WO2023243594A1 - Power supply system - Google Patents

Abstract

A plurality of power supply devices (1A-1C), of which the outputs are connected in parallel with each other, have converter units (3a-3c) that are configured to include a plurality of semiconductor switching elements (10a-10c) and that supply output voltages and output currents. The converter units (3a-3c) are subjected to constant voltage control so as to cause the output voltages (Voa-Voc) to become closer to a voltage command value. Among the plurality of power supply devices (1a-1c), for a power supply device that is in a first temperature state of which a detected temperature is higher than a temperature threshold value, the voltage command value is set as a first voltage value. Meanwhile, for a power supply device that is in a second temperature state of which the detected temperature is equal to or lower than the temperature threshold value, the voltage command value is set as a second voltage value higher than the first voltage value.

Description

power system

The present disclosure relates to a power supply system.

In order to increase the capacity of the power supply, a system configuration has been adopted in which multiple power supply devices are connected in parallel to supply power to the load. At this time, if a difference in output voltage occurs due to component variations among multiple power supplies connected in parallel, the temperature of the components will rise due to the increase in output current in a particular power supply with a high output voltage. There is a risk that the lifespan will be shorter than expected due to an increase in the amount. As a result, there is a concern that the life cycle cost of the equipment will increase due to an increase in the frequency of maintenance.

On the other hand, if a master/slave relationship is established between multiple power supplies connected in parallel and control is introduced to suppress output current bias, the control becomes complicated and the circuit size becomes large. There is a concern that the increased cost and size of the power supply system will result from an increase in the number of connections and wiring.

For this reason, Japanese Unexamined Patent Publication No. 2019-92244 (Patent Document 1) proposes that each power supply device executes similar control without setting a master/slave relationship for multiple power supply devices connected in parallel. A control arrangement for balancing output currents is described.

Specifically, in Patent Document 1, each of a plurality of power supply devices connected in parallel generates a current correction detection signal (Vop) from a detection voltage (Vi) corresponding to the output current of each power supply device, and By connecting them with a common balance line, the average value of the current correction detection signals (Vop) of the plurality of power supply devices appears on the balance line as a balance voltage (Vbi). Further, in each of the plurality of power supply devices, the switching element is controlled so as to reduce the difference between the balanced voltage (Vbi) shared on the balance line and the current correction detection signal (Vop) in the power supply device. .

In Patent Document 1, correction information from a detection voltage (Vi) to a current correction detection signal (Vop) is based on variations in resistance values of current detection resistors and amplification of an amplifier detected in an adjustment process for each of a plurality of power supply devices. It is stored in advance as an arithmetic expression or a conversion table so as to correct variations in the rate. This allows control to balance the output currents between the power supply devices without setting a master device.

JP2019-92244A

However, the current balancing in Patent Document 1 depends on the accuracy of the above-mentioned correction information. For this reason, for example, if there is a difference between the ambient temperature in the adjustment process and the ambient temperature in the actual usage environment, the current will depend on the temperature characteristics of components such as the current detection resistor and signal correction section, and the current will change according to the correction information. There is a possibility that the effect of balancing may be reduced. Furthermore, since correction information is obtained with high precision for each power supply device, the adjustment process requires a lot of time, which may lead to a decrease in productivity.

That is, in Patent Document 1, precise control is required to balance the output currents in order to avoid shortening of life due to imbalance in temperature rise among a plurality of power supplies connected in parallel. As a result, there are concerns that a difference in lifespan will occur between power supply devices due to a decrease in control accuracy, or that an adjustment load for ensuring control accuracy that balances lifespans will increase.

The present disclosure has been made to solve such problems, and an object of the present disclosure is to provide a power supply system that supplies current to a load using a plurality of parallel-connected power supply devices through simple control. The goal is to balance temperature rises between power supplies.

In one aspect of this disclosure, a power supply system is provided. The power supply system includes a plurality of power supply devices whose outputs are connected in parallel. Each of the plurality of power supply devices includes a converter section, a temperature detection section, an output voltage detection section, a switching control section, and a signal control section. The converter section includes a semiconductor switching element and supplies an output voltage and an output current. The temperature detection section measures the temperature of the converter section. The output voltage detection section measures the output voltage of the converter section. The switching control section generates a drive signal for controlling on/off of the semiconductor switching element according to constant voltage control that brings the detected voltage of the output voltage detection section close to the voltage command value. The signal control section increases or decreases the voltage command value in the switching control section based on a comparison between the temperature detected by the temperature detection section and a temperature threshold. Each signal control section mutually shares information related to the setting of the voltage command value in each power supply device. Further, among the plurality of power supply devices, in a power supply device in a first temperature state where the detected temperature is higher than the temperature threshold value, the signal control unit sets the voltage command value to the first voltage value. On the other hand, in a power supply device in a second temperature state where the detected temperature is below the temperature threshold, the voltage command value is set to a second voltage value higher than the first voltage value.

According to the present disclosure, in a power supply system in which a plurality of power supply devices connected in parallel supply current to a load, temperature rises can be balanced among the power supply devices by simple control.

1 is a block diagram illustrating a configuration example of a power supply system according to Embodiment 1. FIG. 5 is a flowchart illustrating constant voltage control of each power supply device in the power supply system according to the first embodiment. 2 is a diagram illustrating an example of the operation of the power supply system according to the first embodiment. FIG. 7 is a conceptual diagram illustrating output control characteristics of each power supply device of the power supply system according to a modification of the first embodiment. 5 is a flowchart illustrating control processing for CVCC control of each converter unit in the power supply system according to the first embodiment. 7 is a conceptual diagram illustrating an operation example of a power supply system according to a modification of the first embodiment. FIG. FIG. 2 is a block diagram illustrating a configuration example of a power supply system according to a second embodiment. 8 is a flowchart for explaining the operations of the cumulative temperature calculating section and the cumulative temperature comparing section shown in FIG. 7. FIG. 7 is a flowchart for explaining the additional operation of the signal control unit in the power supply system according to the second embodiment. 7 is a chart explaining an example of the operation of the power supply system according to Embodiment 2. FIG. FIG. 7 is a block diagram illustrating a configuration example of a power supply system according to a third embodiment. 12 is a flowchart for explaining the operations of the cumulative temperature calculating section and the cumulative temperature determining section shown in FIG. 11. FIG. 7 is a block diagram illustrating a configuration example of a power supply system according to a fourth embodiment. FIG. 7 is a block diagram illustrating a configuration example of a power supply system according to a fifth embodiment.

Embodiments of the present disclosure will be described in detail below with reference to the drawings. In addition, below, the same code|symbol is attached|subjected to the same or equivalent part in a figure, and the description shall not be repeated in principle.

Embodiment 1.
FIG. 1 is a block diagram illustrating a configuration example of a power supply system 100A according to the first embodiment.

As shown in FIG. 1, the power supply system 100A includes a plurality of power supply devices connected in parallel. A configuration in which three power supply devices 1a to 1c are connected in parallel will be described below. The outputs of the power supplies 1a to 1c are connected in parallel and supply an output voltage (DC) and an output current (DC) to a common load 120.

In the example of FIG. 1, the input sides of the power supplies 1a to 1c are connected to a common power supply 110 (AC or DC). In this embodiment, the description will proceed assuming that the power source 110 is a power converter that converts an alternating current voltage from an AC power source into a direct current voltage, or a direct current power source using a power storage element such as a battery. Note that the input sides of the power supplies 1a to 1c can be connected to separate power supplies as long as the input voltage is common.

Since the configurations of the power supply devices 1a to 1c are similar, the configuration of the power supply device 1a will be described as a representative example. The power supply device 1a includes a converter section 3a, a switching control section 4a, an output voltage detection section 5a, an output current detection section 6a, a temperature detection section 7a, and a signal control section 8a.

The converter section 3a includes at least one semiconductor switching element 10a, a rectifier diode 9a, and a smoothing capacitor 15a. The converter section 3a converts the input voltage from the power supply 110 into an output voltage Voa through DC voltage conversion by switching (on/off) the semiconductor switching element 10a. Output voltage Voa and output current Ioa of converter section 3a are supplied to load 120.

The converter section 3a may have any circuit configuration, such as a forward converter or a flyback converter, as long as it performs DC voltage conversion through on/off control of semiconductor switching elements. Further, when the power source 110 is an AC power source, a rectifier circuit is further provided at the input stage of the converter section 3a.

The output voltage detection unit 5a measures the output voltage Voa of the converter unit 3a and outputs an output voltage signal Vva indicating the measured value of the output voltage Voa. The "detection voltage" is indicated by the output voltage signal Vva. Typically, a voltage dividing circuit using resistors can be applied to the output voltage detection section 5a, but any method can be applied as long as the output voltage Voa can be measured.

The output current detection unit 6a measures the output current Ioa of the converter unit 3a and outputs an output current signal Via indicating the measured value of the output current Ioa. The "detection current" is indicated by the output current signal Via. Although it is possible to apply a shunt resistor or a flux gate sensor using a current transformer to the output current detection section 6a, any method can be applied as long as the output current Ioa can be measured. .

The temperature detection section 7a is placed close to a heat generating section such as a rectifier diode 9a, a smoothing capacitor 13a, or a substrate pattern (not shown), and measures the temperature of the location. Temperature detection section 7a outputs a temperature signal Vta indicating the temperature measurement value of converter section 3a. The "detected temperature" is indicated by the temperature signal Vta. The temperature detection section 7a can be constructed by mounting a chip-type thermistor near the heat-generating part on the substrate, or by fixing a film-type or lead-type thermistor directly to the heat-generating part. Any method can be applied to the temperature detection section 7a as long as it is possible to measure the actual temperature of the converter section 3a.

In particular, if a thermistor fixed to the board is used as the temperature detection part 7a, it is possible to place it close to a specific part of the converter part 3a that is likely to generate heat or otherwise shorten its life due to temperature rise. be. Thereby, it is possible to accurately measure the temperature rise that affects the life of the power supply device 1a.

The switching control section 4a corresponds to a gate drive circuit for the semiconductor switching element 10a, and outputs a drive signal Sga for turning on and off the semiconductor switching element 10a. The switching control unit 4a generates a drive signal Sga to perform constant voltage (CV) control to bring the output voltage Voa closer to the voltage command value Vo*. For example, the drive signal is used to adjust the on-period ratio (duty ratio) of the semiconductor switching element 10a by feedback control (typically proportional-integral (PI) control) of the deviation between the output voltage Voa and the voltage command value Vo*. Sga is generated.

Furthermore, the switching control section 4a has a function of increasing or decreasing the voltage command value Vo* according to a switching control signal Ssa from a signal control section 8a, which will be described later. For example, the voltage command value Vo* is set to one of the first voltage value V1 and the second voltage value V2 (Vo*=V1 or V2) according to the switching control signal Ssa. The first voltage value is a value lower than the second voltage value, and for example, V1 is a constant value or a constant percentage (for example, 0.5 (%)) of the rated value V0 of the output voltage to the load 120. V2 is set to a value lower than the rated value V0 by a certain value or a certain percentage (for example, about 0.5 (%)).

As an example, when the switching control signal Ssa is at a logic low level (hereinafter referred to as L level), Vo*=V1 is set, and when it is at a logic high level (hereinafter referred to as H level), Vo* is set to V2. . Furthermore, by configuring the switching control signal Ssa with a plurality of bits, it is possible to instruct the semiconductor switching element 10a to stop (fixed off). The switching control unit 4a can be configured by, for example, a general-purpose microcomputer or an IC (Integrated Circuit) having a power supply control function.

The signal control unit 8a receives the output voltage signal Vva from the output voltage detection unit 5a and the temperature signal Vta from the temperature detection unit 7a, and controls the voltage increase signal Sva, temperature increase signal Sta, and temperature for the converter unit 3a. An abnormality signal Sta* is generated.

Voltage increase signal Sva is set to H level when output voltage signal Vva is higher than voltage threshold VHt (voltage increase state), and set to L level when output voltage signal Vva is lower than voltage threshold VHt. be done. The voltage threshold VHt is set between the first voltage value V1 and the second voltage value V2. Note that the voltage threshold VHt is set to a different value when the voltage increase signal Sva is at the L level and when the voltage increase signal Sva is at the H level so as to have a so-called hysteresis characteristic. Specifically, the voltage threshold VHt in the voltage rising state is set to a lower value than when not in the voltage rising state.

The temperature increase signal Sta is set to H level when the temperature signal Vta is higher than the temperature threshold VTHt (also referred to as a temperature increase state), and is set to H level when the temperature signal Vta is below the temperature threshold (normal temperature state or (also referred to as a temperature non-rise state) is set to L level. Note that the temperature threshold value VTHt is set to a different value when the temperature increase signal Sta is at the L level and when the temperature increase signal Sta is at the H level so as to have a so-called hysteresis characteristic. Specifically, the temperature threshold VTHt is set to a lower value when the temperature is rising than when the temperature is normal. Note that the temperature increase state corresponds to an example of the "first temperature state", and the temperature normal state or the temperature non-rise state corresponds to an example of the "second temperature state".

The temperature abnormality signal Sta* is set to the H level when the temperature signal Vta is higher than the predetermined upper temperature limit VTHlm (also referred to as an over-high temperature state), and is set to the L level when Tva≦THlim. Set. For example, when the temperature threshold value VTHt is set to correspond to around 80 [°C], the temperature upper limit value VTHlm is set to correspond to around 120 [°C].

The power supply device 1b includes a converter section 3a, a switching control section 4a, an output voltage detection section 5a, an output current detection section 6a, a temperature detection section 7a, and a converter section 3b, a switching control section 4b, similar to the signal control section 8a. It includes an output voltage detection section 5b, an output current detection section 6b, a temperature detection section 7b, and a signal control section 8b. Converter section 3b includes semiconductor switching element 10b, rectifier diode 9b, and smoothing capacitor 15b similar to semiconductor switching element 10a, rectifier diode 9a, and smoothing capacitor 15a.

Similarly, the power supply device 1c includes a converter section 3a, a switching control section 4a, an output voltage detection section 5a, an output current detection section 6a, a temperature detection section 7a, and a switching control section similar to the signal control section 8a. 4c, an output voltage detection section 5c, an output current detection section 6c, a temperature detection section 7c, and a signal control section 8c. Further, the converter section 3c includes a semiconductor switching element 10c, a rectifying diode 9c, and a smoothing capacitor 15c similar to the semiconductor switching element 10a, the rectifying diode 9a, and the smoothing capacitor 15a.

The first voltage value V1 and second voltage value V2 of the voltage command value Vo*, the above-mentioned voltage threshold value VHt, temperature threshold value VTHt, and temperature upper limit value VTHlm are common among the power supply devices 1a to 1c.

Therefore, in the signal control section 8b, a voltage increase signal Svb is generated in the same manner as the voltage increase signal Sva by comparing the output voltage signal Vvb of the converter section 3b and the voltage threshold value VHt. Furthermore, by comparing the temperature signal Vtb of the converter section 3b with the temperature threshold value VTHt and the temperature upper limit value VTHlm, a temperature increase signal Stb and a temperature abnormality signal Stb* are generated in the same manner as the temperature increase signal Sta and the temperature abnormality signal Sta*. be done.

Further, in the signal control unit 8c, a voltage increase signal Svc, a temperature increase signal Stc, and a temperature abnormality signal Stc* are similarly generated based on the output voltage signal Vvc and temperature signal Vtc of the converter unit 3c.

In addition, in the following, when describing each circuit element, each signal, each physical quantity (temperature, voltage), etc. comprehensively without distinguishing between the power supplies 1a to 1c, the subscripts "a", "b", Alternatively, "c" shall be omitted. For example, when output voltages Voa, Vob, and Voc are included, it is also written as output voltage Vo.

The power supply system 100A further includes signal generation circuits 15t and 15v. The signal generation circuit 15t generates an overall temperature abnormality signal Sto. The signal generation circuit 15v generates an overall voltage status signal Svo. The overall temperature abnormality signal Sto and overall voltage status signal Svo from the signal generation circuits 15t and 15v are input to each of the signal control units 8a to 8c and shared by the power supplies 1a to 1c.

The overall temperature abnormality signal Sto is set to H level when the temperature signal Vt (Vta to Vtc) exceeds the temperature upper limit value VTHlm in at least one of the power supply devices 1a to 1c. On the other hand, when the temperature signal Vt (Vta to Vtc) in all of the power supply devices 1a to 1c is equal to or lower than the temperature upper limit value VTHlm, the overall temperature abnormality signal Sto is set to the L level. For example, the signal generation circuit 15t is configured with a logical sum (OR) gate that receives the temperature abnormality signals Sta* to Stc* as input and outputs the overall temperature abnormality signal Sto.

The overall voltage status signal Svo is set to H level when the output voltage signal Vv (Vva to Vvc) exceeds the voltage threshold VHt in at least one of the power supply devices 1a to 1c. On the other hand, when the output voltage signals Vv (Vva to Vvc) of all of the power supply devices 1a to 1c are equal to or less than the voltage threshold VHt, the overall voltage state signal Svo is set to L level. For example, the signal generation circuit 15v is configured with a logical sum (OR) gate that receives the voltage increase signals Sva to Svc and outputs the overall voltage status signal Svo. Note that the functions of the signal generation circuits 15t and 15v may be provided inside each of the signal control units 8a to 8c.

In the power supply system 100A according to the first embodiment, while constant voltage control is performed in each converter section 3 according to the voltage command value Vo*, the switching control signal is controlled according to the temperature state and output voltage state of the power supply devices 1a to 1c. The voltage command value Vo* of each power supply device 1 (1a to 1c) is increased or decreased through Ss (Ssa to Sac).

FIG. 2 shows a flowchart illustrating constant voltage control of each power supply device in the power supply system according to the first embodiment. Since the constant voltage control processing in the power supply devices 1a to 1c is similar, in FIG. 2, the constant voltage control of the power supply device 1a executed by the signal control section 8a will be explained.

Referring to FIG. 2, when the power supply system 100A is activated, the signal control unit 8a sets the initial value of the switching control signal Ssa in step (hereinafter simply referred to as "S") 110. Initial value settings are predetermined so that some of the switching control signals Ssa to Sac are set to H level and the rest are set to L level. In this specification, it is assumed that Ssa=H and Sab=Ssc=L are initialized.

The signal control unit 8a monitors the temperature signal Vta in S120. S120 includes S121 in which the temperature signal Vta is compared with the temperature upper limit value VTHlm, and S122 in which the temperature signal Vta is compared with the temperature threshold value VTHt.

S121 is determined to be YES when the temperature signal Vta is less than or equal to the temperature upper limit value VTHlm, that is, when the temperature abnormality signal Sta* is at the L level. On the other hand, when the temperature signal Vta is higher than the temperature upper limit value VTHlm, that is, when the temperature abnormality signal Sta* is at H level (excessive high temperature state), a NO determination is made in S121.

A YES determination is made in S122 when the temperature signal Vta is less than or equal to the temperature threshold VTHt, that is, when the temperature increase signal Sta is at L level (normal temperature state). On the other hand, when the temperature signal Vta is higher than the temperature threshold VTHt, that is, when the temperature increase signal Sta is at the H level (temperature increase state), a NO determination is made in S122.

Through S120 (S121, S122), the power supply device 1a is in an overtemperature state (NO determination in S121), a temperature increase state (YES determination in S121 and NO determination in S122), and a normal temperature (temperature non-rise) state ( It is determined whether the determination is YES in both S121 and S122).

In the over-temperature state (NO determination in S121), the signal control unit 8a advances the process to S170 and sets the switching control signal Ssa to a stop signal for stopping (fixing OFF) the semiconductor switching element 10a of the converter unit 3a. Set.

In the temperature normal state (YES determination in S122), the signal control unit 8a advances the process to S130 and checks the overall voltage state signal Svo. On the other hand, in the temperature rising state (NO determination in S122), after the switching control signal Ssa is set to L level in S125 in order to lower the voltage command value Vo* in the power supply 1a, The process proceeds to S130.

The signal control unit 8a determines YES in S130 when the overall voltage status signal Svo is at L level, that is, when the output voltage signal Vv (Vva to Vvc) of all the power supply devices 1a to 1c is equal to or lower than the voltage threshold VHt. As a determination, the process advances to S140.

In S140, the signal control unit 8a checks whether or not the temperature of the power supply device 1a is normal, as in S122. That is, when the temperature increase signal Sta is at the L level, a YES determination is made in S140, and when the temperature increase signal Sta is at the H level, a NO determination is made in S140.

When the determination is YES in S140, that is, when the power supply device 1a is in a normal temperature state (temperature not rising state), the switching control signal Ssa is set to H level in S150 and S155. Specifically, when Ssa=L (YES determination in S150), the switching control signal Ssa is changed from the L level to the H level in S155. Accordingly, the overall voltage state signal Svo also changes to H level. On the other hand, when Ssa=H (NO determination in S150), S155 is skipped and the switching control signal Ssa is maintained at H level. When the switching control signal Ssa is set to H level or L level in S150 and S155, the process proceeds to S160.

When the determination in S140 is NO, that is, when the temperature of the power supply device 1a is rising, the processing in S150 and S155 is skipped, and the switching control signal Ssa is set to the L level in S145. In this manner, when the temperature of the power supply device 1a is rising, Ssa=L is set by at least one of S125 and S145.

When the overall voltage status signal Svo is at the H level in S130, that is, when the output voltage signal Vv (Vva to Vvc) of at least one of the power supply devices 1a to 1c is higher than the voltage upper limit value VHlim, the signal control unit 8a performs S130. If the determination is NO, the process proceeds to S160. That is, the switching control signal Ssa is maintained at the level (L or H) at the time of determination in S130.

In S160, the signal control unit 8a checks the overall temperature abnormality signal Sto. When the overall temperature abnormality signal Sto is at the H level, that is, when at least one of the power supplies 1a to 1c is overheated (St>VTHlm) (NO determination in S160), the process proceeds to S170, The switching control signal Ssa is set to a stop signal. Thereby, even if the power supply device 1a is not in an overheated state, if at least one of the power supply devices 1b and 1c is in an overheated state, the semiconductor switching element 10a of the converter section 3a is fixed in the off state.

On the other hand, when the overall temperature abnormality signal Sto is at the L level, that is, when all of the power supply devices 1a to 1c are not in an overtemperature state (YES in S160), the process returns to S120. As a result, the processes of S120 to S160 are repeatedly executed until an overtemperature state is detected in any of the power supply devices 1a to 1c (YES determination in S120 or S160).

In the processes of S120 to S160, when the temperature of the power supply device 1a increases, the switching control signal Ssa is set to L level, and the voltage command value Vo* of the converter section 3a is decreased (Vo*=V1).

Further, when the temperature of the power supply device 1a is normal, and when all of the other power supply devices 1a to 1c are not in a voltage rising state (Svo=L level), the voltage command value Vo* of the converter section 3a is increased ( Vo*=V2). As a result, it is possible to restrict Vo*=V2 in all of the power supply devices 1a to 1c. Further, in the initial setting (S110), some of the switching control signals Ssa to Ssc are set to H level and L level. As a result, the voltage command values Vo* of the power supplies 1a to 1c are all controlled to not be maintained at the second voltage value V2 or the first voltage value V1. In other words, it is possible to control the voltage command values Vo* of the power supplies 1a to 1c so that they are not maintained equal to the first voltage value V1 or the second voltage value V2. Note that by using a method different from the example in FIG. 2, for example, by sharing the current levels of the switching control signals Ssa to Ssc between the signal control units 8a to 8c, the voltage command values Vo* of the power supplies 1a to 1c can be changed to The voltage may be controlled so as not to be equal to the first voltage value V1 or the second voltage value V2.

In the power supplies 1b and 1c, the signal control units 8b and 8c also control the voltage of the converter units 3b and 3c by performing control processing in which the subscript “a” in FIG. 2 is replaced with “b” or “c”. Command value Vo* can be set similarly.

FIG. 3 shows an example of the operation of the power supply system 100A according to the first embodiment.
Referring to FIG. 3, state 1 corresponds to the state after initialization in S110 of FIG. In the power supply device 1a, Ssa=H is set (Vo*=V2), while in the power supply devices 1b and 1c, Ssb=Ssc=L is set (Vo*=V1). As a result, the voltage increase signal Sva of the power supply device 1a is at H level, and the overall voltage status signal Svo is also at H level. In state 1, the temperature of the power supply device 1a has not yet increased, and the temperature increase signals Sta to Stc are all at L level.

In state 2, as state 1 continues and the temperature of the power supply device 1a increases, the temperature increase signal Sta changes from L level to H level. Accordingly, in S125 of FIG. 2 (NO determination in S1222), the switching control signal Ssa of the power supply device 1a is set to the L level, and the voltage command value Vo* of the converter section 3a is decreased (Vo*= V1).

In state 3, in response to the voltage command value Vo* of converter section 3a being reduced in state 2, voltage increase signal Sva of power supply device 1a changes from H level to L level. On the other hand, the temperature of the power supply device 1a decreases with a delay of the voltage drop, so in state 3, the temperature increase signal Sta is still at the H level.

In state 3, the overall voltage state signal Svo changes from the H level to the L level in response to the voltage increase signal Sva going to the L level. As a result, in the power supply devices 1b and 1c in a normal temperature state (Stb=Stc=L), the switching control signals Ssb and Ssc are changed from the L level to the H level in S155 of FIG. As a result, voltage command value Vo* of converter sections 3b and 3c is increased (Vo*=V2).

In state 4, since Ssb=Ssc=H was set in state 3, the voltage increase signals Svb and Svc of power supply devices 1b and 1c change from L level to H level. Accordingly, the overall voltage state signal Svo is set to H level. On the other hand, in the power supply device 1a operated under Ssa=L, the temperature decreases and the temperature increase signal Sta changes to the L level. However, since Svo=H, the switching control signal Ssa of the power supply device 1a is maintained at the L level.

In state 5, while the operation of Ssb=Ssc=H in state 4 continues, the temperature of the power supply 1b rises first, and the temperature rise signal Stc of the power supply 1c rises. Stb is changing from L level to H level. Accordingly, in the power supply device 1b, the switching control signal Ssb is set to the L level in S125 of FIG. 2 (YES determination in S1222), and the voltage command value Vo* of the converter section 3b is decreased.

In state 6, the voltage increase signal Svb changes from the H level to the L level in accordance with the decrease in the voltage command value Vo* in the power supply device 1b in state 5. On the other hand, in the power supply device 1c, since the temperature increase signal Stc remains at the L level, the switching control signal Ssc is maintained at H level, and as a result, the voltage increase signal Svc also remains at the H level.

In state 7, the temperature of the power supply device 1c, which is set to Ssc=H, rises, and the temperature rise signal Stc changes from L level to H level. Accordingly, in the power supply device 1c, the switching control signal Ssc is set to the L level in S125 of FIG. 2 (NO determination in S122), and the voltage command value Vo* of the converter section 3c is decreased.

In state 8, since Ssc=L was set in state 7, the voltage increase signal Svc of the power supply device 1c changes from H level to L level. As a result, all of the voltage increase signals Sva to Svc have become the L level, so the overall voltage state signal Svo returns to the L level.

In state 8, the temperature increase signal Sta is at the L level, so in the power supply device 1a, the switching control signal Ssa changes from the L level to the H level in S155 of FIG. Accordingly, the overall voltage state signal Svo also changes from L level to H level. On the other hand, in the power supply devices 1b and 1c in which the temperature increase signals Stb and Stc are still at H level, the switching control signals Ssb and Ssc continue to operate at L level (Vo*=V1), so that the voltage increase signal Svb ．． Svc is maintained at L level.

In this way, according to the constant voltage control explained in FIGS. 2 and 3, the output voltage is intentionally adjusted between the power supplies 1a to 1c connected in parallel based on the temperature state of each power supply 1a to 1c. You can replace the power supply to make it more expensive. On the other hand, if multiple power supplies with different output voltages are simply connected in parallel due to manufacturing variations or component temperature dependence, the output current of the power supply with a relatively higher output voltage will increase. As a result, the temperature rise concentrates.

In the power supply system according to the first embodiment, some of the power supplies that are not in a temperature rising state among the plurality of power supplies connected in parallel are turned on based on the comparison result between the temperature signals Vta to Vtc and the temperature threshold value VTHt. Instead, it is selected to intentionally increase its output voltage. As a result, multiple power supplies 1a are adjusted so that the output current (amount of temperature rise) of a power supply device that is not in a temperature rising state is larger than the output current (amount of temperature rise) of a power supply device that is in a temperature rising state. The parallel operation of ~1c can supply current to the load 120.

As a result, in a power supply system that supplies current to a load using a plurality of power supply devices connected in parallel, temperature increases in the plurality of power supply devices can be balanced by simple control. Thereby, it is possible to prevent uneven lifespans among power supply devices due to concentration of temperature rise in a specific power supply device.

Furthermore, when an overtemperature state exceeding the upper temperature limit VTHlm is detected in any of the power supply devices, a protection operation is implemented in which the entire power supply system 100A is stopped. Further, as described above, by providing the temperature threshold value VTHt and the voltage threshold value VHt with hysteresis characteristics, it is possible to prevent the voltage command value Vo* from changing frequently and to stably operate the constant voltage control.

Modification of Embodiment 1.
In the first embodiment, the temperature increase state of the power supply devices 1a to 1c is detected by the increase in the detected temperature by the temperature detection units 7a to 7c assuming thermistors, but when the temperature rises, the current increases, heat generation increases, and Events of increased measured values occur in sequence. Therefore, in a modification of the first embodiment, control for suppressing a temperature rise in response to a sudden increase in current will be described.

In a modification of the first embodiment, each of the converter sections 3a to 3c of the power supplies 1a to 1c has a so-called CVCC (Constant Voltage Constant Current) control function.

FIG. 4 is a conceptual diagram illustrating the output control characteristics of each power supply device of the power supply system according to a modification of the first embodiment.

Referring to FIG. 4, in the range where the output current Io is lower than the upper limit current Ilm, the converter sections 3 (3a to 3c) of the power supplies 1a to 1c operate at the voltage command value Vo* as described in the first embodiment. Execute constant voltage control according to On the other hand, when the output current Io reaches the upper limit current Ilm during CC control, the control shifts to CC (Constant Current) control in which output limitation is executed, such as limiting the duty ratio of the semiconductor switching elements 10 (10a to 10c). Due to the output restriction, the output power of the converter unit 3 is fixed, so the output voltage Vo decreases as the power consumption in the load 120 increases. The output limit may be made stricter in stages so that the output current Io does not exceed the upper limit current Ilm.

FIG. 5 is a flowchart illustrating control processing for CVCC control of the converter section 3 (3a to 3c). The control process shown in FIG. 5 is executed by each of the switching control units 4a to 4c.

Referring to FIG. 5, in S210, the switching control unit 4 (4a to 4c) determines whether the switching control signal Ss (Ssa to Ssc) is the stop signal set in S170 of FIG. . When the switching control signal Ss is a stop signal (YES in S210), the switching control unit 4 (4a to 4c) controls the drive signal Sg (Sga ~Sgc) is fixed at L level. As a result, the semiconductor switching elements 10 (10a to 10c) are fixed in the off state.

If the switching control signal Ss is not a stop signal (NO determination in S210), the switching control unit 4 (4a to 4c) detects the output current signal Vi( Via to Vic) are compared with the determination value VIlm determined corresponding to the upper limit current Ilm in FIG. As a result, the output current Io and the upper limit current Ilm shown in FIG. 4 are compared in each of the power supply devices 1a to 1c.

When Vi (Via to Vic)<VIlm, that is, the output current Io (Ioa to Ioc) is smaller than the upper limit current Ilm (YES in S215), the process proceeds to S230. In S230, the switching control unit 4 (4a to 4c) is driven according to constant voltage control to bring the output voltage Vo (Voa to Voc) closer to the voltage command value Vo* set in accordance with FIG. 2 (Embodiment 1). A signal Sg (Sga to Sgc) is generated.

On the other hand, when Vi (Via to Vic)≧VIlm, that is, when the output current Io (Ioa to Ioc) reaches the upper limit current Ilm (NO determination in S215), the process proceeds to S240. In S240, the switching control unit 4 (4a to 4c) generates drive signals Sg (Sga to Sgc) to perform output restriction such as fixing the duty ratio to a certain limit value. As shown in FIG. 4, the output limitation may be performed so as to realize a so-called drooping characteristic in which the output voltage Vo decreases while the upper limit current Ilm remains the same, and both the output voltage Vo and the output current Io decrease. It may also be carried out so as to realize the so-called "foldback" characteristic.

Note that the above-mentioned CVCC control represented by the drooping characteristic and the "F" characteristic is well known as a converter output control, but by combining it with the constant voltage control described in Embodiment 1, the When the output current Io rapidly increases in at least one of 1c, it is possible to quickly prevent a large temperature rise from occurring.

FIG. 6 shows a conceptual diagram illustrating an example of the operation of the power supply system according to a modification of the first embodiment.

In FIG. 6(a), the power supplies 1a to 1c operate under constant voltage control, and while the converter section 3a has a voltage command value Vo*=V2, the converter sections 3b and 3c have a voltage command value Vo*. =V1. For example, in FIG. 6A, when the current consumption of the load 120 is 10 [A], the power supply 1a supplies 5 [A] corresponding to the upper limit current Ilm, and the power supply 1b supplies 3 [A], It is assumed that the power supply device 1c is supplying 2 [A].

In FIG. 6(a), when the output current of the power supply device 1a reaches the upper limit current Ilm, the power supply device 1a shifts from constant voltage control to constant current control.

As a result, in FIG. 6(b), the output power is limited in the constant current controlled power supply device 1a, so the output voltage is lower than in FIG. 6(a), and the output current is also reduced. The power supplies 1b and 1c operate under constant voltage control, but for example, in FIG. 6A, the output voltage of the power supply 1c whose output voltage is relatively low and whose temperature rise is small is increased (voltage command value Vo*= V2). On the other hand, in the power supply device 1b, the voltage command value Vo*=V1.

In FIG. 6(b), while the output current of the power supply device 1a decreases, the output current of the power supply device 1c mainly increases, so that a total of 10 [A] of current is supplied to the load 120.

In the state of FIG. 6(b), the output current of the power supply device 1a is decreasing, but when the output current becomes lower than the switching current that is preset to a value lower than the upper limit current Ilm, the power supply device 1a , it is possible to return from constant current control to constant voltage control.

In this way, in the power supply system according to the modification of the first embodiment, in addition to the constant voltage control based on the monitoring of the temperature signals Vta to Vtc in the first embodiment, the output current Io is suppressed to the upper limit current Ilm or less. CVCC control, which is further combined with constant current control, is applied to each of the power supplies 1a to 1c. Thereby, when the output current of a specific power supply device increases due to load fluctuation or the like, concentration of temperature rise can be more quickly prevented. This makes it possible to further balance the temperature rise between the power supply devices, thereby further reliably preventing uneven lifespans among the power supply devices.

In particular, with only constant voltage control that reduces the output voltage in response to temperature detection by a thermistor, it generally takes time on the order of seconds to reduce the output of the converter section 3 (3a to 3b), while the constant current Controlled power reduction can be triggered in milliseconds (ms). Therefore, in addition to preventing steady output imbalance between multiple power supplies, even if a sudden increase in current occurs in some power supplies due to load fluctuations, the output current to a specific power supply can be reduced. In other words, concentration of temperature rise can be avoided.

Embodiment 2.
FIG. 7 is a block diagram illustrating a configuration example of a power supply system 100B according to the second embodiment.

Referring to FIG. 7, power supply system 100B is different from power supply system 100A (FIG. 1) according to the first embodiment in that it further includes cumulative temperature calculation units 11a to 11c and cumulative temperature comparison unit 12. different. Temperature signals Vta to Vtc from temperature detection units 7a to 7c are input to cumulative temperature calculation units 11a to 11c, respectively. The cumulative temperature calculation units 11a to 11c each output cumulative temperature signals Vtta to Vttc indicating the respective integrated values of the temperature signals Vta to Vtc at a predetermined constant period T1 (for example, T1=about 1 hour). The cumulative temperature comparison unit 12 generates control signals Stta to Sttc for the power supplies 1a to 1c based on the cumulative temperature signals Vtta to Vttc from the cumulative temperature calculation units 11a to 11c.

FIG. 8 shows a flowchart for explaining the operations of the cumulative temperature calculation units 11a to 11c and the cumulative temperature comparison unit 12 in the power supply system 100B. That is, the functions of the cumulative temperature calculation units 11a to 11c and the cumulative temperature comparison unit 12 can be realized by a microcomputer or the like executing the processing shown in FIG.

Referring to FIG. 8, in S310, cumulative temperature calculation units 11a to 11c acquire temperature signals Vta to Vtc from temperature detection units 7a to 7c, respectively, at a constant period T2 (for example, T2=10 seconds). The cumulative temperature calculation units 11a to 11c add the acquired temperature signals Vta to Vtc to their respective integrated values. In S320, the cumulative temperature calculation units 11a to 11c increase (increment) the count value i (i: integer) indicating the number of accumulated data by 1, and in S330, compare the incremented count value i with the determination value N1. . The judgment value N1 is predetermined so that the count value i reaches the judgment value N1 at every fixed period T1. Until the count value i reaches the determination value N1 (NO determination in S330), the processes of S310 to S330 are repeated.

When the count value i reaches the determination value N1, that is, when the integrated value for the constant period T1 is determined, a YES determination is made in S330, and the process proceeds to S340. In S340, the cumulative temperature signals Vtta to Vttc are input to the cumulative temperature comparison unit 12 from the cumulative temperature calculation units 11a to 11c. Further, in the cumulative temperature calculation units 11a to 11c, the count value i and the cumulative temperature signals Vtta to Vttc (integrated values) are cleared (i=0, Vtta=Vttb=Vttc=0).

Following S340, in S350, the cumulative temperature comparison unit 12 executes a comparison process of the cumulative temperature signals Vtta to Vttc to extract some power supply devices that are in a relatively high temperature state. For example, the power supply device corresponding to the maximum value of the cumulative temperature signals Vtta to Vttc, ie, the power supply device with the highest temperature, is extracted in S350. That is, the cumulative temperature comparison section 12 corresponds to an embodiment of a "temperature history comparison section".

In S360, the cumulative temperature comparison unit 12 sets the control signals Sttc to Sttc according to the comparison processing result in S350. A portion of the control signals Stta to Sttc corresponding to the power supply device determined to be in a high temperature state is set to the H level, and the remaining portions are set to the L level. For example, when Vva is the maximum value among the cumulative temperature signals Vtta to Vttc, that is, when it is determined that the power supply device 1a is in a high temperature state, the control signal Stta is set to H level, while the control signal Sttb , Sttc are set to L level. Control signals Stta to Sttc are input to signal control units 8a to 8c, respectively.

In the power supply system 100B according to the second embodiment, the signal control units 8a to 8c further execute the operations described below in response to the control signals Stta to Sttc from the cumulative temperature comparison unit 12.

FIG. 9 shows a flowchart illustrating additional operations of the signal control units 8a to 8c in the power supply system 100B according to the second embodiment.

Referring to FIG. 9, the signal control unit 8 (8a to 8c) checks the level of the control signal Stt (Stta to Sttc) from the cumulative temperature comparison unit 12 in S410. When Stt=H (when YES is determined in S410), a standby time LT is provided in S420 when changing the switching control signal Ss (Ssa to Ssc) from the L level to the H level in S155 of FIG. The control process shown in FIG. 2 is modified accordingly. The standby time LT is shorter than the fixed period T1 of the cumulative temperature calculation units 11a to 11c, and is set within a range of about 1 second to 10 minutes, for example. The standby time LT corresponds to the "first time".

On the other hand, when Stt=L (NO determination in S410), a standby time like S420 is not set in S430. Alternatively, a shorter standby time (corresponding to the "second time") than S420 may be provided. Not setting the standby time means setting the "second time" to zero.

As a result, in the power supply system 100B according to the second embodiment, in the power supply device determined to be in a high temperature state among the power supply devices 1a to 1b, S150 is determined to be YES during the constant voltage control control process (FIG. 2). When the process proceeds to S155, that is, when the switching control signal Ss (Ssa to Ssc) changes from the L level to the H level, the waiting time LT is set. On the other hand, in other power supply devices that are not determined to be in a high temperature state, when the determination is YES in S150, the switching control signals Ss (Ssa to Ssc ) changes from L level to H level (S155).

Next, an example of the operation of the power supply system 100B according to the second embodiment will be described using FIG. 10. In the operation example of FIG. 10, it is assumed that the power supply device 1b has been extracted as a high temperature power supply device in S350 of FIG. 8 (Sttb=H, Stta=Sttc=L).

Referring to FIG. 10, state 11 is similar to state 1 in FIG. 3, in which Ssa=H is set (Vo*=V2) in power supply device 1a, while Ssb=H in power supply devices 1b and 1c. Ssc=L is set (Vo*=V1). As a result, the voltage increase signal Sva of the power supply device 1a is at H level, and the overall voltage status signal Svo is also at H level. In state 11, the temperature of the power supply device 1a has not yet increased, and the temperature increase signals Sta to Stc are all at L level.

In state 12, similar to state 2 in FIG. 3, the temperature increase signal Sta changes from L level to H level as the temperature of the power supply device 1a whose output voltage has been increased in state 11 increases. Accordingly, in S125 of FIG. 2 (YES determination in S122), the switching control signal Ssa of the power supply device 1a is set to L level, and the voltage command value Vo* of the converter section 3a is decreased (Vo*= V1).

State 13 is similar to state 3 in FIG. That is, in response to the voltage command value Vo* of the converter section 3a being reduced in state 12, the voltage increase signal Sva of the power supply device 1a changes from the H level to the L level. As a result, the overall voltage state signal Svo changes from H level to L level.

Since the temperature of the power supply device 1a falls with a delay to the voltage drop, the temperature rise signal Sta is still at the H level in state 13. Further, the power supplies 1b and 1c are in a state where the temperature is not rising, and the temperature rise signals Stb and Stc are at the L level. Therefore, in the power supply devices 1b and 1c, the determinations in S122, S122, S130, and S140 in FIG. 2 are all YES. That is, the conditions for switching control signals Ssb and Ssc to change from L level to H level are satisfied.

Therefore, in state 14 immediately after state 13, in the power supply device 1c with control signal Sttc=L, in response to the switching control signal Ssc changing from the L level to the H level, the voltage increase signal Svc is changes from L level to H level. On the other hand, in the power supply device 1b where the control signal Sttb=H, the switching control signal Ssb is maintained at the L level because the standby time LT has not yet elapsed. As a result, the voltage increase signal Svb remains at the L level as in state 13.

In state 15, the standby time LT has elapsed since state 13. Therefore, in response to the switching control signal Ssb of the power supply device 1b changing from the L level to the H level, the voltage increase signal Svb also changes from the L level to the H level.

In state 16, the temperature increase signal Stb of the power supply device 1b, which has been determined to be in a high temperature state, changes from the L level to the H level before the temperature increase signal Stc of the power supply device 1c. As a result, the switching control signal Ssb of the power supply device 1b changes from H level to L level.

As a result, in state 17, the voltage increase signal Svb of the power supply device 1b changes from the H level to the L level. Further, even in the power supply device 1c where the switching control signal Ssc is set to H, the temperature increase signal Stc changes from the L level to the H level. Accordingly, the switching control signal Ssc of the power supply device 1c changes from the H level to the L level.

As a result, in state 18, all the switching control signals Ssa to Ssc of the power supply devices 1a to 1c become L level again, and the overall voltage state signal Svo returns to L level. On the other hand, since there is a delay in the temperature reduction of the power supplies 1b and 1c, the temperature increase signal Sta (power supply 1a) is at the L level, while the temperature increase signals Stb and Stc remain at the H level. Therefore, while the switching control signals Ssb and Ssc are at the L level, only the switching control signal Ssa is changed to the H level.

In state 19, according to the switching control signals Ssa to Ssc set in state 18, voltage increase signal Sva of power supply device 1a is at H level, while voltage increase signals Svb and Svc of power supply devices 1b and 1c are at L level. be. The temperature increase signals Sta to Stc have not changed from state 18.

Note that when the temperature status of the power supplies 1a to 1c changes and the magnitude relationship of the cumulative temperature signals Vtta to Vttc changes, the power supply determined to be in a relatively high temperature state changes (S350), and the switching control signal The settings of Ssa to Ssc also change. By combining this control, in a power supply device that is in a relatively high temperature state (for example, a power supply device that corresponds to the maximum value of the cumulative temperature signal Vtta to Vttc), even when the conditions for increasing the output voltage are met, the actual By increasing the output voltage, it is possible to delay the timing at which the temperature rises. As a result, by taking into consideration the temperature history over a certain period of time, it is expected that the length of the period in which the power supply devices 1a to 1c are in a high temperature state can be balanced.

In this way, in the power supply system according to the second embodiment, as in the first embodiment, it is possible to balance the temperature rise between the power supply devices by simple control, and also to take into account the past temperature history. , the temperature rise between parallel-connected power supplies can be further balanced.

In Embodiment 2, regarding the extraction of power supplies with standby time, an example was explained in which one power supply with the maximum cumulative temperature signal is extracted from three power supplies. It is possible to extract some power supplies that are in a relatively high temperature state from a plurality of power supplies under arbitrary conditions based on the temperature history (cumulative temperature signal).

Furthermore, the standby time LT can be adjusted to an appropriate value through actual machine tests or simulations, taking into consideration the size, heat load, load capacity, etc. of the power supply device. Note that the standby time LT is variably set so that the time becomes longer as the temperature increases, depending on the degree of the high temperature state, for example, the value of the cumulative temperature signal Vtt (Vtta to Vttc) of the power supply device determined to be in the high temperature state. may be done.

Embodiment 3.
FIG. 11 is a block diagram illustrating a configuration example of a power supply system 100C according to the third embodiment.

Referring to FIG. 11, compared to power supply system 100A (FIG. 1) according to the first embodiment, power supply system 100C includes cumulative temperature calculation units 11a to 11c similar to those in the second embodiment, and cumulative temperature determination unit 13 in that it further includes an exchange information display section 14.

The cumulative temperature calculation units 11a to 11c respectively output cumulative temperature signals Vtta to Vttc with a predetermined period T1 (for example, T1=about 1 hour), as in FIG. 7. The cumulative temperature determining unit 13 determines the remaining life of the power supplies 1a to 1c, which is used to determine whether or not to replace the power supplies 1a to 1c, based on the cumulative temperature signals Vtta to Vttc, that is, the past temperature history. For example, the cumulative temperature determination unit 13 determines the remaining life of the power supplies 1a to 1c.

The replacement information display unit 14 is provided to display the determination result by the cumulative temperature determination unit 13, and can be configured with an LED (Light Emitting Diode) lamp, an LED segment, a liquid crystal display, or the like (not shown).

FIG. 12 shows a flowchart for explaining the operations of the cumulative temperature calculation units 11a to 11c and the cumulative temperature determination unit 13 in the power supply system 100C. That is, the functions of the cumulative temperature calculation units 11a to 11c and the cumulative temperature determination unit 13 can be realized by a microcomputer or the like executing the processing shown in FIG.

Referring to FIG. 12, cumulative temperature calculation units 11a to 11c execute S310 to S330 similar to those in FIG. Calculate. In the third embodiment as well, the constant period T1 can be about one hour.

At S510, the cumulative temperature signals Vtta to Vttc are input to the cumulative temperature determining unit 13 from the cumulative temperature calculating units 11a to 11c at every fixed period T1. Further, in S510, the count value i and the cumulative temperature signals Vtta to Vttc are cleared in the cumulative temperature calculation units 11a to 11c (i=0, Vtta=Vttb=Vttc=0), similarly to S340 (FIG. 8). .

In step S520, the cumulative temperature determination unit 13 compares each of the cumulative temperature signals Vtta to Vttc for each fixed period with the specified temperature value Vjd. The specified temperature value Vjd can be determined in consideration of the rated temperature. For example, a temperature slightly lower than the rated temperature (for example, 75°C) is set as the specified temperature (70°C), and it is made to correspond to the cumulative temperature signal Vtta to Vttc that is assumed when the specified temperature continues for 1 hour. The specified temperature value Vjd can be set in advance.

The cumulative temperature determination unit 13 has temperature rise count values Na to Nc corresponding to each of the power supply devices 1a to 1b. Na to Nc are indicated by integers that are set to initial values (Na=Nb=Nc=0) when the power supply system 100C starts to be used.

If any of the cumulative temperature signals Vtta to Vttc is equal to or higher than the specified temperature value Vjd (YES in S520), the temperature rise count values Na to Nc are updated in S530 according to the comparison result in S520. Specifically, the temperature rise count value N (Na to Nc) corresponding to the power supply device whose cumulative temperature signal Vtt (Vtta to Vttc) is equal to or higher than the specified temperature value Vjd is increased by 1 (incremented), while the remaining The temperature rise count value is maintained. For example, when Vtta>Vjd, Vttb<Vjd, and Vttc<Vjd, the temperature rise count value Na is incremented in S530, while the temperature rise count values Nb and Nc are maintained.

Following S530, in S540, the cumulative temperature determination unit 13 compares the temperature rise count values Na to Nc updated in S530 with the upper limit number of times Nt. Then, when at least one of the temperature rise count values Na to Nc reaches the upper limit number of times Nt (when determining YES in S540), the cumulative temperature determination unit 13 determines that the temperature rise count value N (Na to Nc) has reached the upper limit number of times Nt. A power supply device that has reached Nt is identified and a replacement schedule signal Sch is generated.

On the other hand, when all of the temperature rise count values Na to Nc are smaller than the upper limit number of times Nt (NO determination in S540), S550 is skipped and the processing in the corresponding cycle (T1) is ended. Further, in S520, when all of the cumulative temperature signals Vva to Vvc are smaller than the specified temperature value Vjd (NO determination in S520), the values of the temperature rise count values Na to Nc are maintained in S560, and the period (T1 ) is finished.

Referring again to FIG. 11, the replacement schedule signal Sch generated in S550 is input from the cumulative temperature determination section 13 to the replacement information display section 14. Based on the replacement schedule signal Sch, the replacement information display unit 14 displays a power supply device whose temperature rise count value N (Na to Nc) has reached the upper limit number of times Nt to notify the user as a power supply device scheduled to be replaced. do. For example, by selectively lighting up three LED lamps arranged corresponding to the power supplies 1a to 1c, it is possible to notify the user of the power supply to be replaced. Alternatively, it is also possible to notify the user of the power supply device scheduled for replacement by means of an LED segment, text display on a liquid crystal display, or the like.

In this way, according to the power supply system according to Embodiment 3, it is possible to determine the pre-life for replacement of a plurality of parallel-connected power supply devices based on the past temperature history. This makes it possible to provide the user with information for considering the replacement schedule, thereby improving user convenience.

Note that it is also possible to combine the second and third embodiments to create a configuration in which both the cumulative temperature comparison section 12 and the cumulative temperature determination section 13 are arranged. Furthermore, in the power supply system according to the second or third embodiment, and the power supply system according to the combination of the second and third embodiments, the CVCC control according to the modification of the first embodiment is applied to each of the power supply devices 1a to 1c. It is also possible to provide functions.

Embodiment 4.
FIG. 13 is a block diagram illustrating a configuration example of a power supply system 100D according to the fourth embodiment.

Referring to FIG. 13, power supply system 100D differs from power supply system 100C according to the third embodiment (FIG. 11) in that it further includes signal isolation circuit sections 16a to 16c. Further, in the power supply system 100D, the temperature detecting units 7a to 7c are arranged on the high voltage side in the converter units 3a to 3c having a non-insulated configuration due to the arrangement of the signal insulating circuit units 16a to 16c. It can be arranged so as to be directly attached to a heat generating part (circuit element) connected to a "path". Note that when the converter sections 3a to 3c are non-insulated, the high voltage side (positive electrode) terminal of the power supply 110 and the high voltage side (positive electrode) terminal of the load 120 are insulated by a transformer or the like. electrically connected.

Here, the "high voltage side path" refers to the path through which current flows from the high voltage side (positive electrode) terminal of the power supply 110 to the high voltage side (positive electrode) terminal of the load 120 in each of the converter sections 3a to 3c. shall be indicated. For example, among the above-mentioned heat generating parts such as the rectifier diode 9a, the smoothing capacitor 13a, or the substrate pattern (not shown), the temperature detecting parts 7a to 7c are attached to the connection parts with the high voltage side path. be able to.

Similarly, in each of converter sections 3a to 3c, the path through which current returns from the low voltage side (negative electrode) terminal of load 120 to the low voltage side (negative electrode) terminal of power supply 110 is defined as a "low voltage side path." shall be. When the converter sections 3a to 3c are configured of non-insulated type, since the output side (load side) of the converter sections 3a to 3c and the load 120 are connected in parallel, each of the converter sections 3a to 3c In this case, not all of the current flowing on the high voltage side (current flowing toward the load 120) returns as the current flowing on the low voltage side (current flowing toward the power supply 110). Therefore, in order to detect a temperature rise in the converter sections 3a to 3b, it is preferable that the temperature detection sections 7a to 7c accurately measure the temperature of the heat generating section on the high voltage side.

In FIG. 13, the temperature detection units 7a to 7c output temperature signals Vtha to Vthc indicating the measured temperature of the heat generating unit on the high voltage side. The temperature signals Vtha to Vthc are voltage signals based on the potential on the high voltage side because the temperature detection parts 7a to 7c are directly attached to the heat generating part on the high voltage side. It is not possible to directly input the temperature to the signal control units 8a to 8c, cumulative temperature calculation units 11a to 11c, etc., which operate as a reference.

Therefore, signal isolation circuit units 16a to 16c receive temperature signals Vtha to Vthc from temperature detection units 7a to 7c, and generate temperature signals Vtia to Vtic electrically insulated from the high voltage side of converter units 3a to 3c. Output. The temperature signals Vtia to Vtic are generated to have the same amplitude values as the temperature signals Vtha to Vthc with the low voltage side potential as a reference. For example, the signal isolation circuit sections 16a to 16c can be constructed using photocouplers or the like, but any element and circuit configuration can be applied.

The temperature signals Vtia to Vtic output from the signal isolation circuit parts 16a to 16c are controlled by the signal control parts 8a to 8c and the cumulative temperature calculation parts 11a to 11a, similarly to the temperature signals Vta to Vtc in the third embodiment (FIG. 11). 11c. In the power supply system 100D according to the fourth embodiment, the signal control units 8a to 8c and the cumulative temperature calculation units 11a to 11c convert the temperature signals Vtia to Vtic from the signal isolation circuit units 16a to 16c into the temperature signals Vta to Vtic in FIG. It operates by using it as Vtc.

Therefore, in the power supply system according to the fourth embodiment, the temperature detection sections 7a to 7c are directly attached to the heat generating section on the high voltage side, and the implementation is performed based on the temperature (temperature signals Vtha to Vthc) measured with high precision. Control can be performed by the power supply system 100C according to the third embodiment. As a result, temperature rises between power supplies can be further balanced by improving control accuracy.

Note that also in FIG. 1 (Embodiment 1), the temperature signals Vtia to Vtic from the signal isolation circuit sections 16a to 16c can be used as the temperature signals Vta to Vtc input to the signal control sections 8a to 8c. be. Also, in FIG. 7 (Embodiment 2), temperature signals Vtia to Vtic from signal isolation circuit units 16a to 16c are converted to temperature signals Vta input to signal control units 8a to 8c and cumulative temperature calculation units 11a to 11c. ~ Can be used as Vtc.

That is, by appropriately combining Embodiment 4 with each of Embodiments 1 to 3 or a combination thereof, it is possible to improve the accuracy of temperature measurement by temperature detection units 7a to 7c. Thereby, as described above, temperature rises between the power supplies can be further balanced by improving control accuracy.

Embodiment 5.
FIG. 14 is a block diagram illustrating a configuration example of a power supply system 100E according to the fifth embodiment.

Referring to FIG. 14, power supply system 100E differs from power supply system 100C according to the third embodiment (FIG. 11) in that power supply devices 1a to 1c further include power isolation circuit units 17a to 17c. Power insulation circuit sections 17a to 17c comprehensively describe circuit elements for electrically insulating between the output side (load side) of the converter sections 3a to 3c whose temperature is to be measured and the load 120. This can be realized, for example, by an insulated converter such as a flyback converter or a half-bridge converter, which is connected between the non-insulated converter sections 3a to 3c and the load 120.

Alternatively, by configuring the converter sections 3a to 3c themselves with an isolated converter such as a flyback converter or a half bridge converter that includes a transformer, the power isolation circuit sections 17a to 17c can be configured differently from the example shown in FIG. , may be realized by a transformer included in the converter sections 3a to 3c.

By electrically insulating between the power supply 110 and the load 120 by the power insulation circuit parts 17a to 17c, current flowing on the high voltage side (current flowing toward the load 120) in each of the converter parts 3a to 3c and the current flowing on the low voltage side (the current flowing toward the power supply 110) are equal. As a result, when detecting a temperature rise in the converter sections 3a to 3b, it is possible to obtain the same results regardless of whether the temperature of the heat generating section on the high voltage side or the low temperature side is measured.

Therefore, in the power supply system 100E, the temperature detection units 7a to 7c can be arranged so as to be directly attached to the heat generating unit on the “low voltage side” where signal insulation is not required. The temperature signals Vtla to Vtlc output from the temperature detecting parts 7a to 7c directly attached to the heat generating part on the low voltage side are processed according to the third embodiment without passing through the signal isolation circuit parts 16a to 16c shown in FIG. Similar to the temperature signals Vta to Vtc in FIG. 11, these are input to the signal control units 8a to 8c and the cumulative temperature calculation units 11a to 11c.

In the power supply system 100E according to the fifth embodiment, the signal control units 8a to 8c and the cumulative temperature calculation units 11a to 11c convert the temperature signals Vtla to Vtlc from the temperature detection units 7a to 7c into the temperature signals Vta to Vtc in FIG. It operates as a.

Therefore, in the power supply system according to the fifth embodiment, temperature detection units 7a to 7c are arranged as heat generating parts on the low voltage side with respect to converter parts 3a to 3c configured to electrically insulate power supply 110 and load 120. The power supply system 100C according to the third embodiment can be controlled based on the temperature (temperature signals Vtla to Vtlc) measured with high precision by directly attaching the power supply system 100C to the temperature signal Vtla to Vtlc. As a result, temperature rises between the power supplies can be further balanced by improving control accuracy without requiring a configuration for signal isolation.

In addition, in FIG. 1 (Embodiment 1) as well, by electrically insulating between the power supply 110 and the load 120 by the power insulation circuit parts 17a to 17c, the load 120 can be directly attached to the heat generating part on the low voltage side. The temperature signals Vtla to Vtlc from the temperature detection units 7a to 7c can be used as the temperature signals Vta to Vtc input to the signal control units 8a to 8c. Also, in FIG. 7 (Embodiment 2), by providing the power insulation circuit parts 17a to 17c, the temperature signals Vtla to Vtlc from the temperature detection parts 7a to 7c directly attached to the heat generating part on the low voltage side can be It can be used as the temperature signals Vta to Vtc input to the signal control units 8a to 8c and the cumulative temperature calculation units 11a to 11c.

That is, by appropriately combining Embodiment 5 with each of Embodiments 1 to 3 or a combination thereof, it is possible to improve the accuracy of temperature measurement by temperature detection units 7a to 7c. Thereby, as described above, temperature rises between the power supply devices can be further balanced by improving control accuracy without requiring a configuration for signal isolation.

Regarding the multiple embodiments described above, the configurations described in each embodiment may be combined as appropriate, including combinations not mentioned in the specification, to the extent that no inconsistency or contradiction occurs. Also, the points that have been planned from the beginning of the application will be stated for confirmation.

Further, in Embodiments 1 to 5, a configuration in which three power supply devices are connected in parallel is illustrated, but a power supply system in which two or four or more power supply devices are connected in parallel to supply power to a load is also possible. It is possible to apply Embodiment 1, a modification of Embodiment 1, Embodiment 2, Embodiment 3, Embodiment 4, Embodiment 5, or a combination thereof. .

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

1a to 1c power supply device, 3a to 3c converter section, 4a to 4c switching control section, 5a to 5c output voltage detection section, 6a to 6c output current detection section, 7a to 7c temperature detection section, 8 signal control section, 8a to 8c Signal control unit, 9a to 9c rectifier diode, 10a to 10c semiconductor switching element, 11a to 11c cumulative temperature calculation unit, 12 cumulative temperature comparison unit, 13 cumulative temperature determination unit, 14 replacement information display unit, 15a to 15c smoothing capacitor, 15t, 15v signal generation circuit, 16a to 16c signal isolation circuit section, 17a to 17c power isolation circuit section, 100A to 100C power supply system, 110 power supply, 120 load, Ilm upper limit current, Ioa to Ioc output current, LT standby time, Na ~Nc Temperature rise count value, N1, VIlm Judgment value, Nt Upper limit number of times, Sch Replacement schedule signal, Sga ~ Sgc Drive signal, Ssa ~ Ssc Switching control signal, Sta, Stb, Stc Temperature rise signal, Sta*~Stc* Temperature Abnormal signal, Sto overall temperature abnormal signal, Sta~Sttc control signal, Sva~Svc voltage increase signal, Svo overall voltage status signal, VHlim voltage upper limit, VHt voltage threshold, VTHlm temperature upper limit, VTHt temperature threshold, Via~Vic output Current signal, Voa~Voc output voltage, Vo* voltage command value, Vt, Vta~Vtc, Vtha~Vthc, Vtla~Vtlc temperature signal, Vtia~Vtic temperature signal (after insulation), Vtta~Vttc cumulative temperature signal, Vva~ Vvc Output voltage signal.

Claims (16)

1. A power supply system,
   Equipped with multiple power supplies with outputs connected in parallel,
   Each of the plurality of power supplies includes:
   a converter section configured to include a semiconductor switching element and supply an output voltage and an output current;
   a temperature detection unit that measures the temperature of the converter unit;
   an output voltage detection unit that measures the output voltage of the converter unit;
   a switching control unit that generates a drive signal for controlling the semiconductor switching element according to constant voltage control that brings the detected voltage of the output voltage detection unit close to a voltage command value;
   a signal control unit for increasing or decreasing the voltage command value in the switching control unit based on a comparison between the temperature detected by the temperature detection unit and a temperature threshold;
   Each of the signal control units mutually shares information related to the setting of the voltage command value in each of the power supply devices,
   Among the plurality of power supply devices, in a power supply device in a first temperature state where the detected temperature is higher than the temperature threshold value, the signal control unit sets the voltage command value to the first voltage value, while the detected temperature is higher than the temperature threshold value. In the power supply system in a second temperature state where the temperature is below the temperature threshold, the signal control unit sets the voltage command value to a second voltage value higher than the first voltage value.
2. The signal control unit further performs a comparison between the detected voltage by the output voltage detection unit and an output voltage threshold,
   The signal control unit may be configured such that when the voltage command value is the first voltage value, the detected temperature is equal to or lower than the temperature threshold, and the detected voltage is equal to or lower than the output voltage in all of the plurality of power supply devices. The power supply system according to claim 1, wherein the voltage command value is increased from the first voltage value to the second voltage value when the voltage command value is equal to or less than a threshold value.
3. The power supply system according to claim 1 or 2, wherein the temperature threshold is set to a lower value when the temperature is in the first temperature state than when the temperature is in the second temperature state.
4. The converter section is configured to perform DC voltage conversion by on/off control of the semiconductor switching element,
   Each of the signal control units further compares the detected temperature with a temperature upper limit value, and when it is detected that the detected temperature is higher than the temperature upper limit value in at least one of the plurality of power supply devices, the converter unit The power supply system according to any one of claims 1 to 3, wherein the drive signal is generated so as to fix the semiconductor switching element in an off state.
5. At the time of startup of the power supply system, the initial values of the voltage command values of the plurality of power supply devices are all set so that the voltage command values are not equal to one of the first voltage value and the second voltage value. The power supply system according to any one of claims 1 to 4.
6. The power supply system according to any one of claims 1 to 5, wherein the temperature detection section includes a thermistor fixed to a substrate on which components of the converter section are mounted.
7. The first voltage value is lower than a rated value of a supply voltage to a load connected to the output of the plurality of power supply devices,
   The power supply system according to any one of claims 1 to 6, wherein the second voltage value is higher than the rated value.
8. Each of the plurality of power supplies includes:
   further comprising an output current detection unit that measures the output current of the converter unit,
   Each of the signal control units includes:
   The drive signal is generated so as to limit the output of the converter section in order to prevent the output current from increasing any further when the output current detected by the output current detection section reaches a predetermined upper limit current. 8. The power supply system according to any one of 1 to 7.
9. Temperature history comparison for extracting some power supply devices in a relatively high temperature state from the plurality of power supply devices by comparing the history of the temperature detected by the temperature detection unit in each of the plurality of power supply devices. further comprising:
   Each of the signal control units included in some of the power supply devices increases the voltage command value for a first time period when increasing the voltage command value from the first voltage value to the second voltage value as the detected temperature increases. elapses, the voltage command value is increased,
   The signal control unit, which is not included in some of the power supply devices, increases the voltage command value from the first voltage value when increasing the voltage command value from the first voltage value to the second voltage value as the detected temperature increases. The power supply system according to any one of claims 1 to 8, wherein the voltage command value is increased after a second time period shorter than the current time period has elapsed.
10. Each of the plurality of power supplies includes:
    further comprising a cumulative temperature calculation unit that outputs the cumulative value of the detected temperature at every predetermined period,
    The power supply system according to claim 9, wherein the temperature history comparison unit extracts the part of the power supply devices based on a comparison of the integrated values of each of the plurality of power supply devices.
11. a temperature history determination unit for determining the remaining life of the plurality of power supply devices as to whether or not they need to be replaced, using a history of detected temperatures of the temperature detection unit of each of the plurality of power supply devices;
    The power supply system according to any one of claims 1 to 9, further comprising a display unit for notifying a user of the determination result by the temperature history determination unit.
12. Each of the plurality of power supplies includes:
    further comprising a cumulative temperature calculation unit that outputs the cumulative value of the detected temperature at every predetermined period,
    The temperature history determination unit counts, for each of the plurality of power supply devices, the number of times the integrated value outputted from the cumulative temperature calculation unit in the certain period exceeds a predetermined determination value. The power supply system according to claim 11, wherein when the number of times reaches a predetermined upper limit number of times, it is determined that the power supply device needs to be replaced.
13. Each of the plurality of power supply devices is connected between a power source and a load connected to an output of the plurality of power supply devices,
    The converter section of each of the plurality of power supply devices is configured with a non-insulated converter,
    The temperature detection section is attached directly to a circuit element connected to a high voltage side of the converter section through which current flows from the power supply to the load,
    Each of the plurality of power supplies includes:
    The power supply system according to any one of claims 1 to 9, further comprising a signal isolation circuit section for insulating an output signal from the temperature detection section indicating the detected temperature and inputting it to the signal control section. .
14. Each of the plurality of power supply devices is connected between a power source and a load connected to an output of the plurality of power supply devices,
    The converter section of each of the plurality of power supply devices is configured with a non-insulated converter,
    The temperature detection unit is attached directly to a circuit element connected to a high voltage side path through which current flows from the power supply to the load in the converter unit,
    Each of the plurality of power supplies includes:
    The power supply according to claim 10 or 12, further comprising a signal insulation circuit section for insulating an output signal from the temperature detection section indicating the detected temperature and inputting the signal to the signal control section and the cumulative temperature calculation section. system.
15. Each of the plurality of power supply devices is connected between a power source and a load connected to an output of the plurality of power supply devices,
    Each of the plurality of power supply devices further includes a power isolation circuit section for electrically insulating between the power supply and the load,
    The temperature detection unit is directly attached to a circuit element connected to a low voltage side path through which a current toward the power supply flows in the converter unit of each of the plurality of power supply devices,
    The power supply system according to any one of claims 1 to 9, wherein an output signal from the temperature detection unit indicating the detected temperature is input to the signal control unit without signal insulation.
16. Each of the plurality of power supply devices is connected between a power source and a load connected to an output of the plurality of power supply devices,
    Each of the plurality of power supply devices further includes a power isolation circuit section for electrically insulating between the power supply and the load,
    The temperature detection unit is directly attached to a circuit element connected to a low voltage side path through which a current toward the power supply flows in the converter unit of each of the plurality of power supply devices,
    The power supply system according to claim 10 or 12, wherein an output signal from the temperature detection unit indicating the detected temperature is input to the signal control unit and the cumulative temperature calculation unit without signal insulation.

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