JP2013255297A - Vehicular inverter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular inverter device that can quickly and easily perform circuit diagnosis and error communication just upon the application of a low voltage DC power supply.SOLUTION: An inverter circuit 10, a drive circuit 8 and a control circuit 6 are grounded together, an isolated DC power supply 40 is powered by a low voltage battery 12 and electrically isolated from the low voltage battery 12, the control circuit 6 is powered by the isolated DC power supply 40, and a DC voltage output of the isolated DC power supply 40 is connected to a positive line of a high voltage battery 1 via a switching element. This enables circuit diagnosis and error transmission quickly and easily just upon the application of the low voltage DC power supply.

Description

  The present invention relates to a vehicle inverter device including a high-voltage DC power supply and a low-voltage DC power supply that is electrically insulated from the high-voltage DC power supply.

  Generally, in an electric vehicle, a hybrid vehicle, a fuel cell vehicle, and the like, a motor is used as a driving power source, and an inverter device that drives the motor is mounted. This inverter device is supplied with power from a high voltage direct current power source of about 200V to 400V, that is, a high voltage battery. The high-voltage battery is also supplied with power to a DC converter, a power steering inverter device, an electric compressor inverter device, and the like.

  On the other hand, a low voltage direct current power source such as 12V or 24V, that is, a low voltage battery is also provided. This is used to supply power to lighting components such as lighting components, wipers, power windows, car navigation systems, car audios, controller for driving inverters, fan motors, and air conditioning control units for inverters for electric compressors. Is done. The negative side of the low voltage battery is grounded to the vehicle body, but the high voltage battery is not grounded to the vehicle body. The power supply system of the low voltage battery and the power supply system of the high voltage battery are electrically insulated. Further, the energization timing of the power supply system by the key switch operation of the vehicle is energized by the power supply system of the high voltage battery after the power supply system of the low voltage battery is energized.

  An inverter device for an electric compressor using only a high voltage battery as a power source is known (for example, see Patent Document 1). This circuit will be described below.

  FIG. 6 shows an inverter device and its surrounding electric circuit. The control circuit 106 of the inverter device 120 controls the inverter circuit 10 based on the rotational speed command signal from the air conditioning control unit 51, the position information of the magnet rotor 5 constituting the sensorless DC brushless motor 11 (hereinafter referred to as a motor), and the like. An AC current is output to the motor 11 by controlling the switching element 2 (IGBT, FET, transistor, etc.) to be configured and switching the DC voltage from the high voltage battery 1. The position is detected by the induced voltage generated in the stator winding 4 by the magnet rotor 5. The diode 3 constituting the inverter circuit 10 serves as a return route for the current flowing through the stator winding 4. For the switching element 2, the upper arm switching element is defined as U, V, W, and the lower arm switching element is defined as X, Y, Z.

  The capacitor 19 is a smoothing capacitor that smoothes the current to the inverter circuit 10. The switching power supply 140 converts the high voltage battery 1 into a DC voltage of about 20V using the power supply as a power supply, and outputs it to the drive circuit 8, the 5V power supply 14 and the like that drive the switching element 2 of the inverter circuit 10. The DC voltage 5V, which is the output of the 5V power supply 14, is supplied to the control circuit 106. The drive circuit 8 is realized by a charge pump circuit or the like.

  The inverter circuit 10, the drive circuit 8, and the control circuit 106 are connected to a common ground. Therefore, the control circuit 106 can directly control the drive circuit 8. Further, a voltage signal, a current signal and the like related to the inverter circuit 10 can be input to the control circuit 106 as a continuous analog signal. Communication between the control circuit 106 serving as the power supply system of the high-voltage battery 1 and the air conditioning control unit 51 serving as the power supply system of the low-voltage battery 12 requires electrical insulation. This is done via the coupler 16. The boundary between the power supply system of the high voltage battery 1 and the power supply system of the low voltage battery 12 is indicated by a dotted line.

  As for the energization of the power source, the switch 13 is first turned ON by the key switch operation of the vehicle, and the power source system of the low voltage battery 12 is energized. Thereby, the air-conditioning control part 51 becomes operable. Car navigation, car audio, etc. can also be activated. On the other hand, at this time, since the control circuit 106 is not supplied with power, it cannot communicate with the air conditioning control unit 51. In addition, circuit diagnosis cannot be performed.

  Further, by the next key switch operation, the switch 30 is turned ON, and the power supply system of the high voltage battery 1 is energized. As a result, the capacitor 19 is charged from the charge limiting resistor 31. The switching power supply 140 functions to supply power to the drive circuit 8 and the control circuit 106. After the charging is completed, the switch 32 is closed and the inverter circuit 10 can be operated.

  At this time, since the control circuit 106 is powered, a circuit diagnosis is performed. In addition, communication with the air conditioning control unit 51 is possible. When the control circuit 106 receives a command signal for operating the electric compressor from the air conditioning control unit 51, the control circuit 106 operates the motor 11 of the electric compressor via the drive circuit 8 and the inverter circuit 10. In addition, data of the inverter device 120 such as a voltage value, a current value, and a circuit diagnosis result is transmitted to the air conditioning control unit 51. These signals are indicated by arrows. The air conditioning control unit 51 notifies the user of a circuit diagnosis result or the like by an image, sound, or the like.

  As an example of circuit diagnosis, the upper arm switching element U and the lower arm switching element Y of different phases can be simultaneously turned on to check the presence or absence of current flowing in the U-phase and V-phase motors. Thereby, it is possible to diagnose whether or not the U-phase and V-phase are connected between the inverter circuit 10 and the motor 11.

  Although not shown, a circuit including the high voltage battery 1, the switch 30, the charge limiting resistor 31, and the switch 32 is connected to the inverter device 120 in parallel with a traveling inverter device, a DC converter, a power steering inverter device, and the like. ing.

JP 11-189032 A

  However, as described above, in an inverter device using only a high voltage battery as a power source, circuit diagnosis cannot be performed until the high voltage battery is energized. Moreover, it is in the state of the communication error which cannot communicate. Therefore, it is necessary to wait until the second time when the high voltage battery is energized after the first time when the low voltage battery is energized, and the key switch operation of the vehicle cannot be performed quickly due to waiting for the smoothing capacitor to be charged. In addition, if a circuit diagnosis is performed after the high-voltage battery is energized and a failure occurs as a result, it is necessary to wait for the charged smoothing capacitor to discharge, and it is not possible to immediately start inspection and repair.

  When performing circuit diagnosis on a single device that is not mounted on a vehicle, first, a low voltage battery for a controller such as an air conditioning control unit that is a means for notifying a circuit diagnosis result is required. In addition to this, a high-voltage battery must also be prepared. Low voltage batteries are easy to obtain and prepare, but high voltage batteries are not easy to get and prepare.

In circuit diagnosis based on the voltage of a high-voltage battery, the voltage is high, and the current increases greatly even when switching for a short time. Must be. So hard,
Complicated on both sides of the software.

  In addition, when a failure has occurred from the beginning, an excessive current flows through the charge limiting resistor on the vehicle side, and it is necessary to increase the power rating of the charging limiting resistor.

  The present invention solves such a conventional problem, and an object of the present invention is to provide a vehicle inverter device that can quickly and easily perform circuit diagnosis and error transmission only by energizing a low-voltage DC power supply.

  In order to solve the above-described conventional problems, an inverter device for a vehicle according to the present invention includes an upper arm switching element connected to a plus side of a high-voltage DC power source and a lower arm switching element connected to a minus side, and switching is performed. An inverter circuit that outputs an alternating current to a load, a drive circuit that drives a switching element, a control circuit that controls the drive circuit, a smoothing capacitor connected to a high voltage DC power supply, and a voltage of the high voltage DC power supply are detected. A high voltage detection circuit, and an insulation communication means for electrically insulating and communicating between a device operated by a low voltage DC power supply and the control circuit, and the inverter circuit and the control circuit are connected to a common ground. An inverter device for a vehicle that uses a low-voltage DC power supply as a power supply and outputs a DC voltage that is electrically insulated from the low-voltage DC power supply. The control circuit is powered by the isolated DC power source, and the DC voltage output of the isolated DC power source is connected to the positive side line of the high voltage DC power source via a reverse blocking diode and a switching element, or a reverse voltage switching element. Connected.

  The vehicle inverter device of the present invention can perform circuit diagnosis and error communication quickly and easily only by energizing a low-voltage DC power supply.

The inverter apparatus for vehicles which concerns on Embodiment 1 of this invention, and the electric circuit figure of the periphery Output voltage diagram of DC voltage detection circuit according to embodiment 1 of the present invention Output voltage diagram of DC voltage detection circuit according to Embodiment 2 of the present invention Output voltage diagram of DC voltage detection circuit according to Embodiment 3 of the present invention Output voltage diagram of DC voltage detection circuit according to Embodiment 4 of the present invention Conventional vehicle inverter device and its peripheral electrical circuit diagram

  According to a first aspect of the present invention, there is provided an inverter circuit that includes an upper arm switching element connected to a plus side of a high-voltage DC power source and a lower arm switching element connected to a minus side, and outputs an alternating current to a load by switching, and the switching A drive circuit for driving an element; a control circuit for controlling the drive circuit; a smoothing capacitor connected to the high-voltage DC power supply; a high-voltage detection circuit for detecting a voltage of the smoothing capacitor; and the high-voltage DC power supply Is provided with an insulated communication means for electrically insulating and communicating with a device operated by a low-voltage DC power source that is electrically insulated, and the control circuit, and the inverter circuit and the control circuit are connected to a common ground. Inverter device for a vehicle, wherein the low voltage DC power supply is used as a power source and a DC voltage is electrically insulated from the low voltage DC power supply. And the control circuit and the high voltage detection circuit are powered from the isolated DC power supply, and the DC voltage output of the isolated DC power supply is connected to a reverse blocking diode on the plus line of the high voltage DC power supply. It is configured to be connected via a switching element or a reverse withstand voltage switching element.

  As a result, it is possible to provide a vehicle inverter device that can quickly and easily perform circuit diagnosis and error transmission only by energizing the low-voltage DC power supply.

  According to a second invention, in the first invention, the voltage of the smoothing capacitor is detected after a predetermined time by the output of the high voltage detection circuit, and the circuit is diagnosed by the value of the output and transmitted to the outside. Thus, it is possible to provide an inverter device for a vehicle that can quickly and easily perform circuit diagnosis and error transmission only by energizing a low-voltage DC power supply.

  According to a third invention, in the first or second invention, the smoothing capacitor is configured such that the switching element connected between the isolated DC power source and the plus side line of the high voltage DC power source is turned on and off in a predetermined pattern. Can be charged by the insulated DC power supply, and a vehicle inverter device can be provided that can quickly and easily perform circuit diagnosis and error transmission only by energizing the low-voltage DC power supply.

  According to a fourth invention, in the first to third inventions, the voltage of the smoothing capacitor is detected after a predetermined time based on the output of the high voltage detection circuit, and the circuit is diagnosed based on the value of the output. The control circuit is configured to conduct the upper arm switching element and the lower arm switching element in a predetermined pattern via the driving circuit, and a short circuit that can flow when a high voltage is applied only by energizing a low voltage DC power supply. It is possible to provide a vehicle inverter device that can perform circuit diagnosis and error transmission safely, quickly and easily without a large current flowing.

  According to a fifth invention, in the first to fourth inventions, the voltage of the smoothing capacitor is detected after a predetermined time based on the output of the high voltage detection circuit, and the circuit is diagnosed based on the value of the output. The control circuit is configured such that the upper arm switching element and the lower arm switching element are simultaneously turned on and off via the driving circuit, and the high voltage can be obtained only by energizing the low voltage DC power supply. Therefore, it is possible to provide a vehicle inverter device that can perform circuit diagnosis and error transmission safely, quickly and easily without flowing a large current at the time of a short circuit that can flow when applied.

  According to a sixth invention, in the first to fourth inventions, the voltage of the smoothing capacitor is detected after a predetermined time from the output of the high voltage detection circuit, and the circuit is diagnosed by the value of the output. The control circuit is configured to electrically connect the upper arm switching element and the lower arm switching element for each element via the drive circuit, and a short circuit that can flow when a high voltage is applied only by energizing a low voltage DC power supply. Circuit diagnosis and error transmission can be performed safely, quickly and easily without a large current flowing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is an output voltage diagram of a DC voltage detection circuit according to the first embodiment, and FIG. In the following description, the same parts as those in the conventional example are denoted by the same reference numerals.

  In FIG. 1, the control circuit 6 of the inverter device 20 includes a rotational speed command signal from the air conditioning control unit 51, position information of the magnet rotor 5 constituting the DC brushless motor 11 (hereinafter referred to as a motor), Based on the output voltage of the DC voltage detection circuit 9 (high voltage detection circuit) that detects the voltage at both ends by dividing the resistance, the switching element 2 (IGBT, FET, transistor, etc.) constituting the inverter circuit 10 is controlled. Then, an alternating current is output to the motor 11 by switching the direct current voltage from the high voltage battery 1. The position is detected by the induced voltage generated in the stator winding 4 by the magnet rotor 5. The diode 3 constituting the inverter circuit 10 serves as a return route for the current flowing through the stator winding 4.

  For the switching element 2, the upper arm switching element is defined as U, V, W, and the lower arm switching element is defined as X, Y, Z.

  The capacitor 19 is a smoothing capacitor that smoothes the current to the inverter circuit 10. The insulation switching power supply 40 is an insulation DC power supply, converts the low voltage battery 12 to a DC voltage of about 20V using the low voltage battery 12 as a power supply, and outputs it to the drive circuit 8, 5V power supply 14 and the like that drive the switching element 2 of the inverter circuit 10. . The DC voltage 5V, which is the output of the 5V power supply 14, is supplied to the control circuit 6. The drive circuit 8 is realized by a charge pump circuit or the like.

  Here, the inverter circuit 10, the X, Y, Z drive unit of the drive circuit 8 and the control circuit 6 are connected in common to the ground. The U, V, and W driving units are charged by the charge pump circuit during X, Y, and Z operations. Thereby, the control circuit 6 can directly control the drive circuit 8.

  Further, a voltage signal, a current signal and the like related to the inverter circuit 10 can be input to the control circuit 6 as a continuous analog signal. Since communication between the control circuit 6 serving as the power supply system of the high voltage battery 1 and the air conditioning control unit 51 serving as the power supply system of the low voltage battery 12 requires electrical insulation, the photocoupler 15 and the photocoupler which are insulated communication means are required. This is done via the coupler 16.

  The boundary between the power supply system of the high voltage battery 1 and the power supply system of the low voltage battery 12 is indicated by a dotted line. As for the energization of the power source, the switch 13 is first turned ON by the key switch operation of the vehicle, and the power source system of the low voltage battery 12 is energized. Thereby, the air-conditioning control part 51 becomes operable. Further, for example, a car navigation system, a car audio system, etc. can be operated.

  At this time, since the power is supplied to the control circuit 6, the capacitor 19 is charged to about 20 V through the power supply diode 33 by turning on the power supply switching element 34.

  FIG. 2 shows the voltage during charging by the switching operation of the switching element 34 of the capacitor 19 and the output voltage of the DC voltage detection circuit 9. When there is a short circuit in the high voltage circuit connected in parallel to the high voltage battery 1 such as the inverter circuit 10 and the capacitor 19, the load of the 20V power supply is short-circuited. Therefore, the output of the DC voltage detection circuit 9 also decreases in proportion.

  Alternatively, when there is a pseudo short circuit having an indefinite resistance value in the high voltage circuit, the current continues to flow from the capacitor 19 to the pseudo short circuit part. As a result, the DC voltage detection circuit is set at the determination timing set after a certain charging time. The output of 9 falls below a predetermined threshold set outside the normal voltage range. The threshold value can be set in advance from the capacitance of the capacitor 19, the output voltage of the insulating switching power supply 40, and the assumed pseudo short-circuit resistance value.

  In both cases, since the output of the DC voltage detection circuit 9 is below a predetermined threshold set outside the normal voltage range, it is possible to diagnose a circuit short circuit or a pseudo short circuit by determining that the circuit is abnormal. An error can be transmitted from the circuit 6 to the air conditioning control unit 51.

  If there is an error as a result, it is the first key switch operation, and it can be detected quickly in a short time. Even when a circuit connected in parallel to the high voltage battery 1 is short-circuited or pseudo-short-circuited, an error can be detected without causing an excessive current to flow through the high-voltage battery 1 or the charge limiting resistor 31. Further, in the case of a pseudo short circuit, an error can be detected without causing a current that takes time to blow a fuse provided at the output of the high-voltage battery 1 on the vehicle side to flow instantaneously.

  Further, when an upper limit such as a rated voltage of a component to be used is provided for the 20 V output voltage, this can also be determined by providing an upper limit for the normality determination value of the output of the DC voltage detection circuit 9.

  If there is no abnormality in the circuit, the switch 30 is turned on by the next key switch operation, and the power supply system of the high voltage battery 1 is energized. As a result, the capacitor 19 is charged from the charge limiting resistor 31, and the capacitor 19 is charged from 20 V to the voltage of the high voltage battery 1.

  Since the voltage of the high voltage battery 1 is higher than the output voltage of the insulating switching power supply 40, the power supply diode 33 is turned off. Then, the switch 32 is closed after the charging is completed.

  Here, when receiving the command signal for operating the electric compressor from the air conditioning control unit 51, the control circuit 6 operates the motor 11 of the electric compressor via the drive circuit 8 and the inverter circuit 10.

  In addition, data such as the voltage, current, and diagnosis result of the inverter device 20 is transmitted to the air conditioning control unit 51.

  The circuit configuration is not limited to the above as long as power can be supplied to the capacitor 19 by the switching element 34 and the voltage can be detected and protected.

  With the above configuration, it is possible to provide a vehicular inverter device that can quickly and easily perform circuit diagnosis and error transmission only by energizing a low-voltage DC power supply.

(Embodiment 2)
A vehicle inverter device according to Embodiment 2 of the present invention will be described with reference to FIGS. The configuration is the same as that of the first embodiment and is as shown in FIG.

  In this embodiment as well, the switch 13 is first turned ON by the key switch operation of the vehicle, and the power supply system of the low voltage battery 12 is energized. Thereby, the air-conditioning control part 51 becomes operable. Further, for example, a car navigation system, a car audio system, etc. can be operated. At this time, since the power is supplied to the control circuit 6, the capacitor 19 is charged to about 20 V through the power supply diode 33 by turning on the power supply switching element 34.

  FIG. 3 shows a voltage waveform during charging when the switching element 34 of the capacitor 19 is opened and closed at a predetermined time ratio.

  When the high voltage circuit connected in parallel to the high voltage battery 1 such as the capacitor 19 is short-circuited or pseudo short-circuited when charged at a time ratio of 100% as in the first embodiment, the load of the 20V power supply is excessive. If the power that can be output from the insulated switching power supply 40 is exceeded, the power supply voltage of the control circuit 6 may decrease. However, by switching the switching element 34 at a predetermined time ratio, The impact can be reduced.

  In addition, if a limiting resistor for charging current is added in series with the switching element 34, the time required for charging increases, while the power supply voltage drop due to overload can be reduced.

Further, although the current that flows when the voltage of the capacitor 19 is low increases, the current value that flows per ON can be reduced by gradually increasing the time ratio for turning on the switching element 34 from, for example, 1%. Therefore, the same effect can be obtained.

  The determination threshold and the duty ratio are not limited to the above values, and other operations are the same as those in the first embodiment. With the above configuration, it is possible to provide a vehicular inverter device that can quickly and easily perform circuit diagnosis and error transmission only by energizing a low-voltage DC power supply.

(Embodiment 3)
A vehicle inverter apparatus according to Embodiment 3 of the present invention will be described with reference to FIGS. The configuration is the same as that of the first embodiment and is as shown in FIG.

  Similarly to the second embodiment, the control circuit 6 is supplied with power by operating the key switch of the vehicle, and the power supply switching element 34 is turned on at a predetermined time ratio, so that the capacitor 19 is set to about 20 V through the power supply diode 33. Charge until.

  When it is determined that there is no abnormality such as a short circuit or a pseudo short circuit in the circuit, the switching element 34 is set to an on-time ratio of 100%, and then the upper arm drive circuit power supply of the drive circuit 8 is charged by the charge pump circuit.

  The on-time ratio of the switching element 34 may be an on-time at a time ratio in which the voltage ripple due to the influence of the output current and the input current is in a voltage range in which there is no problem.

  Then, by turning on a predetermined pattern, for example, a predetermined time U, V, W, and turning off X, Y, Z, if one phase of X, Y, Z is short-circuited, U, V , W, a short-circuit current flows, and the output of the DC voltage detection circuit 9 decreases. Or, by turning on X, Y and Z for a predetermined time and turning off U, V and W, if one phase of U, V and W is short-circuited, a short-circuit current flows and DC Since the output of the voltage detection circuit 9 is reduced, a failure diagnosis can be performed with the output of the DC voltage detection circuit 9 after a predetermined time. The predetermined time may be calculated and set from the pseudo short-circuit resistance value assumed for the capacitor 19.

  In the failure diagnosis of each phase, when the drive control of the motor 11 is performed by detecting the current of the inverter circuit 10, the short-circuit current can also be detected by monitoring this current.

  By doing this, it is possible to diagnose a failure of one of the upper and lower arms of the switching element, which could not be diagnosed only by energizing the capacitor 19.

  Other operations are the same as those in the first embodiment.

  The above configuration provides a vehicle inverter device that can safely, quickly and easily perform circuit diagnosis and error transmission without flowing a large current at the time of a short circuit that can flow when a high voltage is applied simply by energizing a low-voltage DC power supply. Is something that can be done.

(Embodiment 4)
A vehicle inverter device according to a fourth embodiment of the present invention will be described with reference to FIGS. The configuration is the same as that of the first embodiment and is as shown in FIG.

  As in the second embodiment, the control circuit 6 is powered by the key switch operation of the vehicle, and the power supply switching element 34 is turned on at a predetermined time ratio to charge the capacitor 19 to about 20 V through the power supply diode 33. To do.

  When it is determined that there is no abnormality such as a short circuit or a pseudo short circuit in the circuit, the switching element 34 is set to an on-time ratio of 100%, and then the upper arm drive circuit power supply of the drive circuit 8 is charged by the charge pump circuit.

  The on-time ratio of the switching element 34 may be an on-time at a time ratio in which the voltage ripple due to the influence of the output current and the input current is in a voltage range in which there is no problem.

  Thereafter, by turning on each of U, V, W, X, Y, and Z in order, for example, when the output of the DC voltage detection circuit 9 is lowered after a predetermined time when U is turned on, X has failed. In this way, it is possible to determine which phase is short-circuited.

  The predetermined time may be calculated and set from the pseudo short-circuit resistance value assumed for the capacitor 19. Other operations are the same as those in the third embodiment.

  The above configuration provides a vehicle inverter device that can safely, quickly and easily perform circuit diagnosis and error transmission without flowing a large current at the time of a short circuit that can flow when a high voltage is applied simply by energizing a low-voltage DC power supply. Is something that can be done.

  Each of the above embodiments is shown as an optimum example, and various developments are possible as long as the effects of the present invention are achieved. For example, the reverse blocking diode 33 and the switching element 34 may be composed of a reverse withstand voltage switching element or the like.

  INDUSTRIAL APPLICABILITY The present invention can quickly and easily perform circuit diagnosis and error communication only by energizing a low-voltage DC power supply, and can be applied to inverter devices for various vehicles including electric vehicles and hybrid vehicles.

1 High voltage battery (High voltage DC power supply)
2 switching element 3 diode 4 stator winding 5 magnet rotor 6 control circuit 8 drive circuit 9 DC voltage detection circuit (high voltage detection circuit)
10 Inverter circuit 11 DC brushless motor 12 Low voltage battery (low voltage DC power supply)
13 Switch 14 5V power supply 15, 16 Photocoupler for communication (insulated communication means)
19 Capacitor (smoothing capacitor)
20 Inverter device 30 Switch 31 Charge limiting resistor 32 Switch 33 Power supply diode (reverse blocking diode)
34 Switching elements for power supply (switching elements)
40 Insulated switching power supply (Insulated DC power supply)
51 Air Conditioning Control Unit 106 Control Circuit 120 Inverter Device 140 Switching Power Supply

Claims (6)

An inverter circuit that includes an upper arm switching element connected to the plus side of a high-voltage DC power source and a lower arm switching element connected to the minus side, and outputs an alternating current to a load by switching, and a drive circuit that drives the switching element And a control circuit that controls the drive circuit, a smoothing capacitor connected to the high-voltage DC power supply, a high-voltage detection circuit that detects the voltage of the smoothing capacitor, and the high-voltage DC power supply are electrically insulated. An inverter device for a vehicle having an insulation communication means for electrically insulating and communicating between a device operated by a low-voltage direct current power supply and a control circuit, wherein the inverter circuit and the control circuit are connected to a common ground. Insulating direct current that outputs a DC voltage that is electrically insulated from the low-voltage DC power source using the low-voltage DC power source as a power source. A power supply, wherein the control circuit and the high voltage detection circuit are powered from the isolated DC power supply, and the DC voltage output of the isolated DC power supply is connected to a reverse blocking diode and a switching element on the plus line of the high voltage DC power supply, or A vehicle inverter device connected via a reverse withstand voltage switching element. 2. The vehicle inverter device according to claim 1, wherein the voltage of the smoothing capacitor is detected after a predetermined time by the output of the high voltage detection circuit, the circuit is diagnosed by the value of the output and transmitted to the outside. 3. The smoothing capacitor is charged by the insulated DC power source by switching ON / OFF a switching element connected between the plus side line of the insulated DC power source and the high voltage DC power source in a predetermined pattern. The vehicle inverter device described. The voltage of the smoothing capacitor is detected after a predetermined time by the output of the high voltage detection circuit, and the circuit is diagnosed by the value of the output, and then the control circuit detects the upper arm switching element and the lower arm switching element through the drive circuit. The vehicle inverter device according to any one of claims 1 to 3, wherein the vehicle inverter device is electrically connected in a predetermined pattern. The voltage of the smoothing capacitor is detected after a predetermined time by the output of the high voltage detection circuit, and the circuit is diagnosed by the value of the output, and then the control circuit detects the upper arm switching element and the lower arm switching element through the drive circuit. 5. The vehicle inverter device according to claim 1, wherein the upper three phases and the lower three phases are simultaneously turned on and off, respectively. The voltage of the smoothing capacitor is detected after a predetermined time by the output of the high voltage detection circuit, and the circuit is diagnosed by the value of the output, and then the control circuit is connected to the upper arm switching element and the lower arm switching element via the drive circuit. 5. The vehicle inverter device according to claim 1, wherein each element is electrically connected.