JPH0136040Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention relates to a heat pump type air conditioner.

(Prior Art) Conventionally, when a heat pump type air conditioner starts heating operation, the compressor immediately rotates and starts compression. However, after a long period of stoppage of the compressor (1
time), the compressor temperature has decreased to a value close to the outside air temperature, and it takes about 5 to 8 minutes for the compressor temperature to rise sufficiently. Particularly in the case of a high-pressure container-type rotary compressor, the discharged gas at the start of operation liquefies and remains in the compressor container, and it takes more time for the discharged gas pressure to rise.

Then, indoor heating is started only when the compressor discharge gas pressure increases and the indoor heat exchanger temperature rises to a predetermined value or higher.

For this reason, heat pumps currently use compressors whose capacity is variable by controlling the power supply frequency, and operate at high capacity at startup to accelerate the rise in compressor temperature and discharge gas temperature, shortening the startup time. There is an air conditioner.

FIG. 1 shows temperature changes in the compressor and indoor heat exchanger before and after the start of operation of such a heat pump air conditioner. In the figure, the time at which the operation starts is set as 0 minutes.

Until this 0 minute, the outdoor temperature of the compressor is 4°C, and the indoor temperature of the indoor heat exchanger is 20°C. As the operation starts, the compressor temperature increases. On the other hand, the temperature of the indoor heat exchanger starts to rise after the compressor temperature reaches room temperature or higher.

After this, the temperature of the indoor heat exchanger is set to the specified value (40℃)
Only after this happens will the indoor fan start operating.
This heats the room. During this time, approximately 5 minutes have passed.

(Problem to be solved by the invention) As mentioned above, even in a heat pump type air conditioner with a variable capacity compressor, the rise time is 4
It took about 6 minutes and the startup speed was slow compared to heating appliances such as kerosene stoves, which could not be overcome.

In addition, as shown in Japanese Patent Application Laid-Open No. 58-140571, a heat pump type air conditioner using an inverter device consisting of a rectifier circuit, a smoothing capacitor, and a switching section 5 to control compressor heating is used during the heating operation stoppage. Some compressors heat the compressor by applying low power from an inverter to the compressor due to conditions such as a drop in outside temperature.

However, in the heat pump type air conditioner disclosed in JP-A-58-140571, the energization/de-energization of the compressor during shutdown is controlled by the output of the inverter device, so the inverter device is constantly powered. is supplied.

Therefore, even when conditions such as a drop in outside temperature are not met, the inverter device is energized, and a high voltage is applied across the smoothing capacitor installed on the power supply side of the inverter device. The problem was that it shortened its lifespan.

Therefore, the present invention was made in consideration of such circumstances, and its purpose is to improve the start-up speed of heating operation using an inverter device, and to extend the life of the smoothing capacitor that constitutes the inverter device. .

[Structure of the idea]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a heat pump air conditioner that includes a rectifier circuit that rectifies input from an AC power supply, and a smoothing circuit connected to the output of the rectifier circuit. A switching section is installed between the capacitor, the switching section that is connected to the output of this smoothing capacitor and supplies the compressor with an output that drives the compressor at variable speed and an output that energizes and heats the compressor when it is stopped, and the AC power supply and the rectifier circuit. A relay that controls energization to the rectifier circuit during heating operation and when a predetermined condition is not met, the relay is opened and the energization to the rectifier circuit is cut off, and when the predetermined condition is met, the relay is closed. A heat pump type air conditioner is provided with a control means for supplying electricity to a switching part in a stopped state to output heating to a compressor.

(Function) If predetermined conditions are met while the heating operation is stopped, the heating output is supplied from the switching unit to the compressor in the stopped state, thereby improving the startup speed of the heating operation, and also stopping the heating operation. When the compressor is stopped, the relay closes and voltage is applied to the smoothing capacitor only when the compressor is supplied with an output that heats the compressor in the stopped state, so the life of the smoothing capacitor can be extended.

(Example) An example of the present invention will be described with reference to FIGS. 2 to 6. FIG. 2 is a block diagram showing an inverter which is a power source for driving the compressor motor 1 at variable speed. This inverter first converts alternating current from an alternating current power source 2 into direct current by a rectifier circuit 3, smoothes this direct current by a smoothing circuit 4 consisting of a smoothing capacitor, and reduces ripple. It is supplied to the switching section 5 where the signal is switched.

Further, a main relay 6 having two contacts is connected between the AC power source 2 and the rectifier circuit 3 and is interlocked with a power switch (not shown). A sub-relay 7 is inserted between the OFF-side contact of the main relay 6 and the rectifier circuit 3.

The switching section 5 generates a quasi-sine wave alternating current by turning on/off individual switching elements, and supplies it to the compressor motor 1. This switching element is activated by a signal from the control section 8.
Turns ON/OFF.

The control unit 8 uses a constant voltage circuit 9 that obtains a DC voltage from the AC power supply 2 as a power source.

This control unit 8 includes a ROM in which ON/OFF timings of switching elements are written in advance.
It consists of a CPU etc. that extracts the contents of the ROM.

of the switching element written in the ROM
The ON/OFF timing is set so that the output frequency and output voltage of the switching unit 5 are in a substantially directly proportional relationship because it is necessary to keep the torque of the compressor motor 1 constant. That is, as shown in Figure 3, the lowest frequency is 30Hz, and the highest frequency is 90Hz from point A in the figure.
Hz, the output voltage increases from 80V to point B in the diagram.
It is set to change linearly to 180V.

Furthermore, in this embodiment, a 90 Hz high frequency, 20 V low voltage pattern, indicated by point C in the figure, is written in the ROM as a heating pattern during stoppage.

Further, the control unit 8 is provided with a temperature sensor 10 that detects the compressor temperature and a relay circuit that operates the sub-relay 7. The temperature detected by the temperature sensor 10 is compared with two set values by the CPU in the control section 8, and the relay circuit is operated according to the results.

That is, in this embodiment, the compressor motor 1 is heated on the condition that the compressor temperature decreases.

The refrigeration cycle of this embodiment is a known heat pump type refrigeration cycle shown in FIG.
3. It is constructed by sequentially communicating outdoor heat exchangers 14.

The operation of the above configuration will be explained. When the air conditioner is not operating during heating (thermo is not OFF), the main relay 6 is OFF, and the compressor 1 temperature decreases according to the outside temperature. At this time, when the temperature detected by the temperature sensor 10 becomes lower than the lower limit setting value (20° C.), the CPU operates the relay circuit in the control unit 8, turns on the sub-relay 7, and connects the inverter and the AC power source 2. Furthermore, the CPU specifies the output of the heating pattern to the ROM. As a result, the switching element generates an output of 90 Hz and 20 V, which is a heating pattern, and supplies it to the compressor motor 1.

At this high frequency and low voltage of 90Hz and 20V, the torque is small, so the compressor motor 1 cannot be started and does not rotate. The coil of the compressor motor 1 generates heat due to the 90 Hz, 20 V alternating current, and the compressor motor 1 is heated. If the temperature detected by the compressor's temperature sensor 10 exceeds the upper limit set value of 40℃ due to heating,
The CPU stops outputting the heating pattern and simultaneously turns off the sub-relay 7.

By turning off the relay 7, no voltage from the power supply is applied to both ends of the smoothing capacitor in the smoothing circuit 4.

FIG. 5 shows the temperature change of the compressor when the above-mentioned control is performed. At point E in the figure, the compressor temperature becomes below the lower limit set value, the compressor is heated by the heating pattern of the inverter, reaches the upper limit set value at point F, and then gradually decreases until it reaches the lower limit set value again.

As described above, in this embodiment, heating and natural temperature reduction are repeated while the air conditioner is in the OFF state during the heating operation stop, and the compressor temperature is always maintained within the range of 20°C to 40°C.

Therefore, no matter when the air conditioner starts heating operation by the user, a timer, etc., the compressor temperature remains at or above the lower limit set temperature, and the start-up time of the air conditioner can be significantly shortened. An example will be explained with reference to FIG. In the figure, the start time of operation is set to 0 (minutes).
At this time, the compressor temperature is approximately 28
℃, and the indoor heat exchange temperature is 20℃. When heating starts, the compressor as well as the oil and refrigerant inside the compressor are at about 28°C.

For this reason, the compressor temperature rises rapidly as soon as the compressor starts operating, and the temperature of the indoor heat exchanger rises accordingly, and after about 1.5 minutes, the temperature reaches 40°C, which is enough to start indoor heating, that is, to operate the indoor blower. The specified amount of warm air is blown into the room.

As mentioned above, according to this embodiment, the compressor temperature is
Constantly maintained in the range of 20°C to 40°C, with a rise time of 1
It only takes ~2 minutes, and operation can be started in 1/3 to 1/5 of the start-up time of conventional heat pump air conditioners, significantly shortening the heating start-up time of heat pump air conditioners.

In addition, if the air conditioner is used frequently, the high capacity operation time when starting the compressor can be shortened, resulting in an energy saving effect.

Furthermore, when the compressor motor 1 does not need to be heated when the operation is stopped during heating, the sub-relay 7 is turned OFF.
Since the power supply voltage is no longer applied to the smoothing capacitor, the life of the smoothing capacitor can be extended.

In this embodiment, a sub-relay 7 is provided after the main relay 6, and this sub-relay 7 is used to control the energization of the inverter during heating of the compressor, but the sub-relay 7 is not provided and the main relay 6 itself is It may be configured to turn ON only when necessary.

As described above, in this embodiment, compression heating was controlled based on the compressor temperature, but almost the same effect can be achieved even if the compressor heating is controlled at fixed intervals while the air conditioner is stopped. is obtained.

In addition, by combining the air conditioner ON timer and compressor heating, the compressor heating is controlled under conditions such as outputting a heating pattern a predetermined time before the time set by the ON timer, for example 20 minutes, and when the timer is used. It is also possible to shorten the heating start-up time.

[Effect of idea]

The present invention consists of a rectifier circuit that rectifies input from an AC power source, a smoothing capacitor connected to the output of this rectifier circuit, an output connected to the output of this smoothing capacitor that drives a compressor at variable speed, and A switching unit supplies power to the compressor to heat the compressor when the heating is stopped, a relay is installed between the AC power source and the rectifier circuit, and controls the power supply to the rectifier circuit. When the relay is opened, the rectifier circuit is cut off, and when a predetermined condition is met, the relay is closed, and the switching section is energized to the compressor while it is stopped to output heat. When a predetermined condition is met while the heating operation is stopped, the heating output can be supplied from the switching unit to the compressor in the stopped state, thereby increasing the startup speed of the heating operation.
Since the relay closes and voltage is applied to the smoothing capacitor only when the predetermined conditions are met and the compressor is heated, the life of the smoothing capacitor can be extended.

[Brief explanation of the drawing]

Figure 1 is a graph showing temperature changes in the compressor and indoor heat exchanger before and after the start of operation of a conventional heat pump type air conditioner, and Figure 2 shows the circuit connections of a heat pump type air conditioner according to an embodiment of the present invention. Schematic diagram shown,
Figure 3 is a graph showing the relationship between the voltage and frequency of the inverter used in the air conditioner, Figure 4 is the refrigeration cycle diagram of the air conditioner, and Figure 5 is the temperature change of the air conditioner's compressor. The graph shown in Figure 6 is
It is a graph showing temperature changes of the compressor and indoor heat exchanger before and after the start of operation of the air conditioner. 1... Compressor (motor), 2... AC power supply, 3
... Rectifier circuit, 4 ... Smoothing circuit, 5 ... Switching section, 6 ... Main relay, 7 ... Sub relay, 8 ... Control section, 10 ... Temperature sensor.

Claims (1)

[Scope of claim for utility model registration] Rectification of input from an AC power source in a heat pump air conditioner having a refrigeration cycle consisting of a compressor, a four-way valve, an indoor heat exchanger, a pressure reducing device, and an outdoor heat exchanger connected in sequence. a rectifying circuit connected to the output of the rectifying circuit, a smoothing capacitor connected to the output of the smoothing capacitor, and outputting an output for variable speed of the compressor 3 and an output for heating the compressor in a stopped state. a switching unit that supplies power to the compressor; a relay that is installed between the AC power source and the rectifier circuit and controls the energization of the rectifier circuit; and if a predetermined condition is not met during a heating stop, the relay is opened and the The compressor is characterized by comprising a control means that cuts off the power to the rectifier circuit, closes the relay when a predetermined condition is satisfied, and causes the switching section to output an output that heats the compressor in a stopped state. A heat pump type air conditioner.