Power supply device

Abstract

To provide a power supply device capable of suppressing the influence of loads connected to other phases when one phase becomes overcurrent.SOLUTION: A power supply device includes a bridge circuit including a first phase arm, a second phase arm, and a third phase arm, a first phase current detection portion that detects a first phase current, a second phase current detection portion that detects a second phase current, a third phase current detection portion that detects a third phase current, and a control circuit that switches the first phase arm, the second phase arm, and the third phase arm. The control circuit stops the first phase arm when the control circuit detects that the first phase current is an overcurrent, and stops the second phase arm when the control circuit detects that the second phase current is an overcurrent, and stops the first phase arm, the second phase arm, and the third phase arm when the control circuit detects that the third phase current is an overcurrent.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention relates to a power supply device. [Background technology]

[0002] Patent Document 1 describes an inverter that stops the switching operation of all arms when an overcurrent is detected. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2014 / 147801 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, in a single-phase three-wire inverter, if all arms are stopped when one phase (for example, the U phase) experiences an overcurrent, the AC voltage output between the other phases (for example, the V phase) and the N phase will also stop, affecting the loads connected to the other phases.

[0005] The present invention aims to provide a power supply device that can suppress the impact on loads connected to other phases when one phase experiences an overcurrent. [Means for solving the problem]

[0006] A power supply device according to one embodiment of the present invention is: A power supply device that outputs an AC voltage between the first phase and the third phase, and an AC voltage between the second phase and the third phase, A bridge circuit including a first phase arm, a second phase arm, and a third phase arm, A first-phase current detection unit that detects the current of the first phase, A second-phase current detection unit for detecting the current of the second phase, A third-phase current detection unit for detecting the current of the third phase, A control circuit for switching the first phase arm, the second phase arm, and the third phase arm, Includes, The aforementioned control circuit is If an overcurrent is detected in the first phase, the first phase arm is stopped. If an overcurrent is detected in the second phase, the second phase arm is stopped. It is characterized by the following:

[0007] In the aforementioned power supply device, The aforementioned control circuit is When an overcurrent is detected in the third phase, the first phase arm, the second phase arm, and the third phase arm are stopped. It is characterized by the following:

[0008] In the aforementioned power supply device, The positive overcurrent threshold of the first phase and the positive overcurrent threshold of the second phase are the same value, and the negative overcurrent threshold of the first phase and the negative overcurrent threshold of the second phase are the same value. It is characterized by the following:

[0009] In the aforementioned power supply device, The positive overcurrent threshold of the third phase is greater than the positive overcurrent threshold of the first phase and the positive overcurrent threshold of the second phase, and the negative overcurrent threshold of the third phase is less than the negative overcurrent threshold of the first phase and the negative overcurrent threshold of the second phase. It is characterized by the following:

[0010] In the aforementioned power supply device, The aforementioned control circuit is A first-phase switching signal output unit that outputs a switching signal to the first-phase arm, A second-phase switching signal output unit that outputs a switching signal to the second-phase arm, A third-phase switching signal output unit that outputs a switching signal to the third-phase arm, A first-phase overcurrent detection unit that, when it detects that the first phase is overcurrent, outputs a first-phase overcurrent detection signal to the first-phase switching signal output unit, A second-phase overcurrent detection unit that, when it detects that the second phase is overcurrent, outputs a second-phase overcurrent detection signal to the second-phase switching signal output unit, A third-phase overcurrent detection unit that, when it detects that the third phase is overcurrent, outputs a third-phase overcurrent detection signal to the first-phase switching signal output unit, the second-phase switching signal output unit, and the third-phase switching signal output unit, Includes, The first phase switching signal output section is, When the first phase overcurrent detection signal or the third phase overcurrent detection signal is input, the output of the switching signal to the first phase arm is stopped. The second phase switching signal output section is, When the second phase overcurrent detection signal or the third phase overcurrent detection signal is input, the output of the switching signal to the second phase arm is stopped. The third-phase switching signal output section is, When the third-phase overcurrent detection signal is input, the output of the switching signal to the third-phase arm is stopped. It is characterized by the following: [Effects of the Invention]

[0011] One embodiment of the present invention provides the effect of suppressing the impact on loads connected to other phases when one phase experiences an overcurrent. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 shows the configuration of the power supply unit in the comparative example. [Figure 2] Figure 2 shows the waveforms of each part of the power supply unit in the comparative example. [Figure 3] Figure 3 shows the configuration of the power supply unit according to the embodiment. [Figure 4]FIG. 4 is a diagram showing waveforms of respective parts of the power supply device according to the embodiment.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the power supply device of the present invention will be described in detail based on the drawings. Note that the present invention is not limited by this embodiment.

[0014] <Embodiments and Comparative Examples> Hereinafter, the embodiments will be described. To facilitate understanding of the embodiments, the comparative examples will be described first.

[0015] (Comparative Example) FIG. 1 is a diagram showing the configuration of the power supply device of the comparative example. The power supply device 100 is a single-phase three-wire converter.

[0016] The power supply device 100 receives the supply of the voltage V that is output from the AC power supply 2, rectified by the rectifier circuit 3, and smoothed by the capacitor 4, and outputs power to the loads 6 and 7 via the smoothing filter 5. IN

[0017] The power supply device 100 includes a bridge circuit 11, a control circuit 12, a U-phase current detection unit 13 U and a V-phase current detection unit 13 V and a N-phase current detection unit 13 N .

[0018] The U-phase current detection unit 13 U corresponds to an example of the "first-phase current detection unit" of the present disclosure. The V-phase current detection unit 13 V corresponds to an example of the "second-phase current detection unit" of the present disclosure. The N-phase current detection unit 13 N corresponds to an example of the "third-phase current detection unit" of the present disclosure.

[0019] The bridge circuit 11 includes a U-phase arm 21 U and a V-phase arm 21 V and a N-phase arm 21 N .

[0020] U-phase arm 21 U However, this corresponds to an example of the "first phase arm" in this disclosure. V-phase arm 21 V However, this corresponds to an example of the "second phase arm" in this disclosure. N-phase arm 21 N However, this corresponds to an example of the "third phase arm" in this disclosure.

[0021] U-phase arm 21 U This includes the high-side transistor Tr1 and the low-side transistor Tr2. V-phase arm 21 V This includes the high-side transistor Tr3 and the low-side transistor Tr4. N-phase arm 21 N This includes the high-side transistor Tr5 and the low-side transistor Tr6.

[0022] In this disclosure, each transistor is assumed to be a MOSFET, but this is not limited to this. Each transistor may be a silicon power device, GaN power device, SiC power device, IGBT (Insulated Gate Bipolar Transistor), or the like.

[0023] Each transistor has a parasitic diode (body diode). A parasitic diode is the pn junction between the back gate and the source and drain of a MOSFET. The parasitic diode can be used as a freewheeling diode to dissipate transient back electromotive force when the transistor is off.

[0024] The source of transistor Tr1 is electrically connected to the drain of transistor Tr2. The source of transistor Tr3 is electrically connected to the drain of transistor Tr4. The source of transistor Tr5 is electrically connected to the drain of transistor Tr6.

[0025] The drains of transistors Tr1, Tr3, and Tr5 are electrically connected to the first input terminal 11a of the bridge circuit 11. The first input terminal 11a is electrically connected to one end (high potential side) of capacitor 4.

[0026] The sources of transistors Tr2, Tr4, and Tr6 are electrically connected to the second input terminal 11b of the bridge circuit 11. The second input terminal 11b is electrically connected to the other end (low-potential side) of capacitor 4.

[0027] The voltage V of capacitor 4 is connected to the first input terminal 11a and the second input terminal 11b of the bridge circuit 11. IN The following is entered.

[0028] Switching signals are input from the control circuit 12 to the gates of transistors Tr1 through Tr6.

[0029] The source of transistor Tr1 and the drain of transistor Tr2 are electrically connected to the first output terminal 11c of the bridge circuit 11. The first output terminal 11c is connected to the U-phase output line 14 U It is electrically connected to one end of the U-phase arm 21. U U-phase current I U U-phase output line 14 U Output to [this location].

[0030] The source of transistor Tr3 and the drain of transistor Tr4 are electrically connected to the second output terminal 11d of the bridge circuit 11. The second output terminal 11d is connected to the V-phase output line 14 V It is electrically connected to one end of the V-phase arm 21. V V-phase current I V V-phase output line 14 V Output to [this location].

[0031] The source of transistor Tr5 and the drain of transistor Tr6 are electrically connected to the third output terminal 11e of the bridge circuit 11. The third output terminal 11e is connected to the N-phase output line 14 N It is electrically connected to one end. N-phase arm 21 N The N-phase current I N to N-phase output line 14 N Output to [this location].

[0032] U-phase current detection unit 13 U U-phase current I U Detects U-phase current detection signal S 1U The V-phase current detection unit 13 outputs this to the control circuit 12. V V-phase current I V Detects the V-phase current detection signal S 1V The output is sent to the control circuit 12. N-phase current detection unit 13 N The N-phase current I N Detects N-phase current detection signal S 1N This is output to control circuit 12.

[0033] Load 6 has U-phase output line 14 U and N-phase output line 14 N Line voltage V between UN A voltage smoothed by the smoothing filter 5 is applied to the load 7. V-phase output line 14 V and N-phase output line 14 N Line voltage V between VN A voltage that has been smoothed by the smoothing filter 5 is applied.

[0034] The control circuit 12 includes a PWM (Pulse Width Modulation) signal output unit 31 and a U-phase overcurrent detection unit 32 U and V-phase overcurrent detection unit 32 V And, N-phase overcurrent detection unit 32 N U-phase switching signal output section 33 U And, V-phase switching signal output section 33 V And, N-phase switching signal output section 33 N This includes,

[0035] The PWM signal output unit 31 outputs the U-phase PWM signal PU U-phase switching signal output section 33 U Output to the V-phase PWM signal P V V-phase switching signal output section 33 V Output to the N-phase PWM signal P N N-phase switching signal output section 33 N Output to [this location].

[0036] U-phase overcurrent detection unit 32 U The U-phase current detection signal S 1U U-phase current detection unit 13 U Input is received from. U-phase overcurrent detection unit 32 U A positive U-phase overcurrent threshold and a negative U-phase overcurrent threshold are set for this. U-phase overcurrent detection unit 32 U This is the U-phase current detection signal S 1U The positive and negative U-phase overcurrent thresholds are compared with the U-phase overcurrent detection unit 32. U This is the U-phase current detection signal S 1U The value is above the positive U-phase overcurrent threshold or the U-phase current detection signal S 1U If the value is below the negative U-phase overcurrent threshold, the U-phase overcurrent detection signal S is issued. 2U U-phase switching signal output section 33 U V-phase switching signal output section 33 V and N-phase switching signal output section 33 N Output to [this location].

[0037] V-phase overcurrent detection unit 32 V The V-phase current detection signal S 1V V-phase current detection unit 13 V Input is received from: V-phase overcurrent detection unit 32 V A positive V-phase overcurrent threshold and a negative V-phase overcurrent threshold are set for this. V-phase overcurrent detection unit 32 V This is the V-phase current detection signal S 1V The positive and negative U-phase overcurrent thresholds are compared with the V-phase overcurrent detection unit 32. V This is the V-phase current detection signal S 1V The value is above the positive V-phase overcurrent threshold or the V-phase current detection signal S 1V If the value is below the negative V-phase overcurrent threshold, the V-phase overcurrent detection signal S is issued. 2Vto the U-phase switching signal output section 33 U the V-phase switching signal output section 33 V and the N-phase switching signal output section 33 N and output them.

[0038] The N-phase overcurrent detection section 32 N receives the N-phase current detection signal S 1N from the N-phase current detection section 13 N . The N-phase overcurrent detection section 32 N is set with a positive N-phase overcurrent threshold value and a negative N-phase overcurrent threshold value. The N-phase overcurrent detection section 32 N compares the N-phase current detection signal S 1N with the positive and negative U-phase overcurrent threshold values. Then, when the N-phase overcurrent detection section 32 N determines that the N-phase current detection signal S 1N is greater than or equal to the positive N-phase overcurrent threshold value or the N-phase current detection signal S 1N is less than or equal to the negative N-phase overcurrent threshold value, it outputs the N-phase current detection signal S[[ID= 29]] 2N to the U-phase switching signal output section 33 U the V-phase switching signal output section 33 V and the N-phase switching signal output section 33 N and output them.

[0039] It is exemplified that the positive U-phase overcurrent threshold value, the positive V-phase overcurrent threshold value, and the positive N-phase overcurrent threshold value are the same. It is exemplified that the negative U-phase overcurrent threshold value, the negative V-phase overcurrent threshold value, and the negative N-phase overcurrent threshold value are the same.

[0040] When no U-phase overcurrent detection signal S U , V-phase overcurrent detection signal S 2U and N-phase overcurrent detection signal S 2V 2N are input to the U-phase switching signal output section 33, it outputs the U-phase PWM signal P U to the U-phase arm 21 U . As a result, the U-phase arm 21 U performs a switching operation and outputs the U-phase current I U to the U-phase output line 14 U .

[0041] U-phase switching signal output section 33 U This is the U-phase overcurrent detection signal S 2U V-phase overcurrent detection signal S 2V or N-phase overcurrent detection signal S 2N If this is input, the U-phase PWM signal P U U-phase arm 21 U It does not output to the U-phase arm 21. U It does not perform switching operation, and the U-phase current I U U-phase output line 14 U Do not output to it.

[0042] V-phase switching signal output unit 33 V This is the U-phase overcurrent detection signal S 2U V-phase overcurrent detection signal S 2V and N-phase overcurrent detection signal S 2N If no input is provided, the V-phase PWM signal P V V-phase arm 21 V Output to V-phase arm 21 V It operates in a switching manner, and the V-phase current I V V-phase output line 14 V Output to [this location].

[0043] V-phase switching signal output unit 33 V This is the U-phase overcurrent detection signal S 2U V-phase overcurrent detection signal S 2V or N-phase overcurrent detection signal S 2N If this is input, the V-phase PWM signal P V V-phase arm 21 V It does not output to the V-phase arm 21. V It does not perform switching operation, and the V-phase current I V V-phase output line 14 V Do not output to it.

[0044] N-phase switching signal output unit 33 N This is the U-phase overcurrent detection signal S 2U V-phase overcurrent detection signal S 2V and N-phase overcurrent detection signal S 2NIf no input is provided, the N-phase PWM signal P N N-phase arm 21 N Output to the N-phase arm 21. N It operates in a switching manner, and the N-phase current I N to N-phase output line 14 N Output to [this location].

[0045] N-phase switching signal output unit 33 N This is the U-phase overcurrent detection signal S 2U V-phase overcurrent detection signal S 2V or N-phase overcurrent detection signal S 2N If this is input, the N-phase PWM signal P N N-phase arm 21 N It does not output to the N-phase arm 21. N It does not perform switching operation, and the N-phase current I N to N-phase output line 14 N Do not output to it.

[0046] Figure 2 shows the waveforms of each part of the power supply unit in the comparative example.

[0047] Waveform 200 represents the U-phase current I U This represents the N-phase current I. N Waveform 202 represents the V-phase current I V It represents.

[0048] Waveform 203 is U-phase arm 21 U This represents the PWM signal supplied to the N-phase arm 21. Waveform 204 shows the N-phase arm 21 N This represents the PWM signal supplied to the V-phase arm 21. Waveform 205 shows the V-phase arm 21 V This represents the PWM signal supplied to it.

[0049] Waveform 206 shows the line voltage V UN This represents the voltage smoothed by the smoothing filter 5. Waveform 207 shows the line voltage V VN This represents the voltage after smoothing with smoothing filter 5.

[0050] Line 208 represents the positive U-phase overcurrent threshold. Line 209 represents the negative U-phase overcurrent threshold. Line 210 represents the positive N-phase overcurrent threshold. Line 211 represents the negative N-phase overcurrent threshold. Line 212 represents the positive V-phase overcurrent threshold. Line 213 represents the negative V-phase overcurrent threshold.

[0051] At timing t0, the U-phase current I U When (waveform 200) exceeds the positive U-phase overcurrent threshold (line 208), the U-phase overcurrent detection unit 32 U This is the U-phase overcurrent detection signal S 2U U-phase switching signal output section 33 U V-phase switching signal output section 33 V and N-phase switching signal output section 33 N Output to [this location].

[0052] Therefore, as shown in waveform 203, U-phase switching signal output section 33 U U-phase arm 21 U The output of the PWM signal to is stopped. Similarly, as shown in waveform 204, the N-phase switching signal output section 33 N N-phase arm 21 N The output of the PWM signal to is stopped. Similarly, as shown in waveform 205, the V-phase switching signal output section 33 V V-phase arm 21 V Stop outputting the PWM signal to [the device].

[0053] As a result, the line voltage V is as shown in waveform 206. UN The voltage smoothed by the smoothing filter 5 no longer rises and is no longer a sine wave. Also, as shown in waveform 207, the line voltage V VN The voltage smoothed by the smoothing filter 5 no longer decreases and is no longer a sine wave.

[0054] At timing t1, the U-phase current I U When (waveform 200) falls below the positive U-phase overcurrent threshold (line 208), the U-phase overcurrent detection unit 32 U This is the U-phase overcurrent detection signal S 2U Stop the output.

[0055] Therefore, as shown in waveform 203, U-phase switching signal output section 33 U U-phase arm 21 U The output of the PWM signal to the terminal is initiated. Similarly, as shown in waveform 204, the N-phase switching signal output section 33 N N-phase arm 21 N The output of the PWM signal to the terminal is initiated. Similarly, as shown in waveform 205, the V-phase switching signal output section 33 V V-phase arm 21 V Start outputting a PWM signal to [the specified location].

[0056] As a result, the line voltage V is as shown in waveform 206. UN The voltage smoothed by the smoothing filter 5 returns to a sine wave. Similarly, as shown in waveform 207, the line voltage V VN The voltage smoothed by the smoothing filter 5 also returns to a sine wave.

[0057] At timing t2, the U-phase current I U When (waveform 200) falls below the negative U-phase overcurrent threshold (line 209), the U-phase overcurrent detection unit 32 U This is the U-phase overcurrent detection signal S 2U U-phase switching signal output section 33 U V-phase switching signal output section 33 V and N-phase switching signal output section 33 N Output to [this location].

[0058] Therefore, as shown in waveform 203, U-phase switching signal output section 33 U U-phase arm 21 U The output of the PWM signal to is stopped. Similarly, as shown in waveform 204, the N-phase switching signal output section 33 N N-phase arm 21 N The output of the PWM signal to is stopped. Similarly, as shown in waveform 205, the V-phase switching signal output section 33 V V-phase arm 21 V Stop outputting the PWM signal to [the device].

[0059] As a result, the line voltage V is as shown in waveform 206. UN The voltage smoothed by the smoothing filter 5 no longer decreases and is no longer a sine wave. Also, as shown in waveform 207, the line voltage V VN The voltage smoothed by the smoothing filter 5 no longer rises and is no longer a sine wave.

[0060] At timing t3, the U-phase current I U When (waveform 200) becomes larger than the negative U-phase overcurrent threshold (line 209), the U-phase overcurrent detection unit 32 U This is the U-phase overcurrent detection signal S 2U Stop the output.

[0061] Therefore, as shown in waveform 203, U-phase switching signal output section 33 U U-phase arm 21 U The output of the PWM signal to the terminal is initiated. Similarly, as shown in waveform 204, the N-phase switching signal output section 33 N N-phase arm 21 N The output of the PWM signal to the terminal is initiated. Similarly, as shown in waveform 205, the V-phase switching signal output section 33 V V-phase arm 21 V Start outputting a PWM signal to [the specified location].

[0062] As a result, the line voltage V is as shown in waveform 206. UN The voltage smoothed by the smoothing filter 5 returns to a sine wave. Similarly, as shown in waveform 207, the line voltage V VN The voltage smoothed by the smoothing filter 5 also returns to a sine wave.

[0063] Thus, the power supply unit 100 experiences an overload on load 6, and the U-phase current I U The value is greater than or equal to the positive U-phase overcurrent threshold or the U-phase current I U When the line voltage V falls below the negative U-phase overcurrent threshold, VN This also affects the voltage smoothed by the smoothing filter 5, and thus affects the load 7 which is not connected to the U phase.

[0064] (Embodiment) For components of the embodiment that are the same as those in the comparative example, the same reference numerals are used and their descriptions are omitted.

[0065] Figure 3 shows the configuration of the power supply unit according to the embodiment.

[0066] Compared to power supply unit 100 (see Figure 1), power supply unit 1 includes control circuit 12A instead of control circuit 12.

[0067] In the control circuit 12A, the U-phase overcurrent detection unit 32 U This is the U-phase overcurrent detection signal S 2U U-phase switching signal output section 33 U Output to the V-phase switching signal output section 33 V and N-phase switching signal output section 33 N It will not output to this.

[0068] V-phase overcurrent detection unit 32 V This is the V-phase overcurrent detection signal S 2V V-phase switching signal output section 33 V Output to the U-phase switching signal output section 33 U and N-phase switching signal output section 33 N It will not output to this.

[0069] Furthermore, from the viewpoint of symmetry, it is preferable that the conditions for detecting overcurrent are the same for the U-phase and V-phase. Therefore, it is preferable that the positive U-phase overcurrent threshold and the positive V-phase overcurrent threshold are the same. Similarly, it is preferable that the negative U-phase overcurrent threshold and the negative V-phase overcurrent threshold are the same.

[0070] Furthermore, if the positive and negative N-phase overcurrent thresholds are the same as the positive and negative U-phase and V-phase overcurrent thresholds, then, for example, if an overcurrent is detected in the U-phase, an overcurrent will also be detected in the N-phase. In that case, the V-phase arm 21 V and N-phase arm 21 NThe system will also stop. Therefore, it is preferable that the positive N-phase overcurrent threshold is greater than the positive U-phase and V-phase overcurrent thresholds. Also, it is preferable that the negative N-phase overcurrent threshold is smaller than the negative U-phase and V-phase overcurrent thresholds.

[0071] As a result, for example, even if an overcurrent is detected in the U phase, an overcurrent will not be detected in the N phase, so the V phase arm 21 V and N-phase arm 21 N It can continue to operate.

[0072] Figure 4 shows the waveforms of each part of the power supply device according to the embodiment.

[0073] Waveform 220 shows the U-phase current I U Waveform 221 represents the N-phase current I N Waveform 222 represents the V-phase current I V It represents.

[0074] Waveform 223 is U-phase arm 21 U This represents the PWM signal supplied to the N-phase arm 21. Waveform 224 shows the N-phase arm 21 N This represents the PWM signal supplied to the V-phase arm 21. Waveform 225 is the V-phase arm 21 V This represents the PWM signal supplied to it.

[0075] Waveform 226 shows the line voltage V UN This represents the voltage smoothed by the smoothing filter 5. Waveform 227 shows the line voltage V VN This represents the voltage after smoothing with smoothing filter 5.

[0076] Line 228 represents the positive U-phase overcurrent threshold. Line 229 represents the negative U-phase overcurrent threshold. Line 230 represents the positive N-phase overcurrent threshold. Line 231 represents the negative N-phase overcurrent threshold. Line 232 represents the positive V-phase overcurrent threshold. Line 233 represents the negative V-phase overcurrent threshold.

[0077] timing t 10 In this case, U-phase current I U When (waveform 220) exceeds the positive U-phase overcurrent threshold (line 228), the U-phase overcurrent detection unit 32 UThis is the U-phase overcurrent detection signal S 2U U-phase switching signal output section 33 U Output to [this location].

[0078] Therefore, as shown in waveform 223, U-phase switching signal output section 33 U U-phase arm 21 U Stop outputting the PWM signal to [the device].

[0079] As a result, the line voltage V is as shown in waveform 226. UN The voltage smoothed by the smoothing filter 5 no longer rises and is no longer a sine wave.

[0080] However, N-phase switching signal output section 33 N This includes the U-phase overcurrent detection signal S 2U No input is received. Therefore, as shown in waveform 224, the N-phase switching signal output section 33 N N-phase arm 21 N The output of the PWM signal to the same location continues. Similarly, the V-phase switching signal output section 33 V This includes the U-phase overcurrent detection signal S 2U No input is received. Therefore, as shown in waveform 225, the V-phase switching signal output section 33 V V-phase arm 21 V Continue outputting the PWM signal to [the device].

[0081] As a result, as shown in waveform 227, the line voltage V VN The voltage smoothed by the smoothing filter 5 is maintained as a sine wave.

[0082] In this case, the negative N-phase overcurrent threshold is set to a value smaller than the negative U-phase overcurrent threshold and the negative V-phase overcurrent threshold, so the N-phase overcurrent detection unit 32 N This is the N-phase overcurrent detection signal S 2N It does not output.

[0083] timing t 11 In this case, U-phase current I U When (waveform 220) falls below the positive U-phase overcurrent threshold (line 228), the U-phase overcurrent detection unit 32U This is the U-phase overcurrent detection signal S 2U Stop the output.

[0084] Therefore, as shown in waveform 223, U-phase switching signal output section 33 U U-phase arm 21 U Start outputting a PWM signal to [the specified location].

[0085] As a result, the line voltage V is as shown in waveform 226. UN The voltage smoothed by the smoothing filter 5 returns to a sine wave.

[0086] timing t 12 In this case, U-phase current I U When (waveform 220) falls below the negative U-phase overcurrent threshold (line 229), the U-phase overcurrent detection unit 32 U This is the U-phase overcurrent detection signal S 2U U-phase switching signal output section 33 U Output to [this location].

[0087] Therefore, as shown in waveform 223, U-phase switching signal output section 33 U U-phase arm 21 U Stop outputting the PWM signal to [the device].

[0088] As a result, the line voltage V is as shown in waveform 226. UN The voltage smoothed by the smoothing filter 5 no longer decreases and is no longer a sine wave.

[0089] However, N-phase switching signal output section 33 N This includes the U-phase overcurrent detection signal S 2U No input is received. Therefore, as shown in waveform 224, the N-phase switching signal output section 33 N N-phase arm 21 N The output of the PWM signal to the same location continues. Similarly, the V-phase switching signal output section 33 V This includes the U-phase overcurrent detection signal S 2U No input is received. Therefore, as shown in waveform 225, the V-phase switching signal output section 33 V V-phase arm 21V Continue outputting the PWM signal to [the device].

[0090] As a result, as shown in waveform 227, the line voltage V VN The voltage smoothed by the smoothing filter 5 is maintained as a sine wave.

[0091] In this case, the positive N-phase overcurrent threshold is set to a value greater than the positive U-phase overcurrent threshold and the positive V-phase overcurrent threshold, so the N-phase overcurrent detection unit 32 N This is the N-phase overcurrent detection signal S 2N It does not output.

[0092] timing t 13 In this case, U-phase current I U When (waveform 220) becomes larger than the negative U-phase overcurrent threshold (line 229), the U-phase overcurrent detection unit 32 U This is the U-phase overcurrent detection signal S 2U Stop the output.

[0093] Therefore, as shown in waveform 223, U-phase switching signal output section 33 U U-phase arm 21 U Start outputting a PWM signal to [the specified location].

[0094] As a result, the line voltage V is as shown in waveform 226. UN The voltage smoothed by the smoothing filter 5 returns to a sine wave.

[0095] Although not illustrated in Figure 4, the V-phase current I V If the value becomes greater than or equal to the positive V-phase overcurrent threshold or less than or equal to the negative V-phase overcurrent threshold, the V-phase overcurrent detection unit 32 V This is the V-phase overcurrent detection signal S 2V V-phase switching signal output section 33 V This outputs to the V-phase switching signal output section 33. V This stops the output of the PWM signal and the V-phase arm 21 V This stops the switching operation.

[0096] Also, N-phase current IN If the N-phase overcurrent threshold is exceeded or exceeded, or if the N-phase overcurrent threshold is not exceeded, it is preferable to shut down all phases in order to prevent damage to loads 6 and 7. Therefore, the N-phase overcurrent detection unit 32 N This is the N-phase overcurrent detection signal S 2N U-phase switching signal output section 33 U V-phase switching signal output section 33 V and N-phase switching signal output section 33 N This outputs to the U-phase switching signal output section 33. U V-phase switching signal output section 33 V and N-phase switching signal output section 33 N This stops the output of the PWM signal and the U-phase arm 21 U V-phase arm 21 V and N-phase arm 21 N This stops the switching operation.

[0097] As explained above, when load 6 becomes overloaded, the power supply unit 1 will cause the U-phase current I U The value is greater than or equal to the positive U-phase overcurrent threshold or the U-phase current I U Even if the line voltage V falls below the negative U-phase overcurrent threshold, VN This can suppress the effect of the smoothing filter 5 on the voltage, and also suppress the effect of the load 7 that is not connected to the U phase.

[0098] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0099] 1, 100 power supplies 2 AC power supply 3 Rectifier circuit 4 Capacitors 5. Smoothing Filter 6, 7 Load 11 Bridge Circuit 12 Control circuits 13 U U-phase current detection unit 13 V V-phase current detection unit 13 N N-phase current detection unit twenty one U U-phase arm twenty one V V-phase arm twenty one N N-phase arm 31 PWM signal output section 32 U U-phase overcurrent detection unit 32 V V-phase overcurrent detection unit 32 N N-phase overcurrent detection unit 33 U U-phase switching signal output section 33 V V-phase switching signal output section 33 N N-phase switching signal output section

Claims

1. A power supply device that outputs an AC voltage between the first phase and the third phase, and an AC voltage between the second phase and the third phase, A bridge circuit including a first phase arm, a second phase arm, and a third phase arm, A first-phase current detection unit that detects the current of the first phase, A second-phase current detection unit for detecting the current of the second phase, A third-phase current detection unit for detecting the current of the third phase, A control circuit for switching the first phase arm, the second phase arm, and the third phase arm, Includes, The aforementioned control circuit is If an overcurrent is detected in the first phase, the first phase arm is stopped, but the second phase arm and the third phase arm are not stopped. If an overcurrent is detected in the second phase, the second phase arm is stopped, but the first phase arm and the third phase arm are not stopped. When an overcurrent is detected in the third phase, the first phase arm, the second phase arm, and the third phase arm are stopped. A power supply device characterized by the following features.

2. The positive overcurrent threshold of the first phase and the positive overcurrent threshold of the second phase are the same value, and the negative overcurrent threshold of the first phase and the negative overcurrent threshold of the second phase are the same value. The power supply device according to claim 1, characterized in that

3. The positive overcurrent threshold of the third phase is greater than the positive overcurrent threshold of the first phase and the positive overcurrent threshold of the second phase, and the negative overcurrent threshold of the third phase is less than the negative overcurrent threshold of the first phase and the negative overcurrent threshold of the second phase. A power supply device according to claim 1 or 2, characterized in that...

4. The aforementioned control circuit is A first phase switching signal output unit that outputs a switching signal to the first phase arm, A second-phase switching signal output unit that outputs a switching signal to the second-phase arm, A third-phase switching signal output unit that outputs a switching signal to the third-phase arm, A first-phase overcurrent detection unit that, when it detects that the first phase is overcurrent, outputs a first-phase overcurrent detection signal to the first-phase switching signal output unit, A second-phase overcurrent detection unit that, when it detects that the second phase is overcurrent, outputs a second-phase overcurrent detection signal to the second-phase switching signal output unit, A third-phase overcurrent detection unit that, when it detects that the third phase is overcurrent, outputs a third-phase overcurrent detection signal to the first-phase switching signal output unit, the second-phase switching signal output unit, and the third-phase switching signal output unit, Includes, The first phase switching signal output unit is, When the first phase overcurrent detection signal or the third phase overcurrent detection signal is input, the output of the switching signal to the first phase arm is stopped. The second phase switching signal output section is, When the second-phase overcurrent detection signal or the third-phase overcurrent detection signal is input, the output of the switching signal to the second-phase arm is stopped. The aforementioned third-phase switching signal output section is: When the third-phase overcurrent detection signal is input, the output of the switching signal to the third-phase arm is stopped. A power supply device according to any one of claims 1 to 3, characterized in that

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