having a constant value I1 to capacitor C1.

[0141] At time t2, the voltage V1 of the capacitor C1 changes by ΔV2. This change ΔV2 occurs because the supply of the drive current Id1 from the capacitor C1 is stopped and the supply of the charging current Ic to the capacitor C1 is started, which changes the magnitude of the current flowing through the ESR of the capacitor C1.

[0142] That is, the change amount ΔV2 is the sum of the change amount ΔV21 caused by stopping the supply of the drive current Id1 and the change amount ΔV22 caused by starting the supply of the charging current Ic (ΔV2 = ΔV21 + ΔV22). ΔV21 has a magnitude equal to the product of the ESR and the value of the drive current Id1 (ESR x Id1). ΔV22 has a magnitude equal to the product of the ESR and the value I1 of the charging current Ic (ESR x I1). ΔV21 corresponds to the amount by which the voltage V1 is reduced, and ΔV22 corresponds to the amount by which the voltage V1 is increased.

[0143] The diagnostic circuit 58 detects the amount of change ΔV2 based on the output signal of the charging voltage detection circuit 54, and calculates the ESR by dividing the detected amount of change ΔV2 by the sum of the driving current Id1 and the charging current Ic. Note that the driving current Id1 has a negative value, and the charging current Ic has a positive value.

[0144] The diagnostic circuit 58 diagnoses the degradation state of the capacitor C1 based on the calculated capacitance C. Electrolytic capacitors generally have the characteristic that the ESR increases as they deteriorate. The diagnostic circuit 58 diagnoses the degradation state of the capacitor C1 based on, for example, the amount of change in the current ESR compared to the ESR when the capacitor C1 is in its initial state.

[0145] 9 illustrates an example of a configuration in which ESR is calculated from an increase ΔV3 in voltage V1 at time t2 when the supply of charging current Ic to capacitor C1 begins. However, it is also possible to calculate ESR from a change ΔV4 in voltage V1 at time t4 when the supply of charging current Ic to capacitor C1 is stopped. ΔV4 has a magnitude equal to the product of ESR and the value I1 of charging current Ic (ESR × I1). ΔV4 corresponds to the amount of reduction in voltage V1.

[0146] In the above-described first to third embodiments, an example configuration of a drive power supply that supplies a drive current to a mechanical switch included in a power supply device has been described, but the drive power supply according to the present disclosure is not limited to power supply devices and can be applied to devices that include mechanical switches. When applied to any device, it is possible to diagnose the deterioration state of a capacitor included in the drive power supply without increasing the size of the device.

[0147] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the scope of the claims, and it is intended to include all modifications within the meaning and scope of the claims.

[0148] 1, 5, 6, 21 VCB, 2 High-speed switch, 3 Semiconductor switch, 4 Mechanical switch, 7 Power converter, 8 Bidirectional converter, 9 Fuse, 10, 50, 322, 342 Current detector, 11 Reactor, 12, C1, C2 Capacitor, 20 Transformer, 20a Primary winding, 20b Secondary winding, 22 Operation unit, 23 Control device, 30 Drive power supply, 32, 34 Drive circuit, 32a, 34b Positive input terminal, 32b, 34b Negative input terminal, 32c, 34c Positive output terminal, 32d, 34d Negative output terminal, 36 Charging circuit, 36a Battery, 36b DC / DC converter, 40 Mechanical contact, 42 Open coil, 44 Closing coil, 52 Charging current detection circuit, 54 Charging voltage detection circuit, 56 Charging control circuit, 58 Diagnostic circuit, 60 power failure detection circuit, 71 commercial AC power supply, 72 load, 73 power storage device, 230 CPU, 232 memory, 234 I / O circuit, 236 bus, 320, 340 drive power switch unit, 320a, 340a return circuit, 320b, 340b switch, 324, 344 drive current detection circuit, 326, 346 drive power control circuit, T1 input terminal, T2 output terminal, T3 DC terminal, PL1, PL2 DC positive bus, NL1, NL2 DC negative bus, L1 DC reactor, R1, R2 discharge resistor, D1, D2 diode, Id1, Id2 drive current, Ic charge current, DET power failure detection signal.

Claims

1. A driving power supply for supplying a driving current to a mechanical switch, the mechanical switch including a mechanical contact and a coil that opens and closes the mechanical contact upon receiving the driving current, the driving power supply comprising: a capacitor; and a switch connected between the capacitor and the coil, the switch being configured to supply the driving current from the capacitor to the coil by being temporarily turned on to turn the mechanical switch on or off, the driving power supply further comprising: a charging circuit that charges the capacitor while the switch is off; a detection circuit that detects the charging current and voltage of the capacitor; and a diagnosis circuit that diagnoses the deterioration state of the capacitor from the charging current and the voltage detected by the detection circuit.

2. A driving power supply for a mechanical switch as described in claim 1, wherein the charging circuit charges the capacitor during the off period after the switch is temporarily turned on, and while the capacitor is being charged, the diagnostic circuit: calculates the amount of charge stored in the capacitor during a period in which the voltage of the capacitor increases by a first amount by integrating the charging current during that period; calculates the capacitance of the capacitor by dividing the calculated amount of charge by the first amount; and diagnoses the deterioration state of the capacitor based on the calculated capacitance.

3. A driving power supply for a mechanical switch as described in claim 1 or 2, wherein the charging circuit charges the capacitor so as to increase the voltage of the capacitor by a second amount when the switch is off and a predetermined period has elapsed since the previous diagnosis, and while the capacitor is being charged, the diagnostic circuit: calculates the amount of charge accumulated in the capacitor during a period in which the voltage of the capacitor increases by the second amount by integrating the charging current during that period; calculates the capacitance of the capacitor by dividing the calculated amount of charge by the second amount; and diagnoses the deterioration state of the capacitor based on the calculated capacitance.

4. A driving power supply for a mechanical switch as described in claim 1, wherein the diagnostic circuit calculates an equivalent series resistance of the capacitor from the amount of change in voltage based on the charging current at the start or end of charging of the capacitor, and diagnoses the deterioration state of the capacitor based on the calculated equivalent series resistance.

5. A power supply device comprising: a mechanical switch having a first terminal that receives an AC voltage supplied from an AC power source and a second terminal that is connected to a load; a power converter connected between the second terminal of the mechanical switch and a power storage device; a control device configured to turn on the mechanical switch when the AC power source is normal and turn off the mechanical switch when the AC power source is abnormal; and a drive power source that supplies a drive current to the mechanical switch in response to an instruction from the control device, wherein the mechanical switch includes a mechanical contact and a coil that opens and closes the mechanical contact when the drive current is supplied, the drive power source includes: a capacitor; and a switch connected between the capacitor and the coil, the switch being configured to supply the drive current from the capacitor to the coil by being temporarily turned on to turn the mechanical switch on or off, and the drive power source further including: a charging circuit that charges the capacitor while the switch is off; a detection circuit that detects the charging current and voltage of the capacitor; and a diagnosis circuit that diagnoses deterioration of the capacitor from the charging current and the voltage detected by the detection circuit.

6. A degradation diagnosis method for a capacitor included in a driving power supply that supplies a driving current to a mechanical switch, wherein the mechanical switch includes a mechanical contact and a coil that opens and closes the mechanical contact when supplied with the driving current, and the driving power supply includes a capacitor and a switch connected between the capacitor and the coil, and is configured to supply the driving current from the capacitor to the coil by temporarily turning on the switch to turn the mechanical switch on or off, the degradation diagnosis method comprising the steps of: charging the capacitor during a period when the switch is off; detecting the charging current and voltage of the capacitor; and diagnosing the degradation state of the capacitor from the charging current and the voltage.

7. A degradation diagnosis method according to claim 6, wherein the charging step includes a step of charging the capacitor during the off period after the switch is temporarily turned on, and the diagnosing step includes a step of calculating an amount of charge stored in the capacitor during a period in which the voltage of the capacitor increases by a first amount while the capacitor is being charged, by integrating the charging current during said period, calculating the capacitance of the capacitor by dividing the calculated amount of charge by the first amount, and diagnosing a degradation state of the capacitor based on the calculated capacitance.

8. A degradation diagnosis method as claimed in claim 6 or 7, wherein the charging step includes a step of charging the capacitor so as to increase the voltage of the capacitor by a second amount when a predetermined period has elapsed since the previous diagnosis while the switch is off, and the diagnosing step includes a step of calculating an amount of charge accumulated in the capacitor during a period in which the voltage of the capacitor increases by the second amount while the capacitor is being charged, by integrating the charging current during that period; a step of calculating the capacitance of the capacitor by dividing the calculated amount of charge by the second amount; and a step of diagnosing a degradation state of the capacitor based on the calculated capacitance.

9. A degradation diagnosis method as described in claim 6, wherein the diagnosing step includes the steps of: calculating an equivalent series resistance of the capacitor from an amount of change in voltage based on the charging current at the start or end of charging of the capacitor; and diagnosing a degradation state of the capacitor based on the calculated equivalent series resistance.

Images