Power conversion device and power supply system

Abstract

To provide a power conversion device or the like capable of improving convenience.SOLUTION: A power conversion device according to one embodiment of the present invention includes: an input section; an output section; a conversion circuit; a first detection section for detecting a predetermined parameter as operation control; a second detection section for detecting a parameter as protection; a third detection section for detecting a parameter as fault detection; a comparison circuit for comparing at least one detection value of a first detection value and a second detection value of the parameter with a third detection value of the parameter; and a control circuit. When the at least one detection value and the third detection value match, the control circuit uses the at least one detection value as it is, and when the at least one detection value and the third detection value are different from each other, the control circuit uses the other detection value, which is not a target for comparison with the third detection value, as one of the first detection value and the second detection value to be compared with the third detection value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power conversion device that performs power conversion using switching elements, and a power supply system including such a power conversion device. [Background technology]

[0002] 2. Description of the Related Art Various types of power conversion devices (switching power supply devices) such as DC-DC converters have been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-104294 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for improved convenience in such power conversion devices, etc. It is desirable to provide a power conversion device and a power supply system that can improve convenience. [Means for solving the problem]

[0005] A power conversion device according to one embodiment of the present invention includes an input section to which an input voltage is input, an output section to which an output voltage is output, a conversion circuit including one or more switching elements and performing a conversion operation to convert the input voltage into an output voltage, a first detection section to detect a parameter corresponding to at least one of the input current, the output current, the input voltage, and the output voltage for use in controlling the operation of the switching element, a second detection section to detect the parameter for use in protecting the switching element, a third detection section to detect the parameter for use in detecting a fault in at least one of the first detection section and the second detection section, a comparison circuit to compare at least one of the first detection value of the parameter detected by the first detection section and the second detection value of the parameter detected by the second detection section with the third detection value of the parameter detected by the third detection section, and a control circuit to control the operation of the switching elements in the conversion circuit using the comparison result by the comparison circuit. When a comparison result indicates that the at least one detection value and the third detection value are identical to each other, the control circuit uses the at least one detection value as is, and when a comparison result indicates that the at least one detection value and the third detection value are different from each other, the control circuit uses the other detection value, of the first detection value and the second detection value, that is not compared to the third detection value, as the one detection value that is compared to the third detection value.

[0006] A power supply system according to an embodiment of the present invention includes a power conversion device that performs a predetermined power conversion and a power supply that supplies an input voltage. The power conversion device includes an input unit that receives an input voltage, an output unit that outputs an output voltage, a conversion circuit that includes one or more switching elements and performs a conversion operation of converting the input voltage to an output voltage, a first detection unit that detects a parameter corresponding to at least one of the input current, the output current, the input voltage, and the output voltage for controlling the operation of the switching elements, a second detection unit that detects the parameter for protecting the switching elements, a third detection unit that detects the parameter for detecting a fault in at least one of the first detection unit and the second detection unit, a comparison circuit that compares at least one of the first detection value of the parameter detected by the first detection unit and the second detection value of the parameter detected by the second detection unit with the third detection value of the parameter detected by the third detection unit, and a control circuit that uses a comparison result by the comparison circuit to control the operation of the switching elements in the conversion circuit. When a comparison result indicates that the at least one detection value and the third detection value are identical to each other, the control circuit uses the at least one detection value as is, and when a comparison result indicates that the at least one detection value and the third detection value are different from each other, the control circuit uses the other detection value, of the first detection value and the second detection value, that is not compared to the third detection value, as the one detection value that is compared to the third detection value. Effect of the Invention

[0007] According to a power conversion device and a power supply system according to an embodiment of the present invention, it is possible to improve convenience. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a circuit diagram illustrating a schematic configuration example of a power conversion device according to an embodiment of the present invention. [Diagram 2]FIG. 2 is a block diagram illustrating an example of a detailed configuration of the input current detection unit illustrated in FIG. [Diagram 3] FIG. 3 is a block diagram illustrating an example of a detailed configuration of the output voltage detection unit illustrated in FIG. [Figure 4] FIG. 4 is a block diagram illustrating an example of a detailed configuration of the comparison control circuit illustrated in FIG. [Diagram 5] FIG. 5 is a flowchart illustrating an example of the comparison control process according to the embodiment. [Figure 6] FIG. 6 is a flowchart illustrating another example of the comparison control process according to the embodiment. [Figure 7] FIG. 7 is a flowchart illustrating another example of the comparison control process according to the embodiment. [Figure 8] FIG. 8 is a circuit diagram illustrating a schematic configuration example of a power conversion device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The description will be given in the following order. 1. Embodiment (Example in which the rectifier circuit is a synchronous rectifier circuit) 2. Modification (example of when the rectifier circuit is not a synchronous rectifier circuit) 3. Other Modifications

[0010] <1. Preferred embodiment> [composition] Fig. 1 is a circuit diagram showing an example of a schematic configuration of a power conversion device (power conversion device 1) according to an embodiment of the present invention. Fig. 2 is a block diagram showing a detailed configuration example of a detection unit 52 shown in Fig. 1, which will be described later, and Fig. 3 is a block diagram showing a detailed configuration example of a detection unit 53 shown in Fig. 1, which will be described later. Fig. 4 is a block diagram showing a detailed configuration example of a comparison control circuit 6 shown in Fig. 1, which will be described later.

[0011] This power conversion device 1 functions as a DC-DC converter that converts a DC input voltage Vin supplied from a DC input power source 10 (e.g., a battery) into a DC output voltage Vout and supplies power to a load 9. Note that examples of this load 9 include electronic devices and batteries. The mode of voltage conversion in the power conversion device 1 may be either up-conversion (boosting) or down-conversion (stepping down).

[0012] Here, the DC input voltage Vin corresponds to a specific example of the "input voltage" in the present invention, and the DC output voltage Vout corresponds to a specific example of the "output voltage" in the present invention. The DC input power supply 10 corresponds to a specific example of the "power supply" in the present invention, and a system including the DC input power supply 10 and the power conversion device 1 corresponds to a specific example of the "power supply system" in the present invention.

[0013] The power conversion device 1 includes two input terminals T1, T2, two output terminals T3, T4, an inverter circuit 2, a transformer 3, a rectifier circuit 4, a smoothing circuit 5, a reverse voltage clamp circuit 7, detection units 51 to 54, and a comparison control circuit 6. A DC input voltage Vin is input between the input terminals T1, T2, and a DC output voltage Vout is output from between the output terminals T3, T4.

[0014] Here, the input terminals T1 and T2 correspond to a specific example of an "input section" in the present invention, and the output terminals T3 and T4 correspond to a specific example of an "output section" in the present invention. Also, the inverter circuit 2, the transformer 3, and the rectifier circuit 4 correspond to a specific example of a "conversion circuit" in the present invention.

[0015] As shown in Fig. 1, an input smoothing capacitor Cin and the above-mentioned reverse voltage clamp circuit 7 are disposed between the primary high-voltage line L1H connected to the input terminal T1 and the primary low-voltage line L1L connected to the input terminal T2. The input smoothing capacitor Cin is a capacitor for smoothing the DC input voltage Vin. The reverse voltage clamp circuit 7 is a protection circuit for clamping an overvoltage generated between the primary high-voltage line L1H and the primary low-voltage line L1L.

[0016] (A. Inverter circuit 2) The inverter circuit 2 is disposed between input terminals T1, T2 and a primary winding 31 of the transformer 3, which will be described later. The inverter circuit 2 has four switching elements S1 to S4 and a resonant inductor Lr, and is a so-called "full-bridge type" inverter circuit. Note that the resonant inductor Lr may be formed by a leakage inductance in the transformer 3, which will be described later, or may be provided separately from such a leakage inductance.

[0017] Here, each of the switching elements S1 to S4 corresponds to a specific example of a "first switching element" in the present invention.

[0018] As the switching elements S1 to S4, various types of switching elements are used, such as a field effect transistor (MOS-FET; Metal Oxide Semiconductor-Field Effect Transistor), an IGBT (Insulated Gate Bipolar Transistor), a HEMT (High Electron Mobility Transistor) = HFET (Heterostructure Field-Effect Transistor), etc. An example of a HEMT is a GaN (gallium nitride) transistor.

[0019] In the example shown in Fig. 1, the switching elements S1 to S4 are each configured with a transistor made of a MOS-FET or a HEMT. In this way, when a MOS-FET or a HEMT is used as the switching elements S1 to S4, the diodes (shown in Fig. 1) connected in parallel to each of the switching elements S1 to S4 can be configured with a parasitic diode of the MOS-FET or the HEMT.

[0020] In this inverter circuit 2, two switching elements S1, S2 are connected in series to each other in this order between the input terminals T1, T2 (between the primary high-voltage line L1H and the primary low-voltage line L1L). Specifically, the switching element S1 is arranged between the primary high-voltage line L1H and the connection point P1, and the switching element S2 is arranged between the connection point P1 and the primary low-voltage line L1L. Similarly, in this inverter circuit 2, two switching elements S3, S4 are connected in series to each other in this order between the input terminals T1, T2. Specifically, the switching element S3 is arranged between the primary high-voltage line L1H and the connection point P2, and the switching element S2 is arranged between the connection point P2 and the primary low-voltage line L1L. In addition, the above-mentioned series connection structure (first arm) of the switching elements S1 and S2 and the series connection structure (second arm) of the switching elements S3 and S4 are arranged in parallel with each other between the primary high-voltage line L1H and the primary low-voltage line L1L.

[0021] The resonant inductor Lr in the inverter circuit 2 and a primary winding 31 (described later) in the transformer 3 are connected in series with each other between the connection points P1 and P2. Specifically, in the example of Fig. 1, one end of the primary winding 31 is connected to the connection point P1, the other end of the primary winding 31 is connected to a first end (one end) of the resonant inductor Lr, and a second end (the other end) of the resonant capacitor Cr is connected to the connection point P2.

[0022] With this configuration, in the inverter circuit 2, the switching operation (on / off operation) of each of the switching elements S1 to S4 is controlled in accordance with drive signals SG1 to SG4 supplied from a comparison control circuit 6 (control circuit 62) described later, as follows: That is, the DC input voltage Vin applied between the input terminals T1 and T2 is converted into an AC voltage and output to the transformer 3 (primary winding 31).

[0023] (B.Trance 3) The transformer 3 has one primary winding 31 and one secondary winding 32 .

[0024] In the primary winding 31, a first end (one end) is connected to a connection point P1, and a second end (the other end) is connected to a connection point P2 via a resonant inductor Lr.

[0025] In the secondary winding 32, a first end is connected to a connection point P5 in the rectifier circuit 4 described later, and a second end is connected to a connection point P6 in the rectifier circuit 4.

[0026] In this transformer 3, the rectangular pulse wave voltage generated by the inverter circuit 2 is supplied to the primary winding 31 via a resonant circuit (a resonant circuit configured using a resonant inductor Lr). The voltage (rectangular pulse wave voltage) supplied to the primary winding 31 is transformed in the transformer 3, and a transformed AC voltage is output from an end of the secondary winding 32. In this case, the degree of voltage conversion of the DC output voltage Vout with respect to the DC input voltage Vin is determined by the turns ratio between the primary winding 31 and the secondary winding 32, the switching period, and the on-duty ratio in the inverter circuit 2.

[0027] (C. Rectifier circuit 4, smoothing circuit 5) The rectifier circuit 4 is disposed between the output terminals T3, T4 and the secondary winding 32 of the transformer 3 (specifically, between a smoothing circuit 5, which will be described later, and the secondary winding 32). The rectifier circuit 4 has four switching elements S5 to S8 that operate as rectifier elements, and is a so-called "full-bridge type" synchronous rectifier circuit. In other words, the rectifier circuit 4 is a "full-bridge circuit" that includes the four switching elements S5 to S8.

[0028] That is, in the rectifier circuit 4, two switching elements S5 and S6 functioning as rectifier elements are connected in series to each other in this order between the output terminals T3 and T4 (between the output line LO and the ground line LG). Specifically, the switching element S5 is arranged between the output line LO and the connection point P5, and the switching element S6 is arranged between the connection point P5 and the ground line LG. Similarly, in the rectifier circuit 4, two switching elements S7 and S8 functioning as rectifier elements are connected in series to each other in this order between the output terminals T3 and T4. Specifically, the switching element S7 is arranged between the output line LO and the connection point P6, and the switching element S8 is arranged between the connection point P6 and the ground line LG. In addition, the above-mentioned series connection structure (third arm) of the switching elements S5 and S6 and the series connection structure (fourth arm) of the switching elements S7 and S8 are arranged in parallel to each other between the output line LO and the ground line LG.

[0029] Here, each of the switching elements S5 to S8 corresponds to a specific example of "second switching element (operating as a rectifying element)" in the present invention.

[0030] As the switching elements S5 to S8, various types of switch elements such as MOS-FET, IGBT, HEMT, etc. are used, similar to the switching elements S1 to S4 described above.

[0031] The smoothing circuit 5 is disposed between the output terminals T3, T4 and the secondary winding 32 (specifically, between the output terminals T3, T4 and the rectifier circuit 4). The smoothing circuit 5 has one output smoothing capacitor Cout and one choke coil Lch. Specifically, the output smoothing capacitor Cout is disposed between a connection point P7 on the output line LO and a connection point P8 on the ground line LG (between the output terminals T3 and T4). The choke coil Lch is inserted into the output line LO.

[0032] In the rectifier circuit 4 and smoothing circuit 5 configured as above, the AC voltage output from the transformer 3 is rectified by the four switching elements S5 to S8 operating as rectifier elements. The rectified voltage is smoothed by the output smoothing capacitor Cout and the choke coil Lch to generate a DC output voltage Vout. The DC output voltage Vout generated in this manner causes a DC output current Iout (load current) to flow to the load 9 described above, and power is supplied to the load 9 from the output terminals T3 and T4.

[0033] In addition, in the rectifier circuit 4, the switching elements S5 to S8 themselves are controlled to be turned on (perform synchronous rectification) in synchronization with the period during which the parasitic diodes (shown in FIG. 1) of the switching elements S5 to S8 are conductive. Specifically, such synchronous rectification is performed by controlling the switching operation (on / off operation) of the switching elements S5 to S8 in accordance with drive signals SG5 to SG8 supplied from a comparison control circuit 6 (control circuit 62) described later.

[0034] (D. Detection units 51 to 54) The detection units 51 to are circuits that measure various parameters corresponding to the voltage (DC input voltage Vin, DC output voltage Vout) and the current (input current Iin, output current Iout).

[0035] Specifically, the detection unit 51 is disposed between the connection point P3 on the primary high voltage line L1H and the connection point P4 on the primary low voltage line L1L, and is a circuit that measures the DC input voltage Vin described above. The detection unit 52 is disposed between the connection point P3 on the primary high voltage line L1H and the reverse voltage clamp circuit 7, and is a circuit that measures the DC input current Iin (see FIG. 1) flowing on the primary high voltage line L1H.

[0036] The detection unit 53 is disposed between the output line LO and the ground line LG, and is a circuit that measures the above-mentioned DC output voltage Vout. The detection unit 54 is a circuit that measures the DC output current Iout (see FIG. 1) that flows from the output smoothing capacitor Cout to the load 9.

[0037] Here, as shown in FIG. 2 and FIG. 3, in this embodiment, the above-mentioned detection units 52 and 53 each specifically have the following three types of detection units.

[0038] As shown in Fig. 2, the detector 52 for detecting the input current Iin has three types of input current detectors 521 to 523 that are independent of each other. The input current detector 521 is a circuit that detects the input current Iin as a parameter Pr for use in controlling the operation of the switching elements S1 to S8 (by the control circuit 62, which will be described later). The input current detector 522 is a circuit that detects the input current Iin as a parameter Pr for use in protecting (for protective operation) the switching elements S1 to S8 (by the control circuit 62, which will be described later). The input current detector 523 is a circuit that detects the input current Iin as a parameter Pr for use in detecting a failure in at least one of the input current detectors 521 and 522.

[0039] 3, the detector 53 for detecting the DC output voltage Vout has three types of output voltage detectors 531 to 533 that are independent of each other. The output voltage detector 531 is a circuit that detects the DC output voltage Vout as a parameter Pr for use in controlling the operation of the switching elements S1 to S8 (by the control circuit 62 described later). The output voltage detector 532 is a circuit that detects the DC output voltage Vout as a parameter Pr for use in protecting (for protective operation) the switching elements S1 to S8 (by the control circuit 62 described later). The output voltage detector 533 is a circuit that detects the DC output voltage Vout as a parameter Pr for use in detecting a failure in at least one of the output voltage detectors 531 and 532.

[0040] In this way, the DC input voltage Vin measured by the detection unit 51, the input current Iin measured by the detection unit 52, the DC output voltage Vout measured by the detection unit 53, and the output current Iout measured by the detection unit 54 are each output to the comparison control circuit 6 described later (see FIG. 1). In particular, the detection value Pr1 (detection value Iin1) detected by the input current detection unit 521, the detection value Pr2 (detection value Iin2) detected by the input current detection unit 522, and the detection value Pr3 (detection value Iin3) detected by the input current detection unit 523 are each output as the detection value of the parameter Pr (input current Iin) (see FIG. 2). In addition, the detection value Pr1 (detection value Vout1) detected by the output voltage detection unit 531, the detection value Pr2 (detection value Vout2) detected by the output voltage detection unit 532, and the detection value Pr3 (detection value Vout3) detected by the output voltage detection unit 533 are each output as the detection value of the parameter Pr (DC output voltage Vout) (see FIG. 3).

[0041] Each of the detection unit 51 and the detection unit 53 (output voltage detection units 531-533) is configured using, for example, a resistive element, a comparator, etc. Each of the detection unit 52 (input current detection units 521-523) and the detection unit 54 is configured using, for example, a current transformer, a Hall element, etc.

[0042] Here, the above-mentioned input current Iin and DC output voltage Vout (one example of the above-mentioned parameter Pr) each correspond to a specific example of "parameter" in the present invention. In other words, this parameter Pr includes at least one parameter of the input current Iin and the DC output voltage Vout (in this embodiment, both of these parameters). Also, the above-mentioned input current detection unit 521 and output voltage detection unit 531 each correspond to a specific example of "first detection unit" in the present invention, the input current detection unit 522 and output voltage detection unit 532 each correspond to a specific example of "second detection unit" in the present invention, and the input current detection unit 523 and output voltage detection unit 533 each correspond to a specific example of "third detection unit" in the present invention. Furthermore, the above-mentioned detection values ​​Pr1, Iin1, and Vout1 each correspond to a specific example of a "first detection value" in the present invention, the detection values ​​Pr2, Iin2, and Vout2 each correspond to a specific example of a "second detection value" in the present invention, and the detection values ​​Pr3, Iin3, and Vout3 each correspond to a specific example of a "third detection value" in the present invention.

[0043] (E. Comparison control circuit 6) The comparison control circuit 6 is a circuit that performs a predetermined comparison control process (comparison process and control process) described below. As shown in FIG. 4, the comparison control circuit 6 has a comparison circuit 61 that performs a predetermined comparison process and a control circuit 62 that performs a predetermined control process.

[0044] The comparison circuit 61 is a circuit that performs a predetermined comparison process using the detection values ​​Iin1 to Iin3 of the input current Iin detected by the detection unit 52 (input current detection units 521 to 523) and the detection values ​​Vout1 to Vout3 of the DC output voltage Vout detected by the detection unit 53 (input current detection units 531 to 533). Specifically, the comparison circuit 61 is configured to compare at least one of the detection values ​​Iin1 and Iin2 of the input current Iin detected by the input current detection units 521 and 522 with the detection value Iin3 of the input current Iin detected by the input current detection unit 523. Similarly, the comparison circuit 61 is configured to compare at least one of the detection values ​​Vout1 and Vout2 of the DC output voltage Vout detected by the output voltage detection units 531 and 532 with the detection value Vout3 of the DC output voltage Vout detected by the output voltage detection unit 533.

[0045] The control circuit 62 is a circuit that uses the result of the above comparison process (comparison result) by the comparison circuit 61 to control the operation (switching operation) of the switching elements S1 to S4 in the inverter circuit 2 and the operation (switching operation) of the switching elements S5 to S8 in the rectifier circuit 4. Specifically, the control circuit 62 uses such a comparison result to control the operation of the switching elements S1 to S8 based on the detection values ​​of various parameters (DC input voltage Vin, input current Iin, DC output voltage Vout, and output current Iout) detected by the detection units 51 to 54. At this time, the control circuit 62 individually supplies drive signals SG1 to SG8 to the switching elements S1 to S8, respectively, to individually control the switching operation (on / off operation) of each of the switching elements S1 to S8.

[0046] The comparison control process by the comparison control circuit 6 (the comparison process by the comparison circuit 61 and the control process by the control circuit 62) will be described in detail later (FIGS. 5 to 7).

[0047] [Operation and Effects] (A.Basic movement) In this power conversion device 1, a DC input voltage Vin is supplied from a DC input power source 10 via input terminals T1, T2, and a rectangular pulse wave voltage is generated in the inverter circuit 2 by performing a switching operation by switching elements S1 to S4. This rectangular pulse wave voltage is supplied to a primary winding 31 in a transformer 3 via the above-mentioned resonant circuit (a resonant circuit configured using a resonant inductor Lr). Then, the voltage supplied to the primary winding 31 (rectangular pulse wave voltage) is transformed in the transformer 3, and a transformed AC voltage is output from a secondary winding 32.

[0048] In the rectifier circuit 4, the AC voltage output from the transformer 3 (the above-mentioned transformed AC voltage) is rectified by the switching elements S5 to S8 operating as rectifier elements, and then smoothed in the smoothing circuit 5. As a result, a DC output voltage Vout is output from the output terminals T3 and T4. Then, this DC output voltage Vout causes an output current Iout to flow to the load 9, and power is supplied to the load 9.

[0049] (B. Comparison control process) Generally, in a power conversion device, if the current or voltage detection section at a specific location within the device is damaged (if the detected current or voltage value indicates an abnormal value), the operation (conversion operation) of the power conversion device will be stopped and will not be able to continue, which may result in a loss of convenience.

[0050] Therefore, in the power conversion device 1 of the present embodiment, a comparison control process described in detail below is performed by the comparison control circuit 6. Specific examples of such comparison control process (various processing examples by methods A to C) will be described in order below.

[0051] Fig. 5 to Fig. 7 are flow charts showing an example of the comparison and control process according to the present embodiment. Specifically, Fig. 5 shows an example of the comparison and control process in the case of the above-mentioned method A, Fig. 6 shows an example of the comparison and control process in the case of the above-mentioned method B, and Fig. 7 shows an example of the comparison and control process in the case of the above-mentioned method C.

[0052] In these methods A to C, the comparison control circuit 6 performs the comparison control process as described above in the following manner. That is, the comparison circuit 61 compares at least one of the detection values ​​Pr1 (Iin1, Vout1) and Pr2 (Iin2, Vout2) described above with the detection value Pr3 (Iin3, Vout3). When the comparison result indicates that the at least one of the detection values ​​and the detection value Pr3 match each other, the control circuit 62 uses the at least one of the detection values ​​Pr1 and Pr2 that is not compared with the detection value Pr3 as the other detection value that is not compared with the detection value Pr3, when the comparison result indicates that the at least one of the detection values ​​and the detection value Pr3 are different from each other, the control circuit 62 uses the other detection value that is not compared with the detection value Pr3 as the one of the detection values ​​Pr1 and Pr2 that is compared with the detection value Pr3.

[0053] The details of such a comparison control process will be specifically described using the following methods A and B as examples.

[0054] (B-1. Example of processing for method A) First, a processing example of the method A shown in Fig. 5 will be described. In this processing example, the comparator circuit 61 compares the detection value Pr1 (Iin1, Vout1) with the detection value Pr3 (Iin3, Vout3) as described below.

[0055] In the processing example of the method A, first, the comparison circuit 61 compares the detection value Pr1 with the detection value Pr3 and judges whether or not the detection value Pr1 and the detection value Pr3 match each other (Pr1=Pr3) (step S11 in FIG. 5). Here, if the comparison result shows that the detection value Pr1 and the detection value Pr3 match each other (Pr1=Pr3) (step S11: Y), the following occurs. That is, in this case, the control circuit 62 judges that the detection value Pr1 is a normal value (the detection units 521, 531 are not damaged), and uses the detection value Pr1 as it is to control the operation of the switching elements S1 to S8 (step S12). In this case, the series of processes shown in FIG. 5 is completed.

[0056] On the other hand, when the comparison result indicates that the detection value Pr1 and the detection value Pr3 are different from each other (Pr1 ≠ Pr3) (step S11: N), the following occurs. That is, in this case, the control circuit 62 determines that the detection value Pr1 is an abnormal value (the detection units 521, 531 are damaged), and uses (substitutes) the value of the detection value Pr2 as the detection value Pr1, and controls the operation of the switching elements S1 to S8 (step S13). Then, in this case, the control circuit 62 outputs a warning (warning signal Sw) that the detection value Pr1 is an abnormal value to the outside of the power conversion device 1 (step S14). In this case, the series of processes shown in FIG. 5 is completed.

[0057] (B-2. Processing example for method B) Next, a processing example of the method B shown in Fig. 6 will be described. In this processing example, the comparator circuit 61 compares the detection value Pr2 (Iin2, Vout2) with the detection value Pr3 (Iin3, Vout3) as described below.

[0058] In the processing example of the method B, first, the comparison circuit 61 compares the detection value Pr2 with the detection value Pr3 and judges whether or not the detection value Pr2 and the detection value Pr3 match each other (Pr2=Pr3) (step S21 in FIG. 6). Here, if the comparison result shows that the detection value Pr2 and the detection value Pr3 match each other (Pr2=Pr3) (step S21: Y), the following occurs. That is, in this case, the control circuit 62 judges that the detection value Pr2 is a normal value (the detection units 522, 532 are not damaged), and performs the protection operation of the switching elements S1 to S8 using the detection value Pr2 as it is (step S22). In this case, the series of processing shown in FIG. 6 is ended.

[0059] On the other hand, when the comparison result indicates that the detection value Pr2 and the detection value Pr3 are different from each other (Pr2 ≠ Pr3) (step S21: N), the following occurs. That is, in this case, the control circuit 62 determines that the detection value Pr2 is an abnormal value (the detection units 522, 532 are damaged), uses (substitutes) the value of the detection value Pr1 as the detection value Pr2, and performs a protection operation for the switching elements S1 to S8 (step S23). Then, in this case, the control circuit 62 outputs a warning (warning signal Sw) that the detection value Pr2 is an abnormal value to the outside of the power conversion device 1 (step S24). In this case, the series of processes shown in FIG. 6 is ended.

[0060] (B-3. Example of processing for method C) Next, a processing example of the method C shown in Fig. 7 will be described. In this processing example, as described below, the comparator circuit 61 compares the detection value Pr1 (Iin1, Vout1) with the detection value Pr3 (Iin3, Vout3) and also compares the detection value Pr2 (Iin2, Vout2) with the detection value Pr3 (Iin3, Vout3).

[0061] In other words, method C is a combination of the above-mentioned methods A and B. In particular, in the processing example shown in FIG. 7, after performing each step in method A (steps S11 to S14), each step in method B (steps S21 to S24) is performed.

[0062] (C. Actions and Effects) In this manner, in this embodiment, the comparison circuit 61 compares at least one of the detection values ​​Pr1 (Iin1, Vout1) and Pr2 (Iin2, Vout2) with the detection value Pr3 (Iin3, Vout3). When the control circuit 62 obtains a comparison result indicating that the at least one of the detection values ​​and the detection value Pr3 match each other, the control circuit 62 uses the at least one of the detection values ​​as is. On the other hand, when the control circuit 62 obtains a comparison result indicating that the at least one of the detection values ​​and the detection value Pr3 differ from each other, the control circuit 62 uses the other detection value of the detection values ​​Pr1, Pr2 that is not compared with the detection value Pr3 as the one detection value that is compared with the detection value Pr3.

[0063] As a result, in this embodiment, even if at least one of the detectors 52, 53 is broken (if the detected values ​​of the input current Iin and the DC output voltage Vout indicate abnormal values), the operation (conversion operation) of the power conversion device 1 is not stopped and the operation can be continued. As a result, in this embodiment, it is possible to improve the convenience of the power conversion device 1 compared to the general power conversion device described above.

[0064] In this embodiment, when a comparison result is obtained that at least one of the detection values ​​Pr1 and Pr2 and the detection value Pr3 are different from each other, a warning (warning signal Sw) that at least one of the detection values ​​is an abnormal value is output to the outside of the power conversion device 1, as follows: That is, it becomes possible to promptly notify the user of the power conversion device 1 of such a warning.

[0065] <2. Modifications> Next, a modified example of the above embodiment will be described. In the following, the same components as those in the embodiment will be denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0066] (composition) FIG. 8 is a circuit diagram showing a schematic configuration example of a power conversion device (power conversion device 1A) according to a modified example.

[0067] As in the embodiment, a system including DC input power supply 10 and power conversion device 1A corresponds to a specific example of a "power supply system" of the present invention.

[0068] The modified power conversion device 1A is configured in such a manner that a rectifier circuit 4A is provided instead of the rectifier circuit 4 and a comparison control circuit 6A is provided instead of the comparison control circuit 6 in the power conversion device 1 (Figure 1) of the embodiment, but the other configurations are the same.

[0069] As in the embodiment, the inverter circuit 2, the transformer 3 and the rectifier circuit 4A correspond to a specific example of a "conversion circuit" in the present invention.

[0070] The rectifier circuit 4A described above corresponds to the rectifier circuit 4 (FIG. 1) of the embodiment in which rectifier elements (diodes) D5-D8 are provided instead of the switching elements S5-S8, respectively, and the other configurations are the same. Each of these rectifier elements D5-D8 has an anode on the ground line LG side and a cathode on the output line LO side, which are arranged in the opposite directions. Thus, unlike the rectifier circuit 4, the rectifier circuit 4A is not a synchronous rectifier circuit.

[0071] The comparison control circuit 6A described above is a circuit that basically performs the same processes (such as the comparison control process described above) as the comparison control circuit 6 of the embodiment. However, since the switching elements S5 to S8 are not provided in the rectifier circuit 4A, the comparison control circuit 6A outputs only the drive signals SG1 to SG4 for the switching elements S1 to S4 (see FIG. 8).

[0072] (Action and effect) In the power conversion device 1A of the modified example having such a configuration, basically, the same effects as those of the embodiment and the first modified example can be obtained by the same actions.

[0073] <3. Other Modifications> Although the present invention has been described above by way of the embodiment and modifications, the present invention is not limited to these embodiments and can be modified in various ways.

[0074] For example, in the above embodiment, the configuration of the inverter circuit is specifically given and described, but the present invention is not limited to the above embodiment, and for example, an inverter circuit with another configuration may be used. In addition, in the above embodiment, the configuration of the rectifier circuit is specifically given and described, but the present invention is not limited to the above embodiment, and for example, a rectifier circuit with another configuration (such as a so-called "center tap type" rectifier circuit) may be used. Furthermore, in the above embodiment, the configuration of the smoothing circuit is specifically given and described, but the present invention is not limited to the above embodiment, and for example, a smoothing circuit with another configuration may be used.

[0075] In addition, in the above embodiments, the configuration of the transformer (primary winding and secondary winding) has been specifically given and described, but the present invention is not limited to the examples of the above embodiments, and for example, a transformer (primary winding and secondary winding) with a different configuration may be used.

[0076] Furthermore, in the above embodiment, the configuration and arrangement of the detection units 51 to 54 are specifically described, but the present invention is not limited to the above embodiment, and may be configured in other ways or arranged in other ways. For example, at least one of the detection unit 52 that detects the input current Iin and the detection unit 53 that detects the DC output voltage Vout may be provided. That is, for example, at least one of the parameters Pr of the input current Iin and the DC output voltage Vout may be measured. For example, at least one of the detection units 51 and 54 may not be provided.

[0077] In addition, in the above embodiment etc., specific examples of processing by the comparison control circuit (examples of comparison control processing by the above-mentioned methods A to C) have been given and explained, but the present invention is not limited to the examples of the above embodiment etc. That is, for example, in method C, each step in method A (steps S11 to S14) is performed before each step in method B (steps S21 to S24), but conversely, each step in method B may be performed before each step in method A.

[0078] In the above embodiment, the input current Iin and the DC output voltage Vout are described as specific examples of the "parameter" of the present invention, but the present invention is not limited to this example. For example, when the DC output voltage Vout is calculated based on the DC input voltage Vin, or when the power conversion device is a device that performs bidirectional power conversion, the DC input voltage Vin may be used instead of (or in addition to) the DC output voltage Vout. Similarly, the output current Iout may be used instead of (or in addition to) the input current Iin.

[0079] Furthermore, in the above embodiment, the case where any of the detection values ​​Pr1, Pr2, and Pr3 are compared to determine whether they match has been described, but in this case, "matching" does not necessarily mean that the compared detection values ​​match completely. For example, when comparing the detection values ​​Pr1 and Pr2, if the difference between the detection values ​​Pr1 and Pr2 is within a predetermined range, the comparison result may be that the detection values ​​match each other. In this way, by providing a certain degree of width to the range of "matching," it is possible to compare each detection value while taking into account, for example, the wiring length and voltage drop due to the product environment.

[0080] In the above embodiment, a resonant type and an isolated type DC-DC converter are described as an example of a power conversion device according to the present invention, but the present invention is not limited to these resonant type and isolated type DC-DC converters. That is, the present invention can be applied to, for example, a non-resonant type or non-isolated type DC-DC converter. Furthermore, the present invention is not limited to such DC-DC converters, and can be applied to other types of power conversion devices, such as an AC-DC converter.

[0081] Furthermore, the configuration examples described so far may be applied in any combination.

[0082] It should be noted that the effects described in this specification are merely examples and are not limiting, and other effects may also be obtained.

[0083] The present invention can also have the following configuration. (1) A power conversion device that performs a predetermined power conversion, an input section to which an input voltage is input; an output section that outputs an output voltage; A conversion circuit including one or more switching elements, which performs a conversion operation of converting the input voltage into the output voltage; a first detection unit that detects a parameter corresponding to at least one of an input current, an output current, the input voltage, and the output voltage for use in controlling an operation of the switching element; a second detection unit that detects the parameter for protecting the switching element; a third detection unit that detects the parameter for use in detecting a failure in at least one of the first detection unit and the second detection unit; a comparison circuit that compares at least one of a first detection value of the parameter detected by the first detection unit and a second detection value of the parameter detected by the second detection unit with a third detection value of the parameter detected by the third detection unit; a control circuit that controls an operation of the switching element in the conversion circuit by using a comparison result by the comparison circuit; Equipped with The control circuit includes: When the comparison result indicates that the at least one detection value and the third detection value match each other, the at least one detection value is used as is, When the comparison result indicates that the at least one detection value and the third detection value are different from each other, the other detection value, which is not compared with the third detection value, is used as one of the detection values, which is compared with the third detection value, out of the first detection value and the second detection value. Power conversion equipment. (2) the comparison circuit is configured to compare the first detection value with the third detection value, The control circuit includes: When the comparison result indicates that the first detection value and the third detection value match each other, the first detection value is used as it is, When the comparison result indicates that the first detection value and the third detection value are different from each other, the second detection value, which is the other detection value, is used as the first detection value, which is the one detection value. The power conversion device according to (1) above. (3) the comparison circuit is configured to compare the second detection value with the third detection value, The control circuit includes: When the comparison result indicates that the second detection value and the third detection value match each other, the second detection value is used as it is, When the comparison result indicates that the second detection value and the third detection value are different from each other, the first detection value, which is the other detection value, is used as the second detection value, which is the one detection value. The power conversion device according to (1) above. (4) the comparison circuit is configured to compare the first detection value with the third detection value and to compare the second detection value with the third detection value, The control circuit includes: When the comparison result indicates that the first detection value and the third detection value match each other, the first detection value is used as it is, When the comparison result indicates that the first detection value and the third detection value are different from each other, the second detection value, which is the other detection value, is used as the first detection value, which is the one detection value; When the comparison result indicates that the second detection value and the third detection value match each other, the second detection value is used as it is, When the comparison result indicates that the second detection value and the third detection value are different from each other, the first detection value, which is the other detection value, is used as the second detection value, which is the one detection value. The power conversion device according to (1) above. (5) The conversion circuit, a transformer having a primary winding and a secondary winding; an inverter circuit disposed between the input section and the primary winding and including a first switching element as the switching element; a rectifier circuit including a rectifier element, the rectifier circuit being disposed between the output section and the secondary winding; have A power conversion device according to any one of (1) to (4) above. (6) The rectifier circuit is a synchronous rectifier circuit including the rectifier element operating as the switching element as a second switching element. The power conversion device according to (5) above. (7) The control circuit includes: When the comparison result indicates that the at least one detection value and the third detection value are different from each other, A warning is output to the outside to the effect that at least one of the detected values ​​is an abnormal value. A power conversion device according to any one of (1) to (6) above. (8) A power conversion device that performs a predetermined power conversion; A power supply that supplies the input voltage Equipped with The power conversion device is an input unit to which the input voltage is input; an output section that outputs an output voltage; A conversion circuit including one or more switching elements, which performs a conversion operation of converting the input voltage into the output voltage; a first detection unit that detects a parameter corresponding to at least one of an input current, an output current, the input voltage, and the output voltage for use in controlling an operation of the switching element; a second detection unit that detects the parameter for protecting the switching element; a third detection unit that detects the parameter for use in detecting a failure in at least one of the first detection unit and the second detection unit; a comparison circuit that compares at least one of a first detection value of the parameter detected by the first detection unit and a second detection value of the parameter detected by the second detection unit with a third detection value of the parameter detected by the third detection unit; a control circuit that controls an operation of the switching element in the conversion circuit by using a comparison result by the comparison circuit; It has The control circuit includes: When the comparison result indicates that the at least one detection value and the third detection value match each other, the at least one detection value is used as is, When the comparison result indicates that the at least one detection value and the third detection value are different from each other, the other detection value, which is not compared with the third detection value, is used as one of the detection values, which is compared with the third detection value, out of the first detection value and the second detection value. Power supply system. [Explanation of symbols]

[0084] 1,1A...power conversion device, 10...DC input power supply, 2...inverter circuit, 3...transformer, 31...primary winding, 32...secondary winding, 4,4A...rectifier circuit, 5...smoothing circuit, 51-54...detection unit, 521-523...input current detection unit, 531-533...output voltage detection unit, 6,6A...comparison control circuit, 61...comparison circuit, 62...control circuit, 7...reverse voltage clamp circuit, 9...load, T1,T2...input terminal, T3,T4...output terminal, L1H...primary high voltage line, L1L...primary low voltage line, L O...output line, LG...ground line, Vin...DC input voltage, Vout...DC output voltage, Iin...input current, Iout...output current, Pr...parameter, Pr1 to Pr3, Iin1 to Iin3, Vout1 to Vout3...detection values, Cin...input smoothing capacitor, Cout...output smoothing capacitor, S1 to S8...switching elements, SG1 to SG8...drive signals, D5 to D8...rectifier elements, Sw...warning signal, Lr...resonant inductor, Lch...choke coil, P1 to P8...connection points.

Claims

1. A power conversion device that performs a predetermined power conversion, an input section to which an input voltage is input; an output section that outputs an output voltage; A conversion circuit including one or more switching elements, which performs a conversion operation of converting the input voltage into the output voltage; a first detection unit configured to detect a parameter corresponding to at least one of an input current, an output current, the input voltage, and the output voltage for use in controlling an operation of the switching element; a second detection unit that detects the parameter for protecting the switching element; a third detection unit that detects the parameter for use in detecting a failure in at least one of the first detection unit and the second detection unit; a comparison circuit that compares at least one of a first detection value of the parameter detected by the first detection unit and a second detection value of the parameter detected by the second detection unit with a third detection value of the parameter detected by the third detection unit; a control circuit that controls an operation of the switching element in the conversion circuit by using a comparison result by the comparison circuit; Equipped with The control circuit includes: When the comparison result indicates that the at least one detection value and the third detection value match each other, the at least one detection value is used as is, When the comparison result indicates that the at least one of the detection values ​​and the third detection value is different from each other, the other of the first detection value and the second detection value, which is not compared with the third detection value, is used as the one of the detection values ​​which is compared with the third detection value. Power conversion equipment.

2. the comparison circuit is configured to compare the first detection value with the third detection value, The control circuit includes: When the comparison result indicates that the first detection value and the third detection value are identical to each other, the first detection value is used as is, When the comparison result indicates that the first detection value and the third detection value are different from each other, the second detection value, which is the other detection value, is used as the first detection value, which is the one detection value. The power conversion device according to claim 1 .

3. the comparison circuit is configured to compare the second detection value with the third detection value, The control circuit includes: When the comparison result indicates that the second detection value and the third detection value are identical to each other, the second detection value is used as is, When the comparison result indicates that the second detection value and the third detection value are different from each other, the first detection value, which is the other detection value, is used as the second detection value, which is the one detection value. The power conversion device according to claim 1 .

4. the comparison circuit is configured to compare the first detection value with the third detection value and to compare the second detection value with the third detection value, The control circuit includes: When the comparison result indicates that the first detection value and the third detection value are identical to each other, the first detection value is used as is, When the comparison result indicates that the first detection value and the third detection value are different from each other, the second detection value, which is the other detection value, is used as the first detection value, which is the one detection value; When the comparison result indicates that the second detection value and the third detection value are identical to each other, the second detection value is used as is, When the comparison result indicates that the second detection value and the third detection value are different from each other, the first detection value, which is the other detection value, is used as the second detection value, which is the one detection value. The power conversion device according to claim 1 .

5. The conversion circuit, a transformer having a primary winding and a secondary winding; an inverter circuit disposed between the input section and the primary winding and including a first switching element as the switching element; a rectifier circuit including a rectifier element, the rectifier circuit being disposed between the output section and the secondary winding; have The power conversion device according to any one of claims 1 to 4.

6. The rectifier circuit is a synchronous rectifier circuit including the rectifier element operating as the switching element as a second switching element. The power conversion device according to claim 5 .

7. The control circuit includes: When the comparison result indicates that the at least one detection value and the third detection value are different from each other, A warning is output to the outside to the effect that at least one of the detected values ​​is an abnormal value. The power conversion device according to any one of claims 1 to 4.

8. A power conversion device that performs a predetermined power conversion; A power supply that supplies the input voltage Equipped with The power conversion device is an input unit to which the input voltage is input; an output section that outputs an output voltage; A conversion circuit including one or more switching elements, which performs a conversion operation of converting the input voltage into the output voltage; a first detection unit configured to detect a parameter corresponding to at least one of an input current, an output current, the input voltage, and the output voltage for use in controlling an operation of the switching element; a second detection unit that detects the parameter for protecting the switching element; a third detection unit that detects the parameter for use in detecting a failure in at least one of the first detection unit and the second detection unit; a comparison circuit that compares at least one of a first detection value of the parameter detected by the first detection unit and a second detection value of the parameter detected by the second detection unit with a third detection value of the parameter detected by the third detection unit; a control circuit that controls an operation of the switching element in the conversion circuit by using a comparison result by the comparison circuit; It has The control circuit includes: When the comparison result indicates that the at least one detection value and the third detection value match each other, the at least one detection value is used as is, When the comparison result indicates that the at least one of the detection values ​​and the third detection value is different from each other, the other of the first detection value and the second detection value, which is not compared with the third detection value, is used as the one of the detection values ​​which is compared with the third detection value. Power supply system.

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