阅读说明：本技术 热泵干衣机的压缩机频率控制方法 (Compressor frequency control method of heat pump clothes dryer ) 是由 刘思璇 杨龙 李涛 于 2021-06-18 设计创作，主要内容包括：本发明属于干衣机技术领域,具体涉及一种热泵干衣机的压缩机频率控制方法。本发明旨在解决现有热泵干衣机的压缩机频率调节方式不佳而导致调频慢、控制不精准的问题。为此,本发明的压缩机频率控制方法包括：获取热泵干衣机的运行参数值；在获取到的运行参数值达到预设参数值的情形下,获取运行参数值的增长速率；根据运行参数值的增长速率,确定变频压缩机的降频指数；获取变频压缩机的当前频率；根据获取到的当前频率和确定出的降频指数,确定变频压缩机的目标频率；控制变频压缩机以确定出的目标频率运行。本发明能够根据热泵循环系统前期的运行状态,准确预测热泵循环系统在稳定运行时所需的压缩机频率,以便实现精准降频的控制效果。(The invention belongs to the technical field of clothes dryers, and particularly relates to a compressor frequency control method of a heat pump clothes dryer. The invention aims to solve the problems of slow frequency modulation and inaccurate control caused by poor frequency adjustment mode of the compressor of the conventional heat pump clothes dryer. To this end, the compressor frequency control method of the present invention comprises: acquiring an operation parameter value of the heat pump clothes dryer; acquiring the growth rate of the operation parameter value under the condition that the acquired operation parameter value reaches a preset parameter value; determining the frequency reduction index of the variable frequency compressor according to the increase rate of the operation parameter value; acquiring the current frequency of the variable frequency compressor; determining the target frequency of the variable frequency compressor according to the obtained current frequency and the determined frequency reduction index; and controlling the variable frequency compressor to operate at the determined target frequency. The invention can accurately predict the compressor frequency required by the heat pump circulating system in stable operation according to the early-stage operation state of the heat pump circulating system so as to realize the control effect of accurate frequency reduction.)

1. A compressor frequency control method of a heat pump clothes dryer is characterized in that the heat pump clothes dryer comprises a heat pump circulating system, the heat pump circulating system comprises a variable frequency compressor, and the compressor frequency control method comprises the following steps:

acquiring an operation parameter value of the heat pump clothes dryer;

acquiring the growth rate of the operation parameter value under the condition that the acquired operation parameter value reaches a preset parameter value;

determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the operation parameter value;

acquiring the current frequency of the variable frequency compressor;

determining the target frequency of the variable frequency compressor according to the obtained current frequency and the determined frequency reduction index;

and controlling the variable frequency compressor to operate at the determined target frequency.

2. The method for controlling the frequency of a compressor according to claim 1, wherein the step of determining the downconversion index of the inverter compressor based on the rate of increase of the operating parameter value comprises:

calculating a downconversion index of the inverter compressor by the following calculation:

γ＝av³+bv²+cv+d

wherein gamma is the frequency reduction index of the variable frequency compressor, v is the increasing rate of the operation parameter value, a, b and c are correction coefficients, and d is a correction value.

3. The compressor frequency control method according to claim 2, wherein the correction coefficients a, b, c are determined by the ambient temperature at which the heat pump dryer is located; and/or

The correction value d is determined by the ambient temperature at which the heat pump dryer is located.

4. The method according to any one of claims 1 to 3, wherein the step of determining the target frequency of the inverter compressor according to the obtained current frequency and the determined downconversion index specifically comprises:

calculating a target frequency of the inverter compressor by the following calculation formula:

f_target＝f_o*γ

wherein f is_targetIs a target frequency of the inverter compressor, f_oAnd gamma is the current frequency of the inverter compressor, and gamma is the frequency reduction index of the inverter compressor.

5. The compressor frequency control method according to claim 1, wherein the step of "obtaining the operation parameter value of the heat pump dryer" specifically comprises:

acquiring the temperature of the barrel of the heat pump clothes dryer;

the step of acquiring the growth rate of the operation parameter value when the acquired operation parameter value reaches the preset parameter value specifically includes:

acquiring the increase rate of the barrel entering temperature under the condition that the acquired barrel entering temperature reaches the preset barrel entering temperature;

the step of determining the frequency reduction index of the inverter compressor according to the increase rate of the operating parameter value specifically comprises the following steps:

and determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the barrel inlet temperature.

6. The compressor frequency control method according to claim 1, wherein the step of "obtaining the operation parameter value of the heat pump dryer" specifically comprises:

acquiring the exhaust pressure of the variable frequency compressor;

the step of acquiring the growth rate of the operation parameter value when the acquired operation parameter value reaches the preset parameter value specifically includes:

acquiring the increase rate of the exhaust pressure under the condition that the acquired exhaust pressure reaches a preset exhaust pressure;

the step of determining the frequency reduction index of the inverter compressor according to the increase rate of the operating parameter value specifically comprises the following steps:

and determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the exhaust pressure.

7. The compressor frequency control method according to claim 1, wherein the step of "obtaining the operation parameter value of the heat pump dryer" specifically comprises:

acquiring the condensation temperature of the heat pump circulating system;

the step of acquiring the growth rate of the operation parameter value when the acquired operation parameter value reaches the preset parameter value specifically includes:

acquiring the increase rate of the condensation temperature under the condition that the acquired condensation temperature reaches a preset condensation temperature;

the step of determining the frequency reduction index of the inverter compressor according to the increase rate of the operating parameter value specifically comprises the following steps:

and determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the condensation temperature.

8. The compressor frequency control method according to claim 1, wherein the step of "obtaining the operation parameter value of the heat pump dryer" specifically comprises:

acquiring the barrel inlet temperature of the heat pump clothes dryer, the exhaust pressure of the variable frequency compressor and the condensation temperature of the heat pump circulating system;

the step of acquiring the growth rate of the operation parameter value when the acquired operation parameter value reaches the preset parameter value specifically includes:

acquiring the increase rate of the barrel inlet temperature, the increase rate of the exhaust pressure and the increase rate of the condensation temperature under the condition that at least one of the acquired barrel inlet temperature, the exhaust pressure and the condensation temperature reaches corresponding preset parameter values;

the step of determining the frequency reduction index of the inverter compressor according to the increase rate of the operating parameter value specifically comprises the following steps:

and determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the barrel inlet temperature, the increase rate of the exhaust pressure and the increase rate of the condensation temperature.

9. The compressor frequency control method of claim 8, wherein the step of determining a downconversion index of the inverter compressor based on the rate of increase of the barrel inlet temperature, the rate of increase of the discharge pressure, and the rate of increase of the condensing temperature specifically comprises:

determining a first frequency reduction index according to the increase rate of the barrel inlet temperature;

determining a second downconversion index according to the increase rate of the exhaust pressure;

determining a third downconversion index based on the rate of increase of the condensing temperature;

and determining the frequency reduction index of the variable frequency compressor according to the determined first frequency reduction index, the determined second frequency reduction index and the determined third frequency reduction index.

10. The method as claimed in claim 9, wherein the step of determining the downconversion index of the inverter compressor based on the determined first, second and third downconversion indices specifically comprises:

calculating a downconversion index of the inverter compressor by the following calculation:

γ＝k₁γ₁+k₂γ₂+k₃γ₃

wherein gamma is the frequency reduction index of the variable frequency compressor, and gamma is₁Is said first downconversion index, γ₂Is said second downconversion index, γ₃Is said third downconversion index, k₁、k₂、k₃Are weight coefficients.

Technical Field

The invention belongs to the technical field of clothes dryers, and particularly relates to a compressor frequency control method of a heat pump clothes dryer.

Background

With the continuous development of the clothes dryer technology, users also put forward higher and higher requirements on the clothes drying effect of the clothes dryer. Taking a heat pump clothes dryer as an example, the heat pump clothes dryer condenses water vapor and generates hot air through a heat pump circulating system, thereby realizing the clothes drying effect. In the earlier stage of drying clothes, in order to quickly raise the temperature of the inlet barrel to ensure the drying effect, a compressor of a heat pump circulating system generally operates at a higher frequency, and in the process, not only the temperature of the inlet barrel is continuously raised, but also the exhaust temperature of the compressor is continuously raised; not only is the irreversible damage to the clothes easily caused by the excessively high temperature of the inlet barrel, but also the damage to the compressor can be caused by the excessively high exhaust temperature. In view of this, the existing clothes dryers generally reduce the temperature of the inlet tub and the temperature of the exhaust air by gradually reducing the frequency of the compressor so that the temperature of the inlet tub and the temperature of the exhaust air can be maintained within a proper range. In the process of gradually reducing the frequency of the compressor according to a constant, if the constant is set too small, the problems of long frequency reducing time and insensitive adjustment may be caused, and if the constant is set too large, the heat exchange performance of the heat pump circulation system may be reduced, thereby causing the problem of poor drying effect. In summary, although the temperature reduction effect can be achieved by the adjusting mode, the adjusting mode usually needs to be adjusted repeatedly and continuously, so that the problem that the frequency modulation is slow and the problem that the control is not accurate exist, the reliability of the compressor is greatly reduced, and the overall performance of the clothes dryer is affected.

Accordingly, there is a need in the art for a new compressor frequency control method of a heat pump dryer to solve the above-mentioned problems.

Disclosure of Invention

In order to solve the above problems in the prior art, that is, to solve the problems of slow frequency modulation and inaccurate control caused by the poor frequency modulation manner of the compressor of the conventional heat pump clothes dryer, the present invention provides a method for controlling the frequency of the compressor of the heat pump clothes dryer, wherein the heat pump clothes dryer comprises a heat pump circulation system, the heat pump circulation system comprises a variable frequency compressor, and the method for controlling the frequency of the compressor comprises: acquiring an operation parameter value of the heat pump clothes dryer; acquiring the growth rate of the operation parameter value under the condition that the acquired operation parameter value reaches a preset parameter value; determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the operation parameter value; acquiring the current frequency of the variable frequency compressor; determining the target frequency of the variable frequency compressor according to the obtained current frequency and the determined frequency reduction index; and controlling the variable frequency compressor to operate at the determined target frequency.

In a preferred embodiment of the above method for controlling the frequency of the compressor, "determining the frequency reduction exponent of the inverter compressor according to the increase rate of the operating parameter value" specifically includes:

calculating a downconversion index of the inverter compressor by the following calculation:

γ＝av³+bv²+cv+d

wherein gamma is the frequency reduction index of the variable frequency compressor, v is the increasing rate of the operation parameter value, a, b and c are correction coefficients, and d is a correction value.

In a preferred technical solution of the above compressor frequency control method, the correction coefficients a, b, c are determined by the ambient temperature of the heat pump dryer; and/or the correction value d is determined by the ambient temperature at which the heat pump dryer is located.

In a preferred technical solution of the above-mentioned compressor frequency control method, "determining a target frequency of the inverter compressor according to the obtained current frequency and the determined downconversion index" specifically includes:

calculating a target frequency of the inverter compressor by the following calculation formula:

f_{t arg et}＝f_o*γ

wherein f is_{t arg et}Is a target frequency of the inverter compressor, f_oAnd gamma is the current frequency of the inverter compressor, and gamma is the frequency reduction index of the inverter compressor.

In a preferred technical solution of the above-mentioned compressor frequency control method, "obtaining an operation parameter value of the heat pump dryer" specifically includes: acquiring the temperature of the barrel of the heat pump clothes dryer; the step of acquiring the growth rate of the operation parameter value when the acquired operation parameter value reaches the preset parameter value specifically includes: acquiring the increase rate of the barrel entering temperature under the condition that the acquired barrel entering temperature reaches the preset barrel entering temperature; the step of determining the frequency reduction index of the inverter compressor according to the increase rate of the operating parameter value specifically comprises the following steps: and determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the barrel inlet temperature.

In a preferred technical solution of the above-mentioned compressor frequency control method, "obtaining an operation parameter value of the heat pump dryer" specifically includes: acquiring the exhaust pressure of the variable frequency compressor; the step of acquiring the growth rate of the operation parameter value when the acquired operation parameter value reaches the preset parameter value specifically includes: acquiring the increase rate of the exhaust pressure under the condition that the acquired exhaust pressure reaches a preset exhaust pressure; the step of determining the frequency reduction index of the inverter compressor according to the increase rate of the operating parameter value specifically comprises the following steps: and determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the exhaust pressure.

In a preferred technical solution of the above-mentioned compressor frequency control method, "obtaining an operation parameter value of the heat pump dryer" specifically includes: acquiring the condensation temperature of the heat pump circulating system; the step of acquiring the growth rate of the operation parameter value when the acquired operation parameter value reaches the preset parameter value specifically includes: acquiring the increase rate of the condensation temperature under the condition that the acquired condensation temperature reaches a preset condensation temperature; the step of determining the frequency reduction index of the inverter compressor according to the increase rate of the operating parameter value specifically comprises the following steps: and determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the condensation temperature.

In a preferred technical solution of the above-mentioned compressor frequency control method, "obtaining an operation parameter value of the heat pump dryer" specifically includes: acquiring the barrel inlet temperature of the heat pump clothes dryer, the exhaust pressure of the variable frequency compressor and the condensation temperature of the heat pump circulating system; the step of acquiring the growth rate of the operation parameter value when the acquired operation parameter value reaches the preset parameter value specifically includes: acquiring the increase rate of the barrel inlet temperature, the increase rate of the exhaust pressure and the increase rate of the condensation temperature under the condition that at least one of the acquired barrel inlet temperature, the exhaust pressure and the condensation temperature reaches corresponding preset parameter values; the step of determining the frequency reduction index of the inverter compressor according to the increase rate of the operating parameter value specifically comprises the following steps: and determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the barrel inlet temperature, the increase rate of the exhaust pressure and the increase rate of the condensation temperature.

In a preferred embodiment of the above compressor frequency control method, the step of determining the frequency reduction index of the inverter compressor according to the increase rate of the barrel inlet temperature, the increase rate of the discharge pressure, and the increase rate of the condensing temperature specifically includes: determining a first frequency reduction index according to the increase rate of the barrel inlet temperature; determining a second downconversion index according to the increase rate of the exhaust pressure; determining a third downconversion index based on the rate of increase of the condensing temperature; and determining the frequency reduction index of the variable frequency compressor according to the determined first frequency reduction index, the determined second frequency reduction index and the determined third frequency reduction index.

In a preferred embodiment of the above method for controlling a frequency of a compressor, "determining a downconversion index of the inverter compressor according to the determined first downconversion index, the determined second downconversion index, and the determined third downconversion index" specifically includes:

calculating a downconversion index of the inverter compressor by the following calculation:

γ＝k₁γ₁+k₂γ₂+k₃γ₃

wherein gamma is the frequency reduction index of the variable frequency compressor, and gamma is₁Is said first downconversion index, γ₂Is said second downconversion index, γ₃Is said third downconversion index, k₁、k₂、k₃Are weight coefficients.

As can be understood by those skilled in the art, in a preferred embodiment of the present invention, the heat pump clothes dryer of the present invention includes a heat pump cycle system including a variable frequency compressor, and the compressor frequency control method of the present invention includes: acquiring an operation parameter value of the heat pump clothes dryer; acquiring the growth rate of the operation parameter value under the condition that the acquired operation parameter value reaches a preset parameter value; determining the frequency reduction index of the variable-frequency compressor according to the increase rate of the operation parameter value; acquiring the current frequency of the variable frequency compressor; determining the target frequency of the variable frequency compressor according to the obtained current frequency and the determined frequency reduction index; and controlling the variable frequency compressor to operate at the determined target frequency. Based on the control mode, the invention can accurately predict the compressor frequency required by the heat pump circulating system in the middle drying stage, namely stable operation, according to the operating state of the heat pump circulating system in the early stage, so as to realize the control effect of accurate frequency reduction, thereby effectively improving the frequency modulation efficiency and the temperature control precision, ensuring the drying efficiency of the heat pump clothes dryer while ensuring the heat pump circulating system to be safer and more reliable.

Drawings

FIG. 1 is a flow chart of the main steps of the compressor frequency control method of the present invention;

fig. 2 is a flowchart illustrating the detailed steps of a preferred embodiment of the frequency control method of the compressor of the present invention.

Detailed Description

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention. It should be noted that, the heat pump clothes dryer described in the present invention refers to a clothes drying device with a heat pump circulation system, which may be a heat pump clothes dryer or a heat pump washing and drying all-in-one machine, and this is not a limitation. And can be adjusted as needed by those skilled in the art to suit particular applications. In addition, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be construed broadly, e.g., as meaning both electrically and mechanically connected; either directly or indirectly through intervening media, or through the communication between two elements.

Further, it should be noted that in the description of the present invention, although the steps of the control method of the present invention are described in a specific order in the present application, the order is not limited, and those skilled in the art may perform the steps in a different order without departing from the basic principle of the present invention.

The heat pump clothes dryer comprises a shell, a clothes drying barrel and a drying channel, wherein the clothes drying barrel and the drying channel are arranged in the shell, the clothes drying barrel is communicated with the drying channel, a heat pump circulating system is arranged in the drying channel, the refrigerant circulating system comprises a refrigerant circulating loop, an evaporator, a variable frequency compressor and a condenser, the evaporator, the variable frequency compressor and the condenser are arranged on the refrigerant circulating loop, in the air circulating process, wet air absorbing moisture from the clothes drying barrel is sent into the drying channel and is dehumidified through the evaporator, the dehumidified air flows through the condenser to be heated, and the heated air is sent back into the clothes drying barrel, so that the circulating drying and dehumidifying are achieved, and the clothes drying effect is achieved. It should be noted that, the invention does not limit the specific structure of the heat pump clothes dryer, and the technical personnel can set the heat pump clothes dryer according to the actual use requirement; for example, the types of the evaporator and the condenser are set by themselves; for example, the structure and shape of the drying passage are set by itself.

Further, the heat pump dryer of the present invention further includes a controller capable of acquiring an operation parameter value of the heat pump dryer, such as a tub inlet temperature, an exhaust pressure, a condensing temperature, etc., through various sensors, and also capable of controlling an operation state of the heat pump dryer, such as an operation frequency of the inverter compressor, etc.

It can be understood by those skilled in the art that the present invention does not limit the specific structure and model of the controller, and the controller may be the original controller of the heat pump clothes dryer or a controller separately provided for executing the compressor frequency control method of the present invention, and the structure and model of the controller can be set by those skilled in the art according to the actual use requirement.

Referring first to fig. 1, a flow chart of the main steps of the compressor frequency control method of the present invention is shown. As shown in fig. 1, based on the heat pump dryer described in the above embodiment, the compressor frequency control method of the present invention mainly includes the following steps:

s1: acquiring an operation parameter value of the heat pump clothes dryer;

s2: acquiring the growth rate of the operation parameter value under the condition that the acquired operation parameter value reaches a preset parameter value;

s3: determining the frequency reduction index of the variable frequency compressor according to the increase rate of the operation parameter value;

s4: acquiring the current frequency of the variable frequency compressor;

s5: determining the target frequency of the variable frequency compressor according to the obtained current frequency and the determined frequency reduction index;

s6: and controlling the variable frequency compressor to operate at the determined target frequency.

Specifically, in step S1, the controller may obtain an operation parameter value of the heat pump dryer; it should be noted that, the present invention does not impose any limitation on the specific type of the operation parameter value and the obtaining manner thereof, and a technician can set the operation parameter value according to the actual use requirement as long as the operation parameter value can represent the temperature rise or pressure rise speed of the heat pump circulation system; for example, the operating parameter value may be a barrel inlet temperature, a discharge pressure, a condensation temperature, or even a plurality of parameters may be used simultaneously, which is not restrictive.

Further, in step S2, in a case that the obtained operation parameter value reaches the preset parameter value, it can be understood that a technician needs to set a specific value of the preset parameter value according to an actual use requirement, and as long as the operation parameter value reaches the preset parameter value, it can be said that the heat pump cycle system cannot continue to increase the temperature or increase the pressure. In this case, the controller can further obtain the increasing rate of the operation parameter value, so as to ensure that the heat pump circulation system can be rapidly heated to ensure the drying effect, and meanwhile, the temperature cannot be raised too high to damage the clothes.

Next, in step S3, the controller can determine a down-conversion index of the inverter compressor according to the rate of increase of the operating parameter value; it should be noted that, the present invention does not limit the specific determination manner, and a technician may set the frequency-reducing index of the inverter compressor according to the actual use requirement, and the frequency-reducing index of the inverter compressor is determined according to the increase rate of the operation parameter value. As a preferred arrangement, the calculation may be performed by setting a corresponding mathematical model by means of a polynomial, wherein the various parameters involved are related to the structural design of the heat pump dryer, and may be determined experimentally. Of course, this is not limiting and the technician may also determine this by means of a table or the like.

Further, after determining the down conversion index of the inverter compressor, in step S4, the controller can further obtain the current frequency of the inverter compressor. Next, in step S5, the controller may determine a target frequency of the inverter compressor according to the obtained current frequency and the determined down-conversion index. Of course, it should be noted that the present invention does not limit the specific determination manner, and a skilled person may set the determination manner according to the actual use requirement, and it is within the protection scope of the present invention as long as the target frequency of the inverter compressor is determined according to the current frequency and the frequency reduction index.

Finally, after determining the target frequency of the variable frequency compressor, in step S6, the controller can control the variable frequency compressor to determine the target frequency operation so as to realize the control effect of accurate frequency reduction, thereby effectively improving the frequency modulation efficiency and the temperature control precision, and when the heat pump circulating system is safer and more reliable, the drying efficiency of the heat pump clothes dryer can be effectively ensured.

As a preferred embodiment, the operation parameter value of the heat pump clothes dryer can be selected as the tub temperature, and in the preferred embodiment, the target frequency of the inverter compressor is determined as follows:

firstly, the controller obtains the barrel inlet temperature of the heat pump clothes dryer through a barrel inlet temperature sensor, continuously compares the obtained barrel inlet temperature with a preset barrel inlet temperature, obtains the increase rate of the barrel inlet temperature under the condition that the obtained barrel inlet temperature reaches the preset barrel inlet temperature, and preferably adopts the average increase rate from the current start of the heat pump circulation system to the current moment. It should be noted that, the present invention does not limit the specific value of the preset barrel temperature, and the technical staff can set the temperature according to the actual use requirement.

Then, the controller determines the frequency reduction index of the variable-frequency compressor according to the increase rate of the barrel inlet temperature. It should be noted that the present invention does not limit the specific determination method, and the skilled person can set the determination method according to the actual use requirement. As a preferred arrangement, the calculation may be performed by setting a corresponding mathematical model by means of a polynomial, the number of terms of which may be set by itself according to experimental results, and wherein the respective parameters involved are related to the structural design of the heat pump dryer and may be determined experimentally.

Specifically, as a preferable determination, the down conversion index of the inverter compressor is calculated by the following calculation formula:

γ＝a'v³+b'v²+c'v+d'

wherein gamma is the frequency reduction index of the variable frequency compressor, v is the increase rate of the barrel inlet temperature, a ', b' and c 'are correction coefficients, and d' is a correction value.

It should be noted that, the invention does not limit the specific values of the correction coefficient and the correction value, and the skilled person can determine the correction coefficient and the correction value by himself or herself according to experiments; as a preferable setting manner, the correction coefficients a ', b', c 'and the correction value d' are determined by the ambient temperature of the heat pump clothes dryer, so as to effectively improve the accuracy of the correction result, that is, the frequency reduction index of the inverter compressor is influenced by the increase rate of the temperature of the inlet barrel and the ambient temperature of the heat pump clothes dryer, thereby effectively improving the accuracy of the result.

Further, after determining the frequency-reducing exponent of the inverter compressor, the controller may further obtain a current frequency of the inverter compressor. The controller is then capable of determining a target frequency of the inverter compressor based on the current frequency and the downconversion index.

As a preferable determination, the target frequency of the inverter compressor is calculated by the following calculation formula:

f_{t arg et}＝f_o*γ

wherein f is_{t arg et}Is a target frequency of the inverter compressor, f_oAnd gamma is the current frequency of the inverter compressor, and gamma is the frequency reduction index of the inverter compressor.

It should be noted that the above determination method related to the target frequency is not limited, and the skilled person may also adjust the target frequency according to the actual use requirement, for example, a correction coefficient may also be added to the calculation formula; also for example, the determination may be made in a tabular form, which is not limiting.

As another preferred embodiment, the operation parameter value of the heat pump clothes dryer can be an exhaust pressure, and in the preferred embodiment, the target frequency of the inverter compressor is determined as follows:

firstly, the controller acquires the exhaust pressure of the inverter compressor through an exhaust pressure sensor, continuously compares the acquired exhaust pressure with a preset exhaust pressure, acquires the increase rate of the exhaust pressure under the condition that the acquired exhaust pressure reaches the preset exhaust pressure, and the increase rate of the exhaust pressure preferably adopts the average increase rate from the current start of the heat pump circulation system to the current moment. It should be noted that, the specific value of the preset exhaust pressure is not limited by the present invention, and the technical staff can set the preset exhaust pressure according to the actual use requirement.

Then, the controller determines a downconversion index of the inverter compressor based on a rate of increase of the discharge pressure. It should be noted that the present invention does not limit the specific determination method, and the skilled person can set the determination method according to the actual use requirement. As a preferred arrangement, the calculation may be performed by setting a corresponding mathematical model by means of a polynomial, the number of terms of which may be set by itself according to experimental results, and wherein the respective parameters involved are related to the structural design of the heat pump dryer and may be determined experimentally.

Specifically, as a preferable determination, the down conversion index of the inverter compressor is calculated by the following calculation formula:

γ＝a”v³+b”v²+c”v+d”

wherein gamma is the frequency reduction index of the variable frequency compressor, v is the increasing rate of the exhaust pressure, a ', b' and c 'are all correction coefficients, and d' is a correction value.

It should be noted that, the present invention does not limit the specific values of the correction coefficient and the correction value, and a technician can determine the values by himself according to experiments, and the selected parameter types are different, and the values of the corresponding correction coefficient and the correction value are also different; as a preferable setting manner, the correction coefficients a ", b", c "and the correction value d" are determined by the ambient temperature of the heat pump clothes dryer, so as to effectively improve the accuracy of the correction result, that is, the frequency reduction index of the inverter compressor is influenced by the increase rate of the exhaust pressure and the ambient temperature of the heat pump clothes dryer, thereby effectively improving the accuracy of the result.

Further, after determining the frequency-reducing exponent of the inverter compressor, the controller may further obtain a current frequency of the inverter compressor. The controller is then capable of determining a target frequency of the inverter compressor based on the current frequency and the downconversion index.

As a preferable determination, the target frequency of the inverter compressor is calculated by the following calculation formula:

f_{t arg et}＝f_o*γ

wherein f is_{t arg et}Is a target frequency of the inverter compressor, f_oAnd gamma is the current frequency of the inverter compressor, and gamma is the frequency reduction index of the inverter compressor.

It should be noted that the above determination method related to the target frequency is not limited, and the skilled person may also adjust the target frequency according to the actual use requirement, for example, a correction coefficient may also be added to the calculation formula; also for example, the determination may be made in a tabular form, which is not limiting.

As another preferred embodiment, the operation parameter value of the heat pump clothes dryer can be selected from a condensation temperature, and in the preferred embodiment, the target frequency of the inverter compressor is determined as follows:

firstly, the controller acquires the condensation temperature of the heat pump circulation system through a condensation temperature sensor, continuously compares the acquired condensation temperature with a preset condensation temperature, acquires the increase rate of the condensation temperature under the condition that the acquired condensation temperature reaches the preset condensation temperature, and preferably adopts the average increase rate from the start of the heat pump circulation system to the current moment. It should be noted that, the invention does not limit the specific value of the preset condensing temperature, and the technical staff can set the temperature according to the actual use requirement.

Then, the controller determines a downconversion index of the inverter compressor based on a rate of increase of the condensing temperature. It should be noted that the present invention does not limit the specific determination method, and the skilled person can set the determination method according to the actual use requirement. As a preferred arrangement, the calculation may be performed by setting a corresponding mathematical model by means of a polynomial, the number of terms of which may be set by itself according to experimental results, and wherein the respective parameters involved are related to the structural design of the heat pump dryer and may be determined experimentally.

Specifically, as a preferable determination, the down conversion index of the inverter compressor is calculated by the following calculation formula:

γ＝a”'v³+b”'v²+c”'v+d”'

wherein gamma is the frequency reduction index of the variable frequency compressor, v is the increase rate of the condensation temperature, a ', b', c 'are all correction coefficients, and d' is a correction value.

It should be noted that, the present invention does not limit the specific values of the correction coefficient and the correction value, and a technician can determine the values by himself according to experiments, and the selected parameter types are different, and the values of the corresponding correction coefficient and the correction value are also different; as a preferable setting manner, the correction coefficients a '", b'", c '"and the correction value d'" are all determined by the ambient temperature of the heat pump clothes dryer, so as to effectively improve the accuracy of the correction result, that is, the frequency reduction index of the inverter compressor is influenced by the increase rate of the condensation temperature and the ambient temperature of the heat pump clothes dryer, thereby effectively improving the accuracy of the result.

Further, after determining the frequency-reducing exponent of the inverter compressor, the controller may further obtain a current frequency of the inverter compressor. The controller is then capable of determining a target frequency of the inverter compressor based on the current frequency and the downconversion index.

As a preferable determination, the target frequency of the inverter compressor is calculated by the following calculation formula:

f_{t arg et}＝f_o*γ

wherein f is_{t arg et}Is a target frequency of the inverter compressor, f_oAnd gamma is the current frequency of the inverter compressor, and gamma is the frequency reduction index of the inverter compressor.

It should be noted that the above determination method related to the target frequency is not limited, and the skilled person may also adjust the target frequency according to the actual use requirement, for example, a correction coefficient may also be added to the calculation formula; also for example, the determination may be made in a tabular form, which is not limiting.

Referring next to fig. 2, a flowchart detailing the steps of a preferred embodiment of the compressor frequency control method of the present invention is shown. As shown in fig. 2, based on the heat pump clothes dryer described in the above preferred embodiment, the preferred embodiment of the compressor frequency control method of the present invention specifically includes the following steps:

s101: acquiring the temperature of a barrel entering the heat pump clothes dryer, the exhaust pressure of the variable frequency compressor and the condensation temperature of the heat pump circulating system;

s102: acquiring the increase rates of the barrel inlet temperature, the exhaust pressure and the condensation temperature under the condition that at least one of the acquired barrel inlet temperature, the exhaust pressure and the condensation temperature reaches a corresponding preset parameter value;

s103: determining a first frequency reduction index according to the increase rate of the temperature of the barrel;

s104: determining a second downconversion index according to the increase rate of the exhaust pressure;

s105: determining a third downconversion index based on the rate of increase of the condensing temperature;

s106: determining the frequency reduction index of the variable frequency compressor according to the determined first frequency reduction index, the determined second frequency reduction index and the determined third frequency reduction index;

s107: acquiring the current frequency of the variable frequency compressor;

s108: determining the target frequency of the variable frequency compressor according to the obtained current frequency and the determined frequency reduction index;

s109: and controlling the variable frequency compressor to operate at the determined target frequency.

Specifically, in step S101, the controller may obtain a tub entering temperature of the heat pump dryer, a discharge pressure of the inverter compressor, and a condensing temperature of the heat pump cycle system; it should be noted that, the present invention does not limit the acquiring sequence and the acquiring frequency of the three parameters, and the technician can set the acquiring sequence and the acquiring frequency according to the actual use requirement.

Next, in step S102, the rate of increase of the barrel temperature, the rate of increase of the discharge pressure, and the rate of increase of the condensing temperature are further acquired as long as at least one of the following three determination conditions is satisfied, where condition 1: the barrel inlet temperature reaches a preset barrel inlet temperature; condition 2: the exhaust pressure reaches a preset exhaust pressure; condition 3: the condensation temperature reaches a preset condensation temperature.

Further, after obtaining the increase rate of the barrel inlet temperature, the increase rate of the exhaust pressure, and the increase rate of the condensing temperature, based on the determination manner shown in the above preferred embodiment, in step S103, step S104, and step S105, the controller may determine a first downconversion index according to the increase rate of the barrel inlet temperature, determine a second downconversion index according to the increase rate of the exhaust pressure, and determine a third downconversion index according to the increase rate of the condensing temperature.

Further, after determining the first, second, and third downconversion indices, the controller is capable of determining a downconversion index for the inverter compressor based on the first, second, and third downconversion indices in step S106. It should be noted that the present invention does not limit the specific determination method, and the skilled person can set the determination method according to the actual use requirement, for example, the determination method can be determined by a form corresponding manner.

As a preferable determination, the down conversion index of the inverter compressor is calculated by the following calculation formula:

γ＝k₁γ₁+k₂γ₂+k₃γ₃

wherein gamma is the frequency reduction index of the variable frequency compressor, and gamma is₁Is said first downconversion index, γ₂Is said second downconversion index, γ₃Is said third downconversion index, k₁、k₂、k₃Are weight coefficients.

It should be noted that the present invention does not include the weight coefficient k₁、k₂、k₃The specific value of (a) is subject to any limitation, and a skilled person can set the value according to the actual use requirement as long as the sum of the values is equal to 1. Preferably, k is₁＞k₂＞k₃So as to maximally protect the drying safety of the laundry.

Further, after determining the frequency-reducing exponent of the inverter compressor, the controller may further obtain a current frequency of the inverter compressor. The controller is then capable of determining a target frequency of the inverter compressor based on the current frequency and the downconversion index.

As a preferable determination, the target frequency of the inverter compressor is calculated by the following calculation formula:

f_{t arg et}＝f_o*γ

wherein f is_{t arg et}Is a target frequency of the inverter compressor, f_oAnd gamma is the current frequency of the inverter compressor, and gamma is the frequency reduction index of the inverter compressor.

Finally, after the target frequency of the variable frequency compressor is determined, in step S109, the controller can control the variable frequency compressor to determine the target frequency to operate, so that the control effect of accurate frequency reduction is realized, the frequency modulation efficiency and the temperature control precision are effectively improved, and the drying efficiency of the heat pump clothes dryer can be effectively ensured while the heat pump circulating system is safer and more reliable.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is apparent that the scope of the present invention is not limited to these specific embodiments, as will be readily understood by those skilled in the art. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.