| 摘要 |
PURPOSE:To greatly reduce the frosting of an indoor heat exchanger and to increase the range of temperature used for the space cooling operation of air conditioner by making variable the maximum operational frequency of the compressor during the space cooling operation in the case of a thermostat set temperature being low and an outdoor temperature also being low. CONSTITUTION:Firstly, a set temperature value is read in and set and then an outdoor temperature is read in, and the value thus obtained is compared with the set temperature value to judge whether the former is larger or smaller than the latter. When the outdoor temperature is higher than the set temperature value, a first output mode setting the maximum operational frequency of a normal space cooling operation is selected. When the outdoor temperature is lower than the temperature set value, a second output mode setting the maximum operational frequency having a value smaller than the maximum frequency is selected. A power transistor device 12 produces a three-phase waveform by means of an unequal-width pulse outputted from a microcomputer (LSI), and a compressor 18 is driven at a designated frequency. Further, the frequency-voltage characteristic of the compressor 18 is set depending on the width and period of the pulse outputted from the LSI 11, and the compressor 18 is driven. Thus, the frosting of an indoor heat exchanger can be greatly reduced, and the using temperature range of the space cooling operation can be increased.
|
