JP5413157B2 - Control device for heat pump water heater - Google Patents

Description

  The present invention relates to a control device for controlling a heat pump type hot water heater having a compressor, a hot water supply heat exchanger, an expansion valve, and an evaporator.

FIG. 4 is a circuit diagram of a control device for a heat pump type water heater in the conventional embodiment, and FIG. 5 shows a control flow of the first and second switch means.
In FIG. 4, a diode bridge 12 that rectifies the commercial power supply 11, a capacitor 13 that smoothes the voltage rectified by the diode bridge 12, and a current limiting element 14 that prevents an inrush current that is a charging current to the capacitor 13. First and second switch means 15 and 16, a load 17 driven by using the voltage smoothed by the capacitor 13 as a power source, a voltage detection means 18 for detecting the voltage smoothed by the capacitor 13, and a voltage detection The voltage detected by the means 18 is input, and it is determined whether or not the first switch means 15 is operating normally according to the value of the voltage, or abnormal signals from each circuit of the control device of the heat pump type hot water heater are received. It is comprised from the control part 19 to detect. In this configuration, first, the first switch means 15 is turned on by the control unit 19, the inrush current is limited by the current limiting element 14, the capacitor 13 is charged, the capacitor 13 is charged to some extent, and then the control unit 19 performs the first switching. The second switch means 16 is turned on.

  Among these, as shown in FIG. 5, first, the voltage detection means 18 detects the voltage across the capacitor 13 immediately after the control section 19 outputs the ON signal to the first switch means 15, and the value is a certain threshold value. It is determined whether or not the first switch means 15 is operating normally depending on whether or not the threshold value is exceeded.

JP 2008-96079 A

  However, in the conventional control device, the heat pump type hot water heater is restarted (first and second) after a short time of less than several minutes after the stop (the first and second switch means 15 and 16 are turned off). 2), the capacitor 13 is not sufficiently discharged, and the voltage across the capacitor 13 becomes equal to or higher than the threshold value. Therefore, the first switch means 15 does not operate normally. However, it has a problem that it cannot be determined as abnormal.

  The present invention solves the above-described conventional problems, and an object thereof is to enable failure detection of the first switch means 15 regardless of the time from when the heat pump type hot water heater is stopped until it is restarted. .

  In order to solve the above-mentioned conventional problems, the control device for the heat pump type water heater of the present invention detects the voltage across the capacitor immediately before and after the control unit outputs the ON signal to the first switch means. The control device determines whether or not the first switch means operates normally depending on whether or not the amount of change in the value exceeds a certain threshold value. Accordingly, it is possible to determine a failure of the first switch means regardless of the voltage across the capacitor when the first switch means is turned on.

  Since the controller of the heat pump type hot water heater of the present invention can quickly find the failure of the first switch means, the failure of the compressor that occurs when the heat pump type hot water heater is unintentionally energized when stopped. It is also possible to prevent unsafe accidents such as electric leakage.

Control flow diagram of first and second switch means in Embodiment 1 of the present invention Threshold diagram of change amount of voltage across capacitor in the second embodiment of the present invention Control flow diagram of first and second switch means in Embodiment 3 of the present invention The circuit diagram of the control apparatus of the heat pump type water heater in the conventional embodiment Control flow diagram of first and second switch means in the conventional embodiment

  A control device for a heat pump type water heater according to a first aspect of the present invention includes a diode bridge that rectifies a commercial power supply, a capacitor that smoothes a voltage rectified by the diode bridge, and an inrush current that flows when the capacitor is charged. Current limiting element, first and second switch means placed in series with a commercial power line, voltage detection means for detecting a voltage smoothed by the capacitor, and voltage detected by the voltage detection means And determining whether or not the first switch means is operating normally by calculation using the voltage value, or detecting an abnormal signal from each circuit of the control device of the heat pump water heater And the controller immediately before the controller outputs an ON signal to the first switch means, and the output By detecting the voltage across the capacitor immediately after that and determining whether the first switch means is operating normally or not by determining whether or not the amount of change in the value exceeds a certain threshold value. The failure of the first switch means can be determined regardless of the voltage across the capacitor when the first switch means is turned on.

  According to a second aspect of the present invention, there is provided a control device for a heat pump type hot water supply apparatus, wherein the threshold voltage described in the first aspect is detected immediately before the control unit outputs an ON signal to the first switch means. Depending on the value of. When the first switch means operates normally, the amount of change in the voltage across the capacitor depends on the voltage across the capacitor when the first switch means is turned on (the amount of change increases as the voltage increases). Smaller). Correspondingly, the threshold value is set to a smaller value as the detected voltage value across the capacitor is higher so that the failure of the first switch means can be determined even if the amount of change in the voltage across the capacitor is small. . Thereby, the failure of the first switch means can be determined more strictly.

  According to a third aspect of the present invention, there is provided the control device for the heat pump type hot water supply apparatus according to the first or second aspect, wherein the voltage across the capacitor is detected immediately before the control unit outputs an ON signal to the first switch means. Only when the value of is less than a certain value, it is determined whether or not the first switch means is operating normally. When the voltage across the capacitor is high, that is, when the amount of change in the voltage across the capacitor is small, there is a high possibility that the first switch means is erroneously determined to be abnormal even when operating normally. For this reason, the determination is not performed when the amount of change in the voltage across the capacitor is small, which may cause a determination error. Thereby, it is possible to prevent erroneous determination of failure in the first switch means.

(Embodiment 1)
The circuit diagram of the control device for the heat pump type hot water heater in the first embodiment of the present invention is the same as the circuit diagram of the control device for the conventional heat pump type hot water heater, and will be described with reference to FIG. FIG. 1 shows a control flow of the first and second switch means in the first embodiment of the present invention.

  In FIG. 4, the first switch means 15 is first turned on by the control unit 19, the inrush current is limited by the current limiting element 14, the capacitor 13 is charged, the capacitor 13 is charged to some extent, and then the control unit 19 performs the first switching. The second switch means 16 is turned on.

  In this, as shown in FIG. 1, the voltage detection means 18 detects the voltage across the capacitor 13 immediately before and after the controller 19 outputs the ON signal to the first switch means 15, and the value It is determined whether or not the first switch means 15 is operating normally depending on whether or not the amount of change exceeds a certain threshold value. When the first switch means 15 operates normally, the voltage across the capacitor 13 immediately after outputting the ON signal to the first switch means 15 always increases with respect to the immediately preceding voltage, so the threshold value is set appropriately. As a result, it is possible to determine the failure of the first switch means 15 regardless of the voltage across the capacitor 13 immediately before the ON signal is output to the first switch means 15.

(Embodiment 2)
FIG. 2 shows an example of the threshold value of the change amount of the voltage across the capacitor in the second embodiment of the present invention.

  In FIG. 2, for example, when the voltage across the capacitor 13 when the first switch means 15 is turned on is DC 0 V to DC 50 V, the voltage change amount threshold is 20 V, when DC 50 V to DC 100 V is 10 V, when the voltage change amount is DC 100 V or more, the voltage change amount is Set the threshold to 5V. This makes it possible to adjust the threshold value of the change amount to be determined according to the actual change amount of the voltage across the capacitor 13 when the first switch means 15 is normal. Failure can be determined more precisely.

(Embodiment 3)
FIG. 3 shows a control flow of the first and second switch means in the third embodiment of the present invention.

  In FIG. 3, for example, when the voltage value across the capacitor 13 detected immediately before the control unit 19 outputs the ON signal to the first switch means 15 is equal to or higher than a predetermined value (for example, DC 280 V), The second switch means 16 is turned on regardless of the voltage change amount. Thereby, it is possible to prevent erroneous detection of a failure in the first switch means 15 due to a small amount of voltage change across the capacitor 13.

  As described above, the control device according to the present invention can detect a failure of the switch means when the commercial power supply line is connected / cut off by driving the two switch means. It can also be applied to indoor units of harmonic machines.

DESCRIPTION OF SYMBOLS 11 Commercial power supply 12 Diode bridge 13 Capacitor 14 Current limiting element 15 1st switch means 16 2nd switch means 17 Load 18 Voltage detection means 19 Control part

Claims (3)

A diode bridge for rectifying commercial power, a capacitor for smoothing the voltage rectified by the diode bridge, a current limiting element for preventing an inrush current flowing when charging the capacitor, and a commercial power line in series The first and second switch means inserted, the voltage detection means for detecting the voltage smoothed by the capacitor, the voltage detected by the voltage detection means is input, and the calculation is performed using the voltage value. A controller that determines whether or not the first switch means is operating normally and that detects an abnormal signal from each circuit of the controller of the heat pump type hot water heater, wherein the controller detects the first signal by the voltage detector; The voltage across the capacitor is detected immediately before the ON signal is output to the switch means 1 and immediately after the output. On whether exceeds a certain threshold amount of change, the first switch means control unit of the heat pump water heater, characterized in that a determination is made whether or not operating properly. 2. The heat pump type hot water heater according to claim 1, wherein the threshold value is changed according to a voltage value across the capacitor detected immediately before the control unit outputs an ON signal to the first switch unit. Control device. Only when the voltage across the capacitor detected immediately before the control unit outputs an ON signal to the first switch means is less than a certain value, the first switch means operates normally. The control device for a heat pump type hot water heater according to claim 1 or 2, wherein a determination is made as to whether or not there is.

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