JP2007060855A - Air conditioning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the malfunction of an electromagnetic contactor with a simple structure and welding of an inrush current restriction relay, and prevent abnormal heat generation of an inrush current restriction resistor. <P>SOLUTION: This air conditioning device includes a voltage detecting device 11 which detects DC terminal voltage of a capacitor 6, a first judgment device 40 having a first timer device 40a, and a second judgment device 41 having a second timer device 41a. The DC terminal voltage of the capacitor 6 is compared to the first prescribed voltage before switching on the inrush current restriction relay 15 to judge the welding of the inrush current restriction relay 15. Then the inrush current restriction relay 15 is switched off and the electromagnetic contactor 2 is switched on after charging the capacitor 6 to operate a compressor 8 with a restricted inverter control signal and to judge the malfunction of the electromagnetic contactor 2 by comparing the DC terminal voltage of the capacitor 6 to the second prescribed voltage, thus preventing abnormal heat generation of the inrush current restriction resistor 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for an air conditioner equipped with an inverter device for controlling the rotation speed of a compressor, and particularly to protection control of equipment having an inrush current prevention circuit.

  Conventionally, an inverter air conditioner control device including a converter that converts AC power into DC power is often provided with a capacitor that smoothes the DC power converted by the converter. There is an example in which an inrush current limiting resistor is used as a technique for suppressing the inrush current to the capacitor when the power is turned on (see, for example, Patent Document 1).

  FIG. 4 is a simplified circuit diagram of a conventional inverter air conditioner. 1 is a three-phase commercial AC power source, 2 is an electromagnetic contactor having three contacts, 3 is a converter circuit that converts AC power into DC power, and one end of the electromagnetic contactor 2 is connected to the commercial AC power source 1 and the other. Each end is connected to an AC input section of the converter circuit 3. Reference numeral 6 denotes a capacitor for smoothing the DC power output from the converter circuit 3. The positive side of the capacitor 6 is connected to the positive side of the converter circuit 3, and the negative side is connected to the negative side of the capacitor 6. Reference numeral 7 denotes an inverter circuit which inputs DC power smoothed by the capacitor 6, converts it into three-phase AC power, and outputs it to the compressor 8.

  9 is an operation command input unit for determining operation / stop of the compressor 8, 10 is inverter control means, 11 is voltage detection means for detecting the voltage across the capacitor 6, and 12 is relay drive means. , And signals S12 and S10 to the magnetic contactor 2 and the inrush current limiting relay 15 are output. An inverter base drive circuit 13 receives the signal S13 from the inverter control means 10 and outputs it to the inverter circuit 7. 14 is an inrush current limiting resistor, 15 is an inrush current limiting relay having two contacts 15a and 15b, 16 is a diode, one end of the inrush current limiting resistor 14 is in the R phase of the commercial AC power supply 1, and the other end is inrush. The current limiting relay 15 is connected to the common terminal of the contact 15a. The NO terminal of the contact 15 a of the inrush current limiting relay 15 is connected to the anode terminal of the diode 16. Further, the cathode terminal of the diode 16 is connected to the positive electrode side of the capacitor 6.

  The common terminal of the contact 15 b of the inrush current limiting relay 15 is connected to the S phase of the commercial AC power supply 1, and the NO terminal of the contact 15 b is connected to the S phase input part of the converter circuit 3. The inrush current limiting resistor 14, the inrush current limiting relay 15, and the diode 16 are collectively referred to as an inrush current limiting unit. Reference numeral 18 denotes an abnormality detection means that receives the output signal S11 of the voltage detection means 11 and the relay drive output S9 of the inverter control means 10 and detects an abnormality such as a failure of the inrush current limiting relay. Reference numeral 19 denotes an abnormality display means for notifying the user that there is an abnormality when the abnormality detection means 18 detects an abnormality.

  FIG. 5 is a detailed block diagram of the abnormality detection means 18 in FIG. In FIG. 5, 20 is a timer means, which sends a signal after counting for a certain time (t1) from when the relay drive signal S9 of the inverter control means 10 is turned on. Reference numeral 21 denotes a determination unit. When the voltage detection unit 11 does not detect a constant voltage when the timer unit 20 counts up (the signal S11 is in an off state), the determination unit 21 determines that there is an abnormality and outputs a signal S20. The judging means 21 is a circuit comprising an AND gate 21a and a flip-flop 21b, and sets the flip-flop 21b when a signal from the voltage detecting means 11 is not sent when a signal from the timer means 20 is generated. Reference numeral 29 denotes rising detection means, which generates a pulse when the signal S8 from the operation command input section rises (OFF → ON), and resets the flip-flop 23 (cancels the abnormal state).

  FIG. 6 is a detailed block diagram of the relay driving means 12 in FIG. In FIG. 6, 30 is an AND gate, which generates a signal S10 for turning on the inrush current limiting relay 15 when the relay drive signal S9 is on and the signal S11 from the voltage detecting means 11 is off. An AND gate 31 generates a signal S12 for turning on the electromagnetic contactor 2 when the relay drive signal S9 is on and the signal S11 from the voltage detecting means 11 is on. The operation of the conventional air conditioner control apparatus configured as described above will be described below with reference to FIGS. 4, 5, 7, and 8.

  FIG. 7 is a flowchart for explaining the operation of the control device of the conventional air conditioner, and FIG. 8 is a time chart. In FIG. 7, the commercial AC power source 1 is turned on in step 1. Next, in step 2, the signal S8 is output from the operation command input unit 9 to the inverter control means 10, and if "operation", the process proceeds to step 3, and otherwise, step 2 is repeated. Next, in step 3, the timer of the first timer means 20 is started. Next, in step 4, the inverter control means 10 outputs a signal S9 to the relay driving means 12, and the relay driving means 12 outputs a signal S10 to the inrush current limiting relay 15, thereby turning on the inrush current limiting relay 15. When the inrush current limiting relay 15 is turned on, the capacitor 6 is charged via the inrush current limiting resistor 14 and the diode 16.

  Next, at step 5, it is checked whether or not the timer time of the first timer means 20 has been counted up. When the time is not up, step 6 is executed, and when the time is up, step 7 is executed. Next, in step 6, the charging voltage of the capacitor 6 is detected by the voltage detection means 11, and a signal S11 is output to the inverter control means 10. If the charging voltage is equal to or higher than the specified voltage, the process proceeds to step 11. Repeat from. Next, in step 7, it is determined that an abnormality such as disconnection of the coil of the inrush current limiting relay 15 has occurred because the capacitor 6 is not charged for a long time even though the inrush current limiting relay 15 is turned on. The inrush current limiting relay 15 is turned off, and the operation signal S8 from the operation command input unit is forcibly set from the “operation” to the “off” state (step 8), and the abnormality display means 19 displays the abnormality. (Step 9), the entire system is stopped (Step 10). Here, it is assumed that the time-up time (t1) of the first timer means 20 is set sufficiently longer than the charging time of the capacitor 6.

Next, in step 11, the inrush current limiting relay 12 is turned off. In step 12, the electromagnetic contactor 2 is turned on, and DC power is supplied to the inverter circuit 7. This operation is automatically processed by the circuit (relay driving means 12) shown in FIG. 6 according to the output signal S11 of the voltage detecting means 11. Next, at step 13, the inverter control means 10 outputs a signal S 13 (actually an inverter waveform signal) to the inverter base drive circuit 13, further drives the inverter circuit 7, and supplies AC power of a predetermined frequency to the compressor 8. Then, the compressor 8 is operated (step 14).
JP-A-4-165994

  However, in the conventional configuration, when the inrush current limiting relay is short-circuited (for example, welding of contacts) and the magnetic contactor is not operating (for example, coil breakage), these abnormalities cannot be detected and the compressor is driven. It will move to the step to do. As a result, all of the compressor load current flows through the inrush current limiting resistor, causing a problem that heat is generated.

The control device for an air conditioner of the present invention solves the above-described conventional problems, and easily realizes detection of a short circuit of an inrush current limiting relay and non-operation of an electromagnetic contactor with the same configuration as the conventional one. An object of the present invention is to provide a control device for an air conditioner capable of performing the above.

  In order to solve the above-described conventional problems, the air conditioner of the present invention includes an inrush current limiting unit including a current control relay and an inrush current limiting resistor in parallel with an electromagnetic contactor that opens and closes a converter circuit and a commercial AC power source. In addition, a voltage detection means for detecting the DC terminal voltage of the capacitor for smoothing the output of the converter circuit is provided, and the DC terminal voltage of the capacitor is first detected by the first determination means before operating the current control relay and the electromagnetic contactor. By comparing with the specified voltage, welding detection of the current control relay is performed, the first timer means for counting from the closing operation of the current control relay, and the second timer means for starting counting from the opening operation of the current control relay, The DC terminal voltage of the capacitor after the current control relay is closed and opened and the compressor is loaded is determined by the first judgment. And the second determination means detect the malfunction of the current control relay and the malfunction of the magnetic contactor by comparing with the first predetermined voltage and the second predetermined voltage. The operation of the machine is stopped.

  In the air conditioner of the present invention, even when the current control relay is short-circuited and the magnetic contactor is inoperative, it is possible to detect an abnormality without providing a special detection means. Can be prevented, and abnormal heat generation of the inrush current limiting resistor can be prevented.

  In the air conditioner of the present invention, the voltage detection means for detecting the DC terminal voltage of the capacitor that smoothes the AC power from the converter, and the inrush current limiting relay of the inrush current limiting unit counts for a certain time after the closing operation. Timer means and a second timer means for counting for a certain period of time after the inrush current limiting relay is opened, and when the inrush current limiting relay and the magnetic contactor are open, the DC terminal voltage of the capacitor is the first regulation. If the voltage exceeds the voltage, it is determined that the inrush current limiting relay or the magnetic contactor is welded, and the DC terminal voltage of the capacitor is increased when the first timer means counts up after the inrush current limiting relay is closed. If the voltage does not exceed the first specified voltage, it is determined that the inrush current limiting relay is inoperative, the current control relay is opened, and the magnetic contactor is opened. After that, when the compressor is driven and the DC terminal voltage of the capacitor falls below the second specified voltage when the second timer means counts up, the welding of the electromagnetic contactor is determined. Thereby, abnormality of an inrush current limiting part and an electromagnetic contactor can be detected easily, and abnormal heat generation of an inrush current limiting part can be prevented.

  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 a simplified circuit diagram of a control device in an inverter air conditioner according to the present invention.

1 is a three-phase commercial AC power source, 2 is an electromagnetic contactor having three contacts, 3 is a converter circuit that converts AC power into DC power, and one end of the electromagnetic contactor 2 is connected to the commercial AC power source 1. The other ends are respectively connected to the AC input section of the converter circuit 3. Reference numeral 6 denotes a capacitor for smoothing the DC power output from the converter circuit 3. The positive side of the capacitor 6 is connected to the positive side of the converter circuit 3, and the negative side is connected to the negative side of the capacitor 6. Reference numeral 7 denotes an inverter circuit which inputs DC power smoothed by the capacitor 6, converts it into three-phase AC power, and outputs it to the compressor 8. 9 is an operation command input unit for determining operation / stop of the compressor 8, 10 is an inverter circuit 7
, 11 is a voltage detection means for detecting the voltage across the capacitor 6, and 12 a is an electromagnetic contactor driving means for driving the electromagnetic contactor 2.

  The first determination means 40 has first timer means 40a, and the first timer means 40a starts counting when a relay drive ON signal is input from the relay drive means 12b. The first determination means 40 compares the first predetermined voltage with the DC terminal voltage of the capacitor 6 detected by the voltage detection means 11 after the first timer means has counted up. On the other hand, the second determination means 41 has a second timer means 41a, and the second timer means 41a starts counting when a relay drive off signal is input from the relay drive signal 12b. The second determination means 41 compares the DC terminal voltage of the capacitor 6 detected by the voltage detection means 11 with the second predetermined voltage after the second timer means has counted up.

  The operation command input unit 9 inputs an operation / stop command for the compressor 8 to the first determination means 40 and the second determination means 41, and the first determination means 40 sends a relay drive signal to the relay drive means 12b. At the same time, an inverter drive signal is sent to the inverter control means 10. The second determination unit 41 sends an electromagnetic contactor drive signal to the electromagnetic contactor drive unit 12 a and sends an inverter drive signal to the inverter control unit 10.

  14 is an inrush current limiting resistor, 15 is an inrush current limiting relay having two contacts 15a and 15b. One end of the inrush current limiting resistor 14 is the R phase of the commercial AC power supply 1, and the other end is an inrush current limiting relay 15. Are connected to the common terminal of the contact 15a. The NO terminal of the contact 15a of the inrush current limiting relay 15 is connected to the R-phase input part of the converter circuit 3, and the common terminal and the NO terminal of the contact 15b are the S phase of the commercial AC power supply 1 and the S of the converter circuit 3, respectively. Connected to the phase input. These blocks including the inrush current limiting relay 15 and the inrush current limiting resistor 14 are referred to as an inrush current limiting unit.

  The operation of the air conditioner control apparatus of the present invention configured as described above will be described with reference to FIG. FIG. 2 is a flowchart for explaining the operation of the control device for the air-conditioning apparatus of the present invention. In FIG. 2, the commercial AC power source 1 is turned on in step 1. Next, in step 2, an operation / stop signal of the compressor 8 is sent from the operation command input unit 9 to the first determination means 40 and the second determination means 41. If the signal is “operation”, the process proceeds to step 3 to compare the DC terminal voltage detected by the voltage detection means 11 with the first specified voltage. If the DC terminal voltage is higher than the first specified voltage, the process proceeds to step 31 where the inrush current limiting relay 15 and the magnetic contactor 2 are off, but the capacitor 6 is charged. It is determined that the limit relay 15 or the electromagnetic contactor 2 is welded, and an abnormal signal is output from the abnormal output means 18a. In step 32, the system is stopped. When the DC terminal voltage is lower than the first specified voltage, the routine proceeds to step 4 where an ON signal is sent from the first determination means to the relay driving means 12b, and the inrush current limiting relay 15 is turned ON.

  Next, in step 5, the timer of the first timer means 40a is started. In step 6, it is checked whether or not the first timer means 40 a has counted up. In step 7, it is checked whether or not the DC terminal voltage of the capacitor 6 detected by the voltage detection means 11 is higher than the first specified voltage. If the voltage is higher, the process proceeds to step 8; Since the capacitor 6 is not charged by the unit, it is determined that the inrush current limiting unit is abnormal, an abnormal signal is output from the abnormal output means 18a in step 71, and the system is stopped in step 72. In step 8, an off signal is input from the first determination means 40 to the relay driving means 12b, and the inrush current limiting relay 15 is turned off. In step 9, the timer of the second timer means 41a is started, and in step 10, an ON signal is sent from the second determination means to the electromagnetic contactor 12a to turn on the electromagnetic contactor 2.

  In step 11, the second determination means 41 inputs an inverter drive signal to the inverter control means 10, and the inverter control means 10 operates the inverter circuit 7, thereby supplying AC power to the compressor 8 for operation. Here, the inverter drive signal input from the second determination means is such that the power supplied to the compressor 8 is limited to a small value, and the power supplied to the capacitor 6 per cycle of the commercial AC power supply 1 is determined. By setting so as to be much lower, the fluctuation of the DC terminal voltage of the capacitor 6 is made minute.

  Next, in step 12, it is checked whether or not the timer of the second timer means 41a has been counted up. If it has been counted up, the process proceeds to step 13, and if not, the limiting operation of the compressor 8 is continued. In step 13, it is checked whether or not the DC terminal voltage of the capacitor 6 detected by the voltage detection means 11 exceeds the second specified voltage. If it is higher, the process proceeds to step 14 and is sent from the second determination means. The restriction of the limited inverter control signal is released and normal compressor operation is performed. If it is lower, it is determined that the magnetic contactor 2 is not operating due to disconnection of the operating coil, for example, because power is not supplied from the commercial AC power supply 1, and an abnormal signal is output from the abnormal output means 18a in step 131. In step 132, the system is stopped.

  Here, the time t1 that the timer of the second timer means 41a counts up is stored in the capacitor 6 and the AC power that can be consumed by the compressor 8 by the limited inverter control signal sent out by the second determination means. Suppose that the DC terminal voltage of the capacitor 6 is set to be larger than the time t2 when the DC terminal voltage of the capacitor 6 falls below the second specified voltage in the absence of power supplied from the commercial AC power supply 1.

  Therefore, when the compressor 8 is driven, that is, when large power is supplied from the commercial AC power source 1, it is possible to easily detect the inrush current control unit and the welding / non-operation of the magnetic contactor 2 in advance. Thus, abnormal heat generation of the inrush current limiting resistor can be prevented.

  As described above, the control device for an air conditioner according to the present invention includes an inrush current limit including a current control relay by a combination of the opening / closing operation of the current control relay, the load operation of the compressor, and the DC terminal voltage detection means of the capacitor. This is applicable to applications such as inverter equipment having an inrush current control unit.

The circuit block diagram of the control apparatus of the air conditioning apparatus of this invention The flowchart explaining operation | movement of the control apparatus of the air conditioning apparatus of this invention. The time chart explaining operation | movement of the control apparatus of the air conditioning apparatus of this invention Circuit diagram of conventional air conditioner control device Detailed block diagram of the abnormality detection means 18 in FIG. Detailed block diagram of the relay drive means 12 in FIG. The flowchart explaining operation | movement of the control apparatus of the conventional air conditioning apparatus. Time chart explaining the operation of the control device of the conventional air conditioner

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Commercial AC power supply 2 Magnetic contactor 3 Converter circuit 6 Capacitor 7 Inverter circuit 9 Operation command input part 10 Inverter control means 11 Voltage detection means 12 Relay drive means 12a Electromagnetic contactor drive means 12b Relay drive means 13 Inverter base drive circuit 14 Inrush Current limiting resistor 15 Inrush current limiting relay 15a First contact 15b of inrush current limiting relay 15 Second contact of inrush current limiting relay 15 16 Diode 18 Abnormality detecting means 18a Abnormal output means 20 Timer means 21 Determination means 21a AND gate 21b Flip-flop 23 Flip-flop 29 Rising detection means 30 AND gate 31 AND gate 40 First determination means 40a First timer means 41 Second determination means 41a Second timer means

Claims (1)

Converter circuit for converting AC power to DC power, electromagnetic contactor for opening and closing the converter circuit and commercial AC power supply, capacitor for smoothing DC power converted by the converter circuit, and DC smoothed by the capacitor An inverter circuit that inputs electric power and converts it to AC power to control the compressor, voltage detection means that detects the voltage of the capacitor, and two phases of the commercial AC power supply are connected via a current control relay and an inrush current limiting resistor. An inrush current limiting unit having a configuration connected in parallel to the output end of the electromagnetic contactor, an operation command input unit for determining operation / stop of the compressor, and an electromagnetic contactor driving means for driving the electromagnetic contactor Relay driving means for driving the current control relay, inverter control means for driving the inverter circuit, and the current control relay closing operation First timer means for counting for a certain period of time and second timer means for counting for a certain period of time after the current control relay is opened, and when an operation command is issued from the operation command input unit When the DC terminal voltage detected by the voltage detecting means is higher than the first predetermined voltage, the operation is stopped, and when it is lower, the electromagnetic contactor is opened and the current control relay is closed. When the DC terminal voltage detected by the voltage detection means exceeds a first predetermined voltage at the time when the first timer means counts up after charging the capacitor, the current control relay is Opening, closing the electromagnetic contactor and limiting the operating frequency of the compressor by the inverter control means to operate as a load, the second timer If the DC terminal voltage detected by the voltage detecting means is below a second predetermined voltage at the time when the means counts up, the operation of the inverter control means is stopped, and if it is above, the compressor The air conditioner characterized by canceling the restriction operation.

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