JP3599846B2 - Air conditioner power supply - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power supply device for an air conditioner, particularly to a power supply device for a compressor.
[0002]
[Prior art]
BACKGROUND ART Conventionally, a magnet switch for turning on / off (turning on / off) power supply to a compressor is interposed in a power supply circuit of a compressor of an air conditioner. In this magnet switch, an abnormal phenomenon in which the operation of the contacts is not stable and repeats turning on and off repeatedly, that is, chattering may occur due to fluctuations in the power supply or failure of the magnet switch itself.
[0003]
[Problems to be solved by the invention]
The occurrence of chattering may cause not only damage to the contacts of the magnet switch but also burn-in of the windings of the compressor. However, the power supply device of the conventional air conditioner cannot detect a power supply abnormality due to chattering and stop the operation of the air conditioner.
[0004]
An object of the present invention is to provide a power supply device for an air conditioner that can reliably detect an abnormality occurring in a switch unit such as a magnet switch of a power supply circuit and improve safety.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is provided in a power supply circuit, a switch means inserted into a power supply circuit from a power supply to a compressor of an air conditioner to turn on / off the power supply to the compressor. And a power supply control circuit for controlling the on / off operation of the switch means based on a detection signal from the current detection means, wherein the power supply control circuit comprises: Chattering has occurred in the switch means when the peak current value of the current detection signal output from the detection means is a predetermined time or more than the peak current value obtained by calculating the effective value of the current detection signal. Is output, and the peak current value of the current detection signal is calculated by calculating the effective value of the current detection signal. If it is less than the predetermined times than the current value, the overcurrent, or configured to include a determination means for outputting an abnormality determination signal indicating that the overload lock has occurred.
[0009]
According to this invention, when the current detection signal is output from the current detection means, the determination means determines the switching means based on the peak current value of the current detection signal and the peak current value obtained by calculating the effective value of the current detection signal. Is determined, and an abnormality determination signal is output.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, a preferred embodiment of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 shows the configuration of the air conditioner. In FIG. 1, reference numeral 10 denotes a power supply of 200 VAC, and three-phase current from the power supply 10 is supplied to a compressor 14 via a magnet switch 12. A current transformer (CT) 16 as current detection means is provided in a current path between the magnet switch 12 and the compressor 14, and a detection signal from the CT 16 is supplied to a controller 18. When the controller 18 determines an abnormal operation of the magnet switch 12 based on the detection signal, the controller 18 turns off the magnet switch 12 to cut off the current to the compressor 14.
[0016]
Next, FIG. 2 shows a circuit of the controller 18. 2, detection signals from the CT16 is supplied to the controller 18, it is supplied to both ends of the resistor _{R 3} in the controller 18. The resistor _{R 3} is a CT load resistance ie resistance I / V (current / voltage) for conversion. One end of the resistor _{R 3} is connected to a coupling point between the resistor _R 1 (= _10KΩ) and a resistor _R 2 (= _10KΩ), the other end of the resistor _{R 3} is connected to the A / D input terminal of the microcomputer 20 I have. The other end of the resistor _{R 1} is connected to the microcomputer of the reference voltage Vres (= + 5V), the other end of the resistor _{R 2} is connected.
[0017]
The resistors R ₁ and R ₂ are used to input an input to the A / D input terminal of the microcomputer 20 with a sine waveform whose middle point is 2.5V.
[0018]
When the current _{I 1} flows through the CT16, a predetermined voltage V across the resistor _{R 3} is to generate, the resistance _{R 3} is set. The relationship between the current I ₁ and the voltage V ₁ is adjusted in advance so as to have, for example, the waveforms of FIGS. That is, in FIG. 3 (A), the current _{I 1} of the P-P (peak-to-peak) is 50A, P-P (peak-to-peak) of the voltages _{V 1} is 2.5V. When the current I ₁ is OA, since the voltage V ₁ = 0 V, a DC of bias voltage 2.5 V of the resistors R ₁ and R ₂ is applied to the A / D input terminal of the microcomputer 20. When the voltages _{V 1} to a value that is changed from 0V, the A / D input terminal of the microcomputer 20, voltages _{V 1} centered on the 2.5V is applied.
[0019]
The microcomputer 20, the relationship between the amplitude and the current I ₁ of the voltages V ₁ is preset so that the relationship of FIG. 4, as shown Fig. 5, is performed detection of the overload detection and rock. For example, in FIG. 5, the current at point a is determined to be overload, and the current at point b is determined to be locked.
[0020]
Next, FIG. 6 shows a circuit for turning the magnet switch 12 on and off. In FIG. 6, three-phase current from a power source 10 is supplied to a compressor motor (CM) 14 via a magnet switch 12, and the magnet switch 12 responds to the three-phase current. It has switch pieces 12R, 12S, and 12T. Further, the magnet switch 12 has an excitation coil 13 for turning on and off the switch pieces 12R, 12S, and 12T. One end of the excitation coil 13 is connected to the S phase of the three-phase current. The other end is connected to the R phase of the three-phase current via a switch 19 in a controller (control board) 18. When the switch 19 in the controller 18 is turned on and off, the exciting coil 13 is turned on and off, and as a result, the switch pieces 12R, 12S, and 12T are turned on and off, and current is supplied to the compressor 14. Be blocked or shut off.
[0021]
In the circuit of FIG. 6, for example, when the current causes a voltage drop (200V → 100 to 110V), the exciting force of the exciting coil 13 of the magnet switch 12 decreases, and the contacts 12R, 12S, and 12T easily enter the chattering state. . This is shown by the current waveform in FIG. At the time of normal operation, the current waveform is as shown in FIG. 7A, but at the time of chattering, the current waveform is as shown in FIG. 7B. At the time of the chattering, as shown in FIG. 7B, a current lacking half-waves continues to flow irregularly, and if this chattering state is left, trouble such as burning of the windings of the compressor 14 occurs. If the current waveform at the time of chattering in FIG. 7B exceeds the point b in FIG. 5, an alarm operation or a stop operation of the device can be performed. In some cases, the temperature may be lower than the point b or lower than the point A. In such a case, the alarm operation or the device stop operation cannot be performed.
[0022]
Therefore, in the embodiment of the present invention, the chattering state is detected inside the microcomputer by the following method.
[0023]
In the first chattering state detection method, the chattering state is determined using the effective value calculation. That is, when the peak current Ip is a large current that cannot be considered in normal operation, but is low in the effective value calculation, it is determined that the chattering state is present, and the apparatus is stopped. On the other hand, when the peak current Ip is a large current and a large value in the calculation of the effective value, it is determined that an overcurrent or a locked state occurs, and the apparatus is stopped. In addition, in order to distinguish and notify when chattering and an overcurrent or a locked state, a different alarm or display may be used.
[0024]
In the second chattering state detection method, the chattering state is determined based on the peak current value. That is, when the peak current value is continuous at a certain current value or more, it is determined that an overcurrent or a locked state is present, and even when the peak current value is discontinuous, the same as in the first detection method described above. In addition, if it is determined that the chattering state or the overcurrent or the lock state, the device will be stopped, and also to distinguish and notify the chattering time and the overcurrent or the lock time, even if different alarms and displays Good.
[0025]
First, FIG. 8 shows an overall control flowchart for abnormality detection based on a detected current by CT. In FIG. 8, the CT control is started in step 100, the current value is calculated in step 102, and if the current value calculation is not completed in step 104, the next control is performed in step 105. When the calculation of the current value is completed in step 104, the process proceeds to steps 106, 108, 110, and 112. In steps 106, 108, 110, and 112, the following various controls are performed based on the calculated current value. . That is, chattering detection control is performed in step 106, lock current control is performed in step 108, overcurrent control is performed in step 110, CT sensor abnormality detection is performed in step 112, and then, the next control is performed in step 105. Note that the calculation of the current value in step 102 and the chattering detection control in step 106 are important parts in the embodiment of the present invention.
[0026]
FIG. 9 shows a detailed flow of the current value calculation step 102. In FIG. 9, the current is calculated in step 120, and it is determined in step 122 whether X [μs] has elapsed. The sampling speed is set as high as possible, so that a more accurate current effective value can be sampled. In this example, the sampling value is about 10 μs to 500 μs. If X [μs] has not elapsed in this step 122, the next control proceeds to step 124. However, if X [μs] has elapsed in step 122, A / D input sampling is performed in step 126, and in step 128 It is determined whether or not sampling has been performed for Y cycles. In addition. , Y cycle is, for example, about 0.5 to 5 cycles. If the sampling has not been performed for the Y period in step 128, the process proceeds to the next control in step 124. However, if the sampling has been performed for the Y period in step 128, the effective value and the peak value are calculated from the sampling data in step 130. Is performed, and the process proceeds to the next control in step 124. In step 130, the current values of the sampling data are integrated, the effective value is calculated from the integrated value, and the peak current value is calculated and stored.
[0027]
Next, FIG. 10 shows a flowchart of a determination method in an effective value calculation for executing the first chattering state detection method. The determination method based on peak value detection will be described.
[0028]
In FIG. 10, the determination method in the effective value calculation is started in step 140, and it is determined in step operation 142 whether the peak current value is outside the normal operation range. Outside the normal operation range, the normal operation current × about 1.5 to 5 times is considered abnormal operation. If the peak current value is not out of the normal operation range in step 142, the process proceeds to the next process in step 144. If the peak current value is out of the normal operation range in step 142, the process proceeds to step 146 and the peak current value (Ip) And a peak current value (Ijp) obtained from the effective value to determine whether Ip is Z times Ijp or not. It should be noted that Ip = the sampled peak current value, Ijp = the peak current value obtained by back-calculating the effective value, and Z times = approximately 1.3 to 5 times Ijp. As another method, the effective value is calculated from Ip. It is also conceivable to compare with Ip. If Ip is Z times Ijp in step 146, the process proceeds to step 148. In this step 148, it is determined that chattering occurs, and if the same phenomenon occurs B times in A seconds, the unit of the air conditioner is stopped, and at this time, processing such as alarm display may be performed. Then, the process proceeds to step 144 and proceeds to the next process.
[0029]
FIG. 11 shows a flowchart of a determination method based on peak value detection for executing the second chattering state detection method. In FIG. 11, the determination method based on the peak value current is started in step 150, and it is determined in step 152 whether the peak current (Ip) exceeds a certain current value (Iref). Although a certain current value (Iref) differs depending on the model, it is considered in a range of about 1.5 to 5 times the operating current in the normal operation state.
[0030]
If the peak current (Ip) does not exceed a certain current value (Iref) in step 152, the process proceeds to step 154 and shifts to the next control. In step 152, the peak current (Ip) exceeds a certain current value (Iref). If so, the process proceeds to step 156, where it is determined whether the peak current (Ip) has exceeded a certain current value (Iref) E times in C seconds (D cycle). In addition, as reference numerical data, it is considered that C period is about 0.1 second to 1 second, D cycle is about 5 to 50 cycles, and E cycle is about 3 to 10 cycles.
[0031]
If NO in step 156, the process proceeds to the next control in step 154. However, if YES in step 156, it is determined that the chattering state is present in step 158, and the air conditioner unit is stopped or an alarm is displayed. In step 154, the process proceeds to the next control.
[0032]
Other Aspects (I) of the Present Invention Regarding the first chattering state detection, the power supply control circuit is provided with stopping means for stopping the air conditioner based on the abnormality determination signal. According to this aspect, the judging unit judges the abnormality of the operation of the switch unit based on the peak current value of the current detection signal from the current detection unit and the peak current value obtained by calculating the effective value of the current detection signal, and determines the abnormality. Outputs a judgment signal. The stopping means stops the air conditioner based on the abnormality determination signal, and stops supplying the drive current to the compressor.
[0033]
(II) For the first chattering state detection, the power supply control circuit is provided with a warning display means for displaying a warning based on the abnormality determination signal. According to this aspect, the judging unit judges the abnormality of the operation of the switch unit based on the peak current value of the current detection signal from the current detection unit and the peak current value obtained by calculating the effective value of the current detection signal, and determines the abnormality. Outputs a judgment signal. The stopping means stops the air conditioner based on the abnormality determination signal, and stops supplying an abnormal drive current to the compressor. At the same time, the warning display means displays a warning based on the abnormality determination signal, and notifies an abnormality of the switch means.
[0034]
As a reference example of the present invention, regarding the second chattering state detection, the power supply control circuit includes a stop unit and a warning display unit that stop the air conditioner based on the abnormality confirmation determination signal. According to this aspect, when the current detection signal is output from the current detection unit, the determination unit determines an abnormality in the operation of the switch unit based on the peak current value of the current detection signal, and outputs an abnormality determination signal. The occurrence frequency determination means determines the occurrence frequency of the abnormality determination signal within a predetermined time (or counts the number of occurrences), and outputs an abnormality confirmation signal when the determination value exceeds a reference frequency. The stopping unit stops the air conditioner based on the abnormality confirmation determination signal, and the warning display unit notifies an abnormality of the switch unit.
[0035]
【The invention's effect】
As described above, according to the present invention, it is possible to reliably detect an abnormality occurring in switch means such as a magnet switch of a power supply circuit, and to improve the safety of the power supply device of the air conditioner.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a power supply circuit of a compressor of an air conditioner.
FIG. 2 is a circuit diagram of a controller and an input section of a detection signal.
3 is a waveform diagram of the current I ₁ and voltage V1 of the detection signal.
FIG. 4 is an explanatory diagram showing a relationship between a current I _{1 of a} detection signal and a voltage V ₁ .
FIG. 5 is an explanatory diagram showing a relationship between a current I _{1 of a} detection signal and a voltage V ₁ and overload and lock.
FIG. 6 is a circuit diagram showing a part of a power supply circuit.
FIG. 7 is a waveform diagram showing current waveforms during normal and chattering.
FIG. 8 is a schematic flowchart showing the entirety of abnormality detection.
FIG. 9 is a flowchart of current calculation for abnormality detection.
FIG. 10 is a flowchart illustrating a determination method in calculating an effective value for detecting chattering.
FIG. 11 is a flowchart illustrating a determination method based on peak value current detection for chattering detection.
[Explanation of symbols]
10 Power supply 12 Magnet switch 14 Compressor 16 Current transformer (CT)
18 Controller

Claims (1)

A switch unit inserted into a power supply circuit from the power supply to the compressor of the air conditioner to turn on / off the power supply to the compressor, a current detection unit provided in the power supply circuit, and based on a detection signal from the current detection unit. A power supply control circuit for controlling the on / off operation of the switch means; and
The power control circuit,
When the peak current value of the current detection signal output from the current detection means is a predetermined time or more than the peak current value obtained by calculating the effective value of the current detection signal, chattering occurs in the switch means. Output an abnormality judgment signal indicating that
If the peak current value of the current detection signal is less than or equal to a predetermined multiple of the peak current value obtained by calculating the effective value of the current detection signal, the overcurrent or overload lock has occurred. A power supply device for an air conditioner, comprising: a determination unit that outputs an abnormality determination signal indicating the following .

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