CN112413813B - Fault restart control method and device and air conditioning equipment - Google Patents

Fault restart control method and device and air conditioning equipment Download PDF

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Publication number
CN112413813B
CN112413813B CN202011280257.9A CN202011280257A CN112413813B CN 112413813 B CN112413813 B CN 112413813B CN 202011280257 A CN202011280257 A CN 202011280257A CN 112413813 B CN112413813 B CN 112413813B
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compressor
resistor
bridge arms
current
preset time
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CN112413813A (en
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贺小林
刘文斌
刘涛
陶海莉
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F24F11/32—Responding to malfunctions or emergencies
    • F24F11/37—Resuming operation, e.g. after power outages; Emergency starting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F24F11/32—Responding to malfunctions or emergencies
    • F24F11/38—Failure diagnosis
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
    • F24F11/86—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling compressors within refrigeration or heat pump circuits

Abstract

The invention discloses a fault restart control method and device and air conditioning equipment. Wherein, the method comprises the following steps: after the air conditioner has an overcurrent fault, closing a control signal of a compressor driving circuit; controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be switched on for a second preset time and then to be switched off every other first preset time; acquiring the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all upper bridge arms or all lower bridge arms are switched on; and controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor. According to the invention, after the air conditioner has accidental faults, the rotating speed and the rotor position of the compressor are detected, and the compressor is immediately controlled to restart to be in a stable operation state after the faults are cleared, so that the reliability and the user experience of the air conditioning equipment are improved.

Description

Fault restart control method and device and air conditioning equipment
Technical Field
The invention relates to the technical field of air conditioners, in particular to a fault restart control method and device and an air conditioning device.
Background
For air-conditioning products, problems of power supply faults of a power grid and environmental factors, such as power grid fluctuation faults, upwind operation, lightning stroke, high-temperature influence of other equipment and the like, can cause the air conditioner to judge faults by mistake and stop the machine in a protective mode, so that indoor temperature fluctuation directly influences experience and experience of users, and particularly in places with high requirements for temperature control precision, serious consequences can be brought.
The fault is sporadic and will clear automatically after 2 s. The conventional method for the fault is to stop the air conditioner firstly, so that the air conditioner works in a state with rotating speed, at the moment, the position of a compressor rotor cannot be accurately estimated by the conventional position estimation method, the air conditioner is restarted and started after accidental faults are automatically cleared, and because the position of the compressor rotor cannot be obtained at the moment, if a control system is switched in blindly, the air conditioner cannot be started normally, and overcurrent faults can be caused by very large current impact seriously.
Aiming at the problem that the compressor cannot be restarted smoothly due to the loss of the rotating speed and the rotor position after the compressor is stopped due to faults in the prior art, an effective solution is not provided at present.
Disclosure of Invention
The embodiment of the invention provides a fault restart control method and device and air conditioning equipment, and aims to solve the problem that in the prior art, after a compressor is stopped due to a fault, the rotating speed and the position of a rotor are lost, so that the compressor cannot be restarted smoothly.
In order to solve the technical problem, the invention provides a fault restart control method, which is applied to an air conditioner and comprises the following steps:
after the air conditioner has an overcurrent fault, closing a control signal of a compressor driving circuit;
controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be switched on for a second preset time and then to be switched off every other first preset time;
acquiring the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all upper bridge arms or all lower bridge arms are switched on;
and controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor.
Further, controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be turned off after being turned on for a second preset time at intervals of a first preset time, and the method comprises the following steps:
and applying zero vectors to all the upper bridge arms or all the lower bridge arms at intervals of a first preset time length and continuing for a second preset time length so as to control all the upper bridge arms or all the lower bridge arms to be switched off after the second preset time length is switched on.
Further, acquiring the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are switched on includes:
obtaining the angle error between the actual value of the rotor angle and the estimated value of the rotor angle according to the compressor winding current when all upper bridge arms or all lower bridge arms are switched on;
and acquiring the rotating speed and the rotor position of the compressor according to the angle error.
Further, obtaining an angle error between the actual value of the rotor angle and the estimated value of the rotor angle according to the compressor winding current when all upper bridge arms or all lower bridge arms are switched on includes:
obtaining the current of a compressor winding when all upper bridge arms or all lower bridge arms are conducted;
performing CLARKE transformation on the obtained compressor winding current to obtain a direct-axis component and a quadrature-axis component of the compressor winding current under a static estimation coordinate system;
and calculating the angle error according to the direct axis component and the quadrature axis component.
Further, obtaining the rotation speed and the rotor position of the compressor according to the angle error comprises:
carrying out proportional integral control on the angle error to obtain the rotating speed of the compressor;
and integrating the rotating speed of the compressor and multiplying the rotating speed by the pole pair number of the compressor rotor to obtain the rotor position of the compressor.
Further, controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor comprises the following steps:
and controlling the compressor to be put into operation again according to the rotating speed of the compressor obtained last time and the current corresponding to the rotor position.
Further, when the rotating speed and the rotor position of the compressor are obtained according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are switched on, the method further comprises the following steps:
judging whether the current of the compressor winding exceeds a threshold value;
if so, shortening and updating the second preset time, wherein the updated second preset time is used as the time for conducting all upper bridge arms or all lower bridge arms at the next time;
if not, keeping the current second preset time length unchanged.
Further, after the rotating speed and the rotor position of the compressor are obtained according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are switched on, the method further comprises the following steps:
the load of the compressor is reduced;
judging whether the fault still exists;
if yes, controlling the air conditioner to stop;
and if not, triggering to control the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor.
Further, reducing compressor load, comprising:
controlling the wind shield of an outer fan of the air conditioner to increase, and simultaneously opening a load relief valve of the air conditioner;
judging whether the difference value between the current compressor exhaust temperature and the reference temperature is greater than a preset value or not; wherein the reference temperature is the exhaust temperature of the compressor at the moment of fault occurrence;
if yes, controlling the opening of an electronic expansion valve of the air conditioner to increase;
if not, controlling the electronic expansion valve of the air conditioner to keep the original opening unchanged.
The invention also provides a fault restart control device, which is used for realizing the fault restart control method and comprises the following steps:
the first control module is used for closing a control signal of the compressor driving circuit after the air conditioner has an overcurrent fault;
the second control module is used for controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be switched on for a second preset time and then switched off every interval of a first preset time;
the acquisition module is used for acquiring the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are switched on;
and the third control module is used for controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor.
Further, the apparatus further comprises:
and the current limiting module is used for judging whether the current of the compressor winding exceeds a threshold value or not and reducing the second preset time when the current of the compressor winding exceeds the threshold value.
Further, the current limiting module includes:
the Hall sensors are respectively sleeved on different phase lines of the compressor and used for detecting single-phase current of the compressor;
the at least two current-limiting protection units are connected with the Hall sensors in a one-to-one correspondence manner and used for outputting sampling signals according to the single-phase current of the compressor;
the input end of the signal control unit is connected with each current-limiting protection unit and used for outputting a control signal according to the sampling signal; the control signal is used for controlling the second preset time length.
Further, the current limiting protection unit includes:
the current conversion circuit is used for outputting negative voltage when the single-phase current of the compressor is a negative value, and converting the input current and outputting negative voltage when the single-phase current of the compressor is a positive value;
the first input end of the comparator is connected with the output end of the current conversion circuit, the second input end of the comparator inputs reference voltage, and the output end of the comparator is connected with the signal control unit and used for outputting a sampling signal according to the voltage output by the current conversion circuit; wherein the reference voltage is a negative value.
Further, the current conversion circuit includes:
the first end of the first resistor is connected with the Hall sensor, and the second end of the first resistor is grounded and used for converting the single-phase current of the compressor into a voltage signal;
the first series branch is formed by sequentially connecting a second resistor, a third resistor and a fourth resistor in series, the first end of the first series branch is connected with the first end of the first resistor, and the second end of the first series branch is connected with the first input end of the first operational amplifier;
the second input end of the first operational amplifier is grounded, and the output end of the first operational amplifier is connected with the comparator;
a first input end of the first operational amplifier is connected between the first resistor and the second resistor, a second input end of the first operational amplifier is grounded, an output end of the first operational amplifier is connected between the first resistor and the second resistor sequentially through an anode and a cathode of the first unidirectional element, and the first input end of the first operational amplifier is connected with the anode of the first unidirectional element sequentially through the anode and the cathode of the second unidirectional element;
and a second series branch consisting of a fifth resistor and a sixth resistor which are connected in series, wherein the first end of the second series branch is connected with the first end of the first resistor, the second end of the second series branch is connected with the output end of the first operational amplifier, and a line between the fifth resistor and the sixth resistor is connected with the first input end of the first operational amplifier.
Further, the current conversion circuit further includes:
and the first capacitor is arranged at two ends of the first resistor in parallel and is used for filtering the voltage at two ends of the first resistor.
Furthermore, the fifth resistor R5 is equal to the sixth resistor R6, and the sixth resistor R2 is equal to 2 × the third resistor R3 is equal to 2 × the fourth resistor R4.
Further, the current conversion circuit further includes:
and the seventh resistor is arranged between the first input end of the second operational amplifier and the anode of the second unidirectional element and used for limiting current.
Further, the signal control unit includes:
a third series branch composed of an eighth resistor and a ninth resistor, wherein the first end of the third series branch inputs each phase of sampling signals of the compressor, and the second end is grounded;
and the base electrode of the first switch is connected between the eighth resistor and the ninth resistor, the collector electrode of the first switch is connected with a voltage source through a tenth resistor, the emitter electrode of the first switch is grounded, and the collector electrode of the first switch is also connected with a microprocessor of the compressor through an eleventh resistor and is used for outputting a control signal so as to control the second preset time.
Further, the signal control unit further includes:
and a first end of the second capacitor is connected between the eleventh resistor and the microprocessor, and a second end of the second capacitor is grounded and is used for filtering the control signal.
Further, the signal control unit further includes:
and the first end of the third capacitor is connected with the voltage source, and the second end of the third capacitor is grounded and is used for filtering the voltage provided by the voltage source.
The invention also provides air conditioning equipment which comprises a compressor and the fault restart control device.
The present invention also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the above-described fault restart control method.
By applying the technical scheme of the invention, after the air conditioner has an overcurrent fault, the control signal of the compressor driving circuit is closed; controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be switched on for a second preset time and then to be switched off every other first preset time; acquiring the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all upper bridge arms or all lower bridge arms are switched on; and controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor. The air conditioner can detect the rotating speed and the rotor position of the compressor after accidental faults occur to the air conditioner, and immediately control the compressor to restart and put into a stable operation state after the faults are cleared, so that the reliability and the user experience of the air conditioner are improved.
Drawings
Fig. 1 is a structural view of a compressor driving circuit of an air conditioner according to an embodiment of the present invention;
FIG. 2 is a flow chart of a fail-over control method according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a d and q axis back EMF estimation coordinate system according to an embodiment of the present invention;
FIG. 4 is a flow chart of an estimation of a PLL according to an embodiment of the present invention;
fig. 5 is a structural diagram of a failed restart control apparatus according to an embodiment of the present invention;
fig. 6 is a block diagram of a failed restart control apparatus according to another embodiment of the present invention;
FIG. 7 is a circuit diagram of a current limiting protection unit according to an embodiment of the present invention;
FIG. 8 is a block diagram of a signal control unit according to an embodiment of the present invention;
FIG. 9 is a flow chart of a method of fault restart control according to another embodiment of the present invention;
fig. 10 is a flowchart of a rotational speed and rotor position sensing process of a compressor according to an embodiment of the present invention;
fig. 11 is a flowchart of a process of reducing a load of a compressor according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and "a plurality" typically includes at least two.
It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
It should be understood that although the terms first, second, third, etc. may be used to describe the resistors in the embodiments of the present invention, the resistors should not be limited to these terms. These terms are only used to distinguish between resistors disposed at different locations. For example, a first resistance may also be referred to as a second resistance, and similarly, a second resistance may also be referred to as a first resistance, without departing from the scope of embodiments of the present invention.
The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a stated condition or event)", depending on the context.
It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in the article or device in which the element is included.
Alternative embodiments of the present invention are described in detail below with reference to the accompanying drawings.
Example 1
Fig. 1 is a structural diagram of a compressor driving circuit of an air conditioner according to an embodiment of the present invention, and as shown in fig. 1, the compressor driving circuit includes power switching device VT 1-VT 6, where VT1, VT3, and VT5 are upper bridge arms, and VT2, VT4, and VT6 are lower bridge arms, to form a three-phase bridge inverter topology. D1-D6 are power switch tube device freewheeling diodes, and freewheel to form a closed loop when the power switch tube device is turned off. a. b and c are three-phase leading-out ends of the driving system and are directly connected with three-phase windings of the compressor.
Fig. 2 is a flowchart of a fault restart control method according to an embodiment of the present invention, and as shown in fig. 2, the fault restart control method includes:
and S101, after the air conditioner has an overcurrent fault, closing a control signal of a compressor driving circuit.
Because the air conditioner has overcurrent faults due to power supply faults of a power grid and transient fluctuation of environmental factors, in order to avoid burning out the air conditioner by overcurrent, the driving control signal needs to be turned off firstly.
And S102, controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be switched on for a second preset time and then switching off every other first preset time.
After a control signal of a compressor driving circuit is turned off, all upper bridge arms or all lower bridge arms are turned off, at the moment, no current exists in the circuit, the rotating speed and the rotor position of the compressor cannot be detected, when a fault is cleared and the compressor is controlled to be put into operation again, the rotating speed and the rotor position of the compressor are lost, and the compressor is likely to fail to start, so that in order to acquire the rotating speed and the rotor position of the compressor, all the upper bridge arms or all the lower bridge arms of the compressor driving circuit are controlled to be turned off after being turned on for a second preset time at intervals, wherein the first preset time and the second preset time can be equal or unequal.
And S103, acquiring the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are conducted.
When all upper bridge arms or all lower bridge arms of the compressor driving circuit are controlled to be conducted, current passes through the compressor winding, and the rotating speed and the rotor position of the compressor can be obtained by collecting the current of the compressor winding and carrying out corresponding calculation.
And S104, controlling the compressor to be put into operation again according to the acquired rotating speed and the rotor position of the compressor.
And when the fault is cleared, controlling the parameters of the compressor during the operation again according to the rotating speed and the rotor position of the compressor which are acquired last time in preparation for controlling the compressor to be put into operation again so as to facilitate the smooth start of the compressor.
In the fault restart control method of the embodiment, after the air conditioner has an overcurrent fault, a control signal of a compressor driving circuit is turned off; controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be switched on for a second preset time and then switching off every other first preset time; acquiring the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all upper bridge arms or all lower bridge arms are switched on; and controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor. The air conditioner can detect the rotating speed and the rotor position of the compressor after accidental faults occur to the air conditioner, and immediately control the compressor to restart and put into a stable operation state after the faults are cleared, so that the reliability and the user experience of the air conditioner are improved.
Example 2
In this embodiment, in order to control all upper bridge arms or all lower bridge arms of the compressor driving circuit to be intermittently turned on after the control signal of the compressor driving circuit is turned off, the step S102 specifically includes: and applying zero vectors to all the upper bridge arms or all the lower bridge arms at intervals of a first preset time length and continuing for a second preset time length so as to control all the upper bridge arms or all the lower bridge arms to be switched off after the second preset time length is switched on.
After controlling all the upper bridge arms or all the lower bridge arms to be conducted, the three-phase windings of the compressor are short-circuited, the freewheeling diodes D1, D3, D5 and the three-phase windings form a closed loop, a current is generated in the loop, and in order to obtain the rotating speed and the rotor position of the compressor according to the current, the step S103 specifically includes: acquiring an angle error between a real value of a rotor angle and an estimated value of the rotor angle according to the winding current of the compressor when all upper bridge arms or all lower bridge arms are switched on, and specifically acquiring the winding current of the compressor when all upper bridge arms or all lower bridge arms are switched on; performing CLARKE transformation on the obtained compressor winding current to obtain a direct-axis component and a quadrature-axis component of the compressor winding current under a static estimation coordinate system; an angle error is calculated from the direct (d-axis) component and the quadrature (q-axis) component. In the concrete implementation, the angular error amount is obtained by the following formula (10)
Figure GDA0002906023060000091
In a synchronous rotating coordinate system, the d-axis voltage and the q-axis voltage of the compressorThe voltage can be expressed as the following equation:
Figure GDA0002906023060000092
Figure GDA0002906023060000093
fig. 3 is a schematic diagram of d-axis and q-axis back electromotive force estimation coordinate systems according to an embodiment of the present invention, and the following equations (3) and (4) can be obtained by decomposing the coordinate systems in fig. 3:
Figure GDA0002906023060000094
Figure GDA0002906023060000095
further simplification can be achieved:
Figure GDA0002906023060000096
substituting equations (3) and (4) into equations (1) and (2) can obtain:
Figure GDA0002906023060000097
Figure GDA0002906023060000098
because the rotation speed is smaller, the current change rate is slower, and because u is smallerd＝0、u q0, further simplified to obtain:
ed＝-Rsid (8)
eq＝-Rsiq (9)
substituting equations (8), (9) into equation (5) yields:
Figure GDA0002906023060000101
wherein R issIs compressor stator resistance, LdFor the component L of the compressor stator inductance in the d-axisqComponent of motor stator inductance in q-axis, idComponent of compressor stator current in d-axis, iqComponent of compressor stator current in q-axis, udComponent of compressor stator voltage on d-axis, uqComponent of the compressor stator voltage in the q-axis, edComponent of counter electromotive force of compressor stator on d-axis, eqComponent of the compressor stator back EMF in the d-axis, ωrIs the rotational speed of the compressor, keIn order to be a counter-electromotive force coefficient,
Figure GDA0002906023060000102
the actual value theta of the rotor angle and the estimated value of the rotor angle are
Figure GDA0002906023060000103
The difference between them.
After obtaining the angle error between the true rotor angle value and the estimated rotor angle value, obtaining the rotation speed omega of the compressor according to the angle errorrAnd rotor position
Figure GDA0002906023060000104
FIG. 4 is a flow chart of the estimation of the PLL according to the present invention, as shown in FIG. 4, for the above-mentioned angle error
Figure GDA0002906023060000105
Proportional integral control (PI control) is carried out to obtain the rotating speed omega of the compressorr(ii) a For the obtained rotation speed omega of the compressorrAfter integration, multiplying the number Pn of the pole pairs of the compressor rotor to obtain the position of the compressor rotor
Figure GDA0002906023060000106
After obtaining the rotation speed and the rotor position of the compressor, in order to achieve smooth start of the compressor, step S104 specifically includes: and controlling the compressor to be put into operation again according to the rotating speed of the compressor obtained last time and the current corresponding to the rotor position.
When the working frequency of the compressor is high, if the short-circuit time of the three-phase winding is long and the current is too large, the over-current damage of the compressor is easily caused, so that the rotating speed and the rotor position of the compressor are obtained according to the winding current of the compressor when all upper bridge arms or all lower bridge arms are conducted, and meanwhile, whether the winding current of the compressor exceeds a threshold value is also required to be judged; if the current is too large, the conduction duration of all the upper bridge arms or all the lower bridge arms is too long, and the second preset duration is shortened and updated; the updated second preset time is used as the time for conducting all upper bridge arms or all lower bridge arms at the next time; if not, the current is not beyond the range, and the current second preset time duration is kept unchanged.
After the fault is cleared, the pressure of the air conditioner system is high, and the compressor is easy to overload and fail to start in the running process, so that the load of the compressor needs to be reduced after the rotating speed and the rotor position of the compressor are obtained according to the winding current of the compressor when all upper bridge arms or all lower bridge arms are conducted; judging whether the fault still exists; if yes, controlling the air conditioner to stop; if not, the control of the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor is triggered. Specifically, the air gear of an external fan of the air conditioner is controlled to be increased, and a load relief valve of the air conditioner is opened; judging whether the difference value between the current compressor exhaust temperature and the reference temperature is greater than a preset value or not; the reference temperature is the exhaust temperature of the compressor at the moment of fault occurrence; if yes, controlling the opening of an electronic expansion valve of the air conditioner to increase; if not, controlling the electronic expansion valve of the air conditioner to keep the original opening unchanged. By changing the control logic of the air conditioner and controlling the opening of the electronic expansion valve, the wind shield of the external fan and the action of the load relief valve, the exhaust pressure of the compressor is reduced, the suction pressure of the compressor is increased, and the differential pressure of the compressor is reduced, so that the load of the compressor is reduced.
Example 3
This embodiment provides a fault restart control apparatus for implementing the fault restart control method in the above embodiment, and fig. 5 is a structural diagram of the fault restart control apparatus according to the embodiment of the present invention, as shown in fig. 5, the apparatus includes:
and the first control module 1 is used for turning off a control signal of the compressor driving circuit after the air conditioner has an overcurrent fault. Because the air conditioner has overcurrent faults due to power supply faults of a power grid and transient fluctuation of environmental factors, in order to avoid burning the air conditioner by overcurrent, the driving control signals are required to be firstly closed through the first control module 1.
And the second control module 2 is used for controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be switched on for a second preset time and then to be switched off every interval of the first preset time. After a control signal of the compressor driving circuit is turned off, all upper bridge arms or all lower bridge arms are turned off, at the moment, no current exists in the circuit, the rotating speed and the rotor position of the compressor cannot be detected, when the fault is cleared and the compressor is controlled to be put into operation again, the starting failure of the compressor is probably caused due to the fact that the rotating speed and the rotor position of the compressor are lost, and therefore in order to obtain the rotating speed and the rotor position of the compressor, all the upper bridge arms or all the lower bridge arms of the compressor driving circuit are controlled to be turned off after being turned on for a second preset time at intervals through the second control module 2.
And the obtaining module 3 is used for obtaining the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are switched on. When all upper bridge arms or all lower bridge arms of the compressor driving circuit are controlled to be conducted, current passes through the compressor winding, and the acquisition module 3 acquires the current of the compressor winding to perform corresponding calculation, so that the rotating speed and the rotor position of the compressor can be obtained.
And the third control module 4 is used for controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor. When the fault is cleared and the compressor is ready to be controlled to be put into operation again, the third control module 4 controls the parameters of the compressor in operation again according to the rotating speed and the rotor position of the compressor which are obtained last time, so that the compressor can be started smoothly.
According to the fault restart control device, through the first control module 1, after the air conditioner has an overcurrent fault, a control signal of a compressor driving circuit is turned off; controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be switched on for a second preset time period and then to be switched off at intervals of a first preset time period by the second control module 2; the rotating speed and the rotor position of the compressor are obtained through the obtaining module 3 according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are conducted; and controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor. The air conditioner can detect the rotating speed and the rotor position of the compressor after accidental faults occur to the air conditioner, and immediately control the compressor to restart and put into a stable operation state after the faults are cleared, so that the reliability and the user experience of the air conditioner are improved.
Example 4
In order to control all upper bridge arms or all lower bridge arms of the compressor driving circuit to be intermittently turned on after the control signal of the compressor driving circuit is turned off, the second control module 2 is specifically configured to: and applying zero vectors to all the upper bridge arms or all the lower bridge arms at intervals of a first preset time length and continuing for a second preset time length so as to control all the upper bridge arms or all the lower bridge arms to be switched off after the second preset time length is switched on.
Fig. 6 is a structural diagram of a fault restart control apparatus according to another embodiment of the present invention, after all upper arms or all lower arms are controlled to be turned on, three-phase windings of a compressor are short-circuited, a closed loop is formed between freewheeling diodes D1, D3, and D5 and the three-phase windings, a current is generated in the loop, and in order to obtain a rotation speed and a rotor position of the compressor according to the current, as shown in fig. 6, an obtaining module 3 includes:
the first obtaining unit 31 is configured to obtain an angle error between the actual value of the rotor angle and the estimated value of the rotor angle according to the compressor winding current when all the upper bridge arms or all the lower bridge arms are turned on;
and a second obtaining unit 32 for obtaining the rotation speed of the compressor and the rotor position according to the angle error obtained by the first obtaining unit 31. The first obtaining unit 31 specifically includes: the current obtaining subunit 311 is configured to obtain the compressor winding current when all the upper bridge arms or all the lower bridge arms are turned on; a transformation subunit 312, configured to perform CLARKE transformation on the compressor winding current obtained by the current obtaining subunit 311, so as to obtain a direct-axis component and a quadrature-axis component of the compressor winding current in the static estimation coordinate system; and the calculating subunit 313 is configured to calculate an angle error between the true value of the rotor angle and the estimated value of the rotor angle according to the direct-axis component and the quadrature-axis component. A second acquisition unit 32, comprising: a proportional-integral unit 321 for performing proportional-integral control on the angle error to obtain the rotation speed of the compressor; and the position estimation unit 322 is used for integrating the rotating speed of the compressor and multiplying the rotating speed by the pole pair number of the compressor rotor to obtain the rotor position of the compressor.
After obtaining the rotation speed and the rotor position of the compressor, in order to achieve smooth start of the compressor, the third control module 4 is specifically configured to: and controlling the compressor to be put into operation again according to the rotating speed of the compressor obtained last time and the current corresponding to the rotor position.
When the working frequency of the compressor is high, if the short-circuit time of the three-phase winding is long, the current is too large, which easily causes the over-current damage of the compressor, therefore, in order to limit the current of the winding of the compressor, as shown in fig. 6, the device further comprises: and the current limiting module 5 is used for judging whether the compressor winding current exceeds a threshold value or not and reducing a second preset time when the compressor winding current exceeds the threshold value. The flow module 5 includes: at least two Hall sensors 51 respectively sleeved on different phase lines of the compressor and used for detecting single-phase current of the compressor; at least two current limiting protection units 52, which are connected with the hall sensors in a one-to-one correspondence manner, and are used for outputting sampling signals according to the single-phase current of the compressor; a signal control unit 53, the input end of which is connected to each current limiting protection unit 52, and is used for outputting a control signal according to the sampling signal output by each current limiting protection unit 52; wherein, the control signal is used for controlling the second preset duration.
Fig. 7 is a circuit diagram of a current limiting protection unit according to an embodiment of the present invention, and as shown in fig. 7, the current limiting protection unit 52 includes: the current conversion circuit 521 is configured to output a negative voltage when the single-phase current of the compressor is a negative value, and convert the input current and output a negative voltage when the single-phase current of the compressor is a positive value; a comparator a, a first input end of which is connected to the output end of the current conversion circuit 521, a second input end of which is input with a reference voltage Vref, and an output end of which is connected to the signal control unit, and is configured to output a sampling signal according to the voltage output by the current conversion circuit 521; wherein, the reference voltage Vref is a negative value.
In order to detect a negative voltage regardless of whether the current is a positive-going signal or a negative-going signal, as shown in fig. 7, the current conversion circuit 521 includes: a first resistor R1, a first end of which is connected to the hall sensor 51 and a second end of which is grounded, for converting the single-phase current of the compressor into a voltage signal; the first series branch is formed by sequentially connecting a second resistor R2, a third resistor R3 and a fourth resistor R4 in series, the first end of the first series branch is connected with the first end of the first resistor R1, and the second end of the first series branch is connected with the first input end of a first operational amplifier U1; the second input end + of the first operational amplifier U1 is grounded, and the output end is connected with the comparator A; a second operational amplifier U2, a first input terminal of the second operational amplifier U2 is connected between the second resistor R2 and the third resistor R3, a second input terminal thereof is grounded, an output terminal thereof is connected between the third resistor R3 and the fourth resistor R4 sequentially through an anode and a cathode of the first unidirectional element D1, and a first input terminal of the second operational amplifier U2 is further connected with an anode of the first unidirectional element D1 sequentially through an anode and a cathode of the second unidirectional element D2; wherein, the first unidirectional element D1 and the second unidirectional element D2 are both diodes.
The circuit also comprises a second series branch formed by connecting a fifth resistor R5 and a sixth resistor R6 in series, wherein the first end of the second series branch is connected with the first end of the first resistor R1, the second end of the second series branch is connected with the output end of the first operational amplifier U1, and a line between the fifth resistor R5 and the sixth resistor R6 is connected with the first input end of the first operational amplifier U1.
In order to ensure that the voltage value output by the final current conversion circuit 521 is the same when the current is a positive signal and a negative signal, the resistance of the fifth resistor R5 is 2 × the resistance of the sixth resistor R6 is 2 × the resistance of the second resistor R2 is 2 × the resistance of the third resistor R3 is 2 × the resistance of the fourth resistor R4.
When the current is a positive signal, the voltage signal V0 is a positive value, and according to the characteristics that the first operational amplifier U1 and the second operational amplifier U2 are short, the first input end and the second input end are short, and the first unidirectional element D1 and the second unidirectional element D2 can only be conducted in the positive direction, at this time, the second resistor R2, the second operational amplifier U2, the seventh resistor R7, the second unidirectional element D2, and the output end of the second operational amplifier U2 form a conducting loop, and the first unidirectional element D1 is not conducted; meanwhile, the fifth resistor R5, the sixth resistor R6, and the sampling point B at the output end of the first operational amplifier U1 form a conducting loop, so that the voltage Ub at the sampling point B is (-V0 × the resistance of the fifth resistor R5)/the resistance of the sixth resistor R6, and since the resistance of the fifth resistor R5 is equal to the resistance of the sixth resistor R6, Ub is equal to-V0, and since V0 is positive, Ub is negative.
When the current is a negative-going signal, the voltage signal V0 is a negative value, and at this time, the output terminal of the second operational amplifier U2, the first unidirectional element D1, the third resistor R3, and the second resistor R2 form a conducting loop; meanwhile, the output end of the first operational amplifier U1, the sixth resistor R6, and the fifth resistor R5 form a conducting loop, according to the superposition principle, the electric Ub of the sampling point B ═ V0 × the resistance value of the sixth resistor R6)/the resistance value of the fifth resistor R5 + ((the resistance value of the third resistor R3 × the resistance value of the sixth resistor R6)/(the resistance value of the second resistor R2 × the resistance value of the fourth resistor R4)) × V0, and since the resistance value of the fifth resistor R5 ═ the resistance value of the sixth resistor R6 ═ 2 × the resistance value of the second resistor R2 ═ 2 × the resistance value of the third resistor R3 ═ 2 × the resistance value of the fourth resistor R4, Ub ═ V0; since V0 is positive, Ub is negative.
In order to avoid the noise causing the voltage fluctuation across the first resistor, the current converting circuit 521 further includes: the first capacitor C1 and the first capacitor C1 are connected in parallel across the first resistor R1 and are used for filtering the voltage across the first resistor R1.
The current conversion circuit further includes: and a seventh resistor R7, disposed between the first input terminal of the second operational amplifier U2 and the anode of the second unidirectional element D2, for limiting current.
Setting a reference voltage Vref of the comparator A, wherein the reference voltage Vref is a negative value, comparing a voltage Ub of a sampling point B with a reference voltage Vrefi, and when Ub is greater than Vref, a sampling signal S output by the current-limiting protection unit 52 is a low level, and the current reaches a protection value and needs to be limited; when Ub is less than Vref, the sampling signal S output by the current limiting protection unit 52 is at a high level, and the current does not reach the protection value, and no amplitude limitation is required.
Fig. 8 is a structural diagram of a signal control unit according to an embodiment of the present invention, and as shown in fig. 8, the signal control unit 53 includes:
a third series branch composed of an eighth resistor R8 and a ninth resistor R9, wherein the first end of the third series branch is inputted with sampling signals S1, S2 and S3 of each phase of the compressor, and the second end is grounded; the base of the first switch Q1, the base of the first switch Q1 is connected to R9 between the eighth resistor R8 and the ninth resistor, the collector is connected to a voltage source Vcc through a tenth resistor R10, the emitter is grounded, and the collector of the first switch Q1 is also connected to a microprocessor DSP (not shown in the figure) of the compressor through an eleventh resistor R11, so as to output a control signal to control the conduction duration of all upper arms or all lower arms of the compressor driving circuit.
Sampling signals S1, S2 and S3 output by the output terminals of the current-limiting protection units 52 are input to the signal control unit 53 and serve as control signals of a DSP microprocessor of the compressor, when the sampling signals S1, S2 and S3 are all high level, a sampling point C at the first end of a ninth resistor R9 outputs high voltage, at the moment, a first switch Q1 is not conducted, a FL port outputs high level, at the moment, the high level is not used for amplitude limiting, and the upper bridge arm or the lower bridge arm of a compressor driving circuit is controlled to operate according to the original logic; when one of the sampling signals S1, S2 and S3 is at a low level, the sampling point C outputs a low voltage, at the moment, the Q1 is conducted, the FL port outputs a low level signal to the DSP microprocessor, the microprocessor controls to turn off a zero vector in advance, the conduction time of all upper bridge arms or all lower bridge arms is shortened, the purpose of limiting the current is achieved, and the current sampling current value is stored.
In order to avoid clutter in the control signal that signal control unit output, signal control unit still includes: and a first end of a second capacitor C2 and a second end of a second capacitor C2 are connected between the eleventh resistor R11 and the microprocessor DSP, and a second end is grounded and used for filtering the control signal.
Since noise also exists in the voltage supplied from the voltage source Vcc, the signal control unit 53 further includes: and a third capacitor C3, wherein a first end of the third capacitor C3 is connected with the voltage source, and a second end is grounded for filtering the voltage provided by the voltage source Vcc.
Example 5
The embodiment provides a fault restart control method applied to an air conditioner, and as shown in fig. 1 mentioned above, a compressor driving circuit includes power switching device VT 1-VT 6, which form a three-phase bridge inverter topology. D1-D6 are power switch tube device freewheeling diodes, and freewheel to form a closed loop during the turn-off period of the switch tubes. a. b and c are three-phase winding leading-out ends of the driving system and are directly connected with three-phase windings of the compressor.
Fig. 9 is a flowchart of a method for controlling a failed restart according to another embodiment of the present invention, as shown in fig. 9, the method includes:
s1, judging whether the air conditioner has an overcurrent fault; if not, step S8 is performed, and if so, step S2 is performed.
S2, turning off the control signal of the compressor driving circuit. Because the air conditioner has overcurrent faults due to power supply faults of a power grid and transient fluctuation of environmental factors, in order to avoid burning out the air conditioner by overcurrent, the driving control signal needs to be turned off firstly.
And S3, acquiring the rotating speed and the rotor position of the compressor at preset time intervals.
And S4, reducing the load of the compressor. After the fault is cleared, the pressure of the air conditioner system is high, and the compressor is easy to overload and fail to start in the operation process. By changing the control logic of the air conditioner and controlling the opening of the electronic expansion valve, the wind shield of the external fan and the action of the load relief valve, the exhaust pressure of the compressor is reduced, the suction pressure of the compressor is increased, and the differential pressure of the compressor is reduced, so that the load of the compressor is reduced.
S5, judging whether the fault still exists, if yes, executing step S6, and if no, executing step S7. After the load of the compressor is reduced, judging whether the fault still exists again, if so, indicating that the fault is not accidental, namely the air conditioner is stopped and reports the fault; if the fault does not exist, the fault is an accidental fault caused by the power supply fault of the power grid and the transient fluctuation of environmental factors, the fault is cleared at the moment, the rotating speed and the rotor position of the compressor are accurately acquired through the step S3, and the compressor can be controlled to be put into normal operation again directly according to the rotating speed and the rotor position.
And S6, controlling the air conditioner to stop and reporting faults.
And S7, controlling the compressor to be put into operation again.
And S8, controlling the air conditioner to keep stable operation.
Fig. 10 is a flowchart of a process of detecting a rotational speed and a rotor position of a compressor according to an embodiment of the present invention, and as shown in fig. 10, the acquiring the rotational speed and the rotor position of the compressor at preset time intervals specifically includes:
and S31, after the drive control signal is turned off, controlling all upper bridge arms or all lower bridge arms of the compressor drive circuit to be conducted once at preset intervals through zero vector action. Short circuit among three-phase windings of the compressor is realized through zero vector action, and a closed loop is formed among the freewheeling diodes D1, D3 and D5 and the three-phase windings at t0And (4) conducting all lower bridge arms in the compressor driving circuit by using the zero vector action at any time, and lasting for T.
And S32, acquiring the angle error between the actual rotor angle value and the estimated rotor angle value according to the compressor winding current when all the upper bridge arms or all the lower bridge arms are conducted.
Specifically, the winding currents of the compressor at all lower bridge arms are sampled, the two-phase currents of the compressor at the static estimation coordinate system are obtained through Clark conversion, and the angle error amount can be obtained through the following formula (10)
Figure GDA0002906023060000171
In the synchronous rotating coordinate system, the d-axis voltage and the q-axis voltage of the compressor can be expressed as the following equations:
Figure GDA0002906023060000172
Figure GDA0002906023060000173
from the above-mentioned coordinate system decomposition in fig. 3, the following formulas (3), (4) can be obtained:
Figure GDA0002906023060000174
Figure GDA0002906023060000175
further simplification can be achieved:
Figure GDA0002906023060000176
substituting equations (3) and (4) into equations (1) and (2) can obtain:
Figure GDA0002906023060000177
Figure GDA0002906023060000178
because the rotation speed is smaller, the current change rate is slower, and because u is smallerd＝0、u q0, further simplified to obtain:
ed＝-Rsid (8)
eq＝-Rsiq (9)
substituting equations (8), (9) into equation (5) yields:
Figure GDA0002906023060000181
wherein R issIs compressor stator resistance, LdFor the component L of the compressor stator inductance in the d-axisqComponent of motor stator inductance in q-axis, idComponent of compressor stator current in d-axis, iqComponent of compressor stator current in q-axis, udFor the component of the compressor stator voltage in the d-axis, uqComponent of the compressor stator voltage in the q-axis, edComponent of counter electromotive force of compressor stator on d-axis, eqComponent of the compressor stator back EMF in the d-axis, ωrIs the rotational speed of the compressor, keIn order to be a counter-electromotive force coefficient,
Figure GDA0002906023060000182
the actual value theta of the rotor angle and the estimated value of the rotor angle are
Figure GDA0002906023060000183
The difference between them.
S33, correcting the angle error of the compressor rotor
Figure GDA0002906023060000184
And outputting the data to a PLL (phase locked loop), adaptively adjusting in real time to obtain an actual angle, and obtaining the rotating speed and the rotor position of the compressor.
As shown in FIG. 4 mentioned above, the output estimated rotation speed ω is automatically track-regulated by the PI regulatorrBy estimating the rotational speed ωrMultiplying the integrated value by the pole pair number Pn to obtain the rotor position, thereby obtaining the rotor position of the compressor
Figure GDA0002906023060000185
Fig. 11 is a flowchart of a process of reducing a compressor load according to an embodiment of the present invention, and as shown in fig. 11, the process of reducing the compressor load specifically includes:
and S41, storing the discharge temperature of the compressor when the fault occurs. When an overcurrent fault occurs, the exhaust temperature of the compressor at the moment of the fault is collected through the temperature sensing bulb, and the temperature is stored as a reference temperature.
And S42, controlling the wind shield of the external fan of the air conditioner to increase, and simultaneously opening the load relief valve of the air conditioner.
S43, judging whether the difference value between the current compressor exhaust temperature and the reference temperature is larger than a preset value; wherein the reference temperature is the exhaust temperature of the compressor at the moment of fault occurrence; if so, step S44 is performed, and if not, step S45 is performed. The wind shield of the outer fan is increased, so that the heat exchange speed can be accelerated, the heat dissipation is increased, and the exhaust pressure of the system is reduced, so that the load of the air conditioner is reduced rapidly, the heavy load starting is avoided, and the risk of the failure of the starting of the air conditioner is avoided; the method comprises the steps of opening a load relief valve, automatically relieving load of a high-pressure system in the air conditioner to a low-pressure system, reducing system pressure, detecting current compressor exhaust temperature after the operation is carried out, making a difference between the current compressor exhaust temperature and a reference temperature, increasing the opening degree of an electronic expansion valve of the air conditioner when a difference value is larger than a preset value, reducing compressor exhaust pressure, meanwhile, the evaporator has a more remarkable heat absorption effect, increasing compressor suction compression, reducing pressure difference, reducing compressor load and being beneficial to restarting the compressor.
And S44, controlling the opening of the electronic expansion valve of the air conditioner to increase.
And S45, controlling the electronic expansion valve of the air conditioner to keep the original opening unchanged.
According to the fault restart control method, when an overcurrent fault occurs, the driving circuit of the compressor is controlled to be closed, meanwhile, the rotating speed of the compressor and the position of the rotor can be accurately obtained, the air conditioner compressor is rapidly recovered without stopping, and meanwhile, in order to ensure that the compressor is smoothly switched to a normal operation state, the frequency increasing speed is gradually increased in an integral given mode, so that no static difference connection between the states is realized, the operation reliability and user experience of a unit are improved, and the product quality of an air conditioner is ensured.
This embodiment provides still provide a trouble restart controlling means, and trouble restart controlling means includes: the first control module is used for closing a control signal of the compressor driving circuit after the air conditioner has an overcurrent fault; the second control module is used for controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be switched on for a second preset time and then switched off every interval of a first preset time; the acquisition module is used for acquiring the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are switched on; and the third control module is used for controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor.
When compressor operating frequency is higher, if three-phase winding short-circuit time is longer, the electric current is too big, leads to the compressor to overflow easily and damages, consequently, the device still includes:
and the current limiting module is used for judging whether the current of the compressor winding exceeds a threshold value or not and reducing the second preset time when the current of the compressor winding exceeds the threshold value. The current limiting protection module comprises: the Hall sensors are respectively sleeved on different phase lines of the compressor and used for detecting single-phase current of the compressor; the at least two current-limiting protection units are connected with the Hall sensors in a one-to-one correspondence manner and used for outputting sampling signals according to the single-phase current of the compressor; the input end of the signal control unit is connected with each current-limiting protection unit and used for outputting a control signal according to the sampling signal; the control signal is used for controlling the conduction duration of an upper bridge arm or a lower bridge arm of the compressor driving circuit.
As shown in fig. 7 mentioned above, in order to realize the current limiting protection regardless of whether the ac current signal collected by the hall sensor is positive or negative, the hall sensor collects the ac current signal, the first resistor R1 in the current limiting protection unit converts the current signal into the voltage signal V0, and the first capacitor C1 filters the voltage signal V0. When the current is a positive signal, the voltage signal V0 is a positive value, and according to the characteristics that the first operational amplifier U1 and the second operational amplifier U2 are short, the first input end and the second input end are short, and the first unidirectional element D1 and the second unidirectional element D2 can only be conducted in the positive direction, at this time, the second resistor R2, the second operational amplifier U2, the seventh resistor R7, the second unidirectional element D2, and the output end of the second operational amplifier U2 form a conducting loop, and the first unidirectional element D1 is not conducted; meanwhile, the fifth resistor R5, the sixth resistor R6, and the sampling point B at the output end of the first operational amplifier U1 form a conducting loop, so that the voltage Ub at the sampling point B is (-V0 × the resistance of the fifth resistor R5)/the resistance of the sixth resistor R6, wherein the resistance of the fifth resistor R5 is equal to the resistance of the sixth resistor R6, and Ub is equal to-V0, and since V0 is positive, Ub is negative.
When the current is a negative-going signal, the voltage signal V0 is a negative value, and at this time, the output terminal of the second operational amplifier U2, the first unidirectional element D1, the third resistor R3, and the second resistor R2 form a conducting loop; meanwhile, the output end of the first operational amplifier U1, the sixth resistor R6, and the fifth resistor R5 form a conducting loop, and according to the superposition principle, the voltage Ub of the sampling point B ═ V0 × the resistance value of the sixth resistor R6)/the resistance value of the fifth resistor R5 + ((the resistance value of the third resistor R3 × the resistance value of the sixth resistor R6)/(the resistance value of the second resistor R2 × the resistance value of the fourth resistor R4)) × V0, where the resistance value of the fifth resistor R5 ═ the resistance value of the sixth resistor R6 ═ 2 × the resistance value of the second resistor R2 ═ 2 × the resistance value of the third resistor R3 ═ 2 × the resistance value of the fourth resistor R4, and Ub ═ V0; since V0 is positive, Ub is negative.
Setting a reference voltage Vref, wherein the reference voltage Vref is a negative value, comparing a voltage Ub of a sampling point B with a reference voltage Vrefi, when Ub is greater than Vref, a sampling signal S output by the current-limiting protection unit 52 is a low level, and the current reaches a protection value and needs to be limited; when Ub is less than Vref, the sampling signal S output by the current limiting protection unit 52 is at a high level, and the current does not reach the protection value, and no amplitude limitation is required.
As shown in fig. 8 mentioned above, the sampling signals S1, S2, S3 output by the output terminals of the current limiting protection units 52 are input to the signal control unit 53, as the control signal of the DSP microprocessor of the compressor, the sampling signals S1, S2, S3 are all at high level, the sampling point C at the first end of the ninth resistor outputs high voltage, at this time, the first switch Q1 is not turned on, the FL port outputs high level, at this time, no amplitude limiting is performed, and the upper arm or the lower arm of the compressor driving circuit is controlled to operate according to the original logic; one of the sampling signals S1, S2 and S3 is low level, the sampling point C outputs low voltage, at the moment, Q1 is conducted, the FL port outputs low level, the FL port outputs a low level signal to the DSP microprocessor, the microprocessor turns off a zero vector in advance, the conduction time of all upper bridge arms or all lower bridge arms is shortened, the purpose of limiting current is achieved, and the current value of the current compressor winding current is stored.
Example 6
The embodiment provides an air conditioning equipment, which comprises a compressor and a fault restart control device in the embodiment, and is used for controlling the air conditioning equipment to restart smoothly after a fault, so that the user experience of equipment stability is improved.
Example 7
The present embodiment provides a computer-readable storage medium on which a computer program is stored, which when executed by a processor implements the above-described fail-restart control method.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (20)

1. A fault restart control method is applied to an air conditioner and is characterized by comprising the following steps:
after the air conditioner has an overcurrent fault, closing a control signal of a compressor driving circuit;
and controlling all upper bridge arms or all lower bridge arms of the compressor driving circuit to be switched on for a second preset time and then switched off every first preset time interval, wherein the switching off of the upper bridge arms or all lower bridge arms of the compressor driving circuit comprises the following steps: applying zero vectors to all upper bridge arms or all lower bridge arms at intervals of a first preset time length and continuing for a second preset time length so as to control all the upper bridge arms or all the lower bridge arms to be switched off after the second preset time length is switched on;
acquiring the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all upper bridge arms or all lower bridge arms are switched on; which comprises the following steps: obtaining the angle error between the actual value of the rotor angle and the estimated value of the rotor angle according to the compressor winding current when all upper bridge arms or all lower bridge arms are switched on; acquiring the rotating speed and the rotor position of the compressor according to the angle error;
and controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor.
2. The method of claim 1, wherein obtaining the angle error between the actual value of the rotor angle and the estimated value of the rotor angle according to the compressor winding current when all upper bridge arms or all lower bridge arms are turned on comprises:
obtaining the current of a compressor winding when all upper bridge arms or all lower bridge arms are conducted;
performing CLARKE transformation on the obtained compressor winding current to obtain a direct-axis component and a quadrature-axis component of the compressor winding current under a static estimation coordinate system;
and calculating the angle error according to the direct axis component and the quadrature axis component.
3. The method of claim 1, wherein obtaining a rotational speed of the compressor and a rotor position based on the angular error comprises:
carrying out proportional integral control on the angle error to obtain the rotating speed of the compressor;
and integrating the rotating speed of the compressor and multiplying the rotating speed by the pole pair number of the compressor rotor to obtain the rotor position of the compressor.
4. The method of claim 1, wherein controlling the compressor to resume operation based on the speed of the compressor and the rotor position comprises:
and controlling the compressor to be put into operation again according to the rotating speed of the compressor obtained last time and the current corresponding to the rotor position.
5. The method of claim 1, wherein the rotation speed and the rotor position of the compressor are obtained according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are conducted, and the method further comprises the following steps:
judging whether the current of the compressor winding exceeds a threshold value;
if so, shortening and updating the second preset time, wherein the updated second preset time is used as the time for conducting all upper bridge arms or all lower bridge arms at the next time;
if not, keeping the current second preset time length unchanged.
6. The method of claim 1, wherein after the rotating speed and the rotor position of the compressor are obtained according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are conducted, the method further comprises:
the load of the compressor is reduced;
judging whether the fault still exists;
if yes, controlling the air conditioner to stop;
and if not, triggering to control the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor.
7. The method of claim 6, wherein reducing the compressor load comprises:
controlling the wind shield of an outer fan of the air conditioner to increase, and simultaneously opening a load relief valve of the air conditioner;
judging whether the difference value between the current compressor exhaust temperature and the reference temperature is greater than a preset value or not; wherein the reference temperature is the exhaust temperature of the compressor at the moment of fault occurrence;
if yes, controlling the opening of an electronic expansion valve of the air conditioner to increase;
if not, controlling the electronic expansion valve of the air conditioner to keep the original opening unchanged.
8. A fail-restart control apparatus for implementing the fail-restart control method according to any one of claims 1 to 7, the apparatus comprising:
the first control module is used for closing a control signal of the compressor driving circuit after the air conditioner has an overcurrent fault;
the second control module is configured to control all upper bridge arms or all lower bridge arms of the compressor driving circuit to be turned off after being turned on for a second preset time every interval of a first preset time, and the second control module is specifically configured to: applying zero vectors to all upper bridge arms or all lower bridge arms at intervals of a first preset time length and continuing for a second preset time length so as to control all the upper bridge arms or all the lower bridge arms to be switched off after the second preset time length is switched on;
the acquisition module is used for acquiring the rotating speed and the rotor position of the compressor according to the winding current of the compressor when all the upper bridge arms or all the lower bridge arms are switched on; the acquisition module includes: the first obtaining unit is used for obtaining the angle error between the actual value of the rotor angle and the estimated value of the rotor angle according to the compressor winding current when all upper bridge arms or all lower bridge arms are conducted; the second acquisition unit is used for acquiring the rotating speed and the rotor position of the compressor according to the angle error acquired by the first acquisition unit;
and the third control module is used for controlling the compressor to be put into operation again according to the rotating speed of the compressor and the position of the rotor.
9. The apparatus of claim 8, further comprising:
and the current limiting module is used for judging whether the current of the compressor winding exceeds a threshold value or not and reducing the second preset time when the current of the compressor winding exceeds the threshold value.
10. The apparatus of claim 9, wherein the current limiting module comprises:
the Hall sensors are respectively sleeved on different phase lines of the compressor and used for detecting single-phase current of the compressor;
the at least two current-limiting protection units are connected with the Hall sensors in a one-to-one correspondence manner and used for outputting sampling signals according to the single-phase current of the compressor;
the input end of the signal control unit is connected with each current-limiting protection unit and used for outputting a control signal according to the sampling signal; the control signal is used for controlling the second preset time length.
11. The apparatus of claim 10, wherein the current limiting protection unit comprises:
the current conversion circuit is used for outputting negative voltage when the single-phase current of the compressor is a negative value, and converting the input current and outputting negative voltage when the single-phase current of the compressor is a positive value;
the first input end of the comparator is connected with the output end of the current conversion circuit, the second input end of the comparator inputs reference voltage, and the output end of the comparator is connected with the signal control unit and used for outputting a sampling signal according to the voltage output by the current conversion circuit; wherein the reference voltage is a negative value.
12. The apparatus of claim 11, wherein the current conversion circuit comprises:
the first end of the first resistor is connected with the Hall sensor, and the second end of the first resistor is grounded and used for converting the single-phase current of the compressor into a voltage signal;
the first series branch is formed by sequentially connecting a second resistor, a third resistor and a fourth resistor in series, the first end of the first series branch is connected with the first end of the first resistor, and the second end of the first series branch is connected with the first input end of the first operational amplifier;
the second input end of the first operational amplifier is grounded, and the output end of the first operational amplifier is connected with the comparator;
a first input end of the first operational amplifier is connected between the first resistor and the second resistor, a second input end of the first operational amplifier is grounded, an output end of the first operational amplifier is connected between the first resistor and the second resistor sequentially through an anode and a cathode of the first unidirectional element, and the first input end of the first operational amplifier is connected with the anode of the first unidirectional element sequentially through the anode and the cathode of the second unidirectional element;
and a second series branch consisting of a fifth resistor and a sixth resistor which are connected in series, wherein the first end of the second series branch is connected with the first end of the first resistor, the second end of the second series branch is connected with the output end of the first operational amplifier, and a line between the fifth resistor and the sixth resistor is connected with the first input end of the first operational amplifier.
13. The apparatus of claim 12, wherein the current conversion circuit further comprises:
and the first capacitor is arranged at two ends of the first resistor in parallel and is used for filtering the voltage at two ends of the first resistor.
14. The apparatus of claim 13, wherein the resistance of the fifth resistor R5 = the resistance of the sixth resistor R6 =2 × the resistance of the second resistor R2 =2 × the resistance of the third resistor R3 =2 × the resistance of the fourth resistor R4.
15. The apparatus of claim 12, wherein the current conversion circuit further comprises:
and the seventh resistor is arranged between the first input end of the second operational amplifier and the anode of the second unidirectional element and used for limiting current.
16. The apparatus of claim 10, wherein the signal control unit comprises:
a third series branch composed of an eighth resistor and a ninth resistor, wherein the first end of the third series branch inputs each phase of sampling signals of the compressor, and the second end is grounded;
and the base electrode of the first switch is connected between the eighth resistor and the ninth resistor, the collector electrode of the first switch is connected with a voltage source through a tenth resistor, the emitter electrode of the first switch is grounded, and the collector electrode of the first switch is also connected with a microprocessor of the compressor through an eleventh resistor and is used for outputting a control signal so as to control the second preset time.
17. The apparatus of claim 16, wherein the signal control unit further comprises:
and a first end of the second capacitor is connected between the eleventh resistor and the microprocessor, and a second end of the second capacitor is grounded and is used for filtering the control signal.
18. The apparatus of claim 16, wherein the signal control unit further comprises:
and the first end of the third capacitor is connected with the voltage source, and the second end of the third capacitor is grounded and is used for filtering the voltage provided by the voltage source.
19. An air conditioning apparatus comprising a compressor, characterized by further comprising the failed restart control device of any one of claims 8 to 18.
20. A computer-readable storage medium on which a computer program is stored, the program, when executed by a processor, implementing the fail-over control method of any one of claims 1 to 7.
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