Parallel output control system

Abstract

This invention provides a parallel output control system that controls the balance of the overall output current of a system by connecting multiple power supply units, each of which lacks a balance control function, in parallel. [Solution] The current detector has a core-type magnetic field detection current detector 2, and the core 20 of the core-type magnetic field detection current detector 2 has a first wiring L1 through which a supply current from one of the dual power supply units PD1, PD2 toward the load device LD or a feedback current from the load device LD toward the one side flows, and a second wiring L2 through which a supply current from the other of the dual power supply units PD1, PD2 toward the load device LD or a feedback current toward the other side flows, such that the currents flowing through the first wiring L1 and the second wiring L2 flow in opposite directions within the core 20, and the current balance controller 3 adjusts the output current balance of the dual power supply units PD1, PD2 based on the detection signal output by the core-type magnetic field detection current detector 2.

Description

Technical Field

[0001] The present invention relates to a parallel output control system used when adding a power supply device.

Background Art

[0002] When new functions and operations increase in load devices such as factory equipment like conveyors, robot devices, lighting devices, etc., the power consumption of the load devices increases. Along with this, it is necessary to increase the output power of the power supply device that supplies power to the load device. Conventionally, as one means of increasing the output power of the power supply device, it has been considered to connect one or more power supply devices identical to the existing power supply device in parallel to increase the output current. In this case, as in Patent Document 1, in order to improve the reliability of power supply from the power supply device, a balance control function for balancing the output current of each power supply device has been provided in each power supply device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the existing power supply device does not have a balance control function, it is necessary to replace it with a power supply device having a rated output corresponding to the increased power consumption of the load device due to the newly added functions and operations, or a power supply device having a balance control function. This is costly, and the compatibility of the combination with the load device also needs to be adjusted, making the work complicated. In addition, a power supply device having a balance control function has a circuit configuration for implementing the balance control function, so it is bulkier than an existing power supply device without a balance control function and is difficult to replace smoothly.

[0005] Therefore, in view of the above-mentioned circumstances, the present invention aims to provide a parallel output control system that controls the balance of the overall output current of a system by connecting multiple power supply units, which do not have a balance control function, in parallel. [Means for solving the problem]

[0006] In light of the current situation, the inventors conducted thorough research and found that by connecting an additional power supply unit of the same type and characteristics as an existing power supply unit in parallel, and by using a core-type magnetic field detection current detector to control the balance of the output current, the output current supplied to the load device can be increased, thus completing the present invention.

[0007] In other words, the present invention encompasses the following inventions. (1) A parallel output control system provided between two power supplies connected in parallel and a load device, the parallel output control system having a core-type magnetic field detection current detector, wherein a first wiring through which a supply current from one of the two power supplies toward the load device or a feedback current from the load device toward the one power supply flows, and a second wiring through which a supply current from the other power supply toward the load device or a feedback current from the load device toward the other flow, are arranged such that the currents flowing through the first wiring and the second wiring flow in opposite directions within the core, and the parallel output control system having a current balance controller that adjusts the output current balance of the two power supplies based on a detection signal output by the core-type magnetic field detection current detector.

[0008] (2) The parallel output control system according to (1), wherein, when the magnitudes of the rated output currents of each power supply are different, one or both of the first and second wirings are passed through the core multiple times so that the magnetic field generated in the core of the core-type magnetic field detection current detector is balanced by the currents flowing through each wiring.

[0009] (3) The parallel output control system according to (1) or (2), wherein one or both of the two power supply units are provided with an output adjustment terminal for receiving an adjustment signal output by the current balance controller, and further comprises a fault detector for detecting a fault occurring in either of the two power supply units based on the adjustment signal output by the current balance controller to the output adjustment terminal.

[0010] (4) A parallel output control system provided between three power supply units connected in parallel and a load device, comprising a first core-type magnetic field detection current detector and a second core-type magnetic field detection current detector, wherein a first wiring through which a supply current from one of the two power supply units of the three power supply units toward the load device or a feedback current from the load device toward the one power supply unit flows, and a second wiring through which a supply current from the other power supply unit toward the load device or a feedback current from the load device toward the other power supply unit flows, are passed through the core of the first core-type magnetic field detection current detector such that the currents flowing through the first wiring and the second wiring flow in opposite directions within the core, and are connected on the load device side. A parallel output control system comprising: a third wiring through which a supply current from the remaining one of the three power supplies toward the load device or a feedback current returning from the load device toward the one power supply flows within the core of the second core-type magnetic field detection current detector; and a fourth wiring extending toward the load device from the connection point where the first and second wirings are connected, such that the currents flowing through the third and fourth wirings flow in opposite directions within the core; and a current balance controller that adjusts the output current balance of the three power supplies based on the detection signals output by the first core-type magnetic field detection current detector and the second core-type magnetic field detection current detector.

[0011] (5) The parallel output control system according to (4), wherein, when the magnitudes of the rated output currents of the two power supplies are different, one or both of the first and second wirings are passed through the core multiple times so that the magnetic field generated in the core of the first core-type magnetic field detection current detector is balanced by the currents flowing through the first and second wirings.

[0012] (6) The parallel output control system according to (4) or (5), wherein one or both of the third and fourth wirings are passed through the core multiple times so that the magnetic field generated in the core of the second core-type magnetic field detection current detector is balanced by the currents flowing through each of the third and fourth wirings.

[0013] (7) The parallel output control system according to (4), wherein at least one of the three power supply units is provided with an output adjustment terminal for receiving an adjustment signal output by the current balance controller, and further comprises a fault detector for detecting a fault occurring in any of the three power supply units based on the adjustment signal output by the current balance controller to the output adjustment terminal.

[0014] (8) A parallel output control system provided between four parallel-connected power supplies and a load device, comprising a first core-type magnetic field detection current detector, a second core-type magnetic field detection current detector, and a third core-type magnetic field detection current detector, wherein the core of the first core-type magnetic field detection current detector contains a first wiring through which a supply current from one of the two power supplies of the four power supplies toward the load device or a feedback current from the load device toward the one power supply flows, and a second wiring through which a supply current from the other power supply toward the load device or a feedback current from the load device toward the other power supply flows, the currents flowing through the first wiring and the second wiring flow toward the other power supply within the core and are connected on the load device side, wherein the core of the second core-type magnetic field detection current detector contains a third wiring through which a supply current from one of the remaining two power supplies of the four power supplies toward the load device or a feedback current from the load device toward the one power supply flows, and the other A parallel output control system comprising: a fourth wiring through which a supply current toward the load device or a feedback current returning from the load device to the other flows, the third wiring and the fourth wiring are connected on the load device side such that the currents flowing through them flow in opposite directions within the core; a fifth wiring extending from a first connection point where the first wiring and the second wiring are connected to the load device side, and a sixth wiring extending from a second connection point where the third wiring and the fourth wiring are connected to the load device side, the fifth wiring and the sixth wiring being connected within the core such that the currents flowing through them flow in opposite directions within the core; and a current balancing controller that adjusts the output current balance of the four power supplies based on the detection signals output by the first core-type magnetic field detection current detector, the second core-type magnetic field detection current detector, and the third core-type magnetic field detection current detector.

[0015] (9) The parallel output control system according to (8), wherein, when the magnitudes of the rated output currents of the two power supplies are different, one or both of the first and second wirings are passed through the core multiple times so that the magnetic field generated in the core of the first core-type magnetic field detection current detector is balanced by the currents flowing through the first and second wirings.

[0016] (10) The parallel output control system according to (8) or (9), wherein, when the magnitudes of the rated output currents of the remaining two power supplies are different, one or both of the third and fourth wirings are passed through the core multiple times so that the magnetic field generated in the core of the second core-type magnetic field detection current detector is balanced by the currents flowing through the third and fourth wirings.

[0017] (11) The parallel output control system according to (8), wherein one or both of the fifth and sixth wirings are passed through the core multiple times so that the magnetic field generated in the core of the third core-type magnetic field detection current detector is balanced by the currents flowing through each of the fifth and sixth wirings.

[0018] (12) The parallel output control system according to (8), wherein at least one of the four power supply units is provided with an output adjustment terminal for receiving an adjustment signal output by the current balance controller, and further comprises a fault detector for detecting a fault occurring in any of the four power supply units based on the adjustment signal output by the current balance controller to the output adjustment terminal. [Effects of the Invention]

[0019] According to the parallel output control system according to the present invention described above, when a plurality of power supply devices without a balance control function are connected in parallel, they can be controlled collectively without controlling the balance of the output current for each power supply device. Therefore, the entire system does not become bulky and the cost can be reduced. Further, according to the parallel output control system according to the present invention, when it is detected that a failure has occurred in one of the plurality of power supply devices connected in parallel, the other power supply devices are stopped, and the protection of the load device and the prevention of failure of the other power supply devices that have not failed can be achieved.

Brief Description of the Drawings

[0020] [Figure 1] Explanatory drawing showing a parallel output control system according to Embodiment 1 of the present invention. [Figure 2] Explanatory drawing showing an example of a current balance controller. [Figure 3] Explanatory drawing showing an example of a failure detector. [Figure 4] (a) is an explanatory drawing showing a state where the adjustment signal exceeds the upper limit determination voltage value, and (b) is an explanatory drawing showing a state where the adjustment signal falls below the lower limit determination voltage value. [Figure 5] Explanatory drawing showing a parallel output control system according to Embodiment 2 of the present invention. [Figure 6] Explanatory drawing showing a parallel output control system according to Embodiment 3 of the present invention. [Figure 7] Explanatory drawing showing a parallel output control system according to a modification of Embodiment 1 of the present invention. [Figure 8] Explanatory drawing showing a parallel output control system according to another modification of Embodiment 1 of the present invention.

Modes for Carrying Out the Invention

[0021] Next, each embodiment of the present invention will be described in detail based on the accompanying drawings.

Embodiment

[0022] As shown in Figure 1, the parallel output control system 1A according to Embodiment 1 of the present invention is installed between two power supply units PD1 and PD2 connected in parallel and a load device LD. The parallel output control system 1A has a core-type magnetic field detection current detector 2, and a first wiring L1 and a second wiring L2 pass through the core 20 of the core-type magnetic field detection current detector 2. In this example, the supply current from power supply unit PD1 to load device LD flows through the first wiring L1, and the supply current from power supply unit PD2 to load device LD flows through the second wiring L2, and the currents flowing through the first wiring L1 and the second wiring L2 respectively flow in opposite directions within the core 20. The parallel output control system 1A according to Embodiment 1 of the present invention has a current balance controller 3, and the current balance controller 3 adjusts the output current from power supply unit PD2 to be in balance with the output current from power supply unit PD1 based on the detection signal output by the core-type magnetic field detection current detector 2.

[0023] With this parallel output control system 1A, the difference in current caused by the currents flowing in opposite directions within the core 20 between the first wiring L1 and the second wiring L2 is detected as a detection signal by the core-mounted magnetic field detection type current detector 2, and the current balance controller 3 adjusts the balance of the output currents of the two power supply units PD1 and PD2 based on the detection signal. As a result, the power supply units can be controlled collectively without having to control each one individually, the overall system is not bulky and costs can be reduced.

[0024] In this embodiment, the dual power supply units PD1 and PD2 may be AC-DC switching power supplies that take a single-phase AC voltage as input and output a DC voltage, or they may be DC-DC switching power supplies or linear regulators that boost or buck the output voltage. In this embodiment, the load device LD is assumed to be, for example, a conveyor, a robot, a lighting device, a commercial server, or a door that opens and closes, but is not limited to these.

[0025] The core-type magnetic field detection current detector 2 can be any current detector that detects the difference in the magnetic field created by the magnetic core 20 when current flows through the first wiring L1 and the second wiring L2, and measures that difference as a differential current. A Hall element type current sensor is preferred, but a fluxgate type current sensor may also be used.

[0026] As shown in Figure 2, for example, the current balance controller 3 receives a detection signal (voltage signal) corresponding to the differential current between power supplies PD1 and PD2 detected by the core-type magnetic field detection current detector 2, which is input to the non-inverting input terminal V+ of the error amplifier EA. At this time, the voltage supplied from power supply PD1 is maintained at a voltage value of, for example, 2.5V by the constant voltage diode ZD, and this voltage is input to the inverting input terminal V- as the reference voltage of the error amplifier EA. The error amplifier EA determines whether the detection signal is above or below the reference voltage, and outputs an adjustment signal (voltage signal) to adjust at least one of the two power supplies PD1 and PD2 based on the determination result. Although the voltage supplied to the current balance controller 3 is the voltage supplied from power supply PD1, any voltage that can be used as the reference voltage for the error amplifier EA is acceptable, and a separate power supply may be provided. Furthermore, the resistors R1 to R5 in the current balance controller 3 shown in Figure 2 play a role in protecting circuit components from overcurrent and ensuring the stability of control by the current balance controller 3. As this is a well-known technology, a detailed explanation will be omitted.

[0027] One or both of the two power supply units PD1 and PD2 are provided with an output adjustment terminal OT that receives an adjustment signal output by the current balance controller 3. In this embodiment, the output adjustment terminal OT is provided on power supply unit PD2, and when the output adjustment terminal OT receives the adjustment signal, the output current of power supply unit PD2 is adjusted to balance with the output current of power supply unit PD1. As a result, the output current of each power supply unit is distributed evenly, and the current balance of the entire system is maintained.

[0028] The parallel output control system 1A further includes a fault detector 4 that detects a fault occurring in either of the dual power supplies PD1 or PD2 based on an adjustment signal output by the current balance controller 3 to the output adjustment terminal OT. When the fault detector 4 detects a fault occurring in at least one of the dual power supplies PD1 or PD2, it shuts off the output of the other dual power supply PD1 or PD2 that is not faulty, or all outputs of the dual power supplies PD1 or PD2, including the faulty one. Such a fault detector 4 prevents the other dual power supply PD1 or PD2 from failing and also prevents adverse effects on the load device LD.

[0029] The fault detector 4 is composed of comparators C1 and C2, as shown in Figure 3. In this example, the voltage supplied from the power supply PD1 is maintained at 1V by the constant voltage diode ZD2 and input to the inverting input terminal V- of comparator C2 as the lower limit judgment voltage. The voltage supplied from the power supply PD1 is a combination of the voltage maintained at 3V by the constant voltage diode ZD1 and the voltage maintained at 1V by the constant voltage diode ZD2, resulting in 4V, which is input to the non-inverting input terminal V+ of comparator C1. Although the voltages maintained by the constant voltage diodes ZD1 and ZD2 are the voltages supplied from the power supply PD1, any voltage that can be used as the upper and lower limit judgment voltages is acceptable, and a separate power supply may be provided. The resistor R in the fault detector 4 shown in Figure 3 plays a role in protecting the circuit components from overcurrent, and since this is a well-known technology, a detailed explanation is omitted.

[0030] The fault detector 4 determines whether the adjustment signal output from the current balance controller 3 exceeds the upper limit judgment voltage value or falls below the lower limit judgment voltage value, as determined by comparators C1 and C2. In this embodiment, as shown in Figure 4(a), if the adjustment signal exceeds the upper limit judgment voltage value, the fault detector 4 determines that power supply unit PD1 is faulty and stops the output of power supply unit PD2 to prevent excessive output from power supply unit PD2. Also, as shown in Figure 4(b), if the adjustment signal falls below the lower limit judgment voltage value, the fault detector 4 determines that power supply unit PD2 is faulty and stops the output of power supply unit PD1 to prevent excessive output from power supply unit PD1. As a modification, the fault detector 4 may not determine whether either of the two power supply units PD1 or PD2 is faulty, but may stop the output of both power supply units PD1 and PD2. If you want to determine which of the two power supplies PD1 and PD2 has failed, stopping the outputs of both power supplies PD1 and PD2 simultaneously will eliminate the output current, causing the output signal from the error amplifier EA of the current balance controller 3 to become undefined. This makes it difficult to accurately determine the order and location of the failures. However, by recording the output signal of the error amplifier EA using a memory circuit such as a data logger (not shown), it is possible to determine which power supply was faulty even after both power supplies PD1 and PD2 have been stopped. Note that although the fault detector 4 detects the failure of the two power supplies PD1 and PD2 using a circuit that includes comparators C1 and C2, it may also detect the failure using a microcontroller or other processor.

[0031] In this embodiment, the explanation is based on the premise that the two power supplies PD1 and PD2 both supply the same rated output current. However, the magnitudes of the rated output currents of the two power supplies PD1 and PD2 may differ. If the magnitudes of the rated output currents of the two power supplies PD1 and PD2 differ, one or both of the first and second wirings are passed through the core 20 multiple times. This balances the magnetic field generated in the core 20 of the core-type magnetic field detection current detector 2 by the currents flowing through the first wiring L1 and the second wiring L2. [Examples]

[0032] Example 2 will be described focusing on the differences from Example 1. As shown in Figure 5, the parallel output control system 1B according to Embodiment 2 of the present invention is installed between three parallel-connected power supplies PD1, PD2, and PD3 and a load device LD. The parallel output control system 1B has a first core-type magnetic field detection current detector 21 and a second core-type magnetic field detection current detector 22. A first wire L1 and a second wire L2 pass through the first core 201 of the first core-type magnetic field detection current detector 21, and the first wire L1 and the second wire L2 that have passed through the first core 201 are connected on the load device side of the first core 201. A third wire L3 and a fourth wire L4 pass through the second core 202 of the second core-type magnetic field detection current detector 22, and the fourth wire L4 extends from the connection point of the first wire and the second wire.

[0033] In this embodiment, the supply current from the power supply unit PD1 to the load device LD flows through the first wiring L1, the supply current from the power supply unit PD2 to the load device LD flows through the second wiring L2, and the currents flowing through the first wiring L1 and the second wiring L2 in the first core 201 flow in opposite directions. The supply current from the power supply unit PD3 to the load device LD flows through the third wiring L3, the combined current of the two wirings L1 and L2 flows through the fourth wiring L4 from the connection point of the first wiring L1 and the second wiring L2, and the currents flowing through the third wiring L3 and the fourth wiring L4 in the second core 202 flow in opposite directions. The parallel output control system 1B according to Embodiment 2 of the present invention has a first current balance controller 31 and a second current balance controller 32. The first current balance controller 31 adjusts the output current from power supply unit PD2 to balance with the output current from power supply unit PD1, based on the detection signal output by the first core-type magnetic field detection current detector 21. The second current balance controller 32 adjusts the output current from power supply unit PD3 to balance with the output currents from power supply units PD1 and PD2, based on the detection signal output by the second core-type magnetic field detection current detector 22.

[0034] In this embodiment, the three power supply units PD1, PD2, and PD3 all supply the same rated output current. Therefore, currents of similar magnitude flow through the first wiring L1 and the second wiring L2, generating balanced magnetic fields within the first core 201 of the first core-type magnetic field detection current detector 21, and measuring the difference caused by anomalies as differential current. However, one of the currents flowing through the second core 202 of the second core-type magnetic field detection current detector 22 is a combined current formed by the merger of the currents flowing through the two wirings L1 and L2. Therefore, one or both of the third wiring L3 and the fourth wiring L4 are passed through the second core 202 multiple times so that the magnetic fields generated in the second core 202 of the second core-type magnetic field detection current detector 22 are balanced.

[0035] Furthermore, as mentioned above, although the three power supply units PD1, PD2, and PD3 all supply the same rated output current, as a variation, the rated output currents of each power supply unit PD1, PD2, and PD3 may be different. In that case, it is preferable that the magnetic field generated in the core be balanced by the number of times each of the two wires passed through the core. One or both of the first wire L1 and the second wire L2 pass through the first core 201 multiple times to balance the magnetic field generated in the first core 201 of the first core-type magnetic field detection current detector 21. Also, one or both of the third wire L3 and the fourth wire L4 pass through the second core 202 multiple times to balance the magnetic field generated in the second core 202 of the second core-type magnetic field detection current detector 22.

[0036] Furthermore, in this embodiment, although output adjustment terminals OT1 and OT2 are provided on two of the three power supply units PD1, PD2, and PD3, it is sufficient if they are provided on at least one of the three power supply units PD1, PD2, and PD3. Output adjustment terminal OT1 receives an adjustment signal output by the first current balance controller 31, and the first fault detector 41 detects a fault occurring in either of the two power supply units PD1 or PD2. Output adjustment terminal OT2 receives an adjustment signal output by the second current balance controller 32, and the second fault detector 42 detects a fault occurring in either of the two power supply units PD2 or PD3.

[0037] When the first fault detector 41 detects a fault in at least one of the dual power supply units PD1 and PD2, it stops the output of the other dual power supply unit PD1 or PD2 that is not faulty, or all of the dual power supply units PD1 and PD2, including the faulty one. The second fault detector 42 receives an adjustment signal resulting from the shutdown of one or both of the dual power supply units PD1 and PD2, detects the fault, and stops the output from power supply unit PD3. Also, when the second fault detector 42 detects a fault in power supply unit PD3, it stops the output of the non-faulty power supply unit PD2. The first fault detector 41 receives an adjustment signal resulting from the shutdown of power supply unit PD2, detects the fault, and stops the output from power supply unit PD1.

[0038] Although not shown in the diagram, as an example of variation, the parallel output control system 1B may further connect one or more power supplies in parallel to the three power supplies PD1, PD2, and PD3 that are connected in parallel. In this case, depending on the number of power supplies connected in parallel, one or both of the two wires are passed through each core multiple times so that the magnetic field generated in each core is balanced, as described above. [Examples]

[0039] Example 3 will be described focusing on the differences from Examples 1 and 2. As shown in Figure 6, the parallel output control system 1C according to Embodiment 3 of the present invention is installed between four parallel-connected power supplies PD1, PD2, PD3, and PD4 and a load device LD. It has a first core-type magnetic field detection current detector 21, a second core-type magnetic field detection current detector 22, and a third core-type magnetic field detection current detector 23. The first core 201 of the first core-type magnetic field detection current detector 21 has a first wiring L1 and a second wiring L2 passing through it, and the first wiring L1 and the second wiring L2 passing through the first core 201 are connected on the load device side of the first core 201. The second core 202 of the second core-type magnetic field detection current detector 22 has a third wiring L3 and a fourth wiring L4 passing through it, and the third wiring L3 and the fourth wiring L4 passing through the second core 202 are connected on the load device side of the second core 202. The third core 203 of the third core-type magnetic field detection current detector 23 has a fifth wiring L5 and a sixth wiring L6 running through it. The fifth wiring L5 extends from the connection point with the first wiring L1 and the second wiring L2, and the sixth wiring L6 extends from the connection point with the third wiring L3 and the fourth wiring L4.

[0040] In this embodiment, the supply current from the power supply unit PD1 to the load unit LD flows through the first wiring L1, and the supply current from the power supply unit PD2 to the load unit LD flows through the second wiring L2, and the currents flowing through the first wiring L1 and the second wiring L2 in the first core 201 flow in opposite directions. The supply current from the power supply unit PD3 to the load unit LD flows through the third wiring L3, and the supply current from the power supply unit PD4 to the load unit LD flows through the fourth wiring L4, and the currents flowing through the third wiring L3 and the fourth wiring L4 in the second core 202 flow in opposite directions. Then, the combined current of the two wirings L1 and L2 flows through the fifth wiring L5 from the connection point of the first wiring L1 and the second wiring L2, and the combined current of the two wirings L3 and L4 flows through the sixth wiring L6 from the connection point of the third wiring L3 and the fourth wiring L4, and within the third core 203, the currents flowing through the fifth wiring L5 and the sixth wiring L6 flow in opposite directions. The parallel output control system 1C according to Embodiment 3 of the present invention has a first current balance controller 31, a second current balance controller 32 and a third current balance controller 33. The first current balance controller 31 adjusts the output current from power supply unit PD2 to be in balance with the output current from power supply unit PD1 based on the detection signal output by the first core-in-magnetic-field detection type current detector 21. Furthermore, the second current balance controller 32 adjusts the output current from power supply unit PD4 to balance with the output current from power supply unit PD3, based on the detection signal output by the second core-type magnetic field detection current detector 22. Then, the third current balance controller 33 adjusts the output current from power supply unit PD3 to balance with the output currents from power supply units PD1 and PD2, and the output currents from power supply units PD3 and PD4, based on the detection signal output by the third core-type magnetic field detection current detector 23.

[0041] In this embodiment, the four power supply units PD1, PD2, PD3, and PD4 all supply the same rated output current. Therefore, since the same magnitude of current passes through the first wiring L1 and the second wiring L2, and the third wiring L3 and the fourth wiring L4, the magnetic fields generated in the first core 201 and the second core 202 of the first core-type magnetic field detection current detector 21 and the second core-type magnetic field detection current detector 22 are balanced. As a modification, the magnitudes of the rated output currents of the four power supply units PD1, PD2, PD3, and PD4 may differ from each other. In that case, it is preferable to balance the magnetic fields generated in the cores by the number of times each of the two wirings passed through the core. To balance the magnetic field generated in the first core 201 of the first core-type magnetic field detection current detector 21, one or both of the first wiring L1 and the second wiring L2 are passed through the first core 201 multiple times. Furthermore, in order to balance the magnetic field generated in the second core 202 of the second core-type magnetic field detection current detector 22, one or both of the third wiring L3 and the fourth wiring L4 are passed through the second core 202 multiple times. Then, in order to balance the magnetic field generated in the third core 203 of the third core-type magnetic field detection current detector 23, one or both of the fifth wiring L5 and the sixth wiring L6 are passed through the third core 203 multiple times.

[0042] Furthermore, in this embodiment, although output adjustment terminals OT1, OT2, and OT3 are provided on three of the four power supply units PD2, PD3, and PD4, it is sufficient if they are provided on at least one of the four power supply units PD1, PD2, PD3, and PD4. Output adjustment terminal OT1 receives an adjustment signal output by the first current balance controller 31, and the first fault detector 41 detects a fault occurring in either of the two power supply units PD1 or PD2. Output adjustment terminal OT2 receives an adjustment signal output by the second current balance controller 32, and the second fault detector 42 detects a fault occurring in either of the two power supply units PD3 or PD4. Also, output adjustment terminal OT3 receives an adjustment signal output by the third current balance controller 33, and the third fault detector 43 detects a fault occurring in either of the two power supply units PD2 or PD3.

[0043] For example, if the adjustment signal output by the first current balance controller 31 exceeds the upper limit judgment voltage value, the first fault detector 41 determines that power supply unit PD1 is faulty and shuts down the outputs of the two power supply units PD1 and PD2, including the power supply unit PD2 which is not faulty. When the outputs of the two power supply units PD1 and PD2 are shut down, the combined current from the two wirings L1 and L2 stops flowing to the fifth wiring L5. Consequently, the adjustment signal output by the third current balance controller 33 exceeds the upper limit judgment voltage value, and the third fault detector 43 determines that the outputs of the two power supply units PD1 and PD2 on the fifth wiring L5 side have stopped, and shuts down the outputs of the two power supply units PD2 and PD3. At this time, since power supply unit PD2 has stopped outputting, the output of power supply unit PD3 is effectively shut down. When the output of power supply unit PD3 stops, current stops flowing through the third wiring, the adjustment signal output by the second current balance controller 32 exceeds the upper limit judgment voltage value, the second fault detector 42 determines that the output of power supply unit PD3 has stopped, and shuts off the outputs of the two power supply units PD3 and PD4. At this time, since power supply unit PD3 has stopped outputting, the output of power supply unit PD4 is effectively shut off. The three fault detectors 41 to 43 have the function of shutting off the outputs from the two power supply units in overlapping manner, so that if one fault detector fails to function, the other fault detector will shut off the outputs from the two power supply units, which is expected to minimize damage to the other power supply units caused by the failure of one power supply unit.

[0044] Although the parallel output control systems according to Embodiments 1, 2, and 3 of the present invention have been described in terms of supply current flowing from a power supply to a load device for the sake of ease of explanation, it is sufficient for the current to flow in opposing directions within the core of the core-type magnetic field detection current detector. For example, as shown in Figure 7, the first wiring L1 through which the supply current from power supply PD1 to load device LD flows, and the second wiring L2 through which the feedback current returning from load device LD to power supply PD2 flows, may both flow in opposing directions within the core 20 of the core-type magnetic field detection current detector 2. Alternatively, as shown in Figure 8, for example, the first wiring L1 and the second wiring L2 through which the feedback current returning from load device LD to power supply PD2 flows may both flow in opposing directions within the core 20 of the core-type magnetic field detection current detector 2. Embodiments 2 and 3 of the present invention may be a combination of any of the parallel output control systems shown in Figure 1, Figure 7, and Figure 8. Furthermore, the term "failure" in the above explanation refers not only to output abnormalities caused by structural defects, but also to output failures due to wear and tear caused by aging and other factors.

[0045] Although embodiments of the present invention have been described above, the present invention is not limited in any way to these embodiments, and can be implemented in various forms without departing from the spirit of the invention. [Explanation of symbols]

[0046] 1A, 1B, 1C Parallel Output Control System 2-core magnetic field detection type current detector 3. Current Balance Controller 4. Fault Detector 20 cores 21. First core-type magnetic field detection current detector 22. Second core-type magnetic field detection current detector 23. Third core-type magnetic field detection current detector 31. First current balance controller 32. Second current balance controller 33. Third Current Balance Controller 41. First fault detector 42 Second fault detector 43. Third fault detector 201 First Core 202 Second Core 203 The Third Core AC single-phase alternating voltage C1,C2 comparator EA Error Amplifier L1 First wiring L2 Second wiring L3 Third Wiring L4 Fourth Wiring L5 Fifth wiring L6, the sixth wiring harness. LD load device OT, OT1, OT2, OT3 Output adjustment terminals PD1, PD2, PD3, PD4 Power Supply Units R1~R5 Resistors ZD, ZD1, ZD2 constant voltage diodes

Claims

1. A parallel output control system provided between a dual power supply unit and a load device connected in parallel, It has a core-type magnetic field detection current detector, Within the core of the core-type magnetic field detection current detector, a first wiring is provided through which a supply current from one of the two power supplies toward the load device or a feedback current from the load device toward the one power supply flows, and a second wiring is provided through which a supply current from the other power supply toward the load device or a feedback current from the load device toward the other power supply flows, such that the currents flowing through the first wiring and the second wiring flow in opposite directions within the core. A parallel output control system having a current balance controller that adjusts the output current balance of the two power supply units based on the detection signal output by the core-type magnetic field detection current detector.

2. The parallel output control system according to claim 1, wherein, when the magnitudes of the rated output currents of each power supply unit are different, one or both of the first and second wirings are passed through the core multiple times so that the magnetic field generated in the core of the core-type magnetic field detection current detector is balanced by the currents flowing through each wiring.

3. One or both of the two power supply units are provided with output adjustment terminals that receive adjustment signals output by the current balance controller. The parallel output control system according to claim 1 or 2, further comprising a fault detector that detects a fault occurring in either of the two power supply units based on the adjustment signal output by the current balance controller to the output adjustment terminal.

4. A parallel output control system provided between three power supply units and a load device connected in parallel, It has a first core-type magnetic field detection current detector and a second core-type magnetic field detection current detector, Within the core of the first core-type magnetic field detection current detector, a first wiring is provided through which a supply current from one of the two power supplies of the three power supplies flows toward the load device, or a feedback current from the load device returns to the one power supply; and a second wiring is provided through which a supply current from the other power supply flows toward the load device, or a feedback current from the load device returns to the other power supply; the currents flowing through the first wiring and the second wiring flow in opposite directions within the core, and are connected on the load device side. Within the core of the second core-type magnetic field detection current detector, a third wire through which a supply current from the remaining one of the three power supplies toward the load device or a feedback current returning from the load device toward the one power supply flows, and a fourth wire extending toward the load device from the connection point where the first and second wires are connected, are routed such that the currents flowing through the third wire and the fourth wire flow in opposite directions within the core. A parallel output control system having a current balance controller that adjusts the output current balance of the three power supply units based on the detection signals output by the first core-type magnetic field detection current detector and the second core-type magnetic field detection current detector.

5. The parallel output control system according to claim 4, wherein, when the magnitudes of the rated output currents of the two power supplies are different, one or both of the first and second wirings are passed through the core multiple times so that the magnetic field generated in the core of the first core-type magnetic field detection current detector is balanced by the currents flowing through the first and second wirings.

6. The parallel output control system according to claim 4 or 5, wherein one or both of the third and fourth wirings are passed through the core multiple times so that the magnetic field generated in the core of the second core-type magnetic field detection current detector is balanced by the currents flowing through each of the third and fourth wirings.

7. At least one of the three power supply units is provided with an output adjustment terminal that receives an adjustment signal output by the current balance controller. The parallel output control system according to claim 4, further comprising a fault detector that detects a fault occurring in any of the three power supply devices based on the adjustment signal output by the current balance controller to the output adjustment terminal.

8. A parallel output control system provided between four parallel-connected power supplies and a load device, It comprises a first core-type magnetic field detection current detector, a second core-type magnetic field detection current detector, and a third core-type magnetic field detection current detector. Within the core of the first core-type magnetic field detection current detector, a first wiring is provided through which a supply current from one of the four power supply units toward the load device or a feedback current from the load device toward the one power supply unit flows, and a second wiring is provided through which a supply current from the other power supply unit toward the load device or a feedback current from the load device toward the other power supply unit flows, such that the currents flowing through the first wiring and the second wiring flow in opposite directions within the core, and are connected on the load device side. Within the core of the second core-type magnetic field detection current detector, a third wire carries a supply current from one of the remaining two power supplies of the four power supplies toward the load device or a feedback current from the load device toward the one power supply, and a fourth wire carries a supply current from the other power supply toward the load device or a feedback current from the load device toward the other power supply, with the currents flowing through the third wire and the fourth wire flowing in opposite directions within the core, and connected on the load device side. Within the core of the third core-type magnetic field detection current detector, a fifth wire extending from a first connection point where the first and second wires are connected to the load device side, and a sixth wire extending from a second connection point where the third and fourth wires are connected to the load device side, are routed such that the currents flowing through the fifth wire and the sixth wire flow in opposite directions within the core. A parallel output control system having a current balance controller that adjusts the output current balance of the four power supply units based on the detection signals output by the first core-type magnetic field detection current detector, the second core-type magnetic field detection current detector, and the third core-type magnetic field detection current detector.

9. The parallel output control system according to claim 8, wherein, when the magnitudes of the rated output currents of the two power supplies are different, one or both of the first and second wirings are passed through the core multiple times so that the magnetic field generated in the core of the first core-type magnetic field detection current detector is balanced by the currents flowing through the first and second wirings.

10. The parallel output control system according to claim 8 or 9, wherein, when the magnitudes of the rated output currents of the remaining two power supplies are different, one or both of the third and fourth wirings are passed through the core multiple times so that the magnetic field generated in the core of the second core-type magnetic field detection current detector is balanced by the currents flowing through the third and fourth wirings.

11. The parallel output control system according to claim 8, wherein one or both of the fifth and sixth wirings are passed through the core multiple times so that the magnetic field generated in the core of the third core-type magnetic field detection current detector is balanced by the currents flowing through each of the fifth and sixth wirings.

12. At least one of the four power supply units is provided with an output adjustment terminal that receives an adjustment signal output by the current balance controller. The parallel output control system according to claim 8, further comprising a fault detector that detects a fault occurring in any of the four power supply devices based on the adjustment signal output by the current balance controller to the output adjustment terminal.

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