Compressor frequency conversion system and frequency conversion method

Abstract

A compressor frequency conversion system and a frequency conversion method. The frequency conversion system comprises: a controller (1), which is in signal connection with a frequency converter unit and a compressor unit in sequence; the frequency converter unit, which comprises several frequency converters (2), wherein an output terminal A of the frequency converter unit is in signal connection with a first input terminal of the controller (1), so as to transmit a unit main control signal, and an output terminal B of the frequency converter unit is connected to an input terminal of the compressor unit; the compressor unit, which comprises several compressors (3) and is configured to output a cooling capacity; and a pressure sensor, which is arranged in a cold storage and is used for measuring a suction pressure in the cold storage, wherein a sensing terminal of the pressure sensor faces an output terminal of the compressor unit, and an output terminal of the pressure sensor is connected to a second input terminal of the controller (1). By means of the frequency conversion system, active control and passive control over frequency conversion can be realized.

Description

Compressor frequency conversion system and frequency conversion method Technical Field

[0001] The present invention belongs to the technical field of compressor frequency conversion, and in particular relates to a compressor frequency conversion system and a frequency conversion method. Background Art

[0002] Currently, conventional cold storage facilities typically require high power, consume high energy, and experience frequent startups and shutdowns. Using variable frequency compressors with inverters allows high-power cold storage facilities to achieve a specified temperature change frequency, achieving energy-saving benefits. Compressor inverter technology can effectively improve the overall energy efficiency of the unit and effectively increase energy utilization.

[0003] However, existing compressors cannot take into account both active frequency conversion and passive frequency conversion.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to provide a compressor frequency conversion system and frequency conversion method, which can realize active and passive control of frequency conversion. To achieve the above purpose, the technical solution adopted is:

[0006] A compressor frequency conversion system, comprising:

[0007] Controller 1, inverter unit and compressor unit are connected in sequence;

[0008] The inverter unit includes a plurality of inverters 2, whose output terminal A is connected to the first input terminal of the controller 1 for transmitting the main control signal of the unit; and whose output terminal B is connected to the input terminal of the compressor unit;

[0009] The compressor unit includes several compressors 3 for outputting cooling capacity;

[0010] And a pressure sensor, which is placed in the cold storage and is used to detect the suction pressure of the cold storage. Its sensing end faces the output end of the compressor unit, and its output end is connected to the second input end of the controller 1.

[0011] Preferably, it also includes:

[0012] The temperature sensor is placed in the cold storage and is used to detect the storage temperature of the cold storage. The output end of the temperature sensor is connected to the third input end of the controller 1.

[0013] Preferably, a low-temperature resistant shell is provided on the surface of the pressure sensor.

[0014] A compressor frequency conversion method comprises the following steps:

[0015] Active control method:

[0016] Step 1: The controller 1 monitors the actual pressure value sensed by the pressure sensor and the actual temperature value sensed by the temperature sensor in real time;

[0017] Step 2: When any of the actual values ​​is lower than the corresponding set value, the controller 1 controls the inverter 2 to reduce the output frequency, thereby reducing the cooling output of the compressor unit, thereby increasing the suction pressure and temperature;

[0018] Otherwise, the controller 1 controls the inverter 3 to increase its output frequency, thereby increasing the cooling output of the compressor unit, thereby reducing the suction pressure and temperature.

[0019] Passive control method:

[0020] Controller 1 sets and stores the frequency range;

[0021] Controller 1 reads the unit master control signal output by the inverter unit in real time;

[0022] Controller 1 controls the storage temperature and suction pressure according to the frequency range and the unit main control signal, without the need to read the temperature or pressure signal.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] 1. It is divided into active control and passive control. Specifically: the controller controls the operating frequency of the compressor in real time according to the sensed storage temperature, meets the cold storage load in real time, and reduces the waste of cooling capacity; the controller can directly read the unit signal and control according to the main control requirements.

[0025] 2. The inverter unit does not require special editing of control logic. The controller automatically controls the inverter, reducing system complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic diagram of signal transmission of a variable frequency compressor;

[0027] Figure 2 is a schematic diagram of the controller model.

[0028] Among them, 1-controller, 2-inverter, 3-compression machine. DETAILED DESCRIPTION

[0029] The following is a more detailed description of the compressor frequency conversion system and frequency conversion method of the present invention, with reference to schematic diagrams. These diagrams illustrate preferred embodiments of the present invention. It should be understood that those skilled in the art may modify the present invention described herein while still achieving the beneficial effects of the present invention. Therefore, the following description should be understood as a general guide for those skilled in the art and not as a limitation of the present invention.

[0030] As shown in Figures 1 and 2, a compressor frequency conversion system includes:

[0031] The controller 1, the inverter 2 and the compressor 3 are signal-connected in sequence.

[0032] The inverter unit has an input terminal connected to the controller 1 for signal transmission, and an output terminal A connected to the first input terminal of the controller 1 for signal transmission; and is used to transmit the unit's main control signal. The inverter unit includes a plurality of inverters 2.

[0033] The compressor unit includes several compressors 3 , which are arranged corresponding to the frequency converter 2 .

[0034] The pressure sensor is placed in the cold storage and is used to detect the suction pressure of the cold storage (the pressure of the gas discharged by the compressor unit), and its output end is connected to the second input end of the controller 1.

[0035] The temperature sensor is placed in the cold storage and is used to detect the storage temperature of the cold storage. The output end of the temperature sensor is connected to the third input end of the controller 1.

[0036] FIG2 includes leads at various ports.

[0037] Frequency conversion method of compression machine:

[0038] 1. Active control method:

[0039] Step 1: The controller 1 monitors the actual pressure value sensed by the pressure sensor and the actual temperature value sensed by the temperature sensor in real time;

[0040] Step 2: When any of the actual values ​​is lower than the corresponding set value, the controller 1 controls the inverter 2 to reduce the output frequency, thereby reducing the cooling output of the compressor unit, thereby increasing the suction pressure or temperature;

[0041] Otherwise, the controller 1 controls the inverter 3 to increase its output frequency, thereby increasing the cooling output of the unit, thereby reducing the suction pressure and temperature. Ultimately, the internal control logic of the controller 1 stabilizes the suction pressure at the set value.

[0042] 2. Passive control method:

[0043] The controller 1 sets and stores the minimum frequency and the maximum frequency, that is, sets the frequency range.

[0044] Controller 1 directly reads the adjustable proportional 4-20mA data (unit master control signal) output by the inverter unit.

[0045] Controller 1 controls the storage temperature according to the frequency range and master control requirements (unit master control signal), without the need to read temperature or pressure signals.

[0046] The above description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any person skilled in the art who, without departing from the scope of the present invention, makes any equivalent substitution, modification, or other changes to the technical solution and technical content disclosed in the present invention shall be deemed to be within the scope of the present invention and still fall within the scope of protection of the present invention.

Claims

1. A compressor frequency conversion system, characterized in that: include: The controller (1), the frequency converter unit and the compressor unit are signal-connected in sequence; The frequency converter unit comprises a plurality of frequency converters (2), the output terminals A of which are signal-connected to the first input terminal of the controller (1) for transmitting the unit main control signal; Its output terminal B is connected to the input terminal of the compressor unit; The compressor unit includes a plurality of compressors (3) for outputting cooling capacity; A pressure sensor is placed in the cold storage and is used to detect the suction pressure of the cold storage. Its sensing end faces the output end of the compressor unit, and its output end is connected to the second input end of the controller (1).

2. The compressor frequency conversion system according to claim 1, characterized in that: Also includes: The temperature sensor is placed in the cold storage and is used to detect the storage temperature of the cold storage. The output end of the temperature sensor is connected to the third input end of the controller (1).

3. The compressor frequency conversion system according to claim 1, characterized in that: A low-temperature resistant shell is provided on the surface of the pressure sensor.

4. A compressor frequency conversion method, characterized in that: The following steps are involved: Active control method: Step 1, the controller (1) monitors in real time the actual pressure value sensed by the pressure sensor and the actual temperature value sensed by the temperature sensor; Step 2: When any of the actual values ​​is lower than the corresponding set value, the controller (1) controls the frequency converter (2) to reduce the output frequency, thereby reducing the cooling output of the compressor unit, thereby increasing the suction pressure and temperature; Otherwise, the controller (1) controls the frequency converter (3) to increase its output frequency, thereby increasing the cooling output of the compressor unit, thereby reducing the suction pressure and temperature; Passive control method: The controller (1) sets and stores the frequency range; The controller (1) reads the unit master control signal output by the inverter unit in real time; The controller (1) controls the storage temperature and the suction pressure according to the frequency range and the main control signal of the unit, without the need to read the temperature or pressure signal.

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