阅读说明：本技术 一种直线压缩机活塞偏移补偿系统及方法 (Linear compressor piston offset compensation system and method ) 是由 梁昆 鲍鑫 李兆华 陈新文 于 2021-09-02 设计创作，主要内容包括：本发明公开了一种直线压缩机活塞偏移补偿系统及方法,包括输入行程信号X,根据行程信号生成驱动指令,驱动指令包括驱动频率信号f和驱动电压信号V-(1)；根据接收到的驱动指令,驱动直线压缩机、压力传感器及电压传感器工作,实现活塞的往复运动；根据电压传感器检测到的稳定的感应电压信号求解,得到活塞偏移信号；将接收到的活塞偏移信号传输到控制器,进行活塞偏移调控；根据活塞偏移信号进行功率补偿,调节驱动频率；使用本发明能减小活塞偏移。(The invention discloses a linear compressor piston offset compensation system and a method, which comprises the steps of inputting a stroke signal X, generating a driving instruction according to the stroke signal, wherein the driving instruction comprises a driving frequency signal f and a driving voltage signal V 1 (ii) a According to the received driving instruction, the linear compressor, the pressure sensor and the voltage sensor are driven to work, and the reciprocating motion of the piston is realized; solving according to the stable induced voltage signal detected by the voltage sensor to obtain a piston offset signal; transmitting the received piston offset signal to a controller for piston offset regulation; according to piston deflection signalsPerforming power compensation and adjusting the driving frequency; the piston offset can be reduced by using the invention.)

1. A method for compensating the offset of a piston of a linear compressor is characterized in that: which comprises the steps of preparing a mixture of a plurality of raw materials,

inputting a stroke signal X, and generating a driving command according to the stroke signal, wherein the driving command comprises a driving frequency signal f and a driving voltage signal V₁；

According to the received driving instruction, the linear compressor, the pressure sensor and the voltage sensor are driven to work, and the reciprocating motion of the piston is realized;

solving according to the stable induced voltage signal detected by the voltage sensor to obtain a piston offset signal;

transmitting the received piston offset signal to a controller for piston offset regulation;

and carrying out power compensation according to the piston offset signal, and adjusting the driving frequency.

2. The linear compressor piston excursion compensation system and method as set forth in claim 1, wherein: the driving frequency signal is output in a sine wave form, and the system is ensured to run in a resonance mode.

3. The linear compressor piston excursion compensation system and method as claimed in claim 1 or 2, wherein: the specific steps for obtaining the piston deflection signal are,

establishing a magnetic linkage between a primary coil and a moving magnetAnd the axial position x of the moving magnet,

whereas a linear motor has a symmetrical flux linkage characteristic, equation (1) can be further expressed as,

the electromotive force generated in the induction coil by the flux linkage change is,

for the electromotive forces V in two periods of the x > 0 and x < 0 domains_emfIs integrated to obtain

Wherein, 0 to t₁Is the interval of x < 0, t₁To t₂Is the interval where x is greater than 0;

the flux linkage difference can be obtained by simply calculating the flux linkage in two periods, so that the piston offset signal is obtained

Wherein the content of the first and second substances,is 0 to t₁The flux linkage in the period is determined by the magnetic flux,is t₁To t₂Flux linkage within a cycle.

4. The linear compressor piston excursion compensation system and method as set forth in claim 3, wherein: the specific steps of the piston offset regulation are as follows,

if the piston is offset signalThe system continues to keep running without the regulation and control work of the electromagnetic valve;

if the piston is offset signalThe system adjusts the duty cycle of the pulse signal applied to the solenoid valve through the PID controller until

5. The linear compressor piston excursion compensation system and method as set forth in claim 4, wherein: the step of performing the power compensation is specifically,

for a clearance ring with diameter D and radial clearance c, the volume flow rateIs composed of

Wherein P is gas pressure, mu is gas viscosity, and x' is the distance between the gap and the top dead center of the piston;

then, mass flow rateCan be expressed as

Wherein R is_gIs a gas constant, T₀Is the gas temperature;

the mass flow rate is constant over the length of the clearance ring, and P and x' satisfy a constant relationship, then equation (8) can be further expressed as L

Wherein, P1 and P2 are the air pressure at two ends of the piston respectively;

power loss due to leakageIs composed of

Equation (10) can be further expressed as

Substituting the mass flow and expanding the logarithmic term, equation (11) can be further expressed as

Since the pressure differential across the gap seal is small, the power loss can be approximated as

Then, the driving frequency f of the power loss adjustment is compensated₁Can be expressed as

By the driving frequency f₁The drive frequency signal f is adjusted to compensate for power loss due to piston deflection.

6. A linear compressor piston offset compensation system, characterized by: which comprises

The collecting module comprises a voltage sensor connected to the induction coil, pressure sensors are respectively arranged in the cylinders on the two sides of the piston and used for detecting induction voltage signals of the induction coil, and the pressure sensors collect the pressure on the two ends of the piston;

the offset detection module is used for receiving the induced voltage signal, processing the induced voltage signal according to the received induced voltage signal and outputting a piston offset regulation and control signal;

the offset compensation module comprises a controller and an electromagnetic valve, one end of the electromagnetic valve is communicated with the compressor main body through a pipeline, the other end of the electromagnetic valve is communicated with an air inlet of the air cylinder through a pipeline, and the controller is used for receiving the piston offset regulation and control signal and controlling the action of the electromagnetic valve according to the piston offset regulation and control signal.

7. The linear compressor piston excursion compensation system of claim 6, wherein: also comprises

The driving module comprises a signal generator and a power amplifier, the signal generator is used for generating a piston driving instruction meeting the working condition requirement, and the power amplifier amplifies a driving voltage signal;

and the execution module receives the amplified driving voltage signal and drives the linear compressor, the pressure sensor and the voltage sensor to work.

Technical Field

The invention relates to the technical field of automatic control, in particular to a linear compressor piston offset compensation system and method.

Background

With the technological progress and the improvement of living standard, people put forward higher requirements on the storage and transportation of different products, thereby promoting the development of refrigeration technology and providing conditions for the development of air conditioners.

The compressor is as the important component part of air conditioner, is the essential element of consumption electric energy, and linear compressor compares and has cancelled crank link mechanism in traditional compressor, directly by linear electric motor drive piston, has higher mechanical efficiency, and can be through the output who changes piston stroke control compressor to the realization is according to real-time operating mode variable displacement operation, has solved the problem that the refrigerating system energy consumption that the compressor frequently opened and stops the operating mode and bring increases, will certainly become the mainstream.

However, because linear compressor adopts clearance seal, the piston can lead to some working mediums to flow to the inside of the engine body through the sealed clearance due to the high pressure generated at the working cylinder side, the internal pressure of the engine body is increased continuously, the pressure difference between the two sides of the piston can lead to the piston to deviate, and the deviation of the piston motion center can lead to the reduction of the volumetric efficiency of the compressor under the same stroke, so that the power loss is brought.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

The present invention has been made in view of the above and/or other problems occurring in the conventional linear compressor.

Accordingly, an object of the present invention is to provide a piston deflection compensating system and method of a linear compressor, which can compensate power loss and reduce piston deflection.

In order to solve the technical problems, the invention provides the following technical scheme: a method for compensating piston offset of linear compressor comprises,

inputting a stroke signal X, and generating a driving command according to the stroke signal, wherein the driving command comprises a driving frequency signal f and a driving voltage signal V₁；

According to the received driving instruction, the linear compressor, the pressure sensor and the voltage sensor are driven to work, and the reciprocating motion of the piston is realized;

solving according to the stable induced voltage signal detected by the voltage sensor to obtain a piston offset signal;

transmitting the received piston offset signal to a controller for piston offset regulation;

and carrying out power compensation according to the piston offset signal, and adjusting the driving frequency.

As a preferable aspect of the method for compensating for piston offset of a linear compressor according to the present invention, wherein: the driving frequency signal is output in a sine wave form, and the system is ensured to operate in a resonance mode.

As a preferable aspect of the method for compensating for piston offset of a linear compressor according to the present invention, wherein: the specific steps for obtaining the piston deflection signal are,

establishing a magnetic linkage between a primary coil and a moving magnetAnd the axial position x of the moving magnet,

whereas a linear motor has a symmetrical flux linkage characteristic, equation (1) can be further expressed as,

the electromotive force generated in the induction coil by the flux linkage change is,

for the electromotive forces V in two periods of the x > 0 and x < 0 domains_emfIs integrated to obtain

Wherein, 0 to t₁Is the interval of x < 0, t₁To t₂Is the interval where x is greater than 0;

the flux linkage difference can be obtained by simply calculating the flux linkage in two periods, thereby obtaining a piston offset signal

Wherein the content of the first and second substances,is 0 to t₁The flux linkage in the period is determined by the magnetic flux,is t₁To t₂Flux linkage within a cycle.

As a preferable aspect of the method for compensating for piston offset of a linear compressor according to the present invention, wherein: the specific steps of the piston offset regulation are as follows,

if the piston is offset signalThe system continues to keep running without the regulation and control work of the electromagnetic valve;

if the piston is offset signalThe system adjusts the duty cycle of the pulse signal applied to the solenoid valve through the PID controller until

As a preferable aspect of the method for compensating for piston offset of a linear compressor according to the present invention, wherein: the step of performing the power compensation is specifically,

for a clearance ring with diameter D and radial clearance c, the volume flow rateIs composed of

Wherein P is gas pressure, mu is gas viscosity, and x' is the distance between the gap and the top dead center of the piston;

then, mass flow rateCan be expressed as

Wherein R is_gIs a gas constant, T₀Is the gas temperature;

the mass flow rate is constant over the length of the clearance ring, and P and x satisfy a constant relationship, then equation (8) can be further expressed as L, based on the seal length

Wherein, P1 and P2 are the air pressure at two ends of the piston respectively;

power loss due to leakageIs composed of

Equation (10) can be further expressed as

Substituting the mass flow and expanding the logarithmic term, equation (11) can be further expressed as

Since the pressure differential across the gap seal is small, the power loss can be approximated as

Then, the driving frequency f of the power loss adjustment is compensated₁Can be expressed as

By the driving frequency f₁The drive frequency signal f is adjusted to compensate for power loss due to piston deflection.

A linear compressor piston offset compensation system includes

The collecting module comprises voltage sensors connected to the induction coil, pressure sensors are respectively arranged in the air cylinders at two sides of the piston and used for detecting induced voltage signals of the induction coil, and the pressure sensors collect the pressure at two ends of the piston;

the offset detection module is used for receiving the induction voltage signal, processing the induction voltage signal according to the received induction voltage signal and outputting a piston offset regulation signal;

the offset compensation module comprises a controller and an electromagnetic valve, one end of the electromagnetic valve is communicated with the compressor main body through a pipeline, the other end of the electromagnetic valve is communicated with an air inlet of the air cylinder through a pipeline, and the controller is used for receiving the piston offset regulation and control signal and controlling the action of the electromagnetic valve according to the piston offset regulation and control signal.

As a preferable aspect of the piston offset compensating system of the linear compressor according to the present invention, wherein: also comprises

The driving module comprises a signal generator and a power amplifier, the signal generator is used for generating a piston driving instruction meeting the working condition requirement, and the power amplifier amplifies a driving voltage signal;

and the execution module receives the amplified driving voltage signal and drives the linear compressor, the pressure sensor and the voltage sensor to work.

The invention has the beneficial effects that: the piston offset is calculated through the flux linkage difference, the precise relation between the position of the piston and the flux linkage does not need to be determined, a displacement sensor is cancelled, the use cost of the compressor is greatly reduced while the structure of the linear compressor is simplified, the piston offset is reduced by adjusting the duty ratio of the electromagnetic valve, meanwhile, the power loss caused by the piston offset is compensated in time through a compensation system, and the safety and the reliability of the operation of the linear compressor are improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:

fig. 1 is a general structural block diagram of the present invention.

Fig. 2 is a schematic diagram of the structure of the main coil and the induction coil in the present invention.

Fig. 3 is a schematic view of a linear compressor according to the present invention.

FIG. 4 is an interface diagram of an offset display according to the present invention.

In the figure, 100 offset display, 200 offset detector, 300 power amplifier, 400 linear compressor, 401 induction coil, 402 main coil, 403 moving magnet, 404 iron core, 405 compressor housing, 406 electromagnetic valve, 407 second pipe, 408 first pipe, 409 voltage sensor, 410 piston, 411 pressure sensor, 412 cylinder, 413 piston rod, 500 signal generator.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Example 1

Referring to fig. 1, a first embodiment of the present invention provides a piston offset compensation method of a linear compressor, which can reduce piston offset.

A method for compensating for offset of a piston of a linear compressor includes,

the stroke signal X is input to the stroke sensor,generating a driving command according to the stroke signal, wherein the driving command comprises a driving frequency signal f and a driving voltage signal V₁The driving frequency signal is output in a sine wave form, so that the system is ensured to operate in a resonance mode;

according to the received driving instruction, the linear compressor 400, the pressure sensor 411 and the voltage sensor 409 are driven to work, and the reciprocating motion of the piston 410 is realized;

solving according to the stable induced voltage signal detected by the voltage sensor 409 to obtain a piston 410 offset signal;

transmitting the received piston 410 deviation signal to a controller for regulating and controlling the deviation of the piston 410;

power compensation is performed based on the piston 410 excursion signal to adjust the drive frequency.

Further, the specific steps for obtaining the piston 410 deflection signal are,

establishing a magnetic linkage between the primary coil 402 and the moving magnet 403And the axial position x of the moving magnet 403,

whereas a linear motor has a symmetrical flux linkage characteristic, equation (1) can be further expressed as,

the electromotive force generated in the induction coil 401 by the flux linkage change is,

for the electromotive forces V in two periods of the x > 0 and x < 0 domains_emfIs integrated to obtain

Wherein, 0 to t₁Is the interval of x < 0, t₁To t₂Is the interval where x is greater than 0;

the flux linkage difference can be obtained by simply calculating the flux linkage in two periods, so as to obtain the offset signal of the piston 410

Wherein the content of the first and second substances,is 0 to t₁The flux linkage in the period is determined by the magnetic flux,is t₁To t₂Flux linkage within a cycle.

Further, the specific steps of the offset adjustment of the piston 410 are,

if the piston 410 is offset by a signalThe system continues to operate without performing the regulation and control operation of the solenoid valve 406;

if the piston 410 is offset by a signalThe system adjusts the duty cycle of the pulse signal applied to the solenoid valve 406 through the PID controller until such time as

Further, the step of performing power compensation specifically includes,

for a clearance ring with diameter D and radial clearance c, the volume flow rateIs composed of

Wherein P is gas pressure, μ is gas viscosity, and x' is the distance from the top dead center of the piston 410 at the gap;

then, mass flow rateCan be expressed as

Wherein R is_gIs a gas constant, T₀Is the gas temperature;

the mass flow rate is constant over the length of the clearance ring, and P and x satisfy a constant relationship, then equation (8) can be further expressed as L, based on the seal length

Wherein, P1 and P2 are the air pressures at the two ends of the piston 410 respectively;

power loss due to leakageIs composed of

Equation (10) can be further expressed as

Substituting the mass flow and expanding the logarithmic term, equation (11) can be further expressed as

Since the pressure differential across the gap seal is small, the power loss can be approximated as

Then, the driving frequency f of the power loss adjustment is compensated₁Can be expressed as

By the driving frequency f₁The driving frequency signal f is adjusted to compensate for the power loss due to the deflection of the piston 410.

In this embodiment, the linear compressor 400 is a moving magnet 403 type linear compressor 400, the linear compressor 400 includes a compressor housing 405, an iron core 404 and a cylinder 412 are disposed in the compressor housing 405, a main coil 402 and an induction coil 401 are wound on the iron core 404, a movable moving magnet 403 is connected between the iron cores 404, a movable piston 410 is connected in the cylinder 412, a piston rod 413 is connected to the piston 410, one end of the piston rod 413 extending outward is connected to the moving magnet 403, pressure sensors 411 are connected to the cylinders 412 at both ends of the piston 410, the induction ends of the pressure sensors 411 are disposed in the inner cavity of the cylinder 412, the air pressures at both ends of the piston 410 are detected by the two pressure sensors 411, a first pipe 408 is connected to the cylinder 412, one end of the first pipe 408 is communicated with the inner cavity of the cylinder 412 corresponding to one end of the piston 410 facing the moving magnet 403, a second pipe 407 is connected to the air inlet of the cylinder 412, the solenoid valve 406 is connected between a first conduit 408 and a second conduit 407.

According to the invention, the offset of the piston 410 is calculated through the flux linkage difference, the accurate relation between the position of the piston 410 and the flux linkage does not need to be determined, the duty ratio of the electromagnetic valve 406 is controlled according to the calculated offset signal of the piston 410, and meanwhile, the driving frequency is calculated to adjust the driving frequency signal, so that the power loss caused by the offset of the piston 410 is compensated.

Example 2

Referring to fig. 1 to 3, a second embodiment of the present invention is different from embodiment 1 in that the present embodiment provides a piston offset compensation system of a linear compressor, which includes,

the acquisition module comprises a voltage sensor 409 connected to the induction coil 401, pressure sensors 411 are respectively arranged in air cylinders 412 on two sides of the piston 410, the voltage sensor 409 is used for detecting an induction voltage signal of the induction coil 401, and the pressure sensors 411 acquire pressures at two ends of the piston 410;

an offset detection module including an offset detector 200 and an offset display 100 for receiving the induced voltage V₃And processes the signal according to the received induced voltage signal to output a piston 410 deviation regulation signal, namely, a flux linkage difference in two periodsAnd inputting the piston 410 displacement signal to the displacement display 100 so as to detect the piston 410 displacement in real time, the displacement display 100 having a user interface for displaying the piston 410 displacement signal in real time;

the offset compensation module comprises a controller and an electromagnetic valve 406, one end of the electromagnetic valve 406 is communicated with the compressor main body through a pipeline, the other end of the electromagnetic valve 406 is communicated with an air inlet of an air cylinder 412 through a pipeline, the controller is used for receiving an offset regulation signal of the piston 410 and controlling the action of the electromagnetic valve 406 according to the offset regulation signal of the piston 410, a specific offset compensation result can be known through the offset display 100, the offset compensation module compensates the real-time waveform of the offset piston 410 and refers to a graph 4, a waveform line in the graph is a real-time waveform of induction voltage, an upper straight line is a real-time flux linkage difference value obtained through calculation, a lower straight line is a balance position line of the piston 410, and the offset compensation module has obvious effect, the flux linkage difference value is gradually reduced, and continuous compensation is carried out until the value is zero, so that the piston 410 reaches the balance position;

the driving module comprises a signal generator 500 and a power amplifier 300, the signal generator 500 is used for generating a driving instruction of the piston 410 according with the working condition requirement, and the power amplifier 300 is used for driving a voltage signal V₁Amplifying to obtain an amplified working voltage V₂；

An execution module for receiving the driving frequency signal and the amplified working voltage signal outputted from the driving module, driving the linear compressor 400 to reciprocate, and outputting an induced voltage signal V₃The linear compressor 400 receives the operating voltage V₂So that a potential difference exists across the primary coil 402 to generate an operating current I₁An axial driving force is formed to drive the moving magnet 403 to move axially, the axial movement of the moving magnet 403 changes the magnetic flux passing through the iron cores 404 to generate an induced voltage in the main coil 402, the polarities of the adjacent iron cores 404 are opposite, the working voltage at the two ends of the main coil 402 is an alternating voltage, and the working current I in the main coil 402 is₁Alternating current to generate alternating axial force to reciprocate the piston 410, and the induced voltage V is generated in the induction coil 401 due to the constant positive and negative change of the operating current in the main coil 402₃The voltage sensor 409 then records the induced voltage V in the induction coil 401₃And sends the signal to the offset detection module.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.