JP2013237340A - Inverter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a charging resistance disposed outside an inverter from being damaged when an upper/lower switching element as an inverter driving circuit element is in a pseud short-circuited state.SOLUTION: An inverter device includes: an inverter circuit 4 comprising a current power supply, a power distribution means serially connected to a direct current generation means, and a driving element for performing an output to a motor 5 by the power distribution of PWM modulation from a direct current power supply, and a current detection means 17 for detecting a current between the direct current power supply and the inverter circuit 4. In the inverter device, a circuit failure determination means 18 communicates with the outside to notify a circuit failure the inverter device when an output of the inverter circuit 4 is stopped and an output of the current detection means 17 is larger than a current value when an output to the motor 5 is stopped, and is a second specific value or larger which is set within a range of a specific value or lower which protects the driving element of the inverter circuit 4.

Description

  The present invention relates to an inverter device that drives an electric compressor for air conditioning from DC power, and more particularly to inverter circuit abnormality processing.

  Conventionally, in an inverter device that drives an electric compressor for air conditioning with DC power, the inverter device that drives the electric compressor for air conditioning supplies a large current to the electric compressor. Moreover, it is known that a voltage surge occurs due to a large current fluctuation (see, for example, Patent Document 1). Therefore, as shown in the current waveform diagram of the electric compressor driving device in FIG. 6, it is necessary to smooth the current supplied from the battery with a capacitor to suppress electrical noise and current fluctuation.

  Therefore, as shown in the circuit diagram of the conventional inverter device in FIG. 5, a current is passed between the high-voltage battery 1 that is a DC power source and the inverter circuit 4 that is configured by a drive element such as an IGBT of the inverter device 20. A capacitor 3 having a large capacitance is provided for smoothing. Here, in a drive element such as a normal IGBT, an upper arm drive element connected to the plus side of a DC power source and a lower arm drive element connected to the minus side are connected in series. Current detection means 17 is provided between the capacitor 3 and the inverter circuit 4, and the inverter control circuit 13 performs PWM output to the inverter circuit based on the current signal of the current detection means 17 and is connected to the inverter circuit 4. The motor 5 is driven.

  Since the overcurrent protection circuit 14 protects the drive elements constituting the inverter circuit 4 from overcurrent, if the determination value set to a value lower than the absolute rated current value of the drive elements of the inverter circuit 4 is exceeded, the output of the inverter circuit 4 A signal that shuts off is output. A fuse 6 for circuit protection is connected in series at a connection intermediate portion between the high voltage battery 1 and the inverter circuit 4. An energizing means 21 is provided between the fuse 6 and the inverter device 20, a charging resistor 9 for charging the main power relay 16 and the capacitor 3, a voltage detection circuit 15 for detecting the charging voltage of the capacitor 3, and a high voltage battery. A charge control circuit 10 for controlling the relay 8, the main power supply relay 16, and the relay 8 for supplying power from 1 to the inverter circuit 4 is provided. The diode 12 is provided so that the capacitor 3 is not charged and the circuit is not damaged when the high voltage battery 1 that is a DC power supply is connected in reverse polarity. The relay 8 is closed by the charge control circuit 10 after the voltage detection circuit 15 confirms the completion of charging of the capacitor 3. A state of charging the capacitor 3 will be described with reference to FIG.

  The charging voltage of the capacitor is charged through the charging resistor 9, and when the voltage exceeds A by the voltage detection circuit 15 at time t1, the charging control circuit 10 closes the contact of the relay 8, so the charging voltage of the capacitor 3 is high. It becomes the voltage Vbat of the voltage battery 1.

JP-A-9-109667

However, in the conventional configuration, when both the upper arm driving element and the lower arm driving element of the inverter circuit 4 are in a short-circuit state having a certain resistance value, the overcurrent protection circuit 14 is used as the driving element of the inverter circuit 4. If a current having a current value lower than the judgment value set to a value lower than the absolute rated current flows, the overcurrent protection circuit 14 cannot judge and an abnormality cannot be judged. Further, as shown in FIG. 8, since the driving element has a resistance, when the charging voltage is divided by the charging resistance and the resistance of the driving element and the charging voltage does not exceed A, the charging current continues to flow through the charging resistance, It was sometimes damaged.

  In order to solve the above-described problems, an inverter device according to the present invention includes a DC power supply, energization means connected in series with DC voltage generation means, and a drive element that outputs the DC power from the DC power supply to the motor by energization of PWM modulation. And an inverter device comprising a current detection means for detecting a current between the DC power source and the inverter circuit, the output of the inverter circuit is in a stopped state, and the output of the current detection means is If the current value is larger than the current value when the output to the motor is stopped and is equal to or greater than a second predetermined value set in a range equal to or smaller than a predetermined value that protects the drive element of the inverter circuit, the inverter device circuit is abnormal. Is provided with a circuit abnormality determination means for transmitting to the outside by communication.

  As a result, even when a failure having a certain resistance value occurs in both the upper arm driving element and the lower arm driving element of the inverter circuit, the abnormality of the inverter circuit can be determined by the circuit abnormality determining means. As a result, an abnormality can be transmitted to the outside of the inverter device, and the abnormality can be detected by a system outside the inverter device, so that the relay can be opened to prevent damage to the charging resistor.

  The inverter device according to the present invention can determine an abnormality in the inverter circuit even when a failure having a certain resistance value occurs in both the upper arm drive element and the lower arm drive element of the inverter circuit. The abnormality can be transmitted to the outside of the inverter, and the abnormality can be detected and dealt with by the system outside the inverter device, so that the charging resistance can be prevented from being damaged.

The inverter apparatus which concerns on Embodiment 1 of this invention, and its surrounding electric circuit diagram The flowchart which shows the operation example of the circuit abnormality determination means of the inverter apparatus Time chart showing the stop state of the inverter circuit of the inverter device The inverter apparatus which concerns on Embodiment 2 of this invention, and its surrounding electric circuit diagram Conventional inverter device and peripheral electrical circuit diagram Current waveform diagram for conventional inverter Time chart showing how a capacitor of a conventional inverter device is charged Time chart showing how a capacitor of an inverter device is charged when a conventional inverter circuit fails

According to a first aspect of the present invention, there is provided a DC power source, an energizing unit connected in series to a DC voltage generating unit, an inverter circuit configured to output from the DC power source to a motor by energization of PWM modulation, and the DC power source And a current detection means for detecting a current between the inverter circuits, the output of the inverter circuit is in a stopped state, and the output of the current detection means is a current when output to the motor is stopped. A circuit that communicates to the outside that the circuit of the inverter device is abnormal when greater than a second predetermined value that is greater than the value and set to a range equal to or less than a predetermined value that protects the drive element of the inverter circuit An abnormality determining means is provided. As a result, even if a failure having a certain resistance value occurs in both the upper arm drive element and the lower arm drive element of the inverter circuit, the abnormality of the inverter circuit can be determined. Since the abnormality can be detected and dealt with by the system outside the inverter device, the charging resistance can be prevented from being damaged.

  According to a second aspect, in the inverter device according to the first aspect, the energization means receives a signal from the circuit abnormality determination means, and interrupts the energization to the inverter apparatus. Thereby, since it has the function which interrupted | blocks the electricity supply to an inverter apparatus to an electricity supply means, it can anticipate that it can implement | achieve cheaply.

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

(Embodiment 1)
FIG. 1 is an electric circuit diagram of the inverter device 20 according to the first embodiment of the present invention and its periphery. 5 differs from FIG. 5 in the background art in that a circuit abnormality determination unit 18 is added to the inverter device 20 and an external control circuit 22 that cuts off the main power relay 16 in response to a signal from the circuit abnormality determination unit 18. It is a point that is added. The other circuits are the same as those in FIG. 5, and the symbols and the like are applied as they are.

  FIG. 2 is an operation flowchart of the circuit abnormality determination means 18. It is determined whether the operating state of the inverter circuit is operating or stopped (step 1). Next, it is determined whether or not the signal from the current detection means 17 is equal to or greater than a second predetermined value (step 2). If the determination result in step 2 is Y, a circuit abnormality is transmitted to the outside (in this embodiment, the external control circuit 22) by communication. If the determination result in step 2 is N, the processing is terminated without performing any processing. Here, the stop time will be described with reference to FIG. The inverter circuit 4 uses a plurality of drive elements such as IGBTs, and means that all the drive elements are in an OFF state when stopped. At this time, the current flowing through the current detecting means 17 has a maximum leakage current of several tens of mA in the drive element.

  Next, the second predetermined value will be described. As described above, when the inverter circuit 4 is stopped, the drive elements constituting the inverter circuit 4 flow as leakage currents at a maximum of about several tens of mA, so that the current detection means 17 outputs a detection value of about a maximum of several tens of mA. Has been. Therefore, the circuit abnormality determination means 18 sets a value larger than the above-mentioned several tens mA and lower than the absolute maximum rated current value of the drive element of the inverter circuit 4 as a determination value (= second predetermined value).

  Therefore, when the inverter circuit is stopped, if the current detected by the current detection means 17 is larger than the second predetermined value, it is determined that an abnormality has occurred in the inverter circuit 4, and an abnormality signal is communicated to the external control circuit 22. To output. When the external control circuit 22 receives an abnormality signal from the circuit abnormality determining means 18 by communication, it opens the main power supply relay 16 and cuts off the power supply to the energizing means 21 and the inverter device 20. Can be prevented.

(Embodiment 2)
FIG. 4 is an electric circuit diagram of the inverter device 20 and its surroundings in the second embodiment of the present invention. The difference from FIG. 1 in the first embodiment is that an output signal from the circuit abnormality determination unit 18 is output to the charging control circuit 10 of the energization unit 21. When the charging control circuit 10 receives the abnormality signal from the circuit abnormality determining means 18, the main power supply relay 16 is opened. Therefore, the energization to the energizing means 21 and the inverter device 20 is cut off, so that the charging resistance is the same as in the first embodiment. 9 can be prevented, and a protection system can be realized at low cost.

  As described above, in the inverter device according to the present invention, the output of the inverter circuit is in a stopped state, and the output of the current detection means is larger than the current value when the output to the motor is stopped. In the case of the second predetermined value or more set in the range of the predetermined value or less that protects the drive element, circuit abnormality determination means for transmitting to the outside that it is a circuit abnormality of the inverter device is provided. Applicable to various consumer products and automotive equipment.

DESCRIPTION OF SYMBOLS 1 High voltage battery 4 Inverter circuit 5 Motor 18 Circuit abnormality determination means 17 Current detection means 20 Inverter device 21 Energization means

Claims (2)

A DC power supply; a current-carrying means connected in series to a DC voltage generating means; an inverter circuit composed of a drive element that outputs the DC power from the DC power supply to a motor by energization of PWM modulation; and between the DC power supply and the inverter circuit In an inverter device comprising current detection means for detecting current, the output of the inverter circuit is in a stopped state, and the output of the current detection means is greater than the current value when output to the motor is stopped, Provided with circuit abnormality determination means for transmitting to the outside by communication that the inverter device has a circuit abnormality when it is greater than or equal to a second predetermined value set in a range of a predetermined value or less that protects the drive element of the inverter circuit An inverter device characterized by that. 2. The inverter device according to claim 1, wherein the energizing means receives a signal from the circuit abnormality determining means and interrupts energization to the inverter device.