JP3367619B2 - Control device for air conditioner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an air conditioner by inverter control.

[0002]

2. Description of the Related Art A conventional control device for an air conditioner by inverter control will be described below with reference to the drawings. FIG. 9 is a configuration example diagram of a conventional air conditioner control device by inverter control, and FIG. 10 is a timing chart of its protective operation.

In FIG. 9, 1 is a compressor, 2 is a power device, and 3 is a controller. In the power device 2, 4 is a group of 6 semiconductor switching elements, 5 is temperature detection means, 6 is current detection means, 7 is timer means (A), 8 is protection operation signal output means, and 10 is power device PWM drive signal. The output means 18 is an AND circuit, and the power device 2 has a temperature and current protection function. 9 in the control unit 3 is a control unit PWM signal output means,
An AND circuit of the PWM signal from the control unit PWM signal output means 9 and the protection operation signal of the protection operation signal output means 8
At 18, the power device PWM drive signal is created by AND.

Further, the protection operation signal from the protection operation signal output means 8 causes the output of the temperature detection means 5 and the current detection means 6 to be a signal for at least a fixed time by the timer means (A) 7.

In FIG. 10, (a) shows the case of overcurrent protection.
(b) shows each control operation in the case of temperature protection. In the control operation of the overcurrent protection of FIG. 10A, when the current value a2 is smaller than the overcurrent setting level, the semiconductor switching element group 4 in the power device 2 is driven by the control section PWM signal a1. When the overcurrent setting level is reached, the protection operation signal a3
As a result, the semiconductor switching element group 4 in the power device 2 is stopped and the power device 2 is protected. The current value a2 immediately decreases due to the stop and falls below the overcurrent setting level, so that the protection operation signal a3 is generated for a fixed time (T1), and the control unit PWM signal a1 stops the signal output within the time T1. The actual PWM drive in the power device 2 at this time is a4 in (a).
The period is shown in.

In FIG. 10 (b), when the temperature b2 of the power device 2 reaches the set temperature during the temperature protection control operation,
The power device 2 is stopped by the protection operation signal b3.
This protection operation signal b3 is generated for T1 time, but in the case of temperature protection, even if the power device is stopped, the temperature does not immediately drop and the protection operation signal b3 is kept for a certain time (T1) until the return temperature is reached. Is output. In either case of temperature or current, the power device 2 is protected and the protection signal b3
Is transmitted to the control unit. In addition, b1, b3, b4 of (b)
Corresponds to a1, a3, and a4 in (a).

[0007]

However, in the conventional air conditioner control device by inverter control, the power device is stopped and protected by the protection operation signal regardless of temperature or current, and the protection operation signal is sent to the control unit. Although transmitted, the protection operation signal is transmitted to the control unit through one signal line, so that the content of the protection operation of the power device is unknown.

For this reason, for example, in the case of temperature protection, factors such as the mounting state of the power device on the heat sink and in the current protection may be factors such as the overload state of the refrigeration cycle and failure of the power device / circuit. However, there is a problem in that, when it is repeatedly operated by the returning operation after a certain time, other parts such as the compressor are broken and reliability is deteriorated.

On the other hand, when the number of signal lines is increased and the contents of the protection operation are grasped, it is disadvantageous in terms of cost, space and assembling property.

Therefore, the present invention judges the current and temperature which are the protection operation of the power device by one protection operation signal, and the content of the protection operation of the control power supply reduction to the power device, and performs appropriate control after the protection operation. It is also an object of the present invention to realize an appropriate and detailed failure diagnosis display, and at the same time, to improve serviceability such as shortening the determination time of a defective portion by the display.

[0011]

In order to solve the above problems and achieve the object, the present invention provides a compressor, a plurality of semiconductor switching elements, a power device having a temperature protection / current protection function, and the power device. In an air conditioner controlled by an inverter including a control unit driven by a PWM signal, the power device includes a temperature detecting means for device protection, a current detecting means, and a timer for keeping signals from the temperature and current detecting means for at least a certain period of time. Means, a protection operation signal output means for generating a protection operation signal which is an output thereof, and a circuit for ANDing the PWM signal and the protection operation signal from the control unit, and the control unit includes timer means of the power device. Equipped with timer means for longer time than timer, temperature / current protection judgment means, control unit PWM signal output means Enter the protection operation signal from the power device to the control unit, and judging the protection operation content of the power device at a temperature-current protection judging means by comparing the timer time of the control unit.

Further, according to the present invention, when the outdoor fan motor rotation speed storage means is provided in the control unit and the protection operation of the power device by the temperature / current protection determination means is temperature protection, the outdoor fan of the air conditioner is protected. It is characterized by increasing the fan motor rotation speed.

Further, according to the present invention, the power device is further provided with a control power supply drop detecting means, the temperature / current protection determining means of the control part is provided with counter means, and the timer in the control part which operates from the time of inputting the protection operation signal. The protection operation signal level is determined for each timer time of the means, and the protection operation determination means determines the protection operation content based on the count number of the counter means in the control unit.

The present invention further comprises a voltage drop detection means for the DC power applied to the power device, and a protection operation signal from the power device which outputs a protection operation signal to the control section in the case of overheat or overcurrent. A circuit is provided for ORing the signal from the DC power voltage drop detecting means, the OR output is input to the counter means of the control unit, and the protection is performed for each timer time of the timer means that operates after the protection operation signal is input. It is characterized in that the level of the operation signal is judged and the protection operation content is judged by the temperature / current protection judging means by the count number of the counter means.

[0015]

In the present invention, since the protection operation contents of temperature and current are judged by one protection operation signal, when the protection operation signal of the power device is current protection, the signal width of the constant time T1 by the timer means. From this, by operating the timer T2, which is longer than the timer T1 of the power device, in the control unit from the time when the protection operation signal is input, and comparing the signal width of the protection operation signal from the power device, it is possible to determine the protection operation contents of temperature and current. .

Further, according to the present invention, when the protection operation of the power device by the temperature / current protection determination means is the temperature protection, the outdoor fan of the air conditioner is increased above the fan motor rotation speed during the protection operation.

Further, according to the present invention, in the power device further comprising a control power source drop detecting means in the power device and outputting a protection operation signal in case of overheat, overcurrent or control power source drop, the protection operation from the power device is performed. By comparing the protection operation signal level for each T2 with a control timer that is slightly longer than the minimum signal width T1, the current is L level at the first time in the case of current protection, and the temperature of the power device is the recovery point in the case of temperature protection. It takes time to reach. In the case of the count number of the time until then, it can be determined that the control power supply to the power device has dropped.

Further, the present invention comprises a DC power voltage drop detecting means applied to the power device, and provides a protection operation signal when the power device is overheated and overcurrent and a protection operation signal caused by the DC power voltage drop. By comparing the protection operation signal level for each T2 with a control timer that is slightly longer than the minimum width T1 of the protection operation signal input to the control unit by the OR connection, in the case of current protection, the first time it becomes L level, temperature protection In this case, it takes time for the temperature of the power device to reach the return point. In the case of the count number of the time until then, it can be determined that the DC power voltage applied to the power device is lowered.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an air conditioner controller according to a first embodiment of the present invention, and FIG. 2 is a timing chart of protective operation of each part of FIG.

As shown in FIG. 1, in this embodiment, the control unit 3 shown in FIG. 9 of the conventional example has a timer means (B) 11 longer than the timer of the timer means (A) 7 of the power device 2 and a power source. The temperature / current protection determining means 12 receives the protection operation signal from the protection operation signal output means 8 of the device 2. In addition, the same components as those of the above-mentioned conventional FIG. 9 are denoted by the same reference numerals and the description thereof will be omitted.

Next, the operation of each part of FIG. 1 will be described with reference to the timing chart of FIG. 2, where (a) shows the control timing in the case of overcurrent protection and (b) shows the control timing in the case of temperature protection. The actual PWM drive signal of the power device 2 in FIG.
It is created by an AND circuit 18 of the PWM signal from the WM signal output means 9 and the protection operation signal of the protection operation signal output means 8. This protection operation signal outputs the outputs of the temperature detection means 5 and the current detection means 6 to the timer means (A). 7, it is the same as the conventional signal that the signal is at least the predetermined time T1 or more. The timer means (B) 11 starts timer counting by the protection operation signal from the power device 2, and the temperature / current protection determination means 12 compares the protection operation signal width from the power device 2 after a fixed time T2.

First, in the case of overcurrent protection (a), when the current is less than the overcurrent setting level, the semiconductor switching element group 4 in the power device 2 is driven by the control unit PWM signal a1. When the overcurrent setting level is reached, the semiconductor switching element group 4 in the power device 2 is stopped by the protection operation signal a3, and the power device 2 is protected.
When stopped, the current value immediately decreases and falls below the overcurrent setting level, so the protection operation signal a3 is generated for a fixed time (T1),
The control unit PWM signal a1 stops signal output within the time T1. In addition, a4 shows the period of the PWM actual drive in the power device 2.

In the case of temperature protection (b), when the temperature of the power device 2 reaches the set temperature, the power operation device 2 is stopped by the protection operation signal b3. This protection operation signal b3 is T1
Although generated over time, in the case of temperature protection, the temperature does not immediately drop even when the power device 2 is stopped, and the protection operation signal b3 is output until the return temperature is reached.

The timer means (B) 11 of the control unit 3 starts the timer counting by the protection operation signal b3 from the power device 2, and after a certain time T2, the temperature / current protection determination means 12 outputs the protection operation signal from the power device 2. Compare widths.

The constant time T2 shown in FIGS. 2 (a) and 2 (b) is T1.
Since it is a larger value, in the case of overcurrent protection (a), T2
The protection operation signal a3 of the subsequent power device 2 is released. On the other hand, in the case of temperature protection (b), the temperature of the power device 2 has not decreased even after T2, and the protection operation signal b3 is output. By performing this comparison / judgment by the temperature / current protection judgment means 12 of the control unit 3, one protection operation signal is obtained.
With (a3 or b3), the contents of temperature / current protection operation can be determined.

FIG. 3 is a block diagram of a control device for an air conditioner according to a second embodiment of the present invention, FIG. 4 is a protection operation timing chart of each part of FIG. 3, and FIG. (b) is the case of temperature protection.

As shown in FIG. 3, in this embodiment, the control unit 3
The outdoor fan motor rotation speed storage means 13 is equipped with
In the case of the temperature protection operation by the current protection determination means 12, the rotation speed of the outdoor fan motor 14 is increased during the protection operation. The operation timing of each part at this time is as shown in FIG.
Is the timing to increase the fan speed. Others are the same as those in FIG.

FIG. 5 is a block diagram of a control device for an air conditioner according to a third embodiment of the present invention, FIG. 6 is a timing chart of protection operation of each part of FIG. 5, and FIG. (b) is the case of temperature protection.

As shown in FIG. 5, in this embodiment, the power device 2 is provided with a control power supply drop detecting means 15 and the control section 3 is provided with a counter means 16. In FIG. 6, comparing the protection operation signal levels for each T2 with a control timer slightly longer than the minimum width T1 of the protection operation signals (a3, b3) from the power device 2, it can be seen that in the case of overcurrent protection (a) At the first time, L level is required, and in the case of temperature protection (b), time is required until the temperature of the power device 2 reaches the return point (N times). A count number corresponding to this time is set in the counter means 16 in advance, and if it is the count number up to that time, it is determined that the control power supply to the power device 2 has dropped.

FIG. 7 is a block diagram of a control device for an air conditioner according to a fourth embodiment of the present invention, FIG. 8 is a protection operation timing chart of each part of FIG. 7, and (a) is a case of overcurrent protection, (b) is the case of temperature protection.

As shown in FIG. 7, this embodiment comprises a DC power voltage drop detecting means 17 applied to the power device 2, and the controller 3 has a counter means similar to the third embodiment of FIG. In addition to 16, a protection operation signal output means 8 for the power device 2 and an OR circuit 19 for ORing the respective output signals of the DC power voltage drop detecting means 17 are provided. In FIG. 8, the minimum width T of the protection operation signal (a3, b3) from the power device 2
Comparing the protection operation signal levels for each T2 with a control timer that is slightly longer than 1, in the case of overcurrent protection (a), it becomes L level at the first time, and in the case of temperature protection (b), the power device 2 It takes time for the temperature to reach the return point (N times). A count number corresponding to this time is set in the counter means 16 in advance, and if it is the count number up to that time, it is determined that the DC power voltage applied to the power device 2 has dropped.

[0033]

As described above, according to the present invention, the protection operation signal by the temperature detecting means / current detecting means provided in the power device has the signal width of the constant time T1 by the timer means in the case of overcurrent protection. Therefore, the timer T2, which is longer than the timer T1 of the power device, is operated by the control unit from the time when the protection operation signal is input, and the signal width of the protection operation signal from the power device is compared to determine the protection operation contents of temperature and current. By doing so, the contents of the protection operation of temperature and current can be determined easily and inexpensively with one protection operation signal.

From the result of this judgment, factors such as the mounting state of the power device on the heat sink in the temperature protection, the overload state of the refrigeration cycle and the power device / circuit failure in the current protection can be considered. When the repetitive operation is performed by the return operation after a certain period of time, it is possible to prevent the destruction of other parts such as the compressor and the deterioration of reliability. Further, while realizing an appropriate and detailed failure diagnosis display, it is possible to improve serviceability such as shortening the determination time of a defective portion by the display.

Further, according to the present invention, the temperature of the power device and the internal parts of the air conditioner can be quickly lowered by increasing the rotation speed of the outdoor fan motor when the temperature protection operation is judged, and the reliability of the equipment is improved. Can be achieved.

Further, according to the present invention, the protection operation contents of the power device can be easily and inexpensively provided by the protection function of the power device, in addition to the temperature and the current, and even when the control power supply to the power device is lowered. You can judge.

Further, according to the present invention, in addition to temperature and current as a protection function of the power device, one protection operation signal to the control unit is used even in the case of a DC power voltage drop applied to the power device, so that the power device can be easily and inexpensively. The protection operation details of the power device can be determined.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an air conditioner control device according to a first embodiment of the present invention.

FIG. 2 is a timing chart of a protection operation of each part of FIG.

FIG. 3 is a configuration diagram of an air conditioner control device according to a second embodiment of the present invention.

FIG. 4 is a timing chart of a protection operation of each part of FIG.

FIG. 5 is a configuration diagram of an air conditioner control device according to a third embodiment of the present invention.

6 is a protection operation timing chart of each part of FIG.

FIG. 7 is a configuration diagram of an air conditioner control device in a fourth embodiment of the present invention.

FIG. 8 is a timing chart of a protection operation of each part of FIG.

FIG. 9 is a diagram showing a configuration example of a conventional control device for an inverter air conditioner.

10 is a malfunction timing chart of FIG.

[Explanation of symbols]

1 ... Compressor, 2 ... Power device, 3 ... Control unit,
4 ... Semiconductor switching element group, 5 ... Temperature detecting means,
6 ... Current detection means, 7 ... Timer means (A), 8 ... Protective operation signal output means, 9 ... Control part PWM signal output means,
10 ... Power device PWM drive signal output means, 11 ...
Timer means (B), 12 ... Temperature / current protection determination means, 13
... fan motor rotation speed storage means, 14 ... outdoor fan motor, 15 ... control power supply drop detection means, 16 ... counter means, 17 ... DC power voltage drop detection means, 18 ... AND
Circuit, 19 ... OR circuit.

Continuation of front page (56) Reference JP-A-5-322261 (JP, A) JP-A-5-18559 (JP, A) JP-A-2-231964 (JP, A) JP-A-1-209985 (JP , A) JP 63-290194 (JP, A) JP 5-168273 (JP, A) Actually open 5-4782 (JP, U) Actually open 4-39095 (JP, U) Actually open 56-130387 (JP, U) Actually open 4-27334 (JP, U) Actually open 62-47830 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F24F 11/02 102

Claims (4)

(57) [Claims] 1. An inverter-controlled air conditioner comprising a compressor, a plurality of semiconductor switching elements, a power device having a temperature protection / current protection function, and a control unit for driving the power device by a PWM signal. Includes a device protection temperature detecting means, a current detecting means, a timer means for keeping a signal from the temperature and current detecting means at least for a certain period of time, a protection operation signal output means for generating a protection operation signal as its output, and the control. From the PWM signal and the protection operation signal A
A circuit for taking ND is provided, the control unit is provided with a timer unit for a time longer than the timer of the timer unit of the power device, a temperature / current protection determination unit, and a control unit PWM signal output unit, and the control unit is provided with A control device for an air conditioner, wherein a protection operation signal from a power device is input, and the temperature / current protection determination means determines the protection operation content of the power device by comparison with a timer time of a control unit. 2. The outdoor fan motor rotation speed storage means is provided in the control unit, and when the protection operation of the power device is temperature protection, the outdoor fan of the air conditioner is increased above the fan motor rotation speed during the protection operation. The control device for an air conditioner according to claim 1, wherein: 3. The power device is equipped with a control power supply drop detection means for outputting a protection operation signal in the case of overheat, overcurrent, or control power supply drop, and the temperature / current protection determination means of the control part is equipped with a counter means. , The level of the protection operation signal is determined for each timer time of the timer means in the control section that operates from the time when the protection operation signal is input, and the protection operation determination means determines the protection operation content based on the count number of the counter means in the control section. The control device for an air conditioner according to claim 1, wherein: 4. A voltage drop detection means for DC power applied to the power device, wherein the controller is overheated.
A circuit for ORing the protection operation signal from the power device that outputs the protection operation signal in the case of an overcurrent and the signal from the DC power voltage drop detection means is provided, and the OR output is input to the counter means of the control unit. Then, the level of the protection operation signal is determined for each timer time of the timer means operating after the protection operation signal is input, and the content of the protection operation is determined by the temperature / current protection determination means based on the count number of the counter means. The control device for an air conditioner according to claim 1.