JP2013038871A - Switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply power to a load at low loss while suitably suppressing a rush current.SOLUTION: A series circuit composed of switch circuits SWand SWis provided between a power line 60 connected to a power source side and a power line 64 connected to a load side, and a thermistor 102 is provided in parallel with the switch circuit SW. A load includes a primary load (such as a DC/DC converter) performing power conversion of an output power of the power source, and a secondary load driven by power obtained by the power conversion. In supplying power to the load, a control section instructs the primary load to start the power conversion, switches the switch circuit SWfrom off to on, and then switches the switch circuit SWfrom off to on.

Description

  The present invention relates to a switching device involved in switching between a power source and a load circuit.

  In many cases, a switching device that controls conduction / non-conduction between the unit that outputs power and the load is provided. For example, as shown in FIG. 7, there is a system that supplies output power of a power output unit 901 to a load 903 via a discharge circuit 902. The power output unit 901 is a power source that outputs DC power, such as a storage battery unit. The load 903 includes a DC load driven by DC power or an AC load driven by AC power. For example, DC / DC conversion of the output DC power of the power output unit 901 (storage battery unit) can be performed using a DC / DC converter, and a DC load such as LED lighting can be driven by the obtained DC power. Alternatively, for example, DC / AC conversion of output DC power of the power output unit 901 (storage battery unit) can be performed using a DC / AC converter, and various AC loads can be driven by the obtained AC power. The discharge circuit 902 turns on / off the connection between the power output unit 901 and the load 903. In order to protect the circuit components in the system, the discharge circuit 902 may be provided with a limiter that limits the current passing through the discharge circuit 902.

  Since the circuit forming the load 903 includes an inductance and a capacitor, a large inrush current flows to the discharge circuit 902 when the load 903 is started (when the power output unit 901 and the load 903 are connected). If the limiter functions as the inrush current passes, current supply to the load 903 may be limited, and each device in the load 903 may not be activated. Further, in the case where the limiter is not provided in the discharge circuit 902, there is a possibility that circuit components in the system are damaged or deteriorated due to passage of a large inrush current.

  As a countermeasure against such inrush current, there is a method of inserting a thermistor in series in a path through which the inrush current flows (see, for example, Patent Document 1 below). An NTC (negative temperature coefficient) thermistor can be used as the thermistor.

JP 2008-11688 A

  If an NTC thermistor is used, the resistance value of the NTC thermistor decreases due to the self-heating of the NTC thermistor as time elapses from the start of inrush current passage. Therefore, the loss is large.

  On the other hand, when the load 903 includes a primary load such as a DC / DC converter that performs power conversion and a secondary load that consumes the power obtained by the power conversion, the load 903 enters in relation to the operation of those loads. Although it is necessary to appropriately suppress the current, a technology that satisfies such a need has not yet been proposed.

  Accordingly, an object of the present invention is to provide a switching device that can perform power supply to a load with low loss while appropriately suppressing an inrush current.

  A switching device according to the present invention includes a discharge circuit provided between a first wiring connected to the power source side and a second wiring connected to the load side, and a control unit that controls the state of the discharge circuit. The load includes a primary load that performs power conversion of power supplied through the discharge circuit, and the discharge circuit includes a first switch circuit connected to the first wiring, and the first switch A second switch circuit provided between the circuit and the second wiring; and a resistance element connected in parallel to the second switch circuit, wherein the control unit performs power supply to the load. , Instructing the primary load to start the power conversion, switching the first switch circuit from OFF to ON, and then switching the second switch circuit from OFF to ON.

  By instructing the start of power conversion and switching on the first switch circuit, and supplying current to the primary load via the resistance element, the inrush current associated with the startup of the primary load can be kept low. Thereafter, for example, after the flow of the inrush current is finished, the current can be supplied to the load side with low loss by switching the second switch circuit on.

  In addition, for example, the load further includes a secondary load that is driven by electric power from the primary load, and the discharge circuit includes the second switch circuit and the second switch circuit after the second switch circuit is switched from OFF to ON. A temporary OFF circuit that temporarily turns off the second switch circuit according to a current flowing between the primary loads may be provided.

  By providing the temporary off circuit, it is possible to keep the inrush current that can occur at the time of starting the secondary load low. That is, for example, when the inrush current for starting the secondary load flows, if the second switch circuit is temporarily turned off and current is supplied to the load through the resistance element, the secondary load is started. The inrush current that can sometimes occur can be kept low.

  Specifically, for example, the temporary off circuit is configured to temporarily turn off the second switch circuit based on a signal waveform of the current after the second switch circuit is switched from off to on. A signal or an ON maintaining signal for maintaining ON of the second switch circuit may be switched and output.

  Further, for example, when outputting the temporary OFF signal, the temporary OFF circuit may set a length of time for temporarily turning off the second switch circuit according to the signal waveform.

  Thereby, the second switch circuit can be turned off for an appropriate time according to the magnitude of the inrush current.

  More specifically, for example, when supplying power to the load, the control unit instructs the primary load to start the power conversion, and then switches the first switch circuit from off to on, and then The second switch circuit may be switched from off to on.

  More specifically, for example, the resistance element may be a thermistor having a negative temperature coefficient.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the switching apparatus which can perform the electric power supply to load with low loss, suppressing an inrush current appropriately.

1 is an overall configuration diagram of a power system according to an embodiment of the present invention. It is an internal block diagram of the inrush current control circuit which concerns on 1st Example of this invention. FIG. 2 is a diagram illustrating a configuration example in which two inrush current control circuits are arranged in the discharge circuit of FIG. 1 and a configuration example in which one inrush current control circuit is arranged. 6 is an operation timing chart of the DC / DC converter and the two switch circuits according to the first embodiment of the present invention. It is an internal block diagram of the inrush current control circuit which concerns on 2nd Example of this invention. It is a figure which shows the waveform of each voltage signal concerning 2nd Example of this invention. It is a block diagram of the system containing the conventional switching apparatus.

  Hereinafter, an example of an embodiment of the present invention will be specifically described with reference to the drawings. In each of the drawings to be referred to, the same part is denoted by the same reference numeral, and redundant description regarding the same part is omitted in principle. In this specification, for simplification of description, a symbol or reference that refers to information, signal, physical quantity, state quantity, member, or the like is written to indicate information, signal, physical quantity, state quantity or Names of members and the like may be omitted or abbreviated.

  FIG. 1 is an overall configuration diagram of a power system according to an embodiment of the present invention. The power system is formed including all or a part of the parts shown in FIG. 1 and includes at least a BMU (battery management unit) 1 and a BSU (battery switching unit) 2.

The BSU 2 includes a microcomputer (hereinafter referred to as a microcomputer) 20, switch circuits 21 to 23, and a discharge circuit 24, and electric power commonly connected to the switch circuits 21 to 23 and the discharge circuit 24. A bus line 60 is provided. The term “line” is synonymous with the term “wiring”. The microcomputer 20 switches each switch circuit on or off by supplying a switching signal to each of the switch circuits provided in the switch circuits 21 to 23 and the discharge circuit 24. The switch circuit provided in the discharge circuit 24 includes switch circuits SW _A and SW _B described later (see FIG. 2). Each of the switch circuits provided in the switch circuits 21 to 23 and the discharge circuit 24 can be formed by a semiconductor switching element, a mechanical relay, or the like. The semiconductor switching element is, for example, a field-effect transistor (Field-Effect Transistor). ) Or an insulated gate bipolar transistor. The microcomputer 20 and the BMU 1 perform bidirectional communication of arbitrary information and signals. The microcomputer 20 can also switch each switch circuit on or off in accordance with an instruction from the BMU 1.

  The on state of the switch circuit means conducting between the wiring connected to one end of the switch circuit and the wiring connected to the other end of the switch circuit. The off state of the switch circuit means that the switch circuit is off. This means that the line connected to one end of the circuit is disconnected from the line connected to the other end of the switch circuit. One ends of the switch circuits 21, 22, and 23 are connected to the power lines 61, 62, and 63, respectively, and the other ends of the switch circuits 21, 22, and 23 are commonly connected to the power bus line 60.

  The solar cell unit 31 is formed of a solar cell, generates power using sunlight, and outputs a DC voltage based on the generated power to the switch 53. The switch 53 switches the output DC voltage of the solar cell unit 31 supplied to the switch 53 to either the power conditioner 52 or the power line 61 under the control of the BMU 1.

  The power system 51 has an AC power source that generates and outputs commercial AC power. When the output power of the solar cell unit 31 is supplied to the power conditioner 52 via the switch 53, the power conditioner 52 converts the output power of the solar cell unit 31 into AC power and is subject to predetermined restrictions. Then, the obtained AC power is output to the power system 51 side. The AC / DC converter 32 performs power conversion for converting AC power from the power system 51 or the power conditioner 52 into DC power, and outputs the obtained DC power to the power line 62.

  The storage battery unit 33 is composed of one or more secondary batteries. The secondary battery forming the storage battery unit 33 is any type of secondary battery, for example, a lithium ion battery or a nickel metal hydride battery. When the storage battery unit 33 includes a plurality of secondary batteries, some or all of the secondary batteries included in the storage battery unit 33 are connected in parallel or in series with each other. The storage battery unit 33 is connected to the power line 63, and the discharge current and the charging current of the secondary battery of the storage battery unit 33 flow through the power line 63. Note that battery state information indicating the state of the storage battery unit 33 (for example, output voltage, output current, remaining capacity, etc. of the storage battery unit 33) can be transmitted to the BMU 1.

  The discharge circuit 24 is interposed between the power bus line 60 and the DC / DC converter 34 and between the power bus line 60 and the DC / AC converter 35. The power line 64 is a wiring connecting the discharge circuit 24 and the DC / DC converter 34, and the power line 65 is a wiring connecting the discharge circuit 24 and the DC / AC converter 35. The discharge circuit 24 connects or disconnects the power bus line 60 and the power line 64 and the power bus line 60 and the power line 65 according to the switching signal from the microcomputer 20.

  When the power bus line 60 and the power line 64 are connected, a DC voltage in the power bus line 60 is applied to the power line 64, and the DC / DC converter 34 converts the DC voltage of the power line 64 to another DC voltage. Power conversion to be converted is performed, and the obtained other DC voltage is output to a DC load (DC load) 44. When the power bus line 60 and the power line 65 are connected, a direct current voltage is applied to the power line 65, and the DC / AC converter 35 performs power conversion to convert the direct current voltage into an alternating current voltage. An AC voltage is output to an AC load 45 (AC load). The DC voltage in the power bus line 60 is obtained by using the output voltage of the solar cell unit 31 supplied via the switch circuit 21, the output voltage of the AC / DC converter 32 supplied via the switch circuit 22, or the switch circuit 23. It is the output voltage of the storage battery unit 33 supplied via the. Note that a limiter for limiting the current passing through the discharge circuit 24 may be provided in the discharge circuit 24 in order to protect circuit components in the power system.

  By turning on the switch circuit 21, 22 or 23 and connecting the power bus line 60 and the power line 64 to the discharge circuit 24, the output power of the solar cell unit 31, the AC / DC converter 32 or the storage battery unit 33 is obtained. Thus, the DC load 44 can be driven. The output power of the storage battery unit 33 is power generated by discharging the secondary battery in the storage battery unit 33. Similarly, the AC load 45 can be driven by the output power of the solar cell unit 31, the AC / DC converter 32 or the storage battery unit 33. Further, by turning on the switch circuit 21 or 22 while turning on the switch circuit 23, the secondary battery in the storage battery unit 33 is charged with the output power of the solar cell unit 31 or the AC / DC converter 32. Can do.

  Further, the BMU 1 can individually control whether or not the power conversion in the DC / DC converter 34 and the power conversion in the DC / AC converter 35 can be executed. In an arbitrary converter represented by the DC / DC converter 34 or the DC / AC converter 35, a state in which power conversion is performed is expressed as a converter on, and a state in which power conversion is not performed is expressed as a converter off. The power consumption of the converter when the converter is off is much smaller than that when the converter is on and can be considered zero. When the DC / DC converter 34 is off, DC power is naturally not supplied from the DC / DC converter 34 to the DC load 44, and when the DC / AC converter 35 is off, naturally, the DC / AC converter 35 sends AC to the AC load. AC power is not supplied to the load 45.

  The DC load 44 is composed of one or more DC element loads, and the AC load 45 is composed of one or more AC element loads. Each of the DC element load and the AC element load is any electric device (lighting device, air conditioner, etc.) that is independently turned on or off. The DC element load is driven only when the DC element load is on, and the power consumption of the DC element load when the DC element load is off is sufficiently smaller than that when the DC element load is on. It can be considered (the AC element load is the same).

  For the solar cell unit 31, the AC / DC converter 32, or the storage battery unit 33, the DC / DC converter 34 and the DC / AC converter 35 are provided with the primary load (in other words, the discharge circuit 24) that consumes power first. The DC load 44 and the AC load 45 are secondary loads that consume power second (in other words, power obtained by power conversion of the primary load). Secondary load driven by the

  Since the primary load and the secondary load include an inductance and a capacitor, a large current temporarily flows when the power source is started (that is, when the primary load or the secondary load is switched from off to on). This large current that flows when the power supply is started is called inrush current. The discharge circuit 24 includes a circuit that can appropriately cope with an inrush current. Hereinafter, specific configurations and operations of the discharge circuit 24 or technologies related thereto will be described in a plurality of embodiments.

<< First Example >>
A first embodiment will be described. FIG. 2 is an internal configuration diagram of the inrush current control circuit 100 that can be provided in the discharge circuit 24. The inrush current control circuit 100 includes switch circuits SW _A and SW _B , a delay circuit 101, and a thermistor 102 connected in series.

As shown in FIG. 3A, two inrush current control circuits 100 may be provided in the discharge circuit 24 corresponding to the DC / DC converter 34 and the DC / AC converter 35. In such a case, one inrush current control circuit 100 may be disposed between the power bus line 60 and the power line 64, and the other inrush current control circuit 100 may be disposed between the power bus line 60 and the power line 65 (first). The same applies to the inrush current control circuit 110 according to the second embodiment).
Alternatively, as shown in FIG. 3B, the power lines 64 and 65 may be connected in common, and one inrush current control circuit 100 may be disposed between the power lines 64 and 65 and the power bus line 60. (The same applies to the inrush current control circuit 110 according to the second embodiment).

  In the following, for the sake of concrete description, it is assumed that the configuration of FIG. 3A is employed (the same applies to the inrush current control circuit 110 according to the second embodiment), and the power bus line 60 and the power line The configuration and operation of the inrush current control circuit 100 provided between 64 will be described. However, the following configuration and operation of the inrush current control circuit 100 are the same in the inrush current control circuit 100 provided between the power bus line 60 and the power line 65 in FIG. The same applies to the inrush current control circuit 100 of FIG.

_A series circuit of the switch circuits SW _A and SW _B is interposed in series between the power bus line 60 and the power line 64. More specifically, one ends of the switch circuits SW _A and SW _B are connected to the power bus line 60 and the power line 64, respectively, and the other ends of the switch circuits SW _A and SW _B are connected to the power line 103 in common. Has been. The power line 103 including a common connection point between the other ends of the switch circuits SW _A and SW _B is connected to the power line 64 via the thermistor 102. That is, the thermistor 102 is connected in parallel to the switch circuit SW _B. The thermistor 102 is a thermistor having a negative temperature coefficient, that is, an NTC (negative temperature coefficient) thermistor.

The switching signal from the microcomputer 20 is supplied directly to the control terminal of the switch circuit SW _A. The delay circuit 101 gives a predetermined delay to the switching signal from the microcomputer 20 for the switch circuit SW _A, and supplies the delayed switching signal to the control terminal of the switch circuit SW _B. The switching signal includes an on signal having a high level voltage value or an off signal having a low level voltage value. The high level and the low level are different levels. The high level may be assigned to the off signal and the low level may be assigned to the on signal. When the signal level of the switching signal supplied to the control terminal of the switch circuit SW _A is switched by the action of the delay circuit 101, the switching is transmitted to the control terminal of the switch circuit SW _B after a certain time has passed. .

When the ON signal is supplied to the control terminal of the switch circuit SW _A, the switch circuit SW _A causes the conduction between the power bus line 60 and the power line 103 becomes ON, OFF signal to the control terminal of the switch circuit SW _A When supplied, the switch circuit SW _A is turned off, and the power bus line 60 and the power line 103 are disconnected. When the ON signal is supplied to the control terminal of the switch circuit SW _B, the switch circuit SW _B causes the conduction between the power line 103 and the power line 64 turned on, the power-supply OFF signal to the control terminal of the switch circuit SW _B When the switch is set, the switch circuit SW _B is turned off and the power line 103 and the power line 64 are disconnected. However, even when the switch circuit SW _B is OFF, the power line 103 and the power line 64 are connected via the thermistor 102.

FIG. 4 shows an operation timing chart of the DC / DC converter 34 and the switch circuits SW _A and SW _B. In the initial state (time t <t _A1 ), the DC / DC converter 34 and the switch circuits SW _A and SW _B are all turned off.

When an electric power for driving the DC load 44 is to be supplied to the DC load 44 starting from the initial state, the BMU ₁ first switches the operating state of the DC / DC converter 34 from OFF to ON at the timing t _A1 . A converter ON command signal is output to the DC / DC converter 34. The converter-on command signal is a command signal that instructs the DC / DC converter 34 to start power conversion, and the DC / DC converter 34 that has received the converter-on command signal starts executing power conversion. However, at the timing t _A1 , since the direct current voltage of the power conversion source is not applied to the power line 64, the substantial power conversion is not started.

At the subsequent timing t _A2 , the microcomputer 20 outputs an ON signal to the switch circuit SW _A under the control of the BMU 1, whereby the switch circuit SW _A is switched from OFF to ON. By the action of the delay circuit 101, yet the switch circuit SW _B at the timing t _A2 are kept off, the ON signal at the timing t _A3 which a predetermined delay time from the timing t _A2 has elapsed is transmitted to the switch circuit SW _B Thus, the switch circuit SW _B is switched from OFF to ON.

If the on / off timing control is performed as described above, the switch circuit SW _A is switched on at the timing t _A2 to connect the power bus line 60 to the DC / DC converter 34, but the switch is switched until the timing t _A3 is reached. Circuit SW _B is off. At this time, a current flows from the power bus line 60 to the DC / DC converter 34 via the thermistor 102. However, since the resistance value of the thermistor 102 as an NTC thermistor is correspondingly high, the magnitude of the current is kept low. Excessive current does not flow. That is, the inrush current is suppressed, and components through which the inrush current can pass can be protected from damage or the like.

When the current is supplied to the DC / DC converter 34 via the thermistor 102 between the timings t _A2 and t _A3 , and the charging of the capacitor in the DC / DC converter 34 is completed to some extent (or completely), the switch circuit Switch SW _B from off to on. The on resistance of the switch circuit SW _B is lower than the resistance value of the thermistor 102, after the switch circuit SW _B is switched on, to supply current to the load side with low loss through the switch circuit SW _B it can.

  The thermistor is a kind of resistance element. As is well known, the resistance value in the thermistor changes relatively greatly with respect to the temperature change as compared with a normal resistance element (such as a carbon film resistance) intended to obtain a certain resistance value. It is desirable to use an NTC thermistor as the thermistor 102 in order to gradually increase the starting current of the DC / C converter 34 while keeping the peak value of the inrush current low, but the thermistor 102 is not a thermistor. It is also possible to replace it with a film resistance.

In the above description, the converter turned on after the timing _{t A1} to be output to the command signal is a DC / DC converter 34, but the timing _{t A2} of the switch circuit SW _A is switched off is visiting, the timing _{t A1} and timing t _A2 may be the same timing, and the timing t _A2 may be slightly ahead of the timing t _A1 .

In the configuration shown in FIG. 2, the switching signal supplied to the switch circuit SW _A is also supplied to the switch circuit SW _B via the delay circuit 101. However, the microcomputer 20 turns on or off the switch circuits SW _A and SW _B described above. The switching signal for the switch circuit SW _A and the switching signal for the switch circuit SW _B may be separately generated and supplied to the switch circuits SW _A and SW _B so that the switching is realized.

Further, when the switch circuit SW _A is always turned on, or when the switch circuit SW _A is deleted and the power bus line 60 and the switch circuit SW _B are directly connected, the power bus even if the switch circuit SW _B is off. The voltage applied to the line 60 is always supplied to the DC / DC converter 34, and a loss always occurs in the DC / DC converter 34 at all. Such useless loss is undesirable. Further, when the DC / DC converter 34 can be attached to and detached from the BSU 2 via a connection port (not shown) provided in the BSU 2, if the switch circuit SW _A is deleted or the like, the DC / DC converter 34 becomes BSU 2 Since the voltage applied to the power bus line 60 is always applied to the connection port when the power bus line 60 is disconnected, it is not desirable for safety. And a switch circuit SW _A Therefore the inrush control circuit 100.

<< Second Example >>
A second embodiment will be described. The second embodiment is an embodiment based on the first embodiment, and the description of the first embodiment is also applied to the second embodiment with respect to matters not specifically described in the second embodiment.

  The configuration described in the first embodiment can cope with the inrush current when the DC / DC converter 34 is switched from OFF to ON. On the other hand, each DC element load in the DC load 44 is independently and randomly switched from off to on or from on to off regardless of the control of the BMU 1, and when each DC element load is switched from off to on. Therefore, a corresponding inrush current can flow (the same applies to the AC element load). In the second embodiment, a circuit that can cope with an inrush current when each DC element load is switched from OFF to ON will be described.

FIG. 5 is an internal configuration diagram of the inrush current control circuit 110 that can be provided in the discharge circuit 24. The inrush current control circuit 110 includes each part referred to by reference numerals 111 to 115 in addition to the switch circuits SW _A and SW _B , the delay circuit 101 and the thermistor 102.

The connection relationship among the power bus line 60, the switch circuit SW _A , the switch circuit SW _B , the power line 103, the power line 64, and the thermistor 102 in the inrush current control circuit 110 is the same as that in the inrush current control circuit 100. However, the inrush control circuit 110, and outputs the delay circuit 101, a switching signal delayed is supplied to the synthesizing circuit 115, the output signal of the synthesizing circuit 115 is supplied to the control terminal of the switch circuit SW _B.

Current flowing between the DC / DC converter 34 is a switch circuit SW _B and the primary load, i.e. the current flowing through the power line 64 represented by the symbol _{I A.} The current sensor 111 outputs a voltage signal V _A having the value of the current I _A as a signal value. It is assumed that the polarity of the current flowing from the switch circuit SW _B toward the DC / DC converter 34 is positive. Therefore, when a current flows from the switch circuit SW _B to the DC / DC converter 34, a positive voltage signal V _A appears. The amplifier 112 amplifies the voltage signal V _A and outputs the amplified voltage signal V _A as the voltage signal V _B. The waveform shaping circuit 113 outputs a voltage signal V _C obtained by differentiating the voltage signal V _B , and the control pulse generation circuit 114 generates a voltage signal V _D corresponding to the voltage signal V _C. Although details will be described later, the voltage signal V _D can be a control pulse signal for temporarily turning off the switch circuit SW _B (see FIG. 6). The synthesis circuit 115 includes a logic circuit and the like, and includes a voltage signal V _D and a voltage signal V _E output from the delay circuit 101 (that is, a signal obtained by delaying the switching signal supplied from the microcomputer 20 to the switch circuit SW _A ). the voltage signal V _F corresponding to the bets to the control terminal of the switch circuit SW _B.

From the initial state in which the DC / DC converter 34 and the switch circuits SW _A and SW _B are all turned off, the DC / DC converter 34 and the switch circuits SW _A and SW _B are all turned on via timings t _A1 , t _A2 and t _A3. The operation is the same as that described in the first embodiment, and the output signal V _F of the synthesis circuit 115 coincides with the output signal V _E of the delay circuit 101 in the process of the operation.

The timing after the timing t _A3 and when the DC / DC converter 34 and the switch circuits SW _A and SW _B are all turned on is called timing t _B0, and the operation of the power system after the timing t _B0 This will be described with reference to FIG. However, at timing t _B0, it is assumed that all or some of the DC element loads in the DC load 44 are off. The following description is an operation after timing t _B0 unless otherwise _specified .

FIG. 6 shows the waveform of each voltage signal in the inrush current control circuit 110. Waveforms 321, 322, 323, 324 and 325 are the waveforms of the voltage signals V _B , V _C , V _D , V _E and V _F , respectively. Signal waveform and the waveform of the voltage signal V _B of the current I _A is in the relationship similar to the waveform 321. In FIG. 6, a reference waveform 311 is indicated by a one-dot chain line. A waveform 311 shows the waveform of the voltage signal V _B when it is assumed that the switch circuit SW _B is always kept on after the timing t _B0 .

_Assume that one or more DC element loads in the DC load 44 are switched from OFF to ON at timing t _B1 . At this time, since the flows rush current to the DC component load is switched from OFF to ON, the value of the current I _A, and the level of the voltage signal V _B proportional to the value of the current I _A is the timing t _B1 immediately Suddenly rises at The level of the voltage signal and the voltage value of the voltage signal are synonymous.

In response to rapid reduction of elevated levels of the voltage signal V _B, for example, a differential signal of the voltage signal V _B, also rapidly increases the level of the voltage signal V _C. When the voltage signal V _C after the timing t _B1 predetermined inrush current determination condition is satisfied, the control pulse generating circuit 114 outputs a control pulse signal determines that the inrush current is generated. Control pulse generation circuit 114, in principle maintains the level of the voltage signal V _D to the low level as equivalent to that to change the level of the voltage signal V _D temporarily high level outputs a control pulse signal To do. Here, it is assumed that the control pulse signal is output only between timings t _B2 and t _B3 (that is, the level of the voltage signal V _D is set high only between timings t _B2 and t _B3 ).

In the following timing _{t B0,} the level of the voltage signal _{V E} is always high level. Combining circuit 115, although the level of the voltage signal V _D and outputs a voltage signal V _E when a low level as it is as a voltage signal V _F, the voltage signal V _E when the level of the voltage signal V _D is at the high level the level of the voltage signal V _F to a low level irrespective of the level of. Accordingly, the switch circuit SW _B in between time _{t B2} and _{t B3} control pulse signal is output is turned off, the timing _{t B0} and _{t B2} and between the timing _{t B3} and later, the switch circuit SW _B is turned on.

Thus, the inrush current control circuit 110 includes a temporary off circuit that functions beneficially after the timing t _B0 . One o'clock off circuit in accordance with the current _{I A} between the switch circuits SW _B and DC / DC converter 34 (i.e., in response to a signal waveform of the current _{I A),} temporarily has a function of turning off the switching circuit SW _B . In the configuration of FIG. 5, the temporary off circuit is formed at each part referred to by reference numerals 111 to 115, for example. The temporary off circuit can limit the inrush current generated when the secondary load is switched on. During the period when the switch circuit SW _B is temporarily turned off, the primary load is supplied from the power bus line 60 via the thermistor 102 (or a resistance element that is provided in place of the thermistor 102 and is not classified as a thermistor). Current is supplied to the secondary load.

Whether the current I _A at any state current I _A is determined to be inrush current, and turning off the switch circuit SW _B at any timing when the current I _A is determined to be inrush current Whether to do this is determined and controlled by the control pulse generation circuit 114.

Control pulse generation circuit 114, by the voltage signal V _C constantly monitors whether or not a predetermined inrush current determination condition is satisfied, it is possible to detect the occurrence or non-occurrence of the inrush current. When the voltage signal V _C satisfies the inrush current determination condition and it is determined that the inrush current has occurred, a temporary off signal for temporarily turning off the switch circuit SW _B is output from the temporary off circuit (ie, The high level voltage signal V _D is output from the control pulse generation circuit 114, and the low level voltage signal V _F is output from the synthesis circuit 115). Not satisfy the voltage signal V _C inrush current determination condition, when not determined that the inrush current is generated, the on maintaining signal for maintaining the turn on the switch circuit SW _B is output from the temporary off circuit (i.e., A low level voltage signal V _D is output from the control pulse generation circuit 114, and a high level voltage signal V _F is output from the synthesis circuit 115). Since the voltage signal V _C is based on the signal waveform of the current I _A, one o'clock off circuit, based on the signal waveform of the current I _A, it can be said that the output switching transient off signal or an on maintenance signal. Also, since the level of the voltage signal V _C which is proportional to the slope of the signal waveform of the current I _A, one o'clock off circuit outputs switched temporary off signal or an on storage signal based on the gradient of the signal waveform of the current I _A It can be said.

Control pulse generation circuit 114, for example, when the level of the voltage signal V _C becomes equal to or larger than a predetermined reference level V _TH, the voltage signal V _C is determined that inrush current determination condition is satisfied, the level of the voltage signal V _C If it is maintained below the reference level V _TH, it can be determined that the voltage signal V _C does not meet the rush current judging conditions. Alternatively, for example, the control pulse generating circuit 114, when the level of the voltage signal V _C has become continuously for more than the reference level V _TH predetermined time, the voltage signal V _C is determined that inrush current determination condition is satisfied, so If not, it may be determined that the voltage signal V _C does not meet the rush current judging conditions.

When the voltage signal V _C is determined that inrush current determination condition is satisfied, the control pulse generating circuit 114 immediately or after waiting for the predetermined time, and outputs a control pulse signal (i.e., the high-level voltage signal V _D) . Control pulse generation circuit 114, a control pulse signal having a pulse width (i.e., the voltage signal V _D the length of time for maintaining a high level), and current I _A voltage signal V is a signal corresponding to the inclination of the signal waveform It can be set based on _C. Since the generation period of more large gradient inrush current signal waveform of the current I _A is considered long, may increase the pulse width as the inclination is large. Thereby, it is possible to take an appropriate countermeasure against the inrush current according to the scale of the inrush current. For example, the control pulse generation circuit 114 may set the pulse width based on the maximum value of the level of the voltage signal V _C after the timing t _B1 . Alternatively, for example, the control pulse generation circuit 114 integrates the voltage signal V _C during the period between the timing t _B1 and the timing after a predetermined time has elapsed from the timing t _B1, and sets the pulse width based on the obtained integration value. You may do it.

The relationship between the high level and the low level in each voltage signal described above can be reversed. Further, the waveform shaping circuit 113 may output a rectangular signal obtained by shaping the waveform of the differential signal as the voltage signal V _C instead of a simple differential signal of the voltage signal V _B.

<< Deformation, etc. >>
The embodiment of the present invention can be appropriately modified in various ways within the scope of the technical idea shown in the claims. The above embodiment is merely an example of the embodiment of the present invention, and the meaning of the term of the present invention or each constituent element is not limited to that described in the above embodiment. The specific numerical values shown in the above description are merely examples, and as a matter of course, they can be changed to various numerical values. As annotations applicable to the above-described embodiment, annotation 1 and annotation 2 are described below. The contents described in each comment can be arbitrarily combined as long as there is no contradiction.

[Note 1]
A mobile body (electric vehicle, ship, aircraft, elevator, walking robot, etc.) or electronic device (personal computer, portable) that drives the power system of FIG. 1 using the output power of the DC / DC converter 34 or the DC / AC converter 35. It may be installed in a terminal or the like, or may be incorporated in a power system of a house or factory.

[Note 2]
For example, it can be considered as follows. The power system shown in FIG. 1 includes a control unit that controls the state of each switch circuit in the discharge circuit 24. The control unit formed by the microcomputer 20 and the BMU 1 can also instruct switching of the DC / DC converter 34 and the DC / AC converter 35 respectively. The power system of FIG. 1 includes a switching device including at least the control unit and the discharge circuit 24. It may be considered that components other than the control unit and the discharge circuit 24 are further included in the components of the switching device.

24 discharge circuit 34 DC / DC converter 35 DC / AC converter 44 DC load 45 AC load 60 power bus line 64, 65 power line 100, 110 inrush current control circuit SW _A , SW _B switch circuit 101 delay circuit 102 thermistor 111 current sensor 112 Amplifier 113 Waveform Shaping Circuit 114 Control Pulse Generation Circuit 115 Synthesis Circuit

Claims (6)

A discharge circuit provided between the first wiring connected to the power source side and the second wiring connected to the load side;
A control unit for controlling the state of the discharge circuit,
The load includes a primary load that performs power conversion of power supplied through the discharge circuit,
The discharge circuit is connected in parallel to the first switch circuit connected to the first wiring, the second switch circuit provided between the first switch circuit and the second wiring, and the second switch circuit. A resistive element,
The control unit, when supplying power to the load, instructs the primary load to start the power conversion and switches the first switch circuit from off to on, and then turns off the second switch circuit. A switching device characterized by being switched on. The load further comprises a secondary load driven by power from the primary load,
The discharge circuit temporarily turns off the second switch circuit according to a current flowing between the second switch circuit and the primary load after the second switch circuit is switched from off to on. The switching device according to claim 1, further comprising a circuit. The temporary off circuit is configured to temporarily turn off the second switch circuit based on a signal waveform of the current after the second switch circuit is switched from off to on. 3. The switching device according to claim 2, wherein an on-maintenance signal for maintaining the circuit on is switched and output. The said temporary OFF circuit sets the length of time to turn off the said 2nd switch circuit temporarily according to the said signal waveform, when outputting the said temporary OFF signal. Switching device. When supplying power to the load, the control unit instructs the primary load to start the power conversion, switches the first switch circuit from off to on, and then turns off the second switch circuit. The switching device according to claim 1, wherein the switching device is switched from on to off. The switching device according to claim 1, wherein the resistance element is a thermistor having a negative temperature coefficient.

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