Frequency control method of variable frequency air conditioner

Abstract

The invention provides a frequency control method for a variable frequency air conditioner, and relates to the technical field of air conditioners, a first change value of target frequency is calculated through fuzzy control, and if the sum of the current frequency and the first change value of the target frequency is in a frequency hopping band, a second change value of the target frequency is obtained by subtracting the current frequency from the maximum value of the frequency hopping band; calculating a target current according to the target frequency second change value, if the target current is not higher than the maximum current allowed by the operation of the compressor, increasing the frequency according to the target frequency second change value, and if the target current is higher than the maximum current allowed by the operation of the compressor, reducing the target frequency second change value according to a certain rule, and taking the reduced second change value of the target frequency as a new first change value of the target frequency, and recalculating the target current until the target current is not higher than the maximum current allowed by the operation of the compressor, so that the problem of repeated fluctuation of the frequency in the frequency control process of the existing variable frequency air conditioner is solved, and the method is suitable for frequency raising control of the air conditioner.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and in particular to a frequency control method for variable frequency air conditioners. Background Art

[0002] Inverter air conditioners have the advantages of high efficiency and energy saving, high temperature control accuracy, low noise, wide frequency operation range, and good adaptability to ambient temperature. However, the design of inverter air conditioners is complex, and the compressor and system structure are complex. In the design of the entire structural system, there are often system resonance points and noise points that cannot be eliminated. In order to achieve these advantages of inverter air conditioners, the frequency control of inverter air conditioners is complex. The common frequency control schemes in the industry are: fuzzy control or multi-dimensional fuzzy control. Regardless of the type of fuzzy control, the frequency adjustment only takes into account the application temperature requirements. However, under many working conditions, due to factors such as current protection and frequency hopping points, the air conditioner has repeated frequency fluctuations due to factors such as capacity and system resonance. Summary of the invention

[0003] Technical problem solved by the present invention: The present invention provides a frequency control method for a variable frequency air conditioner to solve the problem of repeated frequency fluctuations in the frequency control process of the existing variable frequency air conditioner.

[0004] The present invention solves the above technical problems by adopting a technical solution: a frequency control method for a variable frequency air conditioner, comprising the following steps:

[0005] S1. After the air conditioner is turned on, when the frequency adjustment interval is reached, the first change value of the target frequency is calculated according to the fuzzy control;

[0006] S2. If the sum of the current frequency and the first change value of the target frequency is in the frequency hopping segment, a second change value of the target frequency is calculated by using the maximum value of the frequency hopping segment and the current frequency, so that the sum of the current frequency and the first change value of the target frequency is not in the frequency hopping segment;

[0007] S3, calculating the target current according to the second change value of the target frequency, if the target current is not higher than the maximum current allowed for the compressor operation, proceed to S4, otherwise proceed to S5;

[0008] S4, frequency increase according to the second change value of the target frequency, and enter S1;

[0009] S5. Reduce the second target frequency change value according to a certain rule, use the reduced second target frequency change value as a new first target frequency change value, and enter S2.

[0010] Furthermore, the formula for calculating the second change value of the target frequency by the maximum value of the frequency hopping segment and the current frequency is: ΔF = F MAX -F+A, where ΔF represents the second change value of the target frequency, F MAXIndicates the maximum value of the frequency hopping band, F indicates the current operating frequency of the compressor, and A is the set coefficient.

[0011] Furthermore, the formula for calculating the target current according to the second change value of the target frequency is: Among them, I t Indicates the target current, I i represents the current operating current of the compressor, F represents the current operating frequency of the compressor, ΔF represents the second change value of the target frequency, k represents the parameter, I M1 Indicates the maximum current of the compressor frequency reduction, I M2 Indicates the maximum value of the frequency-limiting current.

[0012] Further, reducing the second change value of the target frequency according to a certain rule includes reducing the second change value of the target frequency by one half or one third.

[0013] Beneficial effects of the present invention: The present invention provides a frequency control method for a variable frequency air conditioner, which calculates a first change value of a target frequency through an existing fuzzy control. If the sum of a current frequency and the first change value of a target frequency is in a frequency hopping band, a second change value of a target frequency is obtained by subtracting the current frequency from the maximum value of the frequency hopping band. A target current is calculated according to the second change value of the target frequency. If the target current is not higher than the maximum current allowed for the operation of the compressor, the frequency is increased according to the second change value of the target frequency, so as to avoid the frequency after frequency modulation being in the frequency hopping band, thereby causing repeated frequency fluctuations. If the target current is higher than the maximum current allowed for the operation of the compressor, the second change value of the target frequency is reduced according to a certain rule, and the reduced second change value of the target frequency is used as the new first change value of the target frequency, and the target current is recalculated until the target current is no higher than the maximum current allowed for the operation of the compressor. In this way, while ensuring the safety of the compressor operation, the problem of repeated frequency fluctuations in the frequency control process of the existing variable frequency air conditioner is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flow chart of a frequency control method of a variable frequency air conditioner provided by the present invention. DETAILED DESCRIPTION

[0015] The present invention aims at the problem that the existing fuzzy control frequency adjustment only takes into account the application temperature requirements, and the air conditioner has repeated frequency fluctuations due to factors such as current protection and frequency hopping points, and provides a variable frequency air conditioner frequency control method, such as Figure 1 As shown, the following steps are included:

[0016] S1. After the air conditioner is turned on, when the frequency adjustment interval is reached, the first change value of the target frequency is calculated according to the fuzzy control;

[0017] Specifically, fuzzy control belongs to the existing air conditioning frequency modulation technology.

[0018] S2. If the sum of the current frequency and the first change value of the target frequency is in the frequency hopping segment, a second change value of the target frequency is calculated by using the maximum value of the frequency hopping segment and the current frequency, so that the sum of the current frequency and the first change value of the target frequency is not in the frequency hopping segment;

[0019] Specifically, if the sum of the current frequency and the first change value of the target frequency is not in the frequency hopping band, the frequency is increased according to the first change value of the target frequency; the formula for calculating the second change value of the target frequency by the maximum value of the frequency hopping band and the current frequency is: ΔF =

[0020] F MAX -F+A, where ΔF represents the second change value of the target frequency, F MAX Indicates the maximum value of the frequency hopping range, F indicates the current operating frequency of the compressor, and A is the set coefficient. For example, if the frequency hopping range is 50Hz to 55Hz, then F MAX is 55Hz, A is 0.1Hz, F is 42Hz, then ΔF is 13.1Hz.

[0021] S3, calculating the target current according to the second change value of the target frequency, if the target current is not higher than the maximum current allowed for the compressor operation, proceed to S4, otherwise proceed to S5;

[0022] Specifically, the formula for calculating the target current according to the second change value of the target frequency is: Among them, I t Indicates the target current, I i represents the current operating current of the compressor, F represents the current operating frequency of the compressor, ΔF represents the second change value of the target frequency, k represents the parameter, I M1 Indicates the maximum current of the compressor frequency reduction, I M2 Indicates the maximum value of the frequency-limiting current.

[0023] S4, frequency increase according to the second change value of the target frequency, and enter S1;

[0024] S5, reducing the second target frequency change value according to a certain rule, using the reduced second target frequency change value as a new first target frequency change value, and entering S2;

[0025] Specifically, reducing the second change value of the target frequency according to a certain rule includes reducing the second change value of the target frequency by one half or one third. For example, when ΔF is 13.1 Hz and the calculated target current is higher than the maximum current allowed for the compressor operation, ΔF is reduced by one half to 6.55 Hz. Normally, 6.6 Hz is taken. Thus, 6.6 Hz is used as the new first change value of the target frequency, and S2 is entered to recalculate the target current until the target current is no higher than the maximum current allowed for the compressor operation. In some cases, ΔF will be reduced multiple times to meet the requirement that the target current is no higher than the maximum current allowed for the compressor operation.

Claims

1. A frequency control method for a variable frequency air conditioner, characterized in that: The following steps are involved: S1. After the air conditioner is turned on, when the frequency adjustment interval is reached, the first change value of the target frequency is calculated according to the fuzzy control; S2. If the sum of the current frequency and the first change value of the target frequency is in the frequency hopping segment, the second change value of the target frequency is calculated by the maximum value of the frequency hopping segment and the current frequency, so that the sum of the current frequency and the first change value of the target frequency is not in the frequency hopping segment; S3, calculating the target current according to the second change value of the target frequency, if the target current is not higher than the maximum current allowed for the compressor operation, proceed to S4, otherwise proceed to S5; S4, frequency increase according to the second change value of the target frequency, and enter S1; S5. Reduce the second target frequency change value according to a certain rule, use the reduced second target frequency change value as a new first target frequency change value, and enter S2.

2. The frequency control method of variable frequency air conditioner according to claim 1, characterized in that: The formula for calculating the second change value of the target frequency by the maximum value of the frequency hopping band and the current frequency is: ΔF = F MAX -F+A, where ΔF represents the second change value of the target frequency, F MAX Indicates the maximum value of the frequency hopping band, F indicates the current operating frequency of the compressor, and A is the set coefficient.

3. The frequency control method of variable frequency air conditioner according to claim 1, characterized in that: The formula for calculating the target current according to the second change value of the target frequency is: Among them, I t Indicates the target current, I i represents the current operating current of the compressor, F represents the current operating frequency of the compressor, ΔF represents the second change value of the target frequency, k represents the parameter, I M1 Indicates the maximum current of the compressor frequency reduction, I M2 Indicates the maximum value of the frequency-limiting current.

4. The frequency control method of variable frequency air conditioner according to claim 1, characterized in that: The reducing the second change value of the target frequency according to a certain rule includes reducing the second change value of the target frequency by one half or one third.

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