CN104266424A - Variable-frequency control system and variable-frequency control method for heat pump - Google Patents
Variable-frequency control system and variable-frequency control method for heat pump Download PDFInfo
- Publication number
- CN104266424A CN104266424A CN201410479861.2A CN201410479861A CN104266424A CN 104266424 A CN104266424 A CN 104266424A CN 201410479861 A CN201410479861 A CN 201410479861A CN 104266424 A CN104266424 A CN 104266424A
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- frequency
- resistance
- variable
- compressor
- heat pump
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
- F25B49/022—Compressor control arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2600/00—Control issues
- F25B2600/02—Compressor control
- F25B2600/021—Inverters therefor
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Positive-Displacement Pumps (AREA)
- Air Conditioning Control Device (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
The invention discloses a variable-frequency control system and a variable-frequency control method for a heat pump. The system comprises a temperature sensor, a single chip, a variable-frequency voltage output circuit, a frequency converter and a compressor, wherein the output end of the temperature sensor sequentially passes through the single chip, the variable-frequency voltage output circuit and the frequency converter and then is connected with the output end of the compressor. The method comprises the following steps of: acquiring an air supply temperature, and comparing the obtained air supply temperature value with a preset target temperature value to obtain an air supply temperature difference value; outputting a corresponding variable-frequency voltage to the frequency converter by the single chip through controlling the variable-frequency voltage output circuit; outputting a corresponding control frequency to the compressor by the frequency converter according to the input variable-frequency voltage; adjusting a rotational speed by the compressor according to a control frequency, and then changing the gas displacement of the compressor. The system and the method disclosed by the invention meet the needed temperature, and are capable of effectively reducing the power consumption generated during the running of a unit, and capable of being widely applied to the field of variable-frequency technologies for heat pumps.
Description
Technical field
The present invention relates to frequency conversion control technique field, particularly relate to a kind of heat pump frequency-changing control system and method.
Background technology
The method of in the past carrying out VFC to heat pump is generally to be combined with controller by frequency-changeable compressor to control, although the method for this VFC reaches the object of frequency conversion, can there is following problem:
1, current this technology is not very ripe, so can not meet the temperature of demand after easily causing frequency conversion;
2, the general cost of frequency-changeable compressor is higher on the market now, and needs to realize frequency conversion function, and again develop a set of new procedures must to controller, its construction cycle is long, and development difficulty is large, is not easy to realize.
Summary of the invention
In order to solve the problems of the technologies described above, the object of this invention is to provide a kind of easily realization, and a kind of heat pump frequency-changing control system that can be energy-efficient.
Another object of the present invention is to provide a kind of easily realization, and a kind of heat pump method for controlling frequency conversion that can be energy-efficient.
The technical solution adopted in the present invention is:
A kind of heat pump frequency-changing control system, comprise temperature sensor, single-chip microcomputer, variable-frequency electric voltage follower circuit, frequency converter and compressor, the output of described temperature sensor is connected with frequency converter and then with the output of compressor by single-chip microcomputer, variable-frequency electric voltage follower circuit successively.
As the further improvement of described a kind of heat pump frequency-changing control system, described variable-frequency electric voltage follower circuit comprises the first resistance, second resistance, 3rd resistance, 4th resistance, 5th resistance, 6th resistance, first electric capacity, second electric capacity and operational amplifier, the output of described single-chip microcomputer is connected with the first end of the first resistance, second end of described first resistance is connected with the first end of the second resistance, second end of described second resistance is by the 3rd resistance and then be connected with the in-phase input end of operational amplifier, second end of described first resistance is connected to ground by the first electric capacity, second end of described second resistance is connected to ground by the second electric capacity, the inverting input of described operational amplifier is connected to ground by the 4th resistance, the output of described operational amplifier is connected with the inverting input of operational amplifier by the 5th resistance, the output of described operational amplifier is by the 6th resistance and then be connected with the input of frequency converter.
As the further improvement of described a kind of heat pump frequency-changing control system, described operational amplifier adopts LM358 chip to realize.
Another technical scheme of the present invention is:
A kind of heat pump method for controlling frequency conversion, comprises the following steps:
A, to air-supply temperature gather, and by the wind pushing temperature value obtained with preset target temperature value compare, obtain wind pushing temperature difference;
B, according to wind pushing temperature difference, single-chip microcomputer exports corresponding variable-frequency electric be depressed into frequency converter by controlling variable-frequency electric voltage follower circuit;
C, frequency conversion voltage according to input, frequency converter exports corresponding controlled frequency to compressor;
D, compressor carry out the adjustment of rotating speed according to controlled frequency, and then change the capacity of compressor.
As the further improvement of described a kind of heat pump method for controlling frequency conversion, described step B comprises:
B1, according to judge start-up time current be in the unit starting stage or air-supply the stabilization sub stage;
B2, judge whether wind pushing temperature difference is less than default deceleration temperature gap or is greater than default acceleration temperature gap, if so, then perform step B3; Otherwise, then keep current output constant;
B3, single-chip microcomputer are depressed into frequency converter according to wind pushing temperature difference by regulating PWM Duty ratio control variable-frequency electric voltage follower circuit to export corresponding variable-frequency electric.
As the further improvement of described a kind of heat pump method for controlling frequency conversion, the computing formula of the frequency conversion voltage in described step B3 is:
U=(PWM register value/255) * 10,
Wherein, U represents frequency conversion voltage.
The invention has the beneficial effects as follows:
A kind of heat pump frequency-changing control system of the present invention and method are according to the difference of wind pushing temperature with the target temperature preset, and then export different frequency conversion voltage to frequency converter, frequency converter exports corresponding controlled frequency to compressor according to the frequency conversion magnitude of voltage of input again, compressor finally exports different power according to corresponding controlled frequency, thus realizes the function of unit frequency-conversion.The present invention can carry out Based Intelligent Control frequency converter according to the difference of temperature this whole process stable export different frequencies from just starting to according to unit, compressor is made to export different power, not only meet the temperature of demand, and the power consumption produced when can also effectively reduce unit operation.Further, the present invention connects by simple circuit and control program realizes, and can greatly reduce the difficulty of realization.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described further:
Fig. 1 is the functional-block diagram of a kind of heat pump frequency-changing control system of the present invention;
Fig. 2 is the circuit theory diagrams of variable-frequency electric voltage follower circuit in a kind of heat pump frequency-changing control system of the present invention;
Fig. 3 is the flow chart of steps of a kind of heat pump method for controlling frequency conversion of the present invention.
Detailed description of the invention
With reference to figure 1, a kind of heat pump frequency-changing control system of the present invention, comprise temperature sensor, single-chip microcomputer, variable-frequency electric voltage follower circuit, frequency converter and compressor, the output of described temperature sensor is connected with frequency converter and then with the output of compressor by single-chip microcomputer, variable-frequency electric voltage follower circuit successively.
With reference to figure 2, as the further improvement of described a kind of heat pump frequency-changing control system, described variable-frequency electric voltage follower circuit comprises the first resistance R1, second resistance R2, 3rd resistance R3, 4th resistance R4, 5th resistance R5, 6th resistance R6, first electric capacity C1, second electric capacity C2 and operational amplifier A, the output of described single-chip microcomputer is connected with the first end of the first resistance R1, second end of described first resistance R1 is connected with the first end of the second resistance R2, second end of described second resistance R2 is by the 3rd resistance R3 and then be connected with the in-phase input end of operational amplifier A, second end of described first resistance R1 is connected to ground by the first electric capacity C1, second end of described second resistance R2 is connected to ground by the second electric capacity C2, the inverting input of described operational amplifier A is connected to ground by the 4th resistance R4, the output of described operational amplifier A is connected with the inverting input of operational amplifier A by the 5th resistance R5, the output of described operational amplifier A is by the 6th resistance R6 and then be connected with the input of frequency converter.
As the further improvement of described a kind of heat pump frequency-changing control system, described operational amplifier adopts LM358 chip to realize.
With reference to figure 3, a kind of heat pump method for controlling frequency conversion of the present invention, comprises the following steps:
A, to air-supply temperature gather, and by the wind pushing temperature value obtained with preset target temperature value compare, obtain wind pushing temperature difference;
B, according to wind pushing temperature difference, single-chip microcomputer exports corresponding variable-frequency electric be depressed into frequency converter by controlling variable-frequency electric voltage follower circuit;
C, frequency conversion voltage according to input, frequency converter exports corresponding controlled frequency to compressor;
D, compressor carry out the adjustment of rotating speed according to controlled frequency, and then change the capacity of compressor.
As the further improvement of described a kind of heat pump method for controlling frequency conversion, described step B comprises:
B1, according to judge start-up time current be in the unit starting stage or air-supply the stabilization sub stage;
B2, judge whether wind pushing temperature difference is less than default deceleration temperature gap or is greater than default acceleration temperature gap, if so, then perform step B3; Otherwise, then keep current output constant;
B3, single-chip microcomputer are depressed into frequency converter according to wind pushing temperature difference by regulating PWM Duty ratio control variable-frequency electric voltage follower circuit to export corresponding variable-frequency electric.
As the further improvement of described a kind of heat pump method for controlling frequency conversion, the computing formula of the frequency conversion voltage in described step B3 is:
U=(PWM register value/255) * 10,
Wherein, U represents frequency conversion voltage.
In the present embodiment, when being in the unit starting stage, default deceleration temperature gap is 1 DEG C, and the acceleration temperature gap preset is 2 DEG C; When being in the air-supply stabilization sub stage, default deceleration temperature gap is 0.5 DEG C, and the acceleration temperature gap preset is 1 DEG C.
When unit just starts, namely the unit starting stage is in, according to the difference of new air temperature and target temperature, SCM PWM function is utilized to control variable-frequency electric voltage follower circuit, by regulating the dutycycle of PWM, computing formula is (PWM register/255) * 10, variable-frequency electric voltage follower circuit carrys out the frequency conversion voltage of a given 0-10V to frequency converter, frequency converter exports different conversion frequencies to compressor according to the frequency conversion magnitude of voltage of given input again, regulate the rotating speed of compression motor, thus change the capacity of compressor, reach and export different power.
If the difference of new air temperature and target temperature is less than 1 DEG C, then the frequency conversion voltage of a given 0-10V is to frequency converter, frequency converter exports corresponding frequency to compressor according to the frequency conversion magnitude of voltage of given input, reach the compression motor rotating speed object that slows down, thus allow compressor export lower power, avoid unit just to open when machine runs and produce too much energy consumption.
If the difference of new air temperature and target temperature is greater than 2 DEG C, then the frequency conversion voltage of a given 0-10V is to frequency converter, frequency converter exports corresponding frequency to compressor according to the frequency conversion magnitude of voltage of given input, reach and accelerate compression motor rotating speed object, thus allow compressor export higher power, meet the demand to temperature when unit starting runs.
When unit blasting air temperature stabilization, according to the difference of wind pushing temperature and target temperature, SCM PWM function is utilized to control variable-frequency electric voltage follower circuit, by regulating the dutycycle of PWM, computing formula is (PWM register/255) * 10, the frequency conversion voltage of the given 0-10V of variable-frequency electric voltage follower circuit is to frequency converter, frequency converter exports different frequencies to compressor according to the frequency conversion magnitude of voltage of given input again, regulate the rotating speed of compression motor, thus change the capacity of compressor, reach and export different power.
If wind pushing temperature and target temperature are less than 0.5 DEG C, then the frequency conversion voltage of a given 0-10V is to frequency converter, frequency converter exports corresponding frequency to compressor according to the frequency conversion magnitude of voltage of given input, reach the compression motor rotating speed object that slows down, thus allow compressor export lower power, avoid producing too much power consumption during unit operation.
If wind pushing temperature and target temperature are greater than 1 DEG C, then the frequency conversion voltage of a given 0-10V is to frequency converter, frequency converter exports corresponding frequency to compressor according to the frequency conversion magnitude of voltage of given input, reach and accelerate compression motor rotating speed object, thus allow compressor export higher power, the demand to temperature when meeting unit operation.
More than that better enforcement of the present invention is illustrated, but the invention is not limited to described embodiment, those of ordinary skill in the art also can make all equivalent variations or replacement under the prerequisite without prejudice to spirit of the present invention, and these equivalent distortion or replacement are all included in the application's claim limited range.
Claims (6)
1. a heat pump frequency-changing control system, it is characterized in that: comprise temperature sensor, single-chip microcomputer, variable-frequency electric voltage follower circuit, frequency converter and compressor, the output of described temperature sensor is connected with frequency converter and then with the output of compressor by single-chip microcomputer, variable-frequency electric voltage follower circuit successively.
2. a kind of heat pump frequency-changing control system according to claim 1, it is characterized in that: described variable-frequency electric voltage follower circuit comprises the first resistance (R1), second resistance (R2), 3rd resistance (R3), 4th resistance (R4), 5th resistance (R5), 6th resistance (R6), first electric capacity (C1), second electric capacity (C2) and operational amplifier (A), the output of described single-chip microcomputer is connected with the first end of the first resistance (R1), second end of described first resistance (R1) is connected with the first end of the second resistance (R2), second end of described second resistance (R2) is by the 3rd resistance (R3) and then be connected with the in-phase input end of operational amplifier (A), second end of described first resistance (R1) is connected to ground by the first electric capacity (C1), second end of described second resistance (R2) is connected to ground by the second electric capacity (C2), the inverting input of described operational amplifier (A) is connected to ground by the 4th resistance (R4), the output of described operational amplifier (A) is connected with the inverting input of operational amplifier (A) by the 5th resistance (R5), the output of described operational amplifier (A) is by the 6th resistance (R6) and then be connected with the input of frequency converter.
3. a kind of heat pump frequency-changing control system according to claim 2, is characterized in that: described operational amplifier adopts LM358 chip to realize.
4. a heat pump method for controlling frequency conversion, is characterized in that, comprises the following steps:
A, to air-supply temperature gather, and by the wind pushing temperature value obtained with preset target temperature value compare, obtain wind pushing temperature difference;
B, according to wind pushing temperature difference, single-chip microcomputer exports corresponding variable-frequency electric be depressed into frequency converter by controlling variable-frequency electric voltage follower circuit;
C, frequency conversion voltage according to input, frequency converter exports corresponding controlled frequency to compressor;
D, compressor carry out the adjustment of rotating speed according to controlled frequency, and then change the capacity of compressor.
5. a kind of heat pump method for controlling frequency conversion according to claim 4, is characterized in that: described step B comprises:
B1, according to judge start-up time current be in the unit starting stage or air-supply the stabilization sub stage;
B2, judge whether wind pushing temperature difference is less than default deceleration temperature gap or is greater than default acceleration temperature gap, if so, then perform step B3; Otherwise, then keep current output constant;
B3, single-chip microcomputer are depressed into frequency converter according to wind pushing temperature difference by regulating PWM Duty ratio control variable-frequency electric voltage follower circuit to export corresponding variable-frequency electric.
6. a kind of heat pump method for controlling frequency conversion according to claim 5, is characterized in that: the computing formula of the frequency conversion voltage in described step B3 is:
U=(PWM register value/255) * 10,
Wherein, U represents frequency conversion voltage.
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104534809A (en) * | 2015-01-09 | 2015-04-22 | 合肥美菱股份有限公司 | Self-adaptive adjusting system and adjusting method for rotating speed of air-cooled variable frequency refrigerator fan |
CN106556112A (en) * | 2016-11-28 | 2017-04-05 | 珠海格力电器股份有限公司 | compressor frequency adjusting method and device |
CN109357436A (en) * | 2018-10-18 | 2019-02-19 | 佛山市顺德区和而泰电子科技有限公司 | Frequency conversion heat pump control method |
CN109708278A (en) * | 2019-01-06 | 2019-05-03 | 上海朗绿建筑科技股份有限公司 | A kind of control method and system of the operation of compressor difference |
CN110793088A (en) * | 2019-10-29 | 2020-02-14 | 广东芬尼克兹节能设备有限公司 | Water temperature control method of heat pump system and heat pump system |
CN113525437A (en) * | 2021-06-30 | 2021-10-22 | 广州鼎汉轨道交通车辆装备有限公司 | R744 refrigerant heat pump air conditioning unit, system and control method thereof |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS58195090A (en) * | 1982-05-10 | 1983-11-14 | Sanyo Electric Co Ltd | Refrigerating device |
GB2148553A (en) * | 1983-10-22 | 1985-05-30 | Chieftain Ind Plc | Heat pump system |
CN101539151A (en) * | 2008-03-18 | 2009-09-23 | 海尔集团公司 | Method and device for controlling inverter compressor |
CN101957067B (en) * | 2010-11-01 | 2012-09-05 | 江苏天舒电器有限公司 | Frequency conversion control method for heat pump water heater |
CN202485280U (en) * | 2012-02-27 | 2012-10-10 | 日照海大自动化科技有限公司 | Environment induction type frequency conversion, compression refrigeration and electricity-saving system |
CN104006592A (en) * | 2014-06-05 | 2014-08-27 | 珠海格力电器股份有限公司 | Frequency adjusting method and device for variable frequency compressor in heat pump system |
-
2014
- 2014-09-18 CN CN201410479861.2A patent/CN104266424B/en active Active
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS58195090A (en) * | 1982-05-10 | 1983-11-14 | Sanyo Electric Co Ltd | Refrigerating device |
GB2148553A (en) * | 1983-10-22 | 1985-05-30 | Chieftain Ind Plc | Heat pump system |
CN101539151A (en) * | 2008-03-18 | 2009-09-23 | 海尔集团公司 | Method and device for controlling inverter compressor |
CN101957067B (en) * | 2010-11-01 | 2012-09-05 | 江苏天舒电器有限公司 | Frequency conversion control method for heat pump water heater |
CN202485280U (en) * | 2012-02-27 | 2012-10-10 | 日照海大自动化科技有限公司 | Environment induction type frequency conversion, compression refrigeration and electricity-saving system |
CN104006592A (en) * | 2014-06-05 | 2014-08-27 | 珠海格力电器股份有限公司 | Frequency adjusting method and device for variable frequency compressor in heat pump system |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104534809A (en) * | 2015-01-09 | 2015-04-22 | 合肥美菱股份有限公司 | Self-adaptive adjusting system and adjusting method for rotating speed of air-cooled variable frequency refrigerator fan |
CN106556112A (en) * | 2016-11-28 | 2017-04-05 | 珠海格力电器股份有限公司 | compressor frequency adjusting method and device |
CN106556112B (en) * | 2016-11-28 | 2019-07-12 | 珠海格力电器股份有限公司 | Compressor frequency adjusting method and device |
CN109357436A (en) * | 2018-10-18 | 2019-02-19 | 佛山市顺德区和而泰电子科技有限公司 | Frequency conversion heat pump control method |
CN109708278A (en) * | 2019-01-06 | 2019-05-03 | 上海朗绿建筑科技股份有限公司 | A kind of control method and system of the operation of compressor difference |
CN110793088A (en) * | 2019-10-29 | 2020-02-14 | 广东芬尼克兹节能设备有限公司 | Water temperature control method of heat pump system and heat pump system |
CN113525437A (en) * | 2021-06-30 | 2021-10-22 | 广州鼎汉轨道交通车辆装备有限公司 | R744 refrigerant heat pump air conditioning unit, system and control method thereof |
CN113525437B (en) * | 2021-06-30 | 2023-10-03 | 广州鼎汉轨道交通车辆装备有限公司 | R744 refrigerant heat pump air conditioning unit, system and control method thereof |
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