AIR-CONDITIONING APPARATUS

• US 20150052922A1
• Filed: 04/26/2012
• Published: 02/26/2015
• Est. Priority Date: 04/26/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Tanaka, Kosuke, Makino, Hiroaki, Ariyama, Tadashi, Sakabe, Akinori
• Granted Patent: US 9,976,766 B2
• Time in Patent Office: Days
• US Class Current: 62/210
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: F24F 11/70 Control systems characterised by their outputs; Constructional details thereof
• CPC Class Codes: F24F 11/83 by controlling the supply of heat-exchange fluids to heat-exchangers
• CPC Class Codes: F24F 11/84 using valves
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2313/0314 Temperature sensors near the indoor heat exchanger
• CPC Class Codes: F25B 2600/01 Timing
• CPC Class Codes: F25B 2600/2513 Expansion valves
• CPC Class Codes: F25B 2700/2104 of an indoor room or compartment
• CPC Class Codes: F25B 2700/21151 at the suction side of the compressor
• CPC Class Codes: F25B 2700/21152 at the discharge side of the compressor
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems
• CPC Class Codes: G05B 15/02 electric

Abstract

An air-conditioning apparatus includes a time constant calculation unit that estimates a response time constant at a time when an opening degree of an expansion device is changed on the basis of specifications of a compressor that forms a refrigeration cycle of the air-conditioning apparatus, specifications of a load side heat exchanger, and an operating state quantity of the air-conditioning apparatus, a control constant calculation means that calculates at least one of a control gain of the opening degree of the expansion device and a control interval on the basis of a calculation result of the time constant calculation means, and a control constant change means that changes a control constant.

Claims

1. An air-conditioning apparatus in which at least one load side unit including a load side heat exchanger is connected to a heat source side unit including a compressor, a heat source side heat exchanger, and an expansion device, and a refrigerant is circulated between the units to form a refrigeration cycle, the apparatus comprising:

a control constant calculation unit that calculates at least either of a control gain of the opening degree of the expansion device, the control gain being a control constant of the opening degree of the expansion device, and a control interval on the basis of an operating state quantity of the refrigeration cycle of the air-conditioning apparatus; and

a control constant change unit that changes the control gain or the control interval on the basis of the calculation result of the control constant calculation unit, and an expansion device controller that changes the opening degree of the expansion device on the basis of the control constant.

2. The air-conditioning apparatus of claim 10,

wherein the control interval is set to be three times the response time constant or less calculated in the time constant calculation unit.

3. The air-conditioning apparatus of claim 10,

wherein, when the response time constant is estimated in the time constant calculation unit, information regarding an operating frequency of the compressor is used.

4. The air-conditioning apparatus of claim 3,

wherein, when the response time constant is estimated in the time constant calculation unit, information regarding at least any of an internal capacity of the heat source side heat exchanger, an internal capacity of the load side heat exchanger, and a displacement of the compressor is used.

5. The air-conditioning apparatus of claim 3,

wherein, when the response time constant is estimated in the time constant calculation unit, a volumetric efficiency of the compressor is used and the volumetric efficiency is estimated on the basis of a discharge pressure, a suction pressure, and an operating frequency of the compressor.

6. The air-conditioning apparatus of claim 10,

wherein the response time constant estimated in the time constant calculation unit satisfies a relationship that an eigenvalue with which a setting time is minimum=(control interval/control gain ratio)/(response time constant+dead time),

the setting time is a time for a control target object to be in a predetermined range from a control target value,

the gain ratio is a value obtained by dividing the control gain by a response gain of the control target object in order to cause the control gain to be a control target value by an operation performed once, and

a dead time is a time from a time when an opening degree change order is issued to the expansion device to a time when a change appears in the control target object.

7. The air-conditioning apparatus of claim 6,

wherein the response time constant is estimated assuming that the dead time is zero.

8. The air-conditioning apparatus of claim 1, wherein the operating state quantity includes specifications of the compressor that forms the refrigeration cycle, and specifications of a heat exchanger that serves as a condenser.

9. The air-conditioning apparatus of claim 1, further comprising a measurement unit that measures the operation state quantity of the refrigeration cycle of the air-conditioning apparatus.

10. The air-conditioning apparatus of claim 1, further comprising a time constant calculation unit that estimates a response time constant at a time when an opening degree of the expansion device is changed.