JP2019205288A - Inverter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inverter device capable of preventing an overcurrent from flowing to a semiconductor switching element or the like even when the inverter device is started in a state where a load is grounded. An inverter device (100) detects an input voltage detection circuit (8) that detects a voltage waveform of each phase of a three-phase alternating current, and a ground fault of a rotating electric machine (7) based on the voltage waveform detected by the input voltage detection circuit (8). And a control circuit 9 for conducting the U-phase lower-stage switching element 5Un, the V-phase lower-stage switching element 5Vn, and the W-phase lower-stage switching element 5Wn at a timing at which the ground fault current due to does not flow into the inverter device 100. [Selection diagram] Figure 1

Description

  The present invention relates to an inverter device that drives a load with AC power.

  An inverter device that drives a rotating electrical machine is often provided with an inverter circuit configured using a semiconductor switching element. In such an inverter device, an overcurrent may flow through the semiconductor switching element due to contact between the inverter circuit case and the inverter circuit. When such an overcurrent flows, the semiconductor element may be destroyed and the life of the inverter device may be shortened. The inverter device described in Patent Document 1 includes an inverter circuit protection mechanism that detects an overcurrent and cuts off power supply to the inverter circuit.

JP 2014-165957 A

  In the technique described in Patent Document 1 described above, when the inverter device is started in a state where the rotating electrical machine connected as a load is grounded, the bootstrap capacitor constituting the bootstrap power source of the overcurrent detection circuit at the time of the start-up Since charging has not been completed, there is a problem that the overcurrent detection circuit does not function at the time of startup.

  The present invention has been made in view of the above, and an inverter device capable of preventing an overcurrent from flowing to a semiconductor switching element or the like even when the inverter device is started in a state where a load is grounded. The purpose is to obtain.

  In order to solve the above-described problems and achieve the object, an inverter device for driving a load by converting AC power supplied from a three-phase AC input power supply according to the present invention is supplied from the three-phase AC input power supply. Three-phase AC rectifying diodes, a bus voltage smoothing capacitor, a U-phase upper switching element, a V-phase upper switching element, a W-phase upper switching element, a U-phase lower switching element, V A three-phase inverter module including a lower phase switching element and a W phase lower switching element. The inverter device includes a U-phase output current detection resistor provided between a first connection point, which is a connection point between the U-phase upper stage switching element and the U-phase lower stage switching element, and a U-phase terminal of the load; A V-phase output current detection resistor provided between a second connection point, which is a connection point between the switching element and the V-phase lower-stage switching element, and the V-phase terminal of the load; a W-phase upper-stage switching element and a W-phase lower-stage switching; A W-phase output current detection resistor provided between a third connection point that is a connection point with the element and a W-phase terminal of the load is provided. In the inverter device, the positive input terminal is connected to one end of the U-phase output current detection resistor, the negative input terminal is connected to the other end of the U-phase output current detection resistor, and the power input terminal on the output voltage detection side is connected to the diode group. Connected to the output power source with the potential at the fourth connection point, which is the connection point between the negative side DC output section and the cathode section of the three-phase inverter module, as the reference potential, and the ground terminal on the output voltage detection side is the first connection The U-phase isolation amplifier connected to the point, the positive input terminal is connected to one end of the V-phase output current detection resistor, the negative input terminal is connected to the other end of the V-phase output current detection resistor, and the power supply on the output voltage detection side A V-phase isolation amplifier whose input terminal is connected to the output power supply and whose ground terminal on the output voltage detection side is connected to the second connection point, and the positive input terminal is connected to one end of the W-phase output current detection resistor, and the negative input End is W phase output Is connected to the other end of the flow detection resistance, a power supply input terminal of the output voltage detection side is connected to the output power, and a W-phase insulating amplifier ground terminal of the output voltage detection side is connected to the third connection point. The inverter device includes a first resistor provided between an output power supply and a power input terminal on the output voltage detection side of the U-phase insulation amplifier, an output power supply, and a power supply input on the output voltage detection side of the U-phase insulation amplifier. A first diode having an anode connected to the first resistor, a cathode connected to the power input terminal on the output voltage detection side of the U-phase insulation amplifier, and one end of the U-phase insulation amplifier Connected between the power input terminal on the output voltage detection side and the first diode, and the other end is connected between the ground terminal on the output voltage detection side of the U-phase isolation amplifier and the first connection point. 1 bootstrap capacitor. The inverter device includes a second resistor provided between an output power supply and a power input terminal on the output voltage detection side of the V-phase insulation amplifier, an output power supply, and a power supply input on the output voltage detection side of the V-phase insulation amplifier. A second diode having an anode connected to the second resistor, a cathode connected to the power input terminal on the output voltage detection side of the V-phase insulation amplifier, and one end of the V-phase insulation amplifier Connected between the power input terminal on the output voltage detection side and the second diode, and the other end connected between the ground terminal on the output voltage detection side of the V-phase isolation amplifier and the second connection point. 2 bootstrap capacitors. The inverter device includes a third resistor provided between the output power supply and the power input terminal on the output voltage detection side of the W-phase insulation amplifier, the output power supply, and the power supply input on the output voltage detection side of the W-phase insulation amplifier. A third diode having an anode connected to the third resistor, a cathode connected to the power input terminal on the output voltage detection side of the W-phase insulation amplifier, and one end of the W-phase insulation amplifier Connected between the power input terminal on the output voltage detection side and the third diode, and the other end connected between the ground terminal on the output voltage detection side of the W-phase isolation amplifier and the third connection point. 3 bootstrap capacitors. The inverter device includes an input voltage detection circuit that detects a voltage waveform of each phase of the three-phase alternating current, and a ground fault current due to a ground fault of the load in the inverter device based on the voltage waveform detected by the input voltage detection circuit. And a control circuit that causes the U-phase lower switching element, the V-phase lower switching element, and the W-phase lower switching element to conduct at a timing that does not flow.

  According to the present invention, it is possible to prevent overcurrent from flowing to a semiconductor switching element or the like even when the inverter device is started in a state where the load is grounded.

The figure for demonstrating schematic structure of the inverter apparatus concerning Embodiment 1 of this invention. The figure for demonstrating schematic structure of the control power supply part which supplies electric power to the control circuit, drive circuit, etc. of the inverter apparatus shown in FIG. The figure for demonstrating schematic structure of the electric current detection circuit of the inverter apparatus shown in FIG. The figure for demonstrating the case where the W phase of a rotary electric machine carries out a ground fault in the state which grounded the S phase of the three-phase alternating current input power supply shown in FIG. The figure for demonstrating the timing which makes the lower stage switching element of the inverter apparatus shown in FIG. The figure for demonstrating schematic structure of the inverter apparatus concerning Embodiment 2 of this invention. The figure for demonstrating schematic structure of the inverter apparatus concerning Embodiment 3 of this invention.

  Below, an inverter device concerning an embodiment of the invention is explained in detail based on a drawing. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
First, the inverter apparatus concerning Embodiment 1 of this invention is demonstrated. FIG. 1 is a diagram for explaining a schematic configuration of the inverter device according to the first embodiment of the present invention. FIG. 2 is a diagram for explaining a schematic configuration of a control power supply unit that supplies power to a control circuit, a drive circuit, and the like of the inverter device shown in FIG. FIG. 3 is a diagram for explaining a schematic configuration of the current detection circuit of the inverter device shown in FIG. 1. In FIG. 3, only the schematic configuration of the W-phase current detection circuit is illustrated, and the schematic configuration of the U-phase current detection circuit and the V-phase current detection circuit is not illustrated.

  A three-phase AC input power source 1 shown in FIG. 1 is a power supply source of the inverter device 100. In the present embodiment, the three-phase AC input power supply 1 is Y-connected, and the S phase is grounded. The three-phase AC input rectifying diode group 2 includes R-phase, S-phase, and T-phase AC input sections, and DC output sections P1 and N1. The AC input unit of the diode group 2 is connected to the R phase, the T phase, and the S phase of the three-phase AC input power source 1 and the input voltage detection circuit 8. An output that is a detection result of the input voltage detection circuit 8 is input to the control circuit 9. The control circuit 9 controls the three-phase inverter module 5 via the drive circuit 10.

  The DC output part P1 of the diode group 2 is connected to one end of the circuit breaker 3a. The DC output unit P1 corresponds to a positive DC output unit. The other end of the circuit breaker 3a is connected to the connection point P. The circuit breaker 3a corresponds to a first circuit breaker. At the other end of the circuit breaker 3a, one end of the bus voltage smoothing capacitor 4, the anode part P2 of the three-phase inverter module 5, one end of the control power supply smoothing capacitor 16 shown in FIG. Is connected to the winding end of the primary winding 19np1.

  The DC output unit N1 of the diode group 2 is connected to the connection point N. The connection point N corresponds to the fourth connection point. The DC output unit N1 corresponds to a negative DC output unit. The DC output unit N1 includes the other end of the capacitor 4, the cathode unit N2 of the three-phase inverter module 5, the other end of the capacitor 16 shown in FIG. 2, the source terminal of the switching element 18 for control power, and the control power The winding end of the secondary winding 19np2 of the transformer 19 is connected to the other end of the secondary winding smoothing capacitor 21c.

  The emitter end of W-phase upper switching element 5Wp is connected to connection point Wp. The connection point Wp corresponds to the third connection point. The emitter end of W-phase upper switching element 5Wp is connected to one end of W-phase output current detection resistor 6c and the positive input end of W-phase insulation amplifier 15 constituting current detection circuit 11 shown in FIG. Similarly, the emitter end of the U-phase upper switching element 5Up is connected to the connection point Up. The connection point Up corresponds to the first connection point. The emitter end of the U-phase upper switching element 5Up is connected to one end of the U-phase output current detection resistor 6a and a positive input end of a U-phase insulation amplifier (not shown) constituting the current detection circuit 11. Similarly, the emitter end of the V-phase upper stage switching element 5Vp is connected to the connection point Vp. The connection point Vp corresponds to the second connection point. The emitter end of the V-phase upper switching element 5Vp is connected to one end of the V-phase output current detection resistor 6b and a positive input end of a V-phase insulation amplifier (not shown) that constitutes the current detection circuit 11.

  The other end of the W-phase output current detection resistor 6c is connected to the negative input end of the W-phase insulation amplifier 15 and the W-phase terminal W1 of the rotating electrical machine 7. Similarly, the other end of the U-phase output current detection resistor 6a is connected to a negative input end of a U-phase insulation amplifier (not shown) and a U-phase terminal U1 of the rotating electrical machine 7. Similarly, the other end of the V-phase output current detection resistor 6b is connected to a negative input end of a V-phase insulation amplifier (not shown) and a V-phase terminal V1 of the rotating electrical machine 7.

  As shown in FIG. 2, the gate voltage input to the gate terminal of the switching element 18 is controlled by the power supply control circuit 17. An anode of a secondary winding rectifier diode 20a is connected to a winding start end of the secondary winding 19ns1 of the control power transformer 19. One end of a secondary winding smoothing capacitor 21a and an output power supply Va1 are connected to the cathode of the diode 20a. The other end of the capacitor 21a and the reference potential of the output power supply Va1 are connected to the winding end of the secondary winding 19ns1.

  The anode of the secondary winding rectifier diode 20b is connected to the winding start end of the secondary winding 19nsn of the control power transformer 19. One end of a secondary winding smoothing capacitor 21b and an output power supply Van are connected to the cathode of the diode 20b. The other end of the capacitor 21b and the reference potential of the output power source Van are connected to the winding end of the secondary winding 19nsn.

  The anode of the secondary winding rectification diode 20c is connected to the winding start end of the secondary winding 19np2. One end of a secondary winding smoothing capacitor 21c and an output power supply VN are connected to the cathode of the diode 20c. The other end of the capacitor 21c and the connection point N are connected to the winding end of the secondary winding 19np2.

  As shown in FIG. 3, one end of a current limiting resistor 12 is connected to the output power supply VN. The resistor 12 corresponds to a third resistor. The other end of the resistor 12 is connected to the anode of a bootstrap diode 13. The diode 13 corresponds to a third diode. One end of the bootstrap capacitor 14 and the power input terminal on the output voltage detection side of the W-phase insulation amplifier 15 are connected to the cathode of the diode 13. The bootstrap capacitor 14 corresponds to a third bootstrap capacitor. The other end of the bootstrap capacitor 14 and the connection point Wp are connected to the ground terminal on the output voltage detection side of the W-phase insulation amplifier 15.

  An output power supply Van that is insulated from the output power supply VN is connected to the power input terminal on the insulated output side of the W-phase insulation amplifier 15. The ground terminal on the insulated output side of the W-phase insulated amplifier 15 is connected to the reference potential of the output power supply Van.

  The U-phase current detection circuit has the same configuration as that of the W-phase current detection circuit, and the connection point Up is connected to the ground terminal on the output voltage detection side of the U-phase insulation amplifier. The V-phase current detection circuit has the same configuration as the W-phase current detection circuit, and the connection point Vp is connected to the ground terminal on the output voltage detection side of the V-phase insulation amplifier.

  In the inverter device 100 described above, the three-phase AC voltage supplied from the three-phase AC input power source 1 is rectified to a DC voltage by the diode group 2 and smoothed by the capacitor 4. A circuit breaker 3 a is inserted between the DC output part P <b> 1 of the diode group 2 and the anode part P <b> 2 of the capacitor 4 and the three-phase inverter module 5. When the inverter device 100 is abnormal, the circuit breaker 3a is opened to cut off the electric circuit between the DC output unit P1 and the connection point P, and the connection with the three-phase AC input power supply 1 is disconnected.

  When the capacitor 4 and the capacitor 16 are charged to a certain potential, the power supply control circuit 17 is activated and the switching element 18 starts a switching operation. When the switching element 18 is turned on, a voltage is generated in the secondary winding of the control power transformer 19. The voltage generated in the secondary winding 19ns1 is rectified by the diode 20a and smoothed by the capacitor 21a. The voltage generated in the secondary winding 19nsn is rectified by the diode 20b and smoothed by the capacitor 21b. The voltage generated in the secondary winding 19np2 is rectified by the diode 20c and smoothed by the capacitor 21c. The reference potential of the output power supply VN is the potential at the connection point N and does not enter a floating state. In this way, a control power supply is established.

  After the control power supply is established, the three-phase inverter module 5 converts the DC voltage smoothed by the capacitor 4 into an AC voltage having an arbitrary frequency component, and the rotating electrical machine 7 is driven. The interior of the three-phase inverter module 5 is composed of semiconductor elements for switching, such as insulated gate bipolar transistors (IGBTs) or field effect transistors (FETs). In the present embodiment, the three-phase inverter module 5 has a module configuration composed of only switching semiconductor elements. However, in the same package, a three-phase rectifier diode, a braking circuit diode, And a module configuration in which an IGBT is built in.

  In the inverter device 100, U inserted between the U-phase, V-phase and W-phase output terminals of the three-phase inverter module 5 and the U-phase terminal U1, V-phase terminal V1 and W-phase terminal W1 of the rotating electrical machine 7. Using the phase output current detection resistor 6a, the V phase output current detection resistor 6b, and the W phase output current detection resistor 6c, the current of each phase is detected, and the detected current information is fed back to the control circuit 9. Controls the three-phase inverter module 5 via the drive circuit 10 to drive the rotating electrical machine 7.

  Regarding the U-phase upper switching element 5Up, the V-phase upper switching element 5Vp, and the W-phase upper switching element 5Wp of the three-phase inverter module 5, the reference potential is different from the potential at the connection point N, so the connection point Up, the connection point Vp, and A gate driving power source using the connection point Wp as a reference potential is required. Regarding the U-phase lower switching element 5Un, V-phase lower switching element 5Vn, and W-phase lower switching element 5Wn of the three-phase inverter module 5, the reference potential is the potential at the connection point N. Therefore, the output power supply VN as the gate driving power supply Connect to.

  The first gate drive power supply of the upper stage switching element uses a multi-output isolated control power supply, and the secondary of the transformer corresponding to the respective reference potentials at the connection point Up, the connection point Vp, and the connection point Wp. One example is to prepare side windings.

  As the configuration of the second gate driving power source of the upper switching element, a bootstrap system can be cited. In the bootstrap system, the lower-side switching element is used as a power source for driving the gate of the upper-stage switching element without preparing the secondary windings of the transformers corresponding to the reference potentials of the connection point Up, the connection point Vp, and the connection point Wp. The output power supply VN whose reference potential is the potential at the connection point N is used in the same manner as in FIG. The potential at the connection point Up, the connection point Vp, and the connection point Wp is different from the potential at the connection point N. For example, a current limiting resistor, a bootstrap diode, and a bootstrap capacitor are inserted in series between the connection point Up and the output power supply VN.

  At the stage where the control power supply is established and the output power supply VN is established, the U-phase lower switching element 5Un of the three-phase inverter module 5 is not switched, so that the potential at the connection point Up is in a floating state. For this reason, there is no path for the output power supply VN to charge the bootstrap capacitor via the resistor and the diode, and the power supply for driving the gate of the upper switching element is not established. In this state, by switching the U-phase lower switching element 5Un at a constant carrier frequency, the potential at the connection point Up periodically becomes the potential at the connection point N. Each time the U-phase lower switching element 5Un is turned on, the bootstrap capacitor is charged to establish a power source for driving the gate of the upper switching element. The same operation is performed for the V phase and the W phase. By switching only the lower switching element after the control power supply is established, it is possible to establish a gate driving power supply for the upper switching element before driving the rotating electrical machine 7.

  According to the present embodiment, each of the R-phase, S-phase, and T-phase AC voltages input to diode group 2 is detected by input voltage detection circuit 8. The AC voltages of the R phase, the S phase, and the T phase are out of phase by 120 ° for each phase at a commercial frequency of 50 Hz or 60 Hz of the three-phase AC input power source 1. The voltage waveform detected by the input voltage detection circuit 8 is input to the control circuit 9.

  A U-phase output current detection resistor 6a, a V-phase output current detection resistor 6b, and a W-phase output current detection resistor 6c are connected to the U-phase, V-phase, and W-phase output terminals of the three-phase inverter module 5, and each detection is performed. Insulation amplifiers that detect voltages generated at both ends of the detection resistors 6a, 6b, and 6c are connected to both ends of the resistors 6a, 6b, and 6c, respectively. Since the U-phase, V-phase, and W-phase have the same circuit configuration, the description will be made with the W-phase circuit configuration.

  The power supply input terminal on the output voltage detection side of the W-phase insulation amplifier 15 is connected to the output power supply VN generated from the control power supply via the resistor 12 and the diode 13. One end of the bootstrap capacitor 14 and the power input terminal on the output voltage detection side of the W-phase insulation amplifier 15 are connected to the cathode of the diode 13. The other end of the bootstrap capacitor 14 and the connection point Wp are connected to the ground terminal on the output voltage detection side of the W-phase insulation amplifier 15. The power source for the current detection circuit 11 is generated by the bootstrap system in the same manner as the gate driving power source for each phase upper switching element of the three-phase inverter module 5 described above. By switching only the lower switching element after the establishment of the control power supply, it is possible to establish the power supply for driving the gate of the upper switching element and the power supply for the current detection circuit 11 before driving the rotating electrical machine 7. .

  FIG. 4 is a diagram for explaining a case where the W phase of the rotating electrical machine is grounded in a state where the S phase of the three-phase AC input power source shown in FIG. 1 is grounded. As shown in FIG. 4, the operation of the inverter device 100 will be described assuming a case where the S phase of the three-phase AC input power supply 1 is grounded and the W phase of the rotating electrical machine 7 is grounded due to dielectric breakdown. In the grounded state, after the control power supply is established, the gate drive power supply of each phase upper switching element of the three-phase inverter module 5 and the power supply of the current detection circuit 11 are established by the bootstrap method. When switching of the element is started, from the S phase of the three-phase AC input power source 1 through the ground, through the W phase output current detection resistor 6c, through the conductive W phase lower switching element 5Wn, through the connection point N, the diode A ground fault current flows through the group 2 along the path returning to the T phase of the three-phase AC input power source 1. Since the W-phase output current detection resistor 6c is on the path through which the ground fault current flows, it is possible to detect an overcurrent with the current detection circuit 11 if a ground fault occurs during steady operation. A measure such as stopping the switching of the module 5 is possible. However, since the power generation of the current detection circuit 11 is a bootstrap system using the switching of the three-phase inverter module 5, there is a problem that the current detection circuit 11 does not function when the inverter device 100 is started.

  In the present embodiment, the control circuit 9 causes the lower switching element to conduct at a timing at which no ground fault current flows based on the voltage waveform detected by the input voltage detection circuit 8. FIG. 5 is a diagram for explaining the timing at which the lower switching element of the inverter device shown in FIG. 1 is turned on. The upper part of FIG. 5 shows an R-phase voltage waveform Vrs, an S-phase voltage waveform Vst, and a T-phase voltage waveform Vtr detected by the input voltage detection circuit 8. Specifically, assuming that the S phase of the three-phase AC input power supply 1 is grounded and the W phase of the rotating electrical machine 7 is grounded, the control circuit 9 performs the period t shown in the lower part of FIG. The W-phase lower switching element 5Wn is turned on at the timing of When the W-phase lower switching element 5Wn is turned on at the timing of the period t, the W-phase lower switching element is turned on through the W-phase output current detection resistor 6c from the S phase of the three-phase AC input power supply 1 through the ground. A ground fault current does not flow through a path passing through 5Wn, passing through the connection point N, passing through the diode group 2, and returning to the T phase of the three-phase AC input power source 1. In a period other than the timing of the period t, the diode group 2 is conductive, and thus a path through which the ground fault current flows is generated. At the timing of the period t, let the ground fault current flow from the cathode of the diode group 2 to the anode. Since the diode group 2 is not conductive, a path through which a ground fault current flows does not occur. The period t is a period from the time when the R-phase voltage waveform Vrs changes from negative to positive to the time when the S-phase voltage waveform Vst changes from negative to positive. Similarly, assuming that the S phase of the three-phase AC input power supply 1 is grounded and the U phase of the rotating electrical machine 7 is grounded, the control circuit 9 controls the U phase at a timing at which no ground fault current flows. The lower switching element 5Un is turned on. Similarly, assuming that the S-phase of the three-phase AC input power supply 1 is grounded and the V-phase of the rotating electrical machine 7 is grounded, the control circuit 9 controls the V-phase at a timing at which no ground-fault current flows. The lower switching element 5Vn is turned on.

  According to the present embodiment, even when the inverter device 100 is started in a state where the rotating electrical machine 7 connected as a load is grounded, the ground fault current can be prevented from flowing to the semiconductor switching element or the like. . Since the lower-stage switching element can be turned on at a period in which the ground fault current does not flow, and the bootstrap power supply of the current detection circuit 11 can be established, the current detection circuit 11 does not function and the ground fault current is generated. It will not flow. When the current detection circuit 11 functions, the control circuit 9 can stop the three-phase inverter module 5 based on the detection result of the current detection circuit 11. Thereby, it becomes possible to prevent the destruction of the semiconductor element due to the overcurrent such as the ground fault current and the decrease in the life of the inverter device.

  According to the present embodiment, since the power generation of the current detection circuit 11 is the bootstrap system, it is possible to reduce the number of windings and the number of pins of the transbobbin required for the control power transformer, and the transformer can be downsized. Further, the inverter device 100 can be downsized.

Embodiment 2. FIG.
Next, the inverter apparatus concerning Embodiment 2 of this invention is demonstrated. FIG. 6 is a diagram for explaining a schematic configuration of the inverter device according to the second embodiment of the present invention. The inverter device 100A according to the second embodiment of the present invention is different from the above-described first embodiment in that the circuit breaker 3b is provided. The description of the same configuration and operation as those in the first embodiment will be omitted, and a description of the different configuration and operation will be given below.

  In the inverter device 100 </ b> A shown in FIG. 6, a circuit breaker 3 b is inserted between the DC output unit N <b> 1 of the diode group 2 and the capacitor 4 and the cathode unit N <b> 2 of the three-phase inverter module 5. The circuit breaker 3b corresponds to a second circuit breaker.

  In the inverter device 100A described above, the three-phase AC voltage supplied from the three-phase AC input power source 1 is rectified to a DC voltage by the diode group 2 and smoothed by the capacitor 4. A circuit breaker 3 a is inserted between the DC output part P <b> 1 of the diode group 2 and the anode part P <b> 2 of the capacitor 4 and the three-phase inverter module 5. By disconnecting the circuit breaker 3a and the circuit breaker 3b when the inverter device 100A is abnormal, the circuit between the DC output unit P1 and the connection point P and the circuit between the DC output unit N1 and the connection point N are interrupted. Disconnect from the 3-phase AC input power supply 1.

  According to the present embodiment, when the current detection circuit 11 functions, the control circuit 9 can detect the ground fault current, and the DC output unit P1 is opened by opening the circuit breaker 3a and the circuit breaker 3b. And the circuit between the DC output unit N1 and the connection point N can be cut off, and the path through which the ground fault current flows can be eliminated. Thereby, the protection against the ground fault of the load in the inverter device 100A can be further ensured.

Embodiment 3 FIG.
Next, the inverter apparatus concerning Embodiment 3 of this invention is demonstrated. FIG. 7 is a diagram for explaining a schematic configuration of the inverter device according to the third embodiment of the present invention. In the inverter device 100B according to the third embodiment of the present invention, a bootstrap switching element and a blocking diode are added to each of the U phase, the V phase, and the W phase inside the three-phase inverter module 5A. The point that the input voltage detection circuit 8 is deleted is different from the first embodiment described above. The description of the same configuration and operation as those in the first embodiment will be omitted, and a description of the different configuration and operation will be given below.

  Inverter device 100B shown in FIG. 7 includes bootstrap switching elements 22a, 22b, and 22c and blocking diodes 23a and 23b in each of the U phase, V phase, and W phase inside three-phase inverter module 5A. , 23c are respectively added. The switching element 22a corresponds to the first switching element. The switching element 22b corresponds to the second switching element. The switching element 22c corresponds to a third switching element. The diode 23a corresponds to a first blocking diode. The diode 23b corresponds to a second blocking diode. The diode 23c corresponds to a third blocking diode. The inverter device 100B does not include the input voltage detection circuit 8.

  Since the functions of the bootstrap switching elements 22a, 22b, and 22c and the functions of the blocking diodes 23a, 23b, and 23c are the same, the U phase in the three-phase inverter module 5A will be described below. Only the explanation is given.

  In the inverter device 100B described above, one end of the current limiting resistor 12a is connected to the output power supply VN generated from the control power supply. The resistor 12a corresponds to the first resistor. The other end of the resistor 12a is connected to the anode of a bootstrap diode 13a. The diode 13a corresponds to the first diode. One end of the bootstrap capacitor 24a and the power input terminal on the output voltage detection side of the U-phase insulation amplifier are connected to the cathode of the diode 13a. The bootstrap capacitor 24a corresponds to the first bootstrap capacitor. The other end of the bootstrap capacitor 24a, the anode of the diode 23a, and the collector terminal of the switching element 22a are connected to the ground terminal on the output voltage detection side of the U-phase insulation amplifier. The emitter terminal of the switching element 22a is connected to the connection point N. The gate voltage input to the gate terminal of the switching element 22 a is controlled by the control circuit 9 via the drive circuit 10. A connection point Up is connected to the cathode of the diode 23a.

  An output power supply Van that is insulated from the output power supply VN is connected to the power input terminal on the insulated output side of the U-phase insulation amplifier. The ground terminal on the insulated output side of the U-phase insulated amplifier is connected to the reference potential of the output power supply Van.

  In the inverter device 100B, the V-phase and W-phase circuit configurations inside the three-phase inverter module 5A are the same as the U-phase circuit configurations as shown in FIG. Is omitted.

  In the inverter device 100B, after the control power supply is established, the bootstrap switching elements 22a, 22b, and 22c of each phase are switched at a constant frequency, thereby providing a power source for the insulation amplifier of each phase of the current detection circuit 11. The bootstrap capacitors 24a, 24b, and 24c are charged. Even when the S phase of the three-phase AC input power supply 1 is grounded and the W phase of the rotating electrical machine 7 is grounded due to a dielectric breakdown, the ground fault current is caused by the diodes 23a, 23b, and 23c inserted in the respective phases. The path that flows is blocked. Therefore, the switching elements 22a, 22b, and 22c can be switched at an arbitrary timing.

  According to the present embodiment, unlike the above-described first embodiment, the power supply of the current detection circuit 11 can be established by switching the bootstrap switching elements 22a, 22b, and 22c at an arbitrary timing. It becomes possible. For this reason, the sequence which considered the voltage waveform of each phase of the three-phase alternating current input power supply 1 becomes unnecessary.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit and change the part.

  1 3-phase AC input power supply, 2 diode group, 3a, 3b circuit breaker, 4, 16, 21a, 21b, 21c capacitor, 5, 5A 3-phase inverter module, 5Un U-phase lower switching element, 5Up U-phase upper switching element, 5Vn V-phase lower switching element, 5Vp V-phase upper switching element, 5Wn W-phase lower switching element, 5Wp W-phase upper switching element, 6a U-phase output current detection resistor, 6b V-phase output current detection resistor, 6c W-phase output current detection Resistance, 7 Rotating electrical machine, 8 Input voltage detection circuit, 9 Control circuit, 10 Drive circuit, 11 Current detection circuit, 12, 12a, 12b, 12c Resistor, 13, 13a, 13b, 13c, 20a, 20b, 20c, 23a , 23b, 23c Diode, 14, 24a, 24b, 24c Boot Trap capacitor, 15 W-phase insulating amplifier, 18,22a, 22b, 22c switching element 19 controls the power supply transformer, 19Np1 1 primary winding, 19Np2,19ns1,19nsn 2 windings, 100, 100A, 100B inverter device.

Claims (4)

An inverter device that converts AC power supplied from a three-phase AC input power to drive a load,
A three-phase AC rectifying diode group supplied from the three-phase AC input power source;
A capacitor for smoothing the bus voltage;
A three-phase inverter module comprising a U-phase upper switching element, a V-phase upper switching element, a W-phase upper switching element, a U-phase lower switching element, a V-phase lower switching element, and a W-phase lower switching element;
A U-phase output current detection resistor provided between a first connection point, which is a connection point between the U-phase upper switching element and the U-phase lower switching element, and a U-phase terminal of the load;
A V-phase output current detection resistor provided between a second connection point, which is a connection point between the V-phase upper stage switching element and the V-phase lower stage switching element, and a V-phase terminal of the load;
A W-phase output current detection resistor provided between a third connection point, which is a connection point between the W-phase upper switching element and the W-phase lower switching element, and a W-phase terminal of the load;
The positive input terminal is connected to one end of the U-phase output current detection resistor, the negative input terminal is connected to the other end of the U-phase output current detection resistor, and the power input terminal on the output voltage detection side is the negative terminal of the diode group. Connected to an output power source having a potential at a fourth connection point, which is a connection point between the DC output portion on the side and the cathode portion of the three-phase inverter module, as a reference potential, and a ground terminal on the output voltage detection side A U-phase isolation amplifier connected to the connection point;
The positive input terminal is connected to one end of the V-phase output current detection resistor, the negative input terminal is connected to the other end of the V-phase output current detection resistor, and the power input terminal on the output voltage detection side is connected to the output power supply. A V-phase isolation amplifier having a ground terminal on the output voltage detection side connected to the second connection point;
The positive input terminal is connected to one end of the W-phase output current detection resistor, the negative input terminal is connected to the other end of the W-phase output current detection resistor, and the power input terminal on the output voltage detection side is connected to the output power supply. A W-phase isolation amplifier having a ground terminal on the output voltage detection side connected to the third connection point;
A first resistor provided between the output power supply and a power input terminal on the output voltage detection side of the U-phase insulation amplifier;
Provided between the output power supply and the power input terminal on the output voltage detection side of the U-phase insulation amplifier, the anode is connected to the first resistor, and the cathode is the output voltage detection side of the U-phase insulation amplifier A first diode connected to the power input terminal of
One end is connected between the power input terminal on the output voltage detection side of the U-phase isolation amplifier and the first diode, and the other end is connected to the ground terminal on the output voltage detection side of the U-phase isolation amplifier and the first A first bootstrap capacitor connected between the connection points;
A second resistor provided between the output power supply and a power input terminal on the output voltage detection side of the V-phase isolation amplifier;
Provided between the output power supply and the power input terminal on the output voltage detection side of the V-phase insulation amplifier, the anode is connected to the second resistor, and the cathode is the output voltage detection side of the V-phase insulation amplifier A second diode connected to the power input terminal of
One end is connected between the power input terminal on the output voltage detection side of the V-phase isolation amplifier and the second diode, and the other end is connected to the ground terminal on the output voltage detection side of the V-phase isolation amplifier and the second A second bootstrap capacitor connected between the connection points;
A third resistor provided between the output power supply and a power input terminal on the output voltage detection side of the W-phase insulation amplifier;
Provided between the output power supply and the power input terminal on the output voltage detection side of the W-phase insulation amplifier, the anode is connected to the third resistor, and the cathode is the output voltage detection side of the W-phase insulation amplifier A third diode connected to the power input terminal of
One end is connected between the power supply input terminal on the output voltage detection side of the W-phase insulation amplifier and the third diode, and the other end is connected to the ground terminal on the output voltage detection side of the W-phase insulation amplifier and the third diode. A third bootstrap capacitor connected between the connection points;
An input voltage detection circuit for detecting a voltage waveform of each phase of the three-phase alternating current;
Based on the voltage waveform detected by the input voltage detection circuit, the U-phase lower stage switching element, the V-phase lower stage switching element, and the timing at which the ground fault current due to the ground fault of the load does not flow into the inverter device, An inverter device comprising: a control circuit for conducting the W-phase lower switching element. 2. The inverter device according to claim 1, further comprising: a first circuit breaker provided between a positive DC output unit of the diode group and the capacitor and an anode unit of the three-phase inverter module. The inverter according to claim 2, further comprising: a second circuit breaker provided between the negative-side DC output unit of the diode group and the capacitor and the cathode unit of the three-phase inverter module. apparatus. An inverter device that converts AC power supplied from a three-phase AC input power to drive a load,
A three-phase AC rectifying diode group supplied from the three-phase AC input power source;
A capacitor for smoothing the bus voltage;
A three-phase inverter module comprising a U-phase upper switching element, a V-phase upper switching element, a W-phase upper switching element, a U-phase lower switching element, a V-phase lower switching element, and a W-phase lower switching element;
A U-phase output current detection resistor provided between a first connection point, which is a connection point between the U-phase upper switching element and the U-phase lower switching element, and a U-phase terminal of the load;
A V-phase output current detection resistor provided between a second connection point, which is a connection point between the V-phase upper stage switching element and the V-phase lower stage switching element, and a V-phase terminal of the load;
A W-phase output current detection resistor provided between a third connection point, which is a connection point between the W-phase upper switching element and the W-phase lower switching element, and a W-phase terminal of the load;
The positive input terminal is connected to one end of the U-phase output current detection resistor, the negative input terminal is connected to the other end of the U-phase output current detection resistor, and the power input terminal on the output voltage detection side is the negative terminal of the diode group. Connected to an output power source having a potential at a fourth connection point, which is a connection point between the DC output portion on the side and the cathode portion of the three-phase inverter module, as a reference potential, and a ground terminal on the output voltage detection side A U-phase isolation amplifier connected to the connection point;
The positive input terminal is connected to one end of the V-phase output current detection resistor, the negative input terminal is connected to the other end of the V-phase output current detection resistor, and the power input terminal on the output voltage detection side is connected to the output power supply. A V-phase isolation amplifier having a ground terminal on the output voltage detection side connected to the second connection point;
The positive input terminal is connected to one end of the W-phase output current detection resistor, the negative input terminal is connected to the other end of the W-phase output current detection resistor, and the power input terminal on the output voltage detection side is connected to the output power supply. A W-phase isolation amplifier having a ground terminal on the output voltage detection side connected to the third connection point;
A first resistor provided between the output power supply and a power input terminal on the output voltage detection side of the U-phase insulation amplifier;
Provided between the output power supply and the power input terminal on the output voltage detection side of the U-phase insulation amplifier, the anode is connected to the first resistor, and the cathode is the output voltage detection side of the U-phase insulation amplifier A first diode connected to the power input terminal of
One end is connected between the power input terminal on the output voltage detection side of the U-phase isolation amplifier and the first diode, and the other end is connected to the ground terminal on the output voltage detection side of the U-phase isolation amplifier and the first A first bootstrap capacitor connected between the connection points;
A first blocking diode having an anode connected to the ground terminal on the output voltage detection side of the U-phase isolation amplifier and the other end of the first bootstrap capacitor, and a cathode connected to the first connection point;
Provided between the ground terminal on the output voltage detection side of the U-phase isolation amplifier, the other end of the first bootstrap capacitor, the cathode of the first blocking diode, and the fourth connection point. A first switching element;
A second resistor provided between the output power supply and a power input terminal on the output voltage detection side of the V-phase isolation amplifier;
Provided between the output power supply and the power input terminal on the output voltage detection side of the V-phase insulation amplifier, the anode is connected to the second resistor, and the cathode is the output voltage detection side of the V-phase insulation amplifier A second diode connected to the power input terminal of
One end is connected between the power input terminal on the output voltage detection side of the V-phase isolation amplifier and the second diode, and the other end is connected to the ground terminal on the output voltage detection side of the V-phase isolation amplifier and the second A second bootstrap capacitor connected between the connection points;
A second blocking diode having an anode connected to the ground terminal on the output voltage detection side of the V-phase insulation amplifier and the other end of the second bootstrap capacitor, and a cathode connected to the second connection point;
Provided between the ground terminal on the output voltage detection side of the V-phase isolation amplifier, the other end of the second bootstrap capacitor, the cathode of the second blocking diode, and the fourth connection point. A second switching element;
A third resistor provided between the output power supply and a power input terminal on the output voltage detection side of the W-phase insulation amplifier;
Provided between the output power supply and the power input terminal on the output voltage detection side of the W-phase insulation amplifier, the anode is connected to the third resistor, and the cathode is the output voltage detection side of the W-phase insulation amplifier A third diode connected to the power input terminal of
One end is connected between the power supply input terminal on the output voltage detection side of the W-phase insulation amplifier and the third diode, and the other end is connected to the ground terminal on the output voltage detection side of the W-phase insulation amplifier and the third diode. A third bootstrap capacitor connected between the connection points;
A third blocking diode having an anode connected to the ground terminal on the output voltage detection side of the W-phase insulation amplifier and the other end of the third bootstrap capacitor, and a cathode connected to the third connection point;
Provided between the ground terminal on the output voltage detection side of the W-phase isolation amplifier, the other end of the third bootstrap capacitor, the cathode of the third blocking diode, and the fourth connection point. An inverter device comprising: a third switching element.

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