JP6515745B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner, and more specifically, when an AC power supply supplied to the air conditioner temporarily reduces its voltage and then recovers to its original voltage in a short time. Related to control.

  Conventionally, the air conditioner of Patent Document 1 is configured as shown in the block diagram of FIG. 5 and is a boost chopper circuit that boosts the DC voltage when the voltage of the AC power supply falls below a predetermined voltage (instantaneous voltage drop). Is supposed to stop its operation.

  The air conditioner 70 of FIG. 5 includes an indoor unit 50 and an outdoor unit 60, which are communicably connected to each other. In this air conditioner 70, the rated voltage of the AC voltage is 230 volts, and the rated voltage range in which the operation is guaranteed is the rated voltage ± 10% (207 to 253 volts). The voltages are all effective values. Also, unless stated otherwise, all AC voltages described hereinafter are effective values.

  The outdoor unit 60 is connected to a rectifier 4 connected to an input end (input end 1 and input end 2) to which an AC power supply (not shown) is connected, and to an output end (positive electrode output end 4a and negative electrode output end 4b) of the rectifier 4 , A boost chopper circuit 5 in which an input end (a positive input 5b and a negative input 5c) is connected to an output end of the rectifier 4 and the smoothing capacitor 5a is provided inside; a boost chopper circuit The inverter 6 is connected to the output terminal 5 (positive electrode output terminal 5 d and negative electrode output terminal 5 e), and the compressor 7 is connected to the output terminal of the inverter 6.

  Furthermore, the outdoor unit 60 is connected in parallel to the output terminal of the step-up chopper circuit 5 and outputs a detected voltage as a DC voltage value, a negative voltage output portion 4b of the rectifier 4 and a negative electrode of the step-up chopper circuit 5 A current detection unit 10 connected in series between the input end 5c, an outdoor unit control unit 9 that controls the entire outdoor unit 60 according to an instruction from the indoor unit 50, and an instantaneous voltage drop occurs in the step-up chopper circuit 5 A stop instruction unit 65 that outputs a stop signal for stopping the operation to the outdoor unit control unit 9 is provided.

  The outdoor unit controller 9 generates a drive signal (switching signal) for driving the compressor 7 at a predetermined rotational speed by PWM control and outputs it to the inverter 6, and the DC voltage value detected by the DC voltage detector 8 is The power factor is improved based on the detected current signal detected by the current detection unit 10 and the rectified output voltage signal detected by the rectified voltage detection unit 3 so as to be the target voltage of the output voltage of the step-up chopper circuit 5. The switching signal is generated by PWM control and output to the step-up chopper circuit 5. Further, when the stop signal is input from the stop instructing unit 65, the outdoor unit controller 9 stops the switching signal output to the step-up chopper circuit 5. Further, the outdoor unit controller 9 outputs a target voltage value that is a target of the output voltage of the step-up chopper circuit 5 to the stop instructing unit 65.

  The stop instruction unit 65 receives the target voltage value and the DC voltage value, and the DC voltage value becomes smaller than the target voltage value, and when this difference deviates to a predetermined voltage difference (voltage difference threshold), for example, 50 volts or more It is determined that an instantaneous voltage drop has occurred in the AC power supply, and a stop signal is output to the outdoor unit controller 9.

  Next, the operation of the air conditioner 70 when an instantaneous voltage drop occurs at the rated voltage will be described with reference to FIG. The horizontal axis in FIG. 7 represents time, and the vertical axis represents voltage. 7 (1) shows the change of the AC voltage applied to the air conditioner 70, FIG. 7 (2) shows the DC voltage output from the step-up chopper circuit 5, and FIG. 7 (3) shows the output from the stop instructing unit 65. The stop signals are respectively shown. Note that t70 to t75 indicate time. As a precondition, it is assumed that the outdoor unit controller 9 controls the step-up chopper circuit 5 with a target voltage value of 380 volts.

  As shown in FIG. 7A, the AC voltage applied to the air conditioner 70 maintains 230 volts of the rated voltage until t71, but an instantaneous voltage drop occurs at t71 and at a minimum of 196 volts (rated voltage After the voltage temporarily drops to -15%), the original voltage of 230 volts is restored at t74.

  On the other hand, in the step-up chopper circuit 5, the DC voltage can not be maintained at the target voltage (380 volts) as shown in FIG. The DC voltage gradually decreases from t72. The outdoor unit controller 9 performs feedback control to maintain the DC voltage at the target voltage. For this reason, the time until the outdoor unit controller 9 outputs the switching signal to set the DC voltage to the target voltage from the change of the DC voltage to the step-up chopper circuit 5 is delayed by the feedback time.

  The stop instruction unit 65 constantly monitors the target voltage value output from the outdoor unit control unit 9 and the DC voltage value, and the voltage difference threshold value (50 volts) in which the DC voltage value is predetermined than the target voltage value. As shown in FIG. 7 (3), the stop signal, which is a pulse signal, is output to the outdoor unit controller 9 at t73 where the above difference occurs. The outdoor unit controller 9 to which this signal is input stops the output of the switching signal to stop the operation of the step-up chopper circuit 5.

  For this reason, as indicated by the broken line in FIG. 7 (2), when the step-up chopper circuit 5 is not stopped, the corresponding feedback is generated even though the AC voltage has already returned to the original voltage at t74. Since the control takes time, the step-up chopper circuit 5 controls the DC voltage to be further raised. For this reason, a jump voltage of the DC voltage which becomes an abnormally high voltage is generated, but prior to this, the step-up chopper circuit 5 is stopped in advance when the DC voltage value deviates by the voltage difference threshold or more from the target voltage value. Can prevent the generation of the bounce voltage. The jump voltage generated when the step-up chopper circuit 5 is not stopped in advance may rise to about 590 to 630 volts depending on the case, and a switching element (not shown) used in the step-up chopper circuit 5 such as an IGBT is the maximum rating The voltage may be exceeded to destroy the IGBT.

  Next, the operation of the air conditioner 70 when an instantaneous voltage drop occurs near the lower limit (200 volts) of the rated voltage range will be described using FIG. The horizontal axis of FIG. 6 represents time, and the vertical axis represents voltage. 6 (1) shows the change of the AC voltage applied to the air conditioner 70, FIG. 6 (2) shows the DC voltage outputted from the step-up chopper circuit 5, and FIG. 6 (3) shows the output from the stop instructing unit 65. The stop signals are respectively shown. Note that t60 to t65 indicate time.

  As shown in FIG. 6 (1), the AC voltage applied to the air conditioner 70 maintains 200 volts (-13% of the rated voltage) until t61, but an instantaneous voltage drop occurs at t61 and the voltage reaches 170 volts. After the voltage drops temporarily, it returns to the original 200 volts at t64.

  On the other hand, in the step-up chopper circuit 5, the DC voltage can not be maintained at the target voltage as shown in FIG. 6 (2) because the voltage output from the rectifier 4 is reduced due to the instantaneous voltage drop. Gradually decreases, temporarily causing a voltage drop of 48 volts with respect to 380 volts.

  Although the stop instruction unit 65 monitors whether the DC voltage value deviates more than the target voltage value by the voltage difference threshold or more, the reduction width of the DC voltage is 48 volts and does not reach the voltage difference threshold (50 volts). Do not output stop signal. On the other hand, since the outdoor unit controller 9 largely deviates the input DC voltage value (332 volts) from the target voltage value (380 volts), the step-up chopper is in spite of the fact that the AC voltage turned to rise at t63. A switching signal for raising the output voltage is output to the circuit 5.

  For this reason, at t65 delayed from t64 at which the AC voltage is restored to 200 volts, a bounce voltage which becomes a peak voltage (600 volts) is generated. This is due to the feedback time until the outdoor unit controller 9 outputs the switching signal output to the step-up chopper circuit 5 to set the DC voltage to the target voltage from the change of the DC voltage as described above.

  By the way, the air conditioner 70 is generally used within the rated voltage range, and within the rated voltage range, it can be used at the rated operating capacity. However, in an environment where power supply conditions are poor, it is required to continue the operation and reduce the user's feeling of discomfort as much as possible even if the air conditioning capacity is reduced even if the voltage is out of the rated voltage range. Therefore, as described with reference to FIG. 6, in an environment where power supply conditions are poor, operation at a voltage lower than the lower limit voltage (207 volts) of the rated voltage range is required.

Next, the difference between the operation of the step-up chopper circuit 5 in the case where the air conditioner 70 is operated at the rated voltage (230 volts) and in the case where the air conditioner 70 is operated at the lower limit voltage of the rated voltage (200 volts) will be described.
When the air conditioner 70 is operated at an AC voltage of 230 volts and 200 volts, the target voltage of the DC voltage is the same at 380 volts.
And when the voltage width of AC voltage drop due to instantaneous voltage drop is constant (30 volts) at each voltage, that is, when AC voltage drops to 200 volts, AC voltage becomes 200 volts to 170 volts. In the case of a drop, the width of the DC drop in each case is also about 48 volts. This is because the current flowing out from the smoothing capacitor 5a to the inverter 6 is larger than the current flowing into the smoothing capacitor 5a provided in the step-up chopper circuit 5, so the voltage is reduced by the insufficient current.

On the other hand, when the instantaneous voltage drop ends and the AC voltage recovers to the original voltage, the higher the AC voltage immediately before the instantaneous voltage drop occurs, the larger the bounce voltage. That is, the bounce voltage due to the instantaneous voltage drop generated when operating at 200 volts is larger than when the air conditioner 70 is operating at an AC voltage of 230 volts.
The outdoor unit controller 9 boosts the voltage rectified by the rectifier 4 via the boost chopper circuit 5 to the target voltage, so that the boost level is increased as the input voltage is lower, that is, as the AC voltage is lower. Control. Specifically, the outdoor unit controller 9 widens the on-duty width of the switching signal.

  Even if the instantaneous voltage drop ends in this state and the AC voltage returns to the original voltage, however, there is a delay in control due to the feedback time described above, so a bounce voltage is generated until a certain feedback time elapses. In particular, when operating at a low AC voltage, the on-duty width of the switching signal becomes wide, and as a result, the bouncing voltage also becomes large, and there is a possibility that the switching element may be broken as described above.

  In order to prevent the generation of the bounce voltage, the step-up chopper circuit 5 may be stopped as soon as the DC voltage is slightly lower than the target voltage. That is, if the voltage difference threshold for monitoring the drop of the DC voltage from the target voltage is reduced by the stop instructing unit 65, it becomes possible to prevent the generation of the bounce voltage during the operation at 200 volts of AC.

  However, if the voltage difference threshold is reduced correspondingly to the operation at 200 volts AC, there arises a problem that the air conditioning is not sufficiently performed when operating at a voltage higher than 200 volts AC, for example, 250 volts.

As described above, the higher the AC voltage, the higher the bounce voltage. In other words, the higher the AC voltage, the lower the bounce voltage, that is, there is no risk of breaking the switching element. When the AC voltage is high as described above, the operation of the step-up chopper circuit 5 is stopped when the DC voltage is lowered by a small voltage difference threshold value, although there is no risk of damaging the switching element. This increases the frequency at which the operation of the step-up chopper circuit 5 is stopped more frequently than when using a large voltage difference threshold determined corresponding to the rated voltage range described in FIG. 7, and as a result, air conditioning is sufficiently performed. Make the user uncomfortable.
As described above, there were different problems when the AC voltage was high and low.

JP, 2015-80317, A (page 13-15, FIG. 1)

  The present invention solves the above-mentioned problems and destroys the elements of the step-up chopper circuit due to the instantaneous voltage drop regardless of the AC voltage of the AC power supply in which the air conditioner is used, and the unnecessary operation stop of the step-up chopper circuit. Aim to reduce the

The present invention solves the above-mentioned problems, the invention according to claim 1 of the present invention comprises two input ends to which an AC power supply is connected, and a rectifier connected between two of the input ends. AC voltage detection means for measuring a voltage between two input ends or a voltage between two output ends of the rectifier and outputting it as an AC voltage value of the AC power supply, and a step-up chopper connected to the output end of the rectifier Circuit, an inverter connected to the output end of the step-up chopper circuit, a compressor connected to the output end of the inverter, and a detected DC voltage value connected in parallel to the output end of the step-up chopper circuit A DC voltage detection unit that outputs a DC voltage value, and a control unit that controls the step-up chopper circuit;
The control unit operates the step-up chopper circuit when a difference between DC voltages detected by the DC voltage detection unit deviates by a predetermined voltage difference threshold or more from a target voltage value that is an output voltage of the step-up chopper circuit as a target. The air conditioner to stop the
The air conditioner includes clock means, voltage data storage means, center voltage extraction means, and voltage difference threshold selection means.
The clocking means outputs the clocked time,
The voltage data storage means is inputted with the detected AC voltage value and the counted time and staying time in which an AC voltage detected for each of a range of AC voltages divided in advance is kept within the range of the AC voltage Store a representative voltage determined for each AC voltage range,
The central voltage extraction means reads out the stored residence time and the representative voltage, extracts the representative voltage in the voltage range in which the residence time is the longest, and outputs it as a central voltage value.
The voltage difference threshold selection means selects and outputs the voltage difference threshold corresponding to the central voltage value input from among a plurality of predetermined voltage difference thresholds.

  By using the above-described means, according to the air conditioner of the present invention, destruction of the elements of the step-up chopper circuit due to instantaneous voltage drop regardless of the AC voltage of the AC power supply in which the air conditioner is used, and boost chopper Unnecessary operation stoppage of the circuit can be reduced.

It is a block diagram which shows the Example of the air conditioner by this invention. It is explanatory drawing of AC voltage data memorize | stored. It is explanatory drawing explaining operation | movement of this invention, and has shown the case where it transfers to a high voltage power supply environment from a standard voltage power supply environment. It is explanatory drawing explaining operation | movement of this invention, and has shown the case where it transfers to a low voltage power supply environment from a standard voltage power supply environment. It is a block diagram showing a conventional air conditioner. It is explanatory drawing explaining operation | movement of the conventional air conditioner, and has shown the time of instantaneous voltage drop generate | occur | producing below the lower limit voltage of a rated voltage. It is explanatory drawing explaining the operation | movement of the conventional air conditioner, and has shown the time of instantaneous voltage fall having generate | occur | produced in rated voltage.

  Hereinafter, embodiments of the present invention will be described in detail as examples based on the attached drawings. Although the air conditioner shown in FIG. 1 is equipped with a heat exchanger, a blower fan, a solenoid valve, etc., these are not directly related to the present invention and therefore will not be shown or described. The same reference numerals are given to the configuration and the part of the air conditioner 70 described with reference to FIG.

  The air conditioner 20 of FIG. 1 includes an indoor unit 50 and an outdoor unit 40, which are communicably connected to each other. In this air conditioner 20, the rated voltage of the AC voltage is 230 volts, and the rated voltage range in which the operation is guaranteed is the rated voltage ± 10% (207 to 253 volts). The voltages are all effective values. Also, unless stated otherwise, all AC voltages described hereinafter are effective values. In addition, when the AC voltage is lower than the lower limit voltage of the rated voltage range, the air conditioner 20 is limited to the air conditioning capacity capable of continuous air conditioning operation to give priority to the continuation of the operation over the maintenance of the room temperature with respect to the set temperature. It has become.

  The outdoor unit 40 detects the voltage between the input end 1 and the input end 2 of the rectifier 4 connected to the input end (the input end 1 and the input end 2) to which an AC power supply (not shown) is connected. The AC voltage detection unit 3 that outputs as the input terminal (positive electrode input terminal 5b and negative electrode input terminal 5c) is connected to the output terminal (positive electrode output terminal 4a and negative electrode output terminal 4b) of the rectifier 4 and the smoothing capacitor 5a is inside A boost chopper circuit 5 provided, an inverter 6 connected to an output end (positive electrode output end 5 d and a negative electrode output end 5 e) of the boost chopper circuit 5, and a compressor 7 connected to an output end of the inverter 6 There is.

  Furthermore, the outdoor unit 40 is connected in parallel to the output end of the step-up chopper circuit 5 and outputs the detected voltage as a DC voltage value, the negative electrode output end 4 b of the rectifier 4 and the negative electrode of the step-up chopper circuit 5 A current detection unit 10 connected in series between the input terminals 5c and an outdoor unit control unit 9 that controls the entire outdoor unit 40 in accordance with an instruction from the indoor unit 50 are provided.

  Further, the outdoor unit 40 includes a clock means 11, a voltage data storage means 12, a central voltage extraction means 13, a voltage difference threshold selection means 14 and a stop instruction means 15. Next, these functions will be described.

The clock means 11 always counts the time if an AC power supply is connected between the input end 1 and the input end 2 regardless of the operating condition of the air conditioner 20, and stores the measured time every hour in voltage data storage Output to means 12.
The voltage data storage means 12 receives the detected AC voltage value and the counted time, respectively, and adds up the total residence time in which the AC voltage detected for each range of the AC voltage divided in advance is kept in the voltage range Remember. Since a microcomputer with a high processing speed is required to measure an accurate residence time, a simple method is used in the present application.

Generally, the AC voltage often rises and falls gradually depending on the time of day, and there are few rapid changes other than instantaneous voltage changes. For this reason, the voltage data storage means 12 sets the dwell time value of the divided voltage range corresponding to the AC voltage value inputted at that time to one minute at the timing when the clocked time is inputted every one minute. to add. That is, although the voltage data storage unit 12 measures the AC voltage value only once per minute, the AC voltage does not change for one minute after the measurement.
As mentioned above, in order to improve this accuracy, it is preferable to measure the AC voltage at shorter intervals.

  In addition, voltage data storage means 12 has voltage data (AC voltage range and residence time) when 24 hours, one week, one month has elapsed, based on the time when the air conditioner 20 is installed and AC voltage is detected for the first time. The representative voltage is output to the center voltage extraction means 13. The representative voltage is a value representative of the divided voltage range, and is stored in advance for each voltage range. The representative voltage will be described in detail later. In addition, the voltage data storage means 12 outputs voltage data in a one-month cycle after one month has passed.

  When the voltage data stored in the voltage data storage unit 12 is input, the center voltage extraction unit 13 extracts a representative voltage of the AC voltage in the voltage range in which the residence time is the longest and outputs it as a center voltage value. The central voltage value is a representative value of the voltage range in which the residence time is longest in a certain period, which will be described in detail later.

The voltage difference threshold selection means 14 selects a voltage difference threshold value corresponding to the input center voltage value from among a plurality of voltage difference threshold values predetermined so that the value may increase as the center voltage value decreases. It is outputted to the stop instructing means 15. In this embodiment, the reference voltage of the center voltage value is defined as three types of 255 volts, 235 volts and 205 volts, and voltage difference threshold values of 80 volts, 50 volts and 20 volts are previously set corresponding to the respective reference voltages. It is allocated and stored in the voltage difference threshold selection means 14. When the input center voltage value is other than the above three reference voltages, the voltage difference threshold selection means 14 is a voltage difference corresponding to the reference voltage closest to the input center voltage value among the three reference voltages. Select a threshold.

  Since the voltage data storage means 12 does not output voltage data unless a predetermined time elapses as described above, the voltage difference threshold selection means 14 receives the voltage difference threshold of the initial value (50 volts) as the first center voltage value. Output until it is done. The voltage difference threshold as an initial value may be set to 20 volts. In this case, although unnecessary stop of the step-up chopper circuit 5 may occur due to the instantaneous voltage drop as described later, the possibility that the circuit element of the step-up chopper circuit 5 is broken is reduced.

  The stop instruction means 15 controls the outdoor unit to stop the stop signal which is an instruction to stop the operation of the step-up chopper circuit when the inputted DC voltage value and the target voltage value deviate by the voltage difference threshold value selection means 14 or more. Output to section 9. For example, when the voltage difference threshold value is 50 volts and the target voltage value is 380 volts, the stop instruction unit 15 outputs a stop signal when the DC voltage value falls to 330 volts or less.

  The outdoor unit controller 9 generates a drive signal (switching signal) for driving the compressor 7 at a predetermined rotational speed by PWM control and outputs it to the inverter 6, and the DC voltage value detected by the DC voltage detector 8 is The power factor is improved based on the detected current signal detected by the current detection unit 10 and the rectified output voltage signal detected by the AC voltage detection unit 3 so as to be the target voltage of the output voltage of the step-up chopper circuit 5. The switching signal is generated by PWM control and output to the step-up chopper circuit 5. Further, when the stop signal is inputted from the stop instructing means 15, the outdoor unit controller 9 stops the switching signal outputted to the step-up chopper circuit 5. Further, the outdoor unit controller 9 outputs a target voltage value which is a target of the output voltage of the step-up chopper circuit 5 to the stop instructing means 15.

  In addition, when the detected AC voltage is lower than the lower limit voltage (207 volts) of the rated voltage range, the outdoor unit controller 9 sets the air conditioning capacity to the minimum, that is, the rotation speed of the compressor 7 by the inverter 6 is minimized. Control the continuation of operation prior to the maintenance of room temperature to temperature.

FIG. 2 is an explanatory view for explaining the storage contents of the three voltage data stored in the voltage data storage means 12 described above. Each voltage data is stored in different power supply environments. Here, in the case of a high voltage power supply environment (A) where the AC voltage supplied to the air conditioner is high, in the case of a standard voltage power supply environment (B) where the AC voltage is standard, a low voltage power supply environment (C) where the AC voltage is low The example of each memory content in the case of is shown.
Items of each voltage data are determined in the order of detection AC voltage (unit: volt), residence time (unit: hour), and representative voltage (unit: volt) from the left, and other than residence time is a predetermined fixed value. is there. The term of the detected AC voltage is divided into 16 steps (10-volt intervals) of voltage range between 300 volts and 160 volts.
In the present embodiment, the central value of this voltage range is determined in advance as a representative voltage in the voltage range. Further, a representative voltage in a voltage range in which the residence time is the longest is referred to as a center voltage.

  The voltage data storage means 12 inputs time from the clock means 11 every 1/60 hour (every 1 minute), 1/60 to the value of the staying time of the voltage range corresponding to the AC voltage value when the time is input. 60 hours are added. This is the residence time for each voltage range described above. In order to improve the detection accuracy, it may be made in units of one second instead of every one minute.

In the case of the high voltage power supply environment (A), the central voltage extracting means 13 has a voltage of less than 260 volts to 250 volts or more because the time during which the AC voltage stays below 260 volts to 250 volts is longer than other voltage ranges. The representative voltage of 255 volts is extracted from the term of the representative voltage corresponding to the range, and is output as the central voltage value of the high voltage power supply environment. Similarly, the central voltage extraction means 13 outputs the central voltage value of 235 volts in the standard environment (B) and 205 volts in the low voltage power supply environment (C). In addition, the central voltage extraction means 13 outputs the representative voltage of the lowest voltage range as a central voltage value, when the residence time of the same value exists in several voltage ranges. This is to give priority to the protection of the device in response to the low AC voltage since the bounce voltage becomes large at the low AC voltage.

  Next, the operation of the air conditioner 20 will be described with reference to FIG. 3 when the instantaneous voltage drop occurs when the AC voltage is at the rated voltage and when the instantaneous voltage drop occurs when the AC voltage is 250 volts. The horizontal axis of FIG. 3 represents time, and the vertical axis represents voltage. 3 (1) shows the change of the AC voltage applied to the air conditioner 20, FIG. 3 (2) shows the DC voltage outputted from the step-up chopper circuit 5, and FIG. 3 (3) shows the voltage difference threshold selection means 14 3 (4) shows the stop signal output from the stop instruction means 15, respectively.

  Note that t0 to t12 indicate time. As a precondition, it is assumed that the outdoor unit controller 9 controls the step-up chopper circuit 5 with a target voltage value of 380 volts. Further, it is assumed that the voltage difference threshold selection means 14 outputs a voltage difference threshold value of 50 volts to the stop instruction means 15 as an initial value.

  As shown in FIG. 3 (1), the AC voltage applied to the air conditioner 20 maintains 230 volts of the rated voltage until t1, but an instantaneous voltage drop occurs at t1, and at minimum 196 volts (rated voltage After the voltage temporarily drops to -15%, the voltage returns to the original 230 volts at t5.

  On the other hand, in the step-up chopper circuit 5, the DC voltage can not be maintained at the target voltage (380 volts) as shown in FIG. The DC voltage gradually decreases from t2.

  The stop instruction means 15 constantly monitors the target voltage value output from the outdoor unit controller 9 and the DC voltage value, and a voltage difference threshold (50 volts) in which the DC voltage value is specified more than the target voltage value. As shown in FIG. 3 (4), the stop signal which is a pulse signal is output to the outdoor unit controller 9 at time t3 when the above difference occurs. The outdoor unit controller 9 to which this signal is input stops the output of the switching signal to stop the operation of the step-up chopper circuit 5.

  Therefore, as previously confirmed by the experiment, the drop of the DC voltage shown by the broken line in FIG. 3 (2) is 52 volts, and as a result, it is possible to prevent in advance the phenomenon that the bounce voltage becomes 590 volts at t6. . The outdoor unit controller 9 resumes the operation of the step-up chopper circuit 5 after one second, for example, after the time when the momentary voltage drop is considered to be settled has elapsed.

  On the other hand, the voltage data storage means 12 is a target voltage of the AC voltage detected every one minute from the time when the AC voltage is detected for the first time after the installation of the air conditioner 20 with respect to the voltage data stored therein. Add 1/60 hours to the column Stay time in the range. Then, after the installation of the air conditioner 20, the stored voltage data is output to the central voltage extraction means 13 at t7 when 24 hours have elapsed on the basis of the first detection of the AC voltage.

When the air conditioner 20 was installed, the AC voltage was at 230 volts of the rated voltage, and then the AC voltage gradually shifted to a voltage higher than the rated voltage, and the voltage data storage means 12 detected the AC voltage for the first time As a result of recording the AC voltage for 24 hours with reference to the time, the voltage data of FIG. 2A is stored in the voltage data storage means 12. The central voltage extraction means 13 to which this voltage data is inputted searches for the residence time of the voltage data of FIG. 2A, and extracts 6.7 H having the longest residence time. Then, the central voltage extraction means 13 outputs 255 volts, which is a representative voltage corresponding to the residence time, as a central voltage value . The voltage difference threshold selection means 14 into which the central voltage value of 255 volts is input is the reference voltage of 255 volts which is the closest voltage among the three reference voltages stored internally, 255 volts, 235 volts and 205 volts. A voltage difference threshold of 80 volts corresponding to the voltage is output to the stop instructing means 15.

  This is because the current power supply environment used by the air conditioner 20 is not the standard voltage power supply environment assumed at the time of product shipment but the high voltage power supply environment, so the standard voltage power supply environment set as the initial value The voltage difference threshold (80 volts) corresponding to the current high voltage power supply environment is set in the stop instructing means 15 instead of the voltage difference threshold (50 volts) corresponding to.

Then, as shown in FIG. 3A, the AC voltage is maintained at 250 volts until t8, but an instantaneous voltage drop occurs at t8 and the voltage temporarily drops to 216 volts, causing a 34 volt voltage drop. Has occurred. The AC voltage is restored to the original 250 volts at t11.
Therefore, as shown in FIG. 3 (2), the DC voltage maintained at 380 volts according to the target voltage gradually drops from t9 delayed from t8, and the maximum voltage drop of 52 volts at t10 It has become.

  As described above, when instantaneous voltage drops of 34 volts respectively occur in the case of 230 volts AC and 250 volts AC, according to the test results of the instantaneous voltage drops carried out on the test, it corresponds to the instantaneous voltage drops of 34 volts The voltage difference threshold is specified at 50 volts, since the DC voltage drops to a maximum of 52 volts each, and in the case of 230 volts AC, the bounce voltage reaches a maximum of 590 volts. On the other hand, in the case of AC 250 volts, the voltage difference threshold is specified at 80 volts because the bounce voltage rises only up to 420 volts at the maximum and there is no concern about element breakdown.

  Next, the operation of the air conditioner 20 will be described with reference to FIG. 4 when the instantaneous voltage drop occurs when the AC voltage is at the rated voltage and when the instantaneous voltage drop occurs when the AC voltage is 200 volts. The horizontal axis in FIG. 4 represents time, and the vertical axis represents voltage. 4 (1) shows the change of the AC voltage applied to the air conditioner 20, FIG. 4 (2) shows the DC voltage outputted from the step-up chopper circuit 5, and FIG. 4 (3) shows the voltage difference threshold selection means 14 FIG. 4 (4) shows the stop signal output from the stop instructing means 15.

  Note that t20 to t34 indicate time. As a precondition, it is assumed that the outdoor unit controller 9 controls the step-up chopper circuit 5 with a target voltage value of 380 volts. Further, it is assumed that the voltage difference threshold selection means 14 outputs a voltage difference threshold value of 50 volts to the stop instruction means 15 as an initial value.

  As shown in FIG. 4 (1), the AC voltage applied to the air conditioner 20 maintains 230 volts of the rated voltage until t21, but an instantaneous voltage drop occurs at t21 and at a minimum of 200 volts (rated voltage After the voltage temporarily drops to -13%), at t25, the voltage returns to the original 230 volts.

  On the other hand, in the step-up chopper circuit 5, the DC voltage can not be maintained at the target voltage (380 volts) as shown in FIG. The DC voltage gradually decreases from t22 and reaches a maximum voltage drop of 48 volts at t24. Since 48 volts of this voltage drop is smaller than 50 volts of the voltage difference threshold, the stop instruction means 15 does not output the stop signal. As a result, at t26, a jump voltage of up to 500 volts is generated.

  On the other hand, the voltage data storage means 12 is a target voltage of the AC voltage detected every one minute from the time when the AC voltage is detected for the first time after the installation of the air conditioner 20 with respect to the voltage data stored therein. Add 1/60 hours to the column Stay time in the range. After the installation of the air conditioner 20, the stored voltage data is output to the central voltage extraction means 13 at t27 when 24 hours have elapsed based on the first detection of the AC voltage.

When the air conditioner 20 was installed, the AC voltage was at 230 volts of the rated voltage, and then the AC voltage gradually shifted to a voltage lower than the rated voltage, and the voltage data storage means 12 detected the AC voltage for the first time As a result of recording the AC voltage for 24 hours with reference to the time, the voltage data of FIG. 2C is stored in the voltage data storage means 12. The central voltage extraction means 13 to which this voltage data is inputted searches for the residence time of the voltage data in FIG. 2C, and extracts 7.8 H having the longest residence time. Then, the central voltage extraction means 13 outputs 205 volts, which is a representative voltage corresponding to this residence time, as a central voltage value . The voltage difference threshold selection means 14 into which the central voltage value of 205 volts is input is the reference voltage of 205 volts which is the closest voltage among the three reference voltages of 255 volts, 235 volts and 205 volts stored inside. A voltage difference threshold of 20 volts corresponding to the voltage is output to the stop instruction means 15.

  This is because the current power supply environment used by the air conditioner 20 is not the standard voltage power supply environment assumed at the time of product shipment but the low voltage power supply environment, so the standard voltage power supply environment set as the initial value The voltage difference threshold (20 volts) corresponding to the current low voltage power supply environment is set in the stop instructing means 15 instead of the voltage difference threshold (50 volts) corresponding to.

  Then, as shown in FIG. 4 (1), the AC voltage is maintained at 200 volts until t28, but an instantaneous voltage drop occurs at t28 and the voltage temporarily drops to 170 volts, causing a voltage drop of 30 volts. Has occurred. The AC voltage is restored to the original 200 volts at t32. For this reason, as shown in FIG. 4 (2), the DC voltage maintained at 380 volts according to the target voltage gradually decreases from t29 delayed from t28. Since the current AC voltage (200 volts) is lower than the lower limit voltage (207 volts) of the rated voltage range, the air conditioner 20 is operated with the air conditioning capacity minimized.

  The stop instruction means 15 constantly monitors the target voltage value output from the outdoor unit controller 9 and the DC voltage value, and a voltage difference threshold (20 volts) in which the DC voltage value is specified more than the target voltage value. As shown in FIG. 4 (4), the stop signal which is a pulse signal is output to the outdoor unit controller 9 at t30 where the above is deviated. The outdoor unit controller 9 to which this signal is input stops the output of the switching signal to stop the operation of the step-up chopper circuit 5.

  For this reason, as shown by the broken line in FIG. 4 (2) confirmed in advance by experiments, it is possible to prevent the phenomenon that the drop of the DC voltage becomes 48 volts and the bounce voltage becomes 600 volts at t34.

Next, a method of experimentally determining the three voltage difference thresholds described above will be described.
First, it operates at the maximum air conditioning capacity at 207 volts of the lower limit voltage (230 V-10%) of the rated voltage range, and in this state, the voltage drop due to the instantaneous voltage drop is gradually lowered. Then, the DC voltage when the peak value of the bounce voltage which gradually rises in conjunction with the voltage drop becomes just before the withstand voltage of the switching element of the step-up chopper circuit 5 is taken as the voltage difference threshold in the standard voltage power supply environment. In this embodiment, the voltage difference threshold in this case is 50 volts.

  Next, the AC voltage is lower than the lower limit voltage 207 V of the rated voltage range, and the air conditioner 20 is operated at the AC voltage which can be continuously operated with the minimum operation capacity (the compressor 7 does not stop), Gradually lower the voltage drop due to the instantaneous voltage drop. Then, the DC voltage when the peak value of the jump voltage which gradually rises in conjunction with the voltage drop becomes just before the withstand voltage of the switching element of the step-up chopper circuit 5 is taken as the voltage difference threshold in the low voltage power supply environment. In this embodiment, the voltage difference threshold in this case is 20 volts.

Next, it operates with the maximum air conditioning capacity at 253 volts, the upper limit voltage (230 V + 10%) of the rated voltage range, and in this state, the voltage drop due to the instantaneous voltage drop is gradually lowered. Then, the DC voltage when the peak value of the jump voltage which gradually rises in conjunction with the voltage drop becomes just before the withstand voltage of the switching element of the step-up chopper circuit 5 is taken as the voltage difference threshold in the high voltage power supply environment. In this embodiment, the voltage difference threshold in this case is 80 volts.
It goes without saying that in determining the voltage difference threshold, the margin is considered in conditions such as the temperature and various voltages.

As described above, the three voltage difference thresholds are determined in consideration of the worst conditions in the AC voltage and the driving ability. For this reason, when the voltage drop threshold due to the instantaneous voltage drop is small under the conditions when the voltage difference threshold is determined, or when the AC voltage is higher than the condition or when operating with a small air conditioning capacity, the bounce voltage determines the voltage difference threshold It becomes smaller than the case of. In the present invention, these three voltage difference thresholds are switched and used in accordance with the power supply environment of the AC voltage.
Therefore, in the wide range of the AC voltage, it is possible to prevent the breakdown of the element due to the bounce voltage and to prevent the unnecessary stop of the step-up chopper circuit 5 due to the instantaneous voltage drop.

  Further, the voltage data storage means 12 stores the voltage data storage means 12 when 24 hours, one week, one month respectively has elapsed based on the time when the installation work is completed and the AC voltage is detected for the first time By outputting the voltage data, the central voltage value and the corresponding voltage difference threshold are updated. Therefore, the air conditioner 20 first updates the voltage difference threshold only with the voltage data collected 24 hours immediately after the installation of the air conditioner 20, and the elapsed time from the installation, that is, the collected voltage data is large As the voltage difference threshold is updated stepwise, the accuracy of the voltage difference threshold selection can be gradually improved.

In the present embodiment, the voltage difference threshold selection means 14 is configured to select and output one voltage difference threshold from among three voltage difference thresholds corresponding to the input center voltage value , but is limited to this. Instead, the voltage difference threshold may be determined at a rate corresponding to the input center voltage value .

  In the present embodiment, although the difference between the target voltage of the DC voltage output from the step-up chopper circuit and the actually detected DC voltage is compared with the voltage difference threshold, the operation / stop of the step-up chopper circuit is determined. The present invention is not limited to this, and for example, the average value of a plurality of continuous DC voltages actually detected in a cycle of 1 millisecond may be used as the target voltage value immediately before the DC voltage sharply drops due to the instantaneous voltage drop. This scheme can detect an accurate DC voltage drop even if the DC voltage is not controlled to the same as the target voltage.

  Further, in the present embodiment, the AC voltage detection unit 3 detects the voltage between the input end 1 and the input end 2 and outputs it as an AC voltage value, but the present invention is not limited to this. Alternatively, the voltage between the positive electrode output end 4a and the negative electrode output end 4b of the rectifier 4 may be detected, converted into an AC voltage value, and output.

  Further, in the present embodiment, the AC voltage is applied to the air conditioner 20 for the first time, and the voltage data stored in the voltage data storage means 12 is output when 24 hours, one week and one month have elapsed respectively, Although the configuration is such that the central voltage value and the corresponding voltage difference threshold are updated, the present invention is not limited to this. The voltage difference threshold is updated each time the voltage data storage unit 12 updates voltage data. It is also good. As a result, it is possible to quickly respond to the current power supply situation by shortening the period for updating the voltage difference threshold.

DESCRIPTION OF SYMBOLS 1 input end 2 input end 3 AC voltage detection part 4 rectifier 4a positive electrode output end 4b negative electrode output end 5 boost chopper circuit 5a smoothing capacitor 5b positive electrode input end 5c negative electrode input end 5d positive electrode output end 5e negative electrode output end 6 inverter 7 compressor 8 DC voltage detection unit 9 outdoor unit control unit 10 current detection unit 11 clocking unit 12 voltage data storage unit 13 central voltage extraction unit 14 voltage difference threshold selection unit 15 stop instruction unit 20 air conditioner 40 outdoor unit 50 indoor unit

Claims (1)

Measuring the voltage between the two input ends or the two output ends of the rectifier, and the rectifier connected between the two input ends to which the AC power supply is connected; AC voltage detection means for outputting as the AC voltage value of the AC power supply, a boost chopper circuit connected to the output end of the rectifier, an inverter connected to the output end of the boost chopper circuit, and an output end of the inverter A compressor connected, a DC voltage detection unit connected in parallel to the output terminal of the step-up chopper circuit and outputting a value of the detected DC voltage as a DC voltage value; and a control unit controlling the step-up chopper circuit Equipped
The control unit operates the step-up chopper circuit when a difference between DC voltages detected by the DC voltage detection unit deviates by a predetermined voltage difference threshold or more from a target voltage value that is an output voltage of the step-up chopper circuit as a target. The air conditioner to stop the
The air conditioner includes clock means, voltage data storage means, center voltage extraction means, and voltage difference threshold selection means.
The clocking means outputs the clocked time,
The voltage data storage means is inputted with the detected AC voltage value and the counted time and staying time in which an AC voltage detected for each of a range of AC voltages divided in advance is kept within the range of the AC voltage Store a representative voltage determined for each AC voltage range,
The central voltage extraction means reads out the stored residence time and the representative voltage, extracts the representative voltage in the voltage range in which the residence time is the longest, and outputs it as a central voltage value.
The air conditioner, wherein the voltage difference threshold selection means selects and outputs the voltage difference threshold corresponding to the central voltage value input from among a plurality of predetermined voltage difference thresholds.

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