JP2005328674A - Inverter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inverter device that can detect the seizure of a switchgear at an early stage. <P>SOLUTION: The inverter device 8 comprising a parallel circuit of a charging circuit 7 and a switch 2 connected between a battery 1 and an inverter module 35 is provided with capacitors 30... charged by the battery 1 via a charging circuit 7; resistors 31... for discharging the capacitors 30; a series circuit composed of resistors 50, 51 that detects voltages of the post-stage of the switch 2; and a diode 70 that is connected between the connection point of the series circuit consisting of the resistors 50, 51 on a positive line 4 and the connection point of the capacitors 30, and in which the capacitor 30 side is arranged as the forward direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inverter device provided with a parallel circuit of a charging device and a switching device connected between a DC power source and an inverter.

  In recent years, an air conditioner equipped with an electric compressor driven by a battery power source has been developed as an air conditioner for an electric vehicle. As shown in FIG. 4, this air conditioner includes a battery (DC power supply) 101, an inverter device 108, and an electric compressor 110.

  The inverter device 108 includes a switch 102 as a switch device connected in series to the battery 101, a charging device 111 including a resistor 104 and a switch 103 connected in parallel with the switch 102, a switching element 114, It is composed of an inverter module 105 configured by molding a switching element group 112 made of a diode (not shown) for absorbing a switching surge in a molded package 115, and a capacitor 106. The switching element group 112 of the inverter module 105 is for converting the DC voltage from the battery 101 into a three-phase pseudo AC voltage and applying it to the electric compressor 110 to drive the motor of the electric compressor 110. .

The capacitor 106 is for stably supplying a voltage to the switching element group 112. The resistor 104 of the charging device 111 is for suppressing an inrush current flowing through the capacitor 106 when a DC voltage of the battery 101 is applied. That is, the presence of the resistor 104 opens the switch 102 when the battery 101 is connected, closes the switch 103, and causes a current to flow through the resistor 104, thereby causing an inrush that occurs when the voltage of the battery 101 is applied. Current can be suppressed (see, for example, Patent Document 1).
Japanese Patent No. 3341327

  By the way, in such an air conditioner, there is a possibility that the switch 102 may be welded and remain in a closed state in spite of a command to open the switch 102 by a control device (not shown). Therefore, conventionally, a voltage dividing resistor is provided before and after the switch 102, and the occurrence of welding of the switch 102 is confirmed by detecting a terminal voltage of the voltage dividing resistor. That is, the plus line 116 and the minus line 118 at a position between the battery 101 in the front stage of the switch 102 and the plus line 116 at the position between the switching element group 112 in the rear stage of the switch 102 and the minus of the battery 101. A voltage detection circuit is connected between the lines 118, and a voltage detected by each voltage detection circuit is input to the controller.

  Here, when the battery 101 is connected, the voltage input to the controller from the voltage detection circuit in the previous stage of the switch 102 is substantially the voltage of the battery 101 regardless of the open / close state of the switch 102. When the switch 102 is open, the voltage from the voltage detection circuit at the subsequent stage of the switch 102 input to the controller becomes zero, and when the switch 102 is closed, the voltage is almost on the front side of the switch 102. It is the same as the voltage from the voltage detection circuit (there is some voltage drop). Thereby, the open / close state of the switch 102 can be detected from the voltage of the voltage detection circuit before and after the switch 102 input to the controller. Therefore, it is possible to determine the state in which the switch 102 is closed despite the control of opening the switch 102 by the controller, that is, so-called welding of the switch 102.

  However, as described above, the inverter device 108 is provided with the large-capacity capacitor 106, and the measured voltage does not decrease immediately due to the discharge voltage of the capacitor 106. Therefore, the welding of the switch 102 cannot be detected at an early stage. It was.

  The present invention has been made to solve the problems of the related art, and an object of the present invention is to provide an inverter device that can detect welding of a switchgear at an early stage.

  An inverter device according to the present invention includes a parallel circuit of a charging device and a switching device connected between a DC power source and an inverter, the capacitor being charged from the DC power source through the charging device, and the capacitor A discharge resistor, a voltage detection circuit for detecting a voltage at the latter stage of the switchgear, and a diode connected between the voltage detection circuit and the capacitor and having the capacitor side in the forward direction are provided.

  According to a second aspect of the present invention, there is provided an inverter device comprising a control device for judging the welding of the switchgear based on the voltage detected by the voltage detection circuit in the above invention.

  In the inverter device according to a third aspect of the present invention, in the second aspect of the invention, the control device compares the voltage at the previous stage of the switchgear with the voltage detected by the voltage detection circuit, and when the difference is within a predetermined range It is determined that the apparatus is welded.

  In the present invention, an inverter device including a parallel circuit of a charging device and a switching device connected between a DC power source and an inverter, the capacitor being charged from the DC power source through the charging device, and for discharging the capacitor The capacitor includes a resistor, a voltage detection circuit that detects a voltage at the latter stage of the switching device, and a diode that is connected between the voltage detection circuit and the capacitor and that has a forward direction on the capacitor side. Even before the discharge is completed, the voltage value of the voltage detection circuit decreases instantaneously if the switchgear is normally broken.

  On the other hand, when the switchgear is welded, the voltage of the voltage detection circuit does not decrease.

  Therefore, for example, based on the voltage detected by the voltage detection circuit as in claim 2, the voltage at the front stage of the switchgear is compared with the voltage detected by the voltage detection circuit as in claim 3, and the difference is within a predetermined range. In some cases, it is possible to determine the welding at an early stage by determining the welding of the switchgear.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a power circuit diagram of an embodiment of an air conditioner for an electric vehicle provided with an inverter device 8 of the present invention.

  In FIG. 1, reference numeral 1 denotes a main battery as a DC power source of an electric vehicle, which supplies electric power to an electric compressor 10 of an air conditioner through an inverter device 8 of the present invention. A direct current voltage is output from the battery 1, and the electric compressor 10 (motor) is supplied with a voltage converted into a three-phase pseudo alternating current by an inverter module 35 (an inverter in the present invention) of an inverter device 8 described later. The

  The inverter device 8 described above includes a switch 2 as a switch device, a charging circuit 7 as a charging device, four capacitors 30..., Discharging resistors 31 and 31, an inverter module 35, and the like.

  The inverter module 35 is provided with a switching element group 12 for converting a voltage into a three-phase pseudo alternating voltage by switching in a molded package 40. The switching element group 12 includes a switching element 14 and a diode (not shown) for absorbing a switching surge, and is connected between the plus line 4 (for example, about DC + 350V) and the minus line 6 of the battery 1.

  The switch 2 is connected to a plus line 4 between the battery 1 and the switching element group 12. The capacitors 30... Are for stably supplying a voltage to the switching element group 12, and are connected in parallel between the plus line 4 and the minus line 6 between the switch 2 and the switching element group 12. . Each capacitor 30 is charged with electric charge from the battery 1 via a charging circuit 7 described later. The discharging resistors 31 and 31 are discharging resistors for discharging the electric charges charged in the capacitors 30... Between the plus line 4 and the minus line 6 between the capacitors 30 and the switching element group 12. Connected to.

  The above-described charging circuit 7 includes a series circuit of the switch 3 and the positive temperature coefficient thermistor 18 and is connected to the switch 2 in parallel. The charging circuit 7 is for suppressing the inrush current flowing in each capacitor 30... And the inrush voltage generated in each capacitor 30.

  On the other hand, the inverter device 8 is provided with voltage dividing resistors 50, 51, 52, 53 for detecting the voltage before and after the switch 2. That is, a series circuit (voltage detection circuit) of resistors 50 and 51 is connected between the plus line 4 at a position between the switch 30 and the rear stage capacitors 30 and the minus line 6 of the battery 1.

  Further, a series circuit (voltage detection circuit) of resistors 52 and 53 is connected between the plus line 4 and the minus line 6 at a position between the battery 1 and the preceding stage of the switch 2. The resistors 50 and 51 are for detecting the voltage at the rear stage of the switch 2, and the resistors 52 and 53 are for detecting the voltage at the front stage of the switch 2.

  In the embodiment, the resistors 50 and 52 have the same resistance value, and similarly, the resistors 51 and 53 have the same resistance value. The resistance values of the resistors 50 and 52 are sufficiently larger than the resistors 51 and 53 connected to the negative line 6 side. Then, the terminal voltages of the resistors 51 and 53 are input to the controller 60. The controller 60 is a control device for the inverter device 8 and controls opening and closing of the switch 2 and the switch 3. Further, the controller 60 determines the welding of the switch 2 based on the terminal voltages of the resistor 51 and the resistor 53 as will be described later.

  In the inverter device 8 of the present invention, a diode 70 is provided in the plus line 4 between the series circuit (voltage detection circuit) of the resistors 50 and 51 and the capacitors 30. That is, the diode 70 is a plus line between the connection point of the resistor 50 and the resistor 51 and the connection point of the capacitor 30 (the capacitor 30 provided on the leftmost side in FIG. 1) installed on the circuit closest to the switch 2. 4 and the capacitor 30... Side is in the forward direction.

  The mold package 40 is provided with pins 20 for connecting the switching element group 12 in the mold package 40 to the battery 1, the switch 2, the electric compressor 10, etc. outside the mold package 40. . With the pins 20..., Devices inside and outside the mold package 40 can be connected without hindrance.

  Next, the operation of the inverter device 8 of the present invention having the above configuration will be described with reference to FIGS. Here, FIG. 2 is a flowchart for explaining the control relating to the welding detection operation of the switch 2 by the controller 60 of the inverter device 8, and FIG. 3 is a timing chart for explaining the operations of the switch 2, the switch 3 and the electric compressor 10. It is. It is assumed that the controller 60 controls the switches 2 and 3 in a state where the electric vehicle is not activated.

  When the electric vehicle is activated in step S1 of FIG. 2 (ING (ignition) ON), the controller 60 receives an operation command signal from a controller of an air conditioner (not shown) provided in the vehicle interior in step S2. Judge whether or not. Now, if the temperature in the passenger compartment is higher than the set value and an operation command signal is input to the controller 60 from the controller of the air conditioner, the controller 60 sets the terminal voltage of the resistor 53 in the previous stage of the switch 2 in step S3. Based on this, it is determined whether or not the voltage V1 of the positive line 4 in the preceding stage of the switch 2 is higher than + 250V and lower than + 400V. At this time, when the voltage of the battery 1 is normal, the voltage V1 of the plus line 4 in front of the switch 2 input to the controller 60 is substantially the same as the voltage of the battery 1 (regardless of the open / close state of the switch 2). + 350V). Therefore, when the voltage V1 input to the controller 60 is + 250V or lower or + 400V or higher, it is determined that the voltage of the battery 1 is abnormal, and the controller 60 proceeds to step S7 and outputs a control output to the inverter device 8. Is stopped and a predetermined alarm operation is performed.

  On the other hand, when the voltage V1 of the plus line 4 in the preceding stage of the switch 2 input to the controller 60 in step S3 in FIG. 2 is higher than 250V and lower than 400V, the voltage of the battery 1 is determined to be normal, and the controller 60 It progresses to step S4 and it is determined whether the voltage V2 of the plus line 4 of the back | latter stage of the switch 2 detected based on the terminal voltage of the resistance 51 of the back | latter stage of the switch 2 is higher than V1-10V. Here, at this time, the controller 60 controls to break the switch 2 and the switch 3. Further, since the diode 70 has a forward direction on the capacitor 30..., Even if the capacitor 30... Has a charge, if the switch 2 and the switch 3 are in a normal state, the switch 2. The voltage V2 of the subsequent plus line 4 becomes zero. Accordingly, when the voltage V2 is higher than the voltage V1-10V (10V is foreseeing the voltage drop of the circuit) before the control for closing the switch 2 and the switch 3 is performed, the switch 2 or the switch It can be determined that 3 is welded and closed.

  That is, the controller 60 compares the voltage V1 of the plus line 4 before the switch 2 with the voltage V2 of the plus line 4 after the switch 2, and the difference (V1−V2) is within a predetermined range (in the embodiment). If it is within the range of less than 10V, it is determined that the switch 2 or the switch 3 is welded and closed, the process proceeds to step S5, the control output to the inverter device 8 is stopped, and a predetermined alarm is given. Thereby, since the switching element 14 is not turned on, the motor of the compressor 10 is not energized.

  On the other hand, when the switch 2 and the switch 3 are not welded and are open, the voltage V2 input to the controller 60 is zero as described above, so the difference (V1−V2) is 10V or more. . Therefore, when the value of the voltage V1-10V is equal to or higher than the voltage V2 in step S4, the controller 60 determines that the switch 2 and the switch 3 are not welded and proceeds from step S4 to step S6. Then, the control of FIG. 3 is started.

  That is, the controller 60 first closes the switch 3 while the switch 2 is open (the switch 2 is broken), and the current from the battery 1 is passed through the positive temperature coefficient thermistor 18 and the diode 70. Flow through capacitors 30 and charge them. Since the positive temperature coefficient thermistor 18 increases its resistance by self-heating, it functions to suppress the resistance of the flowing current value. Thereby, inrush current can be suppressed and the capacitors 30... Can be protected.

  Next, the controller 60 closes the switch 2 at the timing when the charging of the capacitors 30... Is completed (in this embodiment, 3 seconds after closing the switch 3), and then (in this embodiment, the switch 2. 1 second after closing), after opening the switch 3 of the charging circuit 7, the voltage of the battery 1 is applied to the switching element group 12 via the switch 2. Further, the controller 60 controls ON / OFF of the switching element 14 of the switching element group 12 to generate a three-phase pseudo AC voltage having a predetermined frequency, and applies it to the motor of the electric compressor 10 to drive the motor at the above operating frequency. To do.

  When an operation stop signal is input from the controller of the air conditioner, after the switch operation of the switching element 14 of the switching element group 12 is stopped, the controller 60 opens (breaks) the switch 2 to switch the switching element group. The power supply to 12 is stopped, and the operation of the electric compressor 10 is stopped. The charging charges of the capacitors 30 are discharged by the discharging resistors 31 and 31 with a predetermined time constant. However, if the switch 2 and the switch 3 are open, the voltage of the battery 1 is not applied. Due to the presence of the diode 70, the voltage V2 of the plus line 4 subsequent to the switch 2 falls to zero at the moment when the switch 2 is opened.

  Here, immediately after opening the switch 2, the controller 60 compares the voltage V2 with the voltage V1, and the voltage V2 becomes higher than the voltage V1-10V (10V is in anticipation of a voltage drop in the circuit) as described above. Judge whether or not. When the difference (V1−V2) is within a predetermined range (a range smaller than 10V as described above), it is determined that the switch 2 or the switch 3 is welded and closed, and similarly to the inverter device 8 described above. The control output is stopped and a predetermined alarm is issued. As a result, the switching element 14 is not turned on, and the motor of the compressor 10 is not energized.

  By the way, even if the switch 2 is open in the past, the voltage V2 of the plus line 4 subsequent to the switch 2 becomes the charging voltage of the capacitor 30 and does not become zero until the capacitor 30 is completely discharged. That is, even if the switch 2 is opened, the voltage V2 becomes a high value until the electric charge charged in the capacitors 30 is completely discharged by the discharging resistors 31, 31, so that the switch 2 or the switch 3 is temporarily Even if it was welded, it could not be judged immediately from the voltage V2.

  On the other hand, the current does not flow in the reverse direction by installing the diode 70 whose forward direction is the capacitor 30... In the plus line 4 between the connection point of the resistor 50 and the connection point of the capacitor 30. Therefore, even before the capacitors 30 are completely discharged, the voltage V2 instantaneously becomes zero if the switch 2 is normally broken. Thus, even before the capacitor 30 is completely discharged, the open / close state of the switch 2 can be detected by comparing the voltage V1 and the voltage V2 as described above. It becomes possible to determine the welding of the vessel 3 at an early stage.

  In addition, when the battery 1 is reversely connected due to the diode 70, the capacitor 30, the switching element group 12, or the like is damaged, or when a person touches the terminal on the battery 1 side, It is possible to prevent inconvenience of electric shock. As a result, the safety and reliability of the inverter device 8 can be improved.

  In the embodiment, the switch 3 is provided in the charging circuit 7. However, the present invention is not limited to this, and the switch is provided in the plus line 4 immediately after the battery 1 (before the switch 2) without being provided in the charging circuit 7. Also good. Moreover, each numerical value shown in the embodiment is not limited thereto.

It is an electric circuit diagram of one Example of the air conditioner for electric vehicles provided with the inverter apparatus of this invention. It is a control flowchart of the controller of the inverter apparatus of this invention. It is a timing chart which shows operation | movement of the switch of the inverter apparatus of this invention, and an electric compressor. It is an electric circuit diagram of the air-conditioner for electric vehicles provided with the conventional inverter apparatus.

Explanation of symbols

1 Battery 2 Switch (switching device)
DESCRIPTION OF SYMBOLS 3 Switch 7 Charging circuit 8 Inverter apparatus 10 Electric compressor 12 Switching element group 14 Switching element 30 Capacitor 31, 50, 51, 52, 53 Resistance 35 Inverter module (inverter)
60 Controller 70 Diode

Claims (3)

An inverter device comprising a parallel circuit of a charging device and a switching device connected between a DC power source and an inverter,
A capacitor charged via the charging device from the DC power supply;
A resistor for discharging the capacitor;
A voltage detection circuit for detecting a voltage at a subsequent stage of the switchgear;
An inverter device comprising: a diode connected between the voltage detection circuit and the capacitor, the capacitor side being a forward direction.   2. The inverter device according to claim 1, further comprising a control device that determines welding of the switchgear based on a voltage detected by the voltage detection circuit.   The control device compares a voltage at a preceding stage of the switchgear with a voltage detected by the voltage detection circuit, and determines that the switchgear is welded when the difference is within a predetermined range. Item 2. The inverter device according to item 2.

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