Power supply device and power supply control method

Abstract

To provide a power supply device and a power supply control method with high power efficiency.SOLUTION: A power supply device 1 is a power supply device that supplies power to a load whose operating state and non-operating state are alternately switched based on a pulse type signal transmitted from an external device. The power supply device comprises a first capacitor C1, a first switching element SW1, a second switching element SW2, an inductor L, a second capacitor C2, a diode D1, and a switching control circuit 10 for controlling the first switching element SW1 and the second switching element SW2. The switching control circuit 10 acquires the pulse type signal and an output voltage value of a second main circuit CB, and based on the pulse type signal and the output voltage value, at least when the output voltage value exceeds a threshold, controls the first switching element SW1 and the second switching element SW2 to regenerate energy from the second capacitor C2 to the first capacitor C1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to a power supply device and a power supply control method. [Background technology]

[0002] For example, a load such as a radar requires a power supply based on a pulse voltage. A load requiring such a pulse voltage will be referred to as a pulse load hereinafter. The pulse load alternates between an operating state and an inactive state in accordance with, for example, the generated pulse period. When the pulse load is in an inactive state, the power supply device that supplies power to the pulse load is in an unloaded state.

[0003] When power is supplied to a pulse load via a power supply such as a converter, there is a problem that when the pulse load is not operating, the output voltage from the power supply temporarily rises due to factors such as energy stored in the inductor and delays in switching control. Conventionally, a discharge resistor is connected in parallel to the pulse load on the output side of the power supply, and when the pulse load is not operating, current is passed through the discharge resistor, converting the output power into thermal energy and lowering the output voltage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-225579 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the output voltage from the power supply device is reduced using the above method, the volume of the power supply increases in order to dissipate the heat generated by the resistor connections and the entire circuit, and there are also problems such as reduced power efficiency due to the conversion of electric power into thermal energy.

[0006] The embodiments of the present invention have been made in consideration of the above circumstances, and an object of the present invention is to provide a power supply device and a power supply control method that are highly power efficient. [Means for solving the problem]

[0007] a first capacitor electrically connected between a first main circuit to which a voltage is applied from a power supply and a reference voltage circuit, a first switching element and a second switching element connected in series between the first main circuit and the reference voltage circuit, an inductor interposed in a second main circuit electrically connecting a connection between the first switching element and the second switching element and a second terminal connected to the load, a second capacitor electrically connected between the second main circuit and the reference voltage circuit, a diode electrically connected between the first main circuit and the second main circuit with the forward direction being from the second main circuit to the first main circuit, and a switching control circuit that controls the first switching element and the second switching element. The switching control circuit acquires the pulse seed signal and an output voltage value of the second main circuit, and, based on the pulse seed signal and the output voltage value, controls the first switching element and the second switching element to regenerate energy from the second capacitor to the first capacitor in response to at least the output voltage value exceeding a threshold. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration example of a power supply device according to an embodiment. [Figure 2] FIG. 2 is a flowchart illustrating the operation of the switching control circuit in the power supply device of the embodiment. [Figure 3] FIG. 3 is a diagram showing waveforms of various input and output values ​​in the power supply device of the embodiment. [Figure 4] FIG. 4 is a diagram illustrating a schematic configuration of a modified example of the power supply device according to the embodiment. [Figure 5]FIG. 5 is a diagram schematically illustrating an example of the configuration of a power supply device of a comparative example. [Figure 6] FIG. 6 is a diagram showing waveforms of various input and output values ​​in the power supply device of the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings.

[0010] FIG. 1 is a diagram illustrating a schematic configuration example of a power supply device according to an embodiment. The power supply device 1 of the embodiment is a so-called synchronous rectification buck converter that steps down a DC voltage applied from an input power source 2 and outputs the stepped-down voltage to a pulse load 3. The pulse load 3 is a load that requires a pulse voltage, such as a radar. The pulse load 3 alternates between an operating state and a non-operating state at a predetermined cycle based on a pulse seed signal transmitted from an external device (not shown). When in the operating state, the pulse load 3 behaves as a load that requires a predetermined operating voltage for the power supply device 1, but when in the non-operating state, it acts as no load for the power supply device 1.

[0011] The power supply device 1 includes an input capacitor C1, a first switching element SW1, a second switching element SW2, an inductor L, a diode D1, an output capacitor C2, and a switching control circuit .

[0012] The input capacitor C1 is electrically connected between the first main circuit CA and the reference voltage circuit CG. The first main circuit CA is electrically connected between the positive-side input terminal 11P and one end (drain) of the first switching element SW1, and is a circuit to which a voltage is applied from the input power source 2 via the positive-side input terminal 11P (first terminal). The reference voltage circuit CG is electrically connected between the negative-side input terminal 11N and the negative-side output terminal 12N, and is connected to a reference voltage point GND. The input capacitor C1 is capable of storing and discharging supplied electric charge. The input capacitor C1 smoothes, for example, the DC voltage applied from the input power source 2. The input capacitor C1 is an example of a first capacitor.

[0013] The first switching element SW1 and the second switching element SW2 are connected in series between the first main circuit and the reference voltage circuit. Specifically, the first switching element SW1 has one end (drain) connected to the first main circuit. The second switching element SW2 has one end (drain) connected to the other end (source) of the first switching element, and the other end (source) connected to the reference voltage circuit. The first switching element SW1 and the second switching element SW2 are self-extinguishing switching elements such as MOSFETs (metal-oxide semiconductor field-effect transistors) and GaN-FETs (GaN field-effect transistors). The first switching element SW1 and the second switching element SW2 switch their electrical connection states based on gate signals applied to them from the switching control circuit 10.

[0014] The first switching element SW1 and the second switching element SW2 can be any switching element that can be electrically controlled to be on (conductive state) and off (non-conductive state). For example, the first switching element SW1 and the second switching element SW2 may be an injection enhanced gate transistor (IEGT), a gate turn-off thyristor (GTO), a gate communicated turn-off thyristor (GCT), an insulated gate bipolar transistor (IGBT), or the like. When an IGBT or an IEGT is used, the source is replaced with the emitter, and the drain is replaced with the collector.

[0015] The inductor L is interposed in the second main circuit CB, which is a circuit between the connection point of the first switching element SW1 and the second switching element SW2 and the positive-side output terminal 12P (second terminal) connected to the pulse load 3.

[0016] The diode D1 electrically connects the first main circuit CA and the second main circuit CB, with the direction from the second main circuit CB toward the first main circuit CA as the forward direction. In this embodiment, the diode D1 is a body diode of the first switching element SW1. The second switching element SW2 may also have a body diode like the first switching element SW1.

[0017] The output capacitor C2 is connected between the second main circuit CB and the reference voltage circuit CG. The output capacitor C2 can store and release supplied electric charge. The output capacitor C2 smoothes the output voltage output from the inductor L to the pulse load 3 via the output terminal 12P, for example. The output capacitor C2 is an example of a second capacitor.

[0018] The switching control circuit 10 controls the first switching element SW1 and the second switching element SW2. The switching control circuit 10 also acquires a pulse seed signal input to the pulse load 3 from an external device (not shown) and an output voltage value, which is the value of the output voltage Vo of the second main circuit. The switching control circuit 10 may be, for example, a field programmable gate array (FPGA), and includes a computing device including at least one processor such as a central processing unit (CPU) or a micro processing unit (MPU), and a memory storing a program executed by the processor, and a drive circuit that generates control signals to be sent to the first switching element SW1 and the second switching element SW2. The memory of the switching control circuit 10 also stores a regeneration threshold, which is a threshold value of the output voltage when performing a regeneration operation (described later).

[0019] Based on the acquired pulse seed signal, the switching control circuit 10 performs step-down chopper control to step down the voltage input from the input power source 2 and output it to the pulse load 3 while the pulse load 3 is in an operating state. Specifically, while the pulse load 3 is in an operating state, the switching control circuit 10 sends a control signal of a predetermined frequency to the first switching element SW1 and the second switching element SW2, and alternately opens and closes the first switching element SW1 and the second switching element SW2, thereby stepping down the voltage from the input power source 2 and outputting it to the pulse load 3.

[0020] Furthermore, the switching control circuit 10 performs a regenerative operation to regenerate power from the output capacitor C2 to the input capacitor C1 while the pulse load 3 is not in operation, based on the acquired pulse seed signal and output voltage value.

[0021] FIG. 2 is a flowchart for explaining the operation of the switching control circuit 10 in the power supply device of the embodiment. The switching control circuit 10 executes a program stored in the memory to realize the following operations. For example, the switching control circuit 10 starts the following operations when the power supply device 1 is connected to the input power supply 2 and the pulse load 3.

[0022] First, the switching control circuit 10 acquires a pulse seed signal and an output voltage value (step S1). The switching control circuit 10 acquires a pulse seed signal input from the outside to the pulse load 3 and the output voltage value, which is the value of the output voltage Vo of the second main circuit.

[0023] The switching control circuit 10 determines whether the acquired pulse seed signal indicates that the pulse load 3 is in an inactive state (step S2). If the switching control circuit 10 determines that the pulse seed signal does not indicate that the pulse load 3 is in an inactive state (step S2: NO), the switching control circuit 10 controls the first switching element SW1 and the second switching element SW2 to perform a step-down operation (step S3). The switching control circuit 10 outputs a control signal of a predetermined frequency to the first switching element SW1 and the second switching element SW2 so that the first switching element SW1 and the second switching element SW2 alternately open and close.

[0024] After performing the operation of step S3, the switching control circuit 10 returns to step S1. While the acquired pulse seed signal indicates the operating state of the pulse load 3, the switching control circuit 10 repeats the operations of steps S1 to S3, thereby causing the power supply device 1 to perform the step-down operation.

[0025] On the other hand, if the switching control circuit 10 determines that the acquired pulse seed signal indicates that the pulse load 3 is in an inoperative state (step S2: YES), it opens the first switching element SW1 and the second switching element SW2 (step S4).

[0026] The switching control circuit 10 determines whether the acquired value of the output voltage Vo is greater than the regeneration threshold value (step S5). The switching control circuit 10 compares the acquired value of the output voltage Vo with the regeneration threshold value stored in the memory. If the switching control circuit 10 determines that the value of the output voltage Vo is equal to or less than the regeneration threshold value (step S5: NO), the process returns to step S1.

[0027] On the other hand, if the switching control circuit 10 determines that the value of the output voltage Vo is greater than the regeneration threshold (step S5: YES), it executes a regeneration operation (step S6). The switching control circuit 10 sends a control signal to the second switching element SW2 to close and then open the second switching element SW2. This regenerates the power stored in the output capacitor C2 to the input capacitor C1. The operation of the switching control circuit 10 to close and then open the second switching element SW2 is referred to here as one regeneration operation. After performing one regeneration operation, the switching control circuit 10 returns to step S1.

[0028] FIG. 3 is a diagram showing waveforms of various input and output values ​​in the power supply device of the embodiment. The switching control circuit 10 repeats the operations from step S4 to step S6 while the acquired pulse seed signal indicates the non-operating state of the pulse load 3. That is, when the switching control circuit 10 determines that the value of the output voltage Vo of the power supply device 1 is greater than the regeneration threshold, it executes the regeneration operation once and returns to monitoring the output voltage Vo.

[0029] Here, the switching control circuit 10 performs a regenerative operation, thereby performing a boost chopper operation that boosts the voltage of the regenerated power from the output capacitor C2 to the input capacitor C1. Specifically, when the switching control circuit 10 closes the second switching element SW2 while the pulse load 3 is unloaded, a current flows from the output capacitor C2 to the inductor L, and magnetic energy is stored in the inductor L. When the switching control circuit 10 then opens the second switching element SW2, the voltage of the regenerated power from the output capacitor C2 to the input capacitor C1 via the diode D1 is boosted by the energy stored in the inductor L.

[0030] The switching control circuit 10 repeatedly performs regenerative operation while the value of the output voltage Vo is greater than the regenerative threshold, thereby regenerating power from the output side to the input side and reducing the value of the output voltage of the power supply device 1. When the switching control circuit 10 determines that the value of the output voltage Vo is equal to or less than the regenerative threshold, it stops the regenerative operation and waits until it receives a pulse seed signal indicating the operating state of the pulse load 3.

[0031] Note that the frequency of the control signal transmitted to the second switching element SW2 by the switching control circuit 10 when the second switching element SW2 executes the regenerative operation may be the same as the frequency of the control signal that controls the operation of the first switching element SW1 and the second switching element SW2 when performing the step-down operation of the input voltage while the pulse load 3 is in operation. As a result, according to the power supply device 1 of the embodiment, it is not necessary to newly set the frequency of the control signal when performing the regenerative operation in the switching control circuit 10 or to add a new component.

[0032] Next, a modification of the power supply device of the embodiment will be described. In the power supply device 1 of the embodiment, when regenerating power from the output capacitor C2 to the input capacitor C1, the diode D1, which is the body diode of the first switching element SW1, is used. However, some switching elements used as the first switching element SW1, such as GaN-FETs, have a large forward voltage drop in their body diode.

[0033] FIG. 4 is a diagram illustrating a schematic configuration of a modified example of the power supply device according to the embodiment. The power supply device 1 of the modified example differs from the power supply device 1 of the embodiment in that, in addition to the body diode of the first switching element SW1, a diode D2 is provided that electrically connects the first main circuit CA and the second main circuit CB, with the forward direction being from the second main circuit CB to the first main circuit CA. The diode D2 allows current to flow from the inductor L to the high-potential side of the input capacitor C1. It is desirable that the diode D2 has a small forward voltage drop. For example, the diode D2 is a Schottky barrier diode or a fast recovery diode. Note that in the power supply device 1 of the modified example, the first switching element SW1 may also have a body diode (not shown).

[0034] According to the power supply device 1 of the modified example, when the pulse load 3 is not operating, the power regenerated from the output capacitor C2 is supplied to the input capacitor C1 through the diode D2 with a small voltage drop. As a result, the power supply device 1 of the modified example has a small loss of regenerated power and is more efficient at regeneration than the power supply device 1 of the embodiment.

[0035] Next, the effects achieved by the power supply device of the embodiment will be described.

[0036] FIG. 5 is a diagram schematically illustrating an example of the configuration of a power supply device of a comparative example. The power supply device 1 of the comparative example differs from the power supply device 1 of the embodiment in that it includes a switch SW3 and a discharge resistor R connected in series between the second main circuit CB and the reference voltage circuit CG. The switch SW3 opens and closes based on a signal provided from the switching control circuit 10, similar to the first switching element SW1 and the second switching element SW2.

[0037] FIG. 6 is a diagram showing waveforms of various input and output values ​​in the power supply device of the comparative example. The pulse load 3 to which the power supply device 1 of the comparative example is connected switches between an operating state and a non-operating state based on a pulse seed signal input from the outside, as in the embodiment. When the pulse load 3 is in the non-operating state, it is in a non-load state in which no current flows through the power supply device 1.

[0038] The switching control circuit 10 in the power supply device 1 of the comparative example closes the switch SW3 when the pulse load 3 is in an inactive state based on the acquired pulse seed signal. For example, the switching control circuit 10 of the comparative example inverts the acquired pulse seed signal and inputs it to the switch SW3. Alternatively, like the power supply device of the embodiment, the switching control circuit 10 in the power supply device 1 of the comparative example further acquires the value of the output voltage Vo of the power supply device, and controls the switch SW3 to close while the pulse load 3 is in an inactive state and the output voltage value is rising.

[0039] The power supply device 1 of the comparative example converts the power output by the power supply device 1 into thermal energy by connecting a discharge resistor while the pulse load 3 is not operating. This allows the power supply device 1 of the comparative example to reduce the output voltage that temporarily rises when the pulse load 3 is not operating.

[0040] However, the power supply device 1 of the comparative example includes the switch SW3 and the discharge resistor R, and the heat generated when power is consumed by the discharge resistor R increases the heat generated by the entire circuit, resulting in an increase in the volume of the entire device due to heat dissipation. Furthermore, power is converted into thermal energy by the discharge resistor and then discharged, resulting in low power efficiency.

[0041] The power supply device of the embodiment does not include a discharge resistor or switch compared to the power supply device of the comparative example. Therefore, the power supply device of the embodiment generates less heat than the power supply device of the comparative example, and the volume of the power supply device can be made smaller. Furthermore, the power supply device of the embodiment reduces the output voltage value of the power supply device that rises when the pulse load is not operating by regenerating power to the input side. Therefore, the power supply device of the embodiment has higher power efficiency than the power supply device of the comparative example.

[0042] As described above, the power supply device and power supply control method of this embodiment can provide a power supply device and power supply control method with high power efficiency.

[0043] That is, the power supply device 1 of the embodiment is a power supply device that supplies power to a pulse load 3 that alternates between an operating state and a non-operating state based on a pulse seed signal transmitted from the outside, and includes: an input capacitor C1 electrically connected between a first main circuit to which a voltage is applied from an input power source 2 and a reference voltage circuit CG; a first switching element SW1 and a second switching element SW2 connected in series between the first main circuit CA and the reference voltage circuit CG; an inductor L interposed in a second main circuit CB that electrically connects a connection portion between the first switching element SW1 and the second switching element SW2 and an output terminal 12 connected to the pulse load 3; an output capacitor C2 electrically connected between the second main circuit CB and the reference voltage circuit CG; a diode D1 electrically connected between the first main circuit CA and the second main circuit CB, with the direction from the second main circuit CB toward the first main circuit CA as the forward direction; and a switching control circuit 10 that controls the first switching element SW1 and the second switching element SW2. The switching control circuit 10 acquires the pulse seed signal and the output voltage value of the second main circuit CB, and based on the pulse seed signal and the output voltage value, controls the first switching element SW1 and the second switching element SW2 in response to at least the output voltage value exceeding a threshold value to regenerate energy from the output capacitor C2 to the input capacitor C1. The power supply device 1 of the embodiment reduces the output voltage Vo, which rises when the pulse load 3 is not operating, by regenerating power to the input capacitor C1. Therefore, the power supply device 1 of the embodiment can use the surplus voltage without loss, and has high power efficiency.

[0044] The power supply device 1 of the embodiment opens the first switching element SW1 and the second switching element SW2 while the pulse seed signal indicates that the pulse load 3 is in an inoperative state, and when the pulse seed signal indicates that the pulse load 3 is in an inoperative state and the output voltage value exceeds a predetermined regeneration threshold, opens and closes the switching element on the low potential side of the first switching element SW1 or the second switching element SW2 using a control signal of a predetermined frequency. The power supply device 1 of the embodiment monitors the operating state of the pulse load 3 and the output voltage Vo, and when the pulse load 3 is unloaded and the value of the output voltage Vo exceeds a threshold, performs a boost chopper operation from the output side to the input side of the power supply device 1. Therefore, the power supply device 1 of the embodiment can efficiently regenerate surplus voltage on the output side.

[0045] Although the switching control circuit 10 in the power supply device 1 of the embodiment acquires a pulse seed signal input from outside to the pulse load 3 in order to monitor the operating state of the pulse load 3, this is not limited to this. For example, the switching control circuit 10 in the power supply device 1 of the embodiment may determine the operating state of the pulse load 3 by acquiring the value of the current Io flowing from the high-potential side of the output capacitor C2 to the output terminal 12. The pulse load 3 becomes unloaded when it is not operating, and therefore the value of the output voltage Io drops sharply when the pulse load 3 is not operating.

[0046] The program according to this embodiment may be transferred in a state where it is stored in an electronic device, or in a state where it is not stored in an electronic device. In the latter case, the program may be transferred via a network, or in a state where it is stored in a storage medium. The storage medium is a non-transitory tangible medium. The storage medium is a computer-readable medium. The storage medium may be in any form, such as a CD-ROM or a memory card, as long as it is capable of storing the program and is computer-readable.

[0047] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0048] 1...power supply, 2...input power supply, 3...pulse load, 10...switching control circuit, 11P and 11N...input terminals, 12P and 12N...output terminals, CA...first main circuit, CB...second main circuit, CG...reference voltage circuit, C1...input capacitor, C2...output capacitor, SW1...first switching element, SW2...second switching element, SW3...switch, D1 and D2...diode, L...inductor, R...discharge resistor

Claims

1. A power supply device that supplies power to a load that alternates between an operating state and a non-operating state based on a pulse seed signal transmitted from an external device, a first capacitor electrically connected between a first main circuit to which a voltage is applied from the power supply and a reference voltage circuit; a first switching element and a second switching element connected in series between the first main circuit and the reference voltage circuit; an inductor interposed in a second main circuit that electrically connects a connection portion between the first switching element and the second switching element and a second terminal connected to the load; a second capacitor electrically connected between the second main circuit and the reference voltage circuit; a diode electrically connected between the first main circuit and the second main circuit, with a direction from the second main circuit toward the first main circuit as a forward direction; a switching control circuit that controls the first switching element and the second switching element, the switching control circuit acquires the pulse seed signal and the output voltage value of the second main circuit, and, based on the pulse seed signal and the output voltage value, controls the first switching element and the second switching element in response to at least the output voltage value exceeding a predetermined regeneration threshold, to regenerate energy from the second capacitor to the first capacitor.

2. the switching control circuit opens the first switching element and the second switching element while the pulse seed signal indicates an idle state of the load; 2. The power supply device according to claim 1, wherein, in response to the pulse seed signal indicating an idle state of the load and the output voltage value exceeding the regeneration threshold value, the switching element on a lower potential side of the first switching element and the second switching element is opened and closed by a control signal of a predetermined frequency.

3. 3. The power supply device according to claim 2, wherein the predetermined frequency is the same as a frequency of a control signal input from the switching control circuit to the first switching element and the second switching element when the load is in an operating state.

4. 4. The power supply device according to claim 1, wherein the diode is a body diode of the first switching element.

5. 4. The power supply device according to claim 1, wherein the diode is a Schottky barrier diode or a fast recovery diode.

6. a first capacitor electrically connected between a first main circuit to which a voltage is applied from a power source and a reference voltage circuit; a first switching element and a second switching element connected in series between the first main circuit and the reference voltage circuit; an inductor interposed in a second main circuit electrically connecting a connection portion of the first switching element and the second switching element and a second terminal connected to a load; a second capacitor electrically connected between the second main circuit and the reference voltage circuit; a diode electrically connected between the first main circuit and the second main circuit, with a forward direction being a direction from the second main circuit toward the first main circuit; and a switching control circuit that controls the first switching element and the second switching element, a power supply control method for controlling a power supply from the second capacitor to the first capacitor by controlling the first switching element and the second switching element based on the pulse seed signal and the output voltage value, and at least when the output voltage value exceeds a threshold value.

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