JPH03179186A - Capacity controller for air-conditioning motor compressor - Google Patents

Abstract

PURPOSE:To enlarge the extent of capacity control width to a low speed range by driving a compressor motor, as a pole-convertible motor, with an inverter, and when operating frequency comes to lower limit, performing the pole- converting control at need. CONSTITUTION:A refrigerating cycle with a motor compressor 1 equipped with both indoor and outdoor heat exchangers 7, 5 and having a pole-converting motor built-in is driven by output frequency being outputted from an inverter 2 which outputs its moderate frequency by a signal of a sensor 8, but if such a signal as lowering the capacity yet more is entered in the inverter 2 in a lower limit stage, it feeds a signal to a pole-conversion controller 3, and the pole number of a motor is made larger but revolution smaller. Thus, a control range to a low speed area is enlarged and, what is more, energy-saving effect and amenity are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a capacity control device that controls the rotation speed of an electric compressor driven by an electric motor whose number of poles can be changed using an inverter to expand the capacity control range.

[Conventional technology]

The conventional device is a combination of mechanical capacity control and rotation speed control using an inverter, as described in Japanese Patent Application Laid-Open No. 1-167477, and is a combination of mechanical and electrical systems, resulting in a complex structure. . In particular, in a scroll compressor, in a structure in which intermediate pressure between suction pressure and discharge pressure is applied to the back of the orbiting scroll and pressed against the fixed scroll, the intermediate pressure cannot be secured by mechanical capacity control, and the compressor The situation is difficult in terms of reliability and performance.

[Problem to be solved by the invention]

An object of the present invention is to use an inverter to drive the motor of a compressor that is driven by a motor whose number of poles can be changed, which has conventionally been difficult to control using only an inverter. The purpose of this invention is to expand the operating range of low-speed rotation by combining an electric motor whose number of poles can be changed and an inverter.

[Means to solve the problem]

The above purpose is to drive an electric compressor equipped with an electric motor that can change the number of poles using an inverter, and when the output frequency of the inverter reaches the lower limit of the operating frequency range, the inverter control circuit and the number of poles conversion control circuit are It can be distantly related by connecting the poles and controlling the number of poles as necessary.

[Effect]

The inverter that drives the motor of the electric compressor incorporates a transmitting/receiving device for exchanging signals with the outside, an arithmetic processing device for processing the signals, and a control device for controlling output frequency, output voltage, etc. The transmitting/receiving device is electrically connected to an external sensor that transmits a certain state to be controlled and a pole number conversion control circuit.

When the inverter receives a signal from the sensor and is instructed to lower the capacity, it lowers the output frequency, and when the value reaches the lower limit of the operating frequency range and the sensor instructs the inverter to lower the capacity, it controls the number of poles. Activate the circuit to increase the number of poles of the ultimate conversion motor and lower the capacity of the compressor. In this way, it is possible to reliably expand the capacity control range.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

Figure 1 shows indoor heat exchange m7. Outdoor heat exchanger 5, expansion valve 6. Figure 0, which shows a refrigeration cycle composed of a hermetic electric compressor 1 incorporating a four-way switching valve 4 and a pole number changing motor, shows the state of cooling motion. The compressor 1 is driven by the output frequency output from the inverter 2. The output frequency is determined by detecting a certain state quantity in the room by a sensor 8 installed in the room, sending 5 signals to the inverter 2, and using the signal and the current value of the inverter's output frequency to perform arithmetic processing built in the inverter. A suitable output frequency is output through a device or the like to drive the compressor.

When the output frequency of the inverter reaches the lower limit of the operating frequency range, when a signal is sent from the indoor sensor 8 to the inverter 2 to lower the capacity, a signal is sent from the inverter control device to the pole number conversion control device 3. change the motor wiring to increase the number of poles of the pole-converting motor, and reduce the rotation speed of the compressor. In this way, the combination of the inverter and the pole number conversion motor enables operation at a rotation speed lower than the minimum rotation speed that can be operated with the inverter.

〔Effect of the invention〕

According to the present invention, rather than using an inverter alone, mechanical capacity control alone, or capacity control using a pole conversion motor alone,
It becomes possible to change the capacity more widely, and inverter air conditioners improve energy savings and comfort. - Inverter multi-air conditioners that operate multiple indoor units with one compressor can operate with a larger number of indoor units than before, even with smaller capacity indoor units.

[Brief explanation of drawings]

FIG. 1 shows a system diagram of a refrigeration cycle according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Electric compressor, 2... Inverter, 3... Pole number conversion control device, 5... Outdoor heat exchanger, 6... Expansion valve, 7 Fig.

Claims (1)

[Claims] 1. An electric compressor driven by an electric motor that can change the number of poles is driven by an inverter that incorporates a transmitting/receiving device for exchanging signals with the outside, an arithmetic processing device for processing signals, etc., and a control device for output frequency, etc. The inverter and the electric control unit for changing the number of poles are electrically connected, and the electric control unit for changing the number of poles is operable or activated before and after the output frequency of the inverter reaches a lower limit of the operating frequency. Capacity control device for electric compressor for air conditioning.