CN113007084A - Compressor fault early warning method and device - Google Patents
Compressor fault early warning method and device Download PDFInfo
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Abstract
The invention relates to the technical field of compressors, in particular provides a compressor fault early warning method and device, and aims to solve the technical problem of timely and effectively monitoring whether a three-phase imbalance fault occurs before a compressor enters a stable operation state. For this purpose, the method according to the embodiment of the present invention may perform driving current detection on the frequency converter in response to the received frequency converter start instruction; whether the compressor can break down after being started is judged in advance according to the detection result of the driving current, and if the compressor can break down in advance, early warning can be timely carried out before the compressor is started, so that a user is reminded of adopting effective measures, and the compressor is prevented from being damaged due to the fact that the compressor runs in a fault state.
Description
Technical Field
The invention relates to the technical field of compressors, in particular to a compressor fault early warning method and device.
Background
The compressor is used as the core equipment of the air conditioning system, and if the compressor fails, the normal operation of the air conditioning system is greatly influenced. For example, if a current imbalance fault occurs in the three-phase windings of the compressor, the temperature of the over-current windings may increase as the compressor operates, thereby burning the windings and causing the compressor to stop. The conventional three-phase unbalance fault detection method can only detect when the compressor runs stably, and because the starting current of the compressor is large when the compressor is started, if the external power supply of the compressor has three-phase unbalance, the three-phase unbalance fault of the compressor can occur when the compressor is started, and the current in the overcurrent winding can be increased sharply, so that more serious damage to the compressor can be caused.
Accordingly, there is a need in the art for a new compressor fault detection scheme to address the above-mentioned problems.
Disclosure of Invention
In order to overcome the above-mentioned drawbacks, the present invention is proposed to provide a compressor fault early warning method and apparatus that solve or at least partially solve the technical problem of how to timely and effectively monitor whether a three-phase imbalance fault occurs before the compressor enters a stable operation state.
In a first aspect, a compressor fault warning method is provided, where the compressor is connected to an inverter, and the inverter is configured to convert an input power source to output a driving current to the compressor to drive the compressor to operate, where the method includes:
responding to a received frequency converter starting instruction, and carrying out driving current detection on the frequency converter;
judging whether the three-phase driving current output by the frequency converter is unbalanced or not according to the detection result;
if yes, judging that the three-phase imbalance fault occurs after the compressor is started in advance and giving an alarm.
In one technical solution of the above compressor fault early warning method, the frequency converter includes a three-phase full-bridge inverter, an ac side of the three-phase full-bridge inverter is connected to the compressor, the three-phase full-bridge inverter includes three-phase bridge arms, each phase of bridge arm includes an upper bridge arm and a lower bridge arm, and the step of "detecting the driving current of the frequency converter" specifically includes:
for each phase of bridge arm, respectively carrying out drive current detection through the following steps to obtain current detection results of three times of drive current detection:
setting the current phase bridge arm as a main phase detection bridge arm, and setting other two phase bridge arms as phase detection bridge arms;
driving an upper bridge arm of the main phase detection bridge arm and a lower bridge arm of each phase detection bridge arm to be conducted according to a preset PWM signal so as to enable the input power supply to be transmitted through a conducting loop formed by the upper bridge arm, the compressor and one lower bridge arm and enable the input power supply to be transmitted through a conducting loop formed by the upper bridge arm, the compressor and the other lower bridge arm; the preset PWM signal is a PWM signal generated according to a driving current given value;
and acquiring the actual value of the driving current transmitted on each detected phase bridge arm to obtain the current detection result of the current driving current detection.
In one technical solution of the compressor fault warning method, the step of determining whether the three-phase driving current output by the inverter is unbalanced according to the detection result specifically includes:
respectively judging whether the currents transmitted on two bridge arms to be detected in the current detection result of each driving current detection are balanced;
and if the currents transmitted by the two detected phase bridge arms in the current detection result of at least one driving current detection are unbalanced, judging that the three-phase driving current output by the frequency converter is unbalanced.
In one technical solution of the compressor fault early warning method, the step of respectively determining whether the currents transmitted by the two detected phase bridge arms in the current detection result of each driving current detection are balanced specifically includes:
and judging whether the currents transmitted on the two detected phase bridge arms in the current detection results are balanced or not by the following steps respectively according to the current detection results of each driving current detection:
and respectively calculating the current deviation of the actual value of the driving current transmitted on each detected phase bridge arm in the current detection result by adopting a deviation calculation function shown as the following formula:
wherein d represents the current deviation degree, IrRepresenting the actual value of the driving current, wherein I represents the given value of the driving current;
judging whether each current deviation degree is smaller than a preset deviation degree threshold value;
if so, judging that the currents transmitted on the two detected phase bridge arms are balanced; and if not, judging that the currents transmitted on the two detected phase bridge arms are unbalanced.
In one embodiment of the above compressor fault warning method, after the step of "determining that the three-phase driving currents output by the inverter are unbalanced", the method further includes:
and calculating the unbalance of the three-phase driving current output by the frequency converter by adopting a three-phase unbalance calculation method according to the current detection result of the three times of driving current detection.
In a second aspect, there is provided a compressor fault warning device, where the compressor is connected to an inverter, and the inverter is configured to convert electric energy from an input power source to output a driving current to the compressor to drive the compressor to operate, and the device includes:
a current detection module configured to perform drive current detection on the frequency converter in response to a received frequency converter start instruction;
a fault pre-judging module configured to judge whether the three-phase driving current output by the frequency converter is unbalanced according to the detection result; if yes, judging that the three-phase imbalance fault occurs after the compressor is started in advance and giving an alarm.
In one technical solution of the above compressor fault early warning device, the frequency converter includes a three-phase full-bridge inverter, an ac side of the three-phase full-bridge inverter is connected to the compressor, the three-phase full-bridge inverter includes three-phase bridge arms, each phase of bridge arm includes an upper bridge arm and a lower bridge arm, and the current detection module is further configured to detect the driving current for each phase of bridge arm through the following steps, respectively, to obtain current detection results of three times of driving current detection:
setting the current phase bridge arm as a main phase detection bridge arm, and setting other two phase bridge arms as phase detection bridge arms;
driving an upper bridge arm of the main phase detection bridge arm and a lower bridge arm of each phase detection bridge arm to be conducted according to a preset PWM signal so as to enable the input power supply to be transmitted through a conducting loop formed by the upper bridge arm, the compressor and one lower bridge arm and enable the input power supply to be transmitted through a conducting loop formed by the upper bridge arm, the compressor and the other lower bridge arm; the preset PWM signal is a PWM signal generated according to a driving current given value;
and acquiring the actual value of the driving current transmitted on each detected phase bridge arm to obtain the current detection result of the current driving current detection.
In an aspect of the above compressor fault early warning apparatus, the fault pre-judging module includes a current analyzing unit, and the current analyzing unit is configured to perform the following operations:
respectively judging whether the currents transmitted on two bridge arms to be detected in the current detection result of each driving current detection are balanced;
and if the currents transmitted by the two detected phase bridge arms in the current detection result of at least one driving current detection are unbalanced, judging that the three-phase driving current output by the frequency converter is unbalanced.
In an aspect of the above compressor fault warning apparatus, the current analyzing unit is further configured to perform the following operations:
and judging whether the currents transmitted on the two detected phase bridge arms in the current detection results are balanced or not by the following steps respectively according to the current detection results of each driving current detection:
and respectively calculating the current deviation of the actual value of the driving current transmitted on each detected phase bridge arm in the current detection result by adopting a deviation calculation function shown as the following formula:
wherein d represents the current deviation degree, IrRepresenting the actual value of the driving current, wherein I represents the given value of the driving current;
judging whether each current deviation degree is smaller than a preset deviation degree threshold value;
if so, judging that the currents transmitted on the two detected phase bridge arms are balanced; and if not, judging that the currents transmitted on the two detected phase bridge arms are unbalanced.
In one technical solution of the above compressor fault early warning apparatus, the fault pre-judging module includes an unbalance degree calculating unit, and the unbalance degree calculation is configured to calculate the unbalance degree of the three-phase driving current output by the frequency converter by using a three-phase unbalance degree calculating method and according to current detection results of three times of driving current detection.
One or more technical schemes of the invention at least have one or more of the following beneficial effects:
in the technical scheme of the invention, the drive current of the frequency converter can be detected in response to the received frequency converter starting instruction; judging whether the three-phase driving current output by the frequency converter is unbalanced or not according to the detection result; if the three-phase driving current is unbalanced, the three-phase unbalanced fault can be judged in advance after the compressor is started, and an alarm is given. Through the embodiment, whether the compressor fails after starting can be judged in advance according to the detection result of the driving current in the process of controlling the compressor to start running (in the starting process of the compressor) and the compressor is not started yet, and early warning can be given in time before the compressor is started if the compressor fails in advance, so that a user is reminded to adopt effective measures, and the compressor is prevented from being damaged due to running under the fault state.
Drawings
Embodiments of the invention are described below with reference to the accompanying drawings, in which:
FIG. 1 is a schematic flow chart of the main steps of a compressor fault warning method according to one embodiment of the present invention;
fig. 2 is a main structural block diagram of a compressor failure early warning apparatus according to an embodiment of the present invention;
fig. 3 is a main connection configuration diagram of the three-phase full-bridge inverter and the compressor.
List of reference numerals:
11: a current detection module; 12: a fault pre-judging module; 21: a direct current bus; 22: a three-phase full-bridge inverter; 3: a compressor.
Detailed Description
Some embodiments of the invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.
In the description of the present invention, a "module" or "processor" may include hardware, software, or a combination of both. A module may comprise hardware circuitry, various suitable sensors, communication ports, memory, may comprise software components such as program code, or may be a combination of software and hardware. The processor may be a central processing unit, microprocessor, image processor, digital signal processor, or any other suitable processor. The processor has data and/or signal processing functionality. The processor may be implemented in software, hardware, or a combination thereof. Non-transitory computer readable storage media include any suitable medium that can store program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random-access memory, and the like. The term "a and/or B" denotes all possible combinations of a and B, such as a alone, B alone or a and B. The term "at least one A or B" or "at least one of A and B" means similar to "A and/or B" and may include only A, only B, or both A and B. The singular forms "a", "an" and "the" may include the plural forms as well.
Some terms to which the present invention relates are explained first.
The three-phase full-bridge inverter in the frequency converter refers to a three-phase inverter adopting a full-bridge structure, the three-phase inverter can convert direct current into three-phase alternating current, the three-phase full-bridge inverter is connected with the compressor, and the three-phase alternating current output by the three-phase full-bridge inverter can be utilized to drive the compressor to move. The three-phase full-bridge inverter comprises three-phase bridge arms, wherein each phase of bridge arm comprises an upper bridge arm and a lower bridge arm, namely the upper bridge arm and the lower bridge arm. Each upper bridge arm and each lower bridge arm comprise controllable power electronic devices. An example is as follows: the upper bridge arm and the lower bridge arm in each phase of bridge arm respectively comprise a controllable power electronic device, a first main electrode of the controllable power electronic device positioned in the upper bridge arm in each phase of bridge arm is connected with the positive electrode of the direct current bus, a second main electrode of the controllable power electronic device positioned in the upper bridge arm in each phase of bridge arm is connected with a first main electrode of the controllable power electronic device positioned in the lower bridge arm in the corresponding bridge arm, a second main electrode of the controllable power electronic device positioned in the lower bridge arm in each phase of bridge arm is connected with the negative electrode of the direct current bus, and three-phase windings of the compressor are respectively connected between the controllable power electronic devices positioned in the upper bridge arm and the lower bridge arm in the three-phase bridge arms.
The controllable power electronic device may be a fully-controlled power Semiconductor device, such as a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), an Insulated Gate Bipolar Transistor (IGBT), an Integrated Gate Commutated Thyristor (IGCT), or the like. Furthermore, these fully-controlled power semiconductor devices are three-terminal devices, such as a MOSFET comprising a source, a drain and a gate, an IGBT comprising a collector, an emitter and a gate, and an IGCT comprising a collector, an emitter and a gate. Wherein the source, drain, collector and emitter are main electrodes and the gate and gate are control electrodes. For clarity of description of the structure of the power electronic device, the main electrodes in the power input direction in the power electronic device are described as first main electrodes (such as the drain of a MOSFET and the collector of an IGBT), and the main electrodes in the power output direction are described as second main electrodes (such as the source of a MOSFET and the emitter of an IGBT).
It should be noted that "up/down" of the up/down arm in the present invention is not an upper and lower part in the spatial structure, but an upper and lower relation determined by the electrode connection relation of the power electronic device. Specifically, a first main electrode (for example, a collector of the IGBT) of the power electronic device in the upper arm is connected to a positive power supply electrode, a second main electrode (for example, an emitter of the IGBT) of the power electronic device in the upper arm is connected to a first main electrode (for example, a collector of the IGBT) of the power electronic device in the lower arm, and a second main electrode (for example, an emitter of the IGBT) of the power electronic device in the lower arm is connected to a negative power supply electrode. Further, the power electronic devices in the upper bridge arm and the lower bridge arm may also be replaced by a power electronic device unit formed by connecting a plurality of power electronic devices in series, the electrode connection relationship of the two power electronic device units is similar to the electrode connection relationship of the power electronic devices in the upper bridge arm and the lower bridge arm, and for brevity of description, details are not repeated here.
Referring first to fig. 3, fig. 3 illustrates a main connection structure of a three-phase full-bridge inverter and a compressor in an inverter according to an embodiment of the present invention. As shown in fig. 1, two dc-side terminals of the three-phase full-bridge inverter 22 are connected to the positive electrode P and the negative electrode N of the dc bus 21, respectively, and three ac-side terminals of the three-phase full-bridge inverter 22 are connected to the windings U, V and W of the compressor 3, respectively, and the equivalent voltage of the dc bus 11 can be represented by a voltage Vdc across the capacitor C. The three-phase full-bridge inverter 22 includes three-phase legs, each of which includes an upper leg and a lower leg. Each upper bridge arm and each lower bridge arm comprise a power switch assembly, and each power switch assembly comprises a controllable power electronic device and a diode which are connected in parallel in an opposite direction. Specifically, the upper bridge arm of the U-phase bridge arm comprises a power switch assembly formed by reversely connecting a controllable power electronic device VT1 and a diode VD1 in parallel, the lower bridge arm of the U-phase bridge arm comprises a power switch assembly formed by reversely connecting a controllable power electronic device VT2 and a diode VD2 in parallel, the upper bridge arm of the V-phase bridge arm comprises a power switch assembly formed by reversely connecting a controllable power electronic device VT3 and a diode VD3 in parallel, the lower bridge arm of the V-phase bridge arm comprises a power switch assembly formed by reversely connecting a controllable power electronic device VT4 and a diode VD4 in parallel, the upper bridge arm of the W-phase bridge arm comprises a power switch assembly formed by reversely connecting a controllable power electronic device VT5 and a diode VD5 in parallel, the lower bridge arm of the W-phase bridge arm comprises a power switch assembly formed by reversely connecting a controllable power electronic device VT6 and a diode VD6 in parallel, a U-phase winding of the compressor is connected between VT1 and VT2, the V-phase winding is connected between VT3 and VT4, and the W-phase winding is connected between VT5 and VT 6.
With reference to fig. 1, fig. 1 is a schematic flow chart illustrating main steps of a compressor fault warning method according to an embodiment of the present invention, in this embodiment, a compressor may be connected to a three-phase full-bridge inverter in a frequency converter in the connection manner shown in fig. 3, and the frequency converter may perform electric energy conversion on an input power source to output a driving current to the compressor, so that the compressor operates under the control of the driving current. As shown in fig. 1, the compressor fault pre-warning method in the embodiment of the present invention mainly includes the following steps S101 to S104.
Step S101: and responding to the received frequency converter starting instruction, and detecting the driving current of the frequency converter.
The frequency converter starting instruction refers to a starting instruction which is output to the frequency converter when the compressor is controlled to start to operate, the frequency converter can be controlled by the starting instruction to convert electric energy output by an external power supply, and the electric energy after electric energy conversion is output to the compressor (three-phase driving current is output to the compressor) so as to drive the compressor to start to operate. That is to say, this embodiment can carry out drive current electricity to the converter when the in-process (in the compressor start-up process) that the control compressor started the operation and the compressor has not accomplished the start yet to judge in advance whether the compressor can break down after the start according to the result that drive current detected, if judge in advance that can break down then can in time early warning before the compressor finishes starting, remind the user to adopt effective measure, prevent that the compressor from running under the fault condition and leading to the compressor to take place the damage.
In the embodiment of the invention, whether the three-phase imbalance fault occurs after the compressor is started can be judged in advance by analyzing whether the three-phase imbalance occurs in the driving current output by the frequency converter. If the fact that the three-phase current generated by the frequency converter is unbalanced is analyzed, it is indicated that the external power supply is unbalanced in three-phase voltage/power, and further the driving current output by the frequency converter is unbalanced, and if the compressor is started to operate under the power supply of the external power supply, the three-phase imbalance fault is likely to occur. Specifically, in one embodiment of the present invention, the driving current detection may be performed through the following steps 11 to 13 for each phase of the bridge arm, so as to obtain the current detection results of three times of driving current detection, and further, whether the three-phase current imbalance occurs in the driving current output by the inverter may be analyzed according to the current detection results of three times of driving current detection.
Step 11: and setting the current phase bridge arm as a main phase detection bridge arm, and setting other two phase bridge arms as phase detection bridge arms. The phase-to-be-detected bridge arm refers to a bridge arm which needs to judge whether current imbalance occurs in current driving current detection.
Referring to fig. 3, if the current phase arm is a U-phase arm, the U-phase arm may be set as a main phase detection arm, and the V-phase arm and the W-phase arm may be set as detected phase arms.
Step 12: driving an upper bridge arm of a main phase detection bridge arm and a lower bridge arm of each detected phase bridge arm to be conducted according to a preset PWM signal so as to enable an input power supply to be transmitted through a conducting loop formed by the upper bridge arm, a compressor and one lower bridge arm and to be transmitted through a conducting loop formed by the upper bridge arm, the compressor and the other lower bridge arm; the preset PWM signal is a PWM signal generated according to a driving current set value.
It should be noted that, in the present embodiment, a Pulse Width Modulation (Pulse Width Modulation) method, which is conventional in the power electronics technology field, may be adopted to generate the PWM signal according to the driving current set value. For the sake of brevity, detailed descriptions of the specific process of generating the PWM signal by using the pulse width modulation method are omitted here. In addition, a person skilled in the art can flexibly set a specific value of the given driving current value according to actual requirements, for example, the given driving current value can be set to a driving current value required by normal operation of the compressor, and the given driving current value can also be set to a rated driving current value of the compressor.
Continuing to refer to fig. 3, taking the main phase detection bridge arm as a U-phase bridge arm, and the detected phase bridge arm as a V-phase bridge arm and a W-phase bridge arm as an example, the controllable power electronic device VT1 may be driven to be turned on according to a preset PWM signal to turn on the upper bridge arm of the U-phase bridge arm, the controllable power electronic device VT4 may be driven to be turned on to turn on the lower bridge arm of the V-phase bridge arm, and the controllable power electronic device VT6 may be driven to be turned on to turn on the lower bridge arm of the W-phase bridge arm. The positive electrode P, VT1 of the direct current bus 21, the compressors 3 and VT4 and the negative electrode N of the direct current bus 21 form a conducting loop, and the positive electrode P, VT1 of the direct current bus 21, the compressors 3 and VT6 and the negative electrode N of the direct current bus 21 form another conducting loop. And the three-phase alternating current external power supply is rectified by a three-phase full-bridge rectifier of the frequency converter and then is transmitted through the two conduction loops respectively.
Step 13: and acquiring the actual value of the driving current transmitted on each phase bridge arm to be detected to obtain the current detection result of the current driving current detection.
With continued reference to fig. 3, the current detection result of the current driving current detection includes the current I transmitted by the V-phase bridge armVAnd current I transmitted on W-phase bridge armW. Further, if the current-phase bridge arm is a V-phase bridge arm, the current detection result obtained through the above steps 11 to 13 includes the current I transmitted by the U-phase bridge armUAnd current I transmitted on W-phase bridge armW. If the current phase bridge arm is the W phase bridge arm, the current detection result obtained through the steps 11 to 13 includes the current I transmitted by the U phase bridge armUAnd the current I transmitted on the V-phase bridge armV. That is to say, two actual values of the driving current can be obtained for each phase of the bridge arm after three times of electrical measurement of the driving current, and for the purpose of clearly describing the two actual values of the driving current, the actual values of the driving current transmitted on the two U-phase bridge arms obtained through three times of electrical measurement of the driving current are represented as IU1And IU2And the actual value of the driving current transmitted on the two V-phase bridge arms obtained by electrically measuring the driving current for three times is represented as IV1And IV2And the actual value of the driving current transmitted on the two W-phase bridge arms obtained by electrically measuring the driving current for three times is represented as IW1And IW2。
Step S102: judging whether the three-phase driving current output by the frequency converter is unbalanced; if the compressor is judged to be unbalanced, judging that a three-phase unbalanced fault occurs after the compressor is started in advance and giving an alarm (step S103); if the compressor is judged to be balanced, the three-phase unbalanced fault is judged not to occur after the compressor is started in advance and an alarm is given, so that the alarm is not needed (step S104).
In step S102, it may be determined whether the currents transmitted through the two detected phase arms in the current detection result of each driving current detection are balanced, and if the currents transmitted through the two detected phase arms in the current detection result of at least one driving current detection are unbalanced, it is determined that the three-phase driving current output by the frequency converter is unbalanced. Refer to the attached drawingsFIG. 3, if the current detection result of the current driving current detection includes the current I transmitted by the V-phase bridge armVAnd current I transmitted on W-phase bridge armWAnd IVAnd IWAnd if the three-phase driving current output by the frequency converter is not balanced, the three-phase driving current output by the frequency converter can be judged to be not balanced.
In an implementation manner of the embodiment of the present invention, it may be determined whether the currents transmitted through the two detected phase arms in the current detection result are balanced through the following steps 21 to 22, respectively, with respect to the current detection result detected each time the current is driven.
Step 21: respectively calculating the current deviation of the actual value of the driving current transmitted on each phase bridge arm to be detected in the current detection result by adopting a deviation calculation function shown in the following formula (1):
the meaning of each parameter in the formula (1) is: d represents the degree of current deviation, IrRepresenting the actual value of the drive current and I representing the drive current setpoint.
Continuing to refer to fig. 3, if the current detection result of the current driving current detection includes the current I transmitted by the V-phase bridge armVAnd current I transmitted on W-phase bridge armWAnd IVAnd IWImbalance, then can be calculated according to equation (1): current IVDegree of current deviation of
Current IWDegree of current deviation of
Step 22: and judging whether each current deviation degree is smaller than a preset deviation degree threshold value. If each current deviation degree is smaller than a preset deviation degree threshold value, such as 10%, the current balance transmitted on the two detected phase bridge arms can be judged; and if at least one current deviation degree is greater than or equal to a preset deviation degree threshold value, determining that the currents transmitted by the two detected phase bridge arms are unbalanced.
Further, after determining that the three-phase drive current output by the inverter is unbalanced (step S103), it is also possible to calculate the degree of unbalance of the three-phase drive current output by the inverter using a three-phase unbalance degree calculation method and based on the current detection results of the three drive current detections (step S105).
Specifically, referring to fig. 3, in one implementation manner of the embodiment of the present invention, if the actual value I of the driving current transmitted by the U-phase bridge arm is electrically measured through three times of driving currents, the actual value I of the driving current is obtainedU1And IU2Actual value of drive current I transmitted on V-phase bridge armV1And IV2Actual value I of drive current transmitted on W-phase bridge armW1And IW2Then, the calculated driving current value of each phase of bridge arm can be obtained according to the two actual driving current values of each phase of bridge arm. For example: the average or accumulated value of the two actual values of the drive current may be used as the calculated value of the drive current. Further, the unbalance of the three-phase drive current outputted from the inverter is calculated from the calculated drive current value of each phase of the bridge arm by using a three-phase unbalance calculation method. For example: the calculated values of the driving currents of the U, V, W-phase bridge arms may be IU1+IU2、IV1+IV2、IW1+IW2The calculated values of the driving currents of the U, V, W-phase bridge arms may be sequentially
In the present embodiment, a conventional three-phase imbalance degree calculation method may be employed to calculate the imbalance degree of the three-phase drive current output by the inverter from the calculated drive current value of each phase arm. An example is as follows: the calculated value of the maximum driving current and the calculated value of the minimum driving current in the calculated values of the driving currents of the bridge arms of each phase can be respectively obtained, then the deviation between the calculated value of the maximum driving current and the calculated value of the minimum driving current is calculated, finally the ratio of the deviation to the calculated value of the maximum driving current is calculated, and the ratio can be set as the unbalance degree of the three-phase driving current output by the frequency converter. As another example: the mean value of the calculated values of the driving currents of the three-phase bridge arms can be obtained, then the deviation between the calculated value of the driving current of each phase of bridge arm and the mean value is calculated respectively, the maximum deviation is selected, finally, the ratio of the maximum deviation to the mean value is calculated, and the ratio can also be set as the unbalance degree of the three-phase driving currents output by the frequency converter.
It should be noted that, although the foregoing embodiments describe each step in a specific sequence, those skilled in the art will understand that, in order to achieve the effect of the present invention, different steps do not necessarily need to be executed in such a sequence, and they may be executed simultaneously (in parallel) or in other sequences, and these changes are all within the protection scope of the present invention.
Further, the invention also provides a compressor fault early warning device.
Referring to fig. 2, fig. 2 is a main structural block diagram of a compressor failure early warning apparatus according to an embodiment of the present invention. In embodiments of the present invention, the compressor is coupled to an inverter, which may be configured to convert electrical energy from an input power source to output a drive current to the compressor. As shown in fig. 2, the compressor fault early warning apparatus in the embodiment of the present invention mainly includes a current detection module 11 and a fault pre-determination module 12. In some embodiments, the current detection module 11 and the fault anticipation module 12 may be combined together into one module. In some embodiments, the current detection module 11 may be configured to perform drive current detection on the frequency converter in response to a received frequency converter start instruction. The fault pre-judging module 12 may be configured to judge whether the three-phase driving current output by the frequency converter is unbalanced according to the detection result; if so, it is predicted that a three-phase imbalance fault occurs after the compressor is started and an alarm is given, and in an embodiment, the specific implementation functions may be described in steps S101 to S104. It should be noted that the structure of the frequency converter in the embodiment of the present invention is the same as that of the frequency converter described in the foregoing method embodiment. For brevity of description, no further description is provided herein.
In an embodiment, the current detection module 11 may be further configured to perform driving current detection for each phase of the bridge arm by the following steps, respectively, to obtain current detection results of three driving current detections: setting the current phase bridge arm as a main phase detection bridge arm, and setting other two phase bridge arms as phase detection bridge arms; driving an upper bridge arm of a main phase detection bridge arm and a lower bridge arm of each detected phase bridge arm to be conducted according to a preset PWM signal so as to enable an input power supply to be transmitted through a conducting loop formed by the upper bridge arm, a compressor and one lower bridge arm and to be transmitted through a conducting loop formed by the upper bridge arm, the compressor and the other lower bridge arm; the preset PWM signal is a PWM signal generated according to a driving current given value; and acquiring the actual value of the driving current transmitted on each phase bridge arm to be detected to obtain the current detection result of the current driving current detection. In one embodiment, the specific implementation functions may be described in steps 11 to 13.
In one embodiment, the fault anticipation module 12 may include a current analysis unit. In this embodiment the current analysis unit may be configured to perform the following operations: respectively judging whether the currents transmitted on two bridge arms to be detected in the current detection result of each driving current detection are balanced; and if the currents transmitted by the two detected phase bridge arms in the current detection result of at least one driving current detection are unbalanced, judging that the three-phase driving current output by the frequency converter is unbalanced. In one embodiment, the description of the specific implementation function may be referred to in step S102.
In one embodiment, the current analysis unit may be further configured to determine, for each current detection result detected by driving the current, whether the currents transmitted by the two detected phase legs in the current detection results are balanced by: respectively calculating the current deviation of the actual value of the driving current transmitted on each detected phase bridge arm in the current detection result by adopting a deviation calculation function shown in formula (1); judging whether each current deviation degree is smaller than a preset deviation degree threshold value; if so, judging that the currents transmitted on the two detected phase bridge arms are balanced; and if not, judging that the currents transmitted on the two detected phase bridge arms are unbalanced. In one embodiment, the specific implementation functions may be described in reference to steps 21-22.
In one embodiment, the fault pre-determination module 12 may include an unbalance degree calculation unit. The unbalance degree calculation in the present embodiment may be configured to employ a three-phase unbalance degree calculation method and calculate the unbalance degree of the three-phase drive current output by the frequency converter based on the current detection result of the three times of drive current detection. In one embodiment, the description of the specific implementation function may be referred to in step S105.
The compressor failure early warning apparatus is used for executing the embodiment of the compressor failure early warning method shown in fig. 1, and the technical principles, the solved technical problems, and the generated technical effects of the two are similar, and it can be clearly understood by those skilled in the art that, for convenience and simplicity of description, the specific working process and related description of the compressor failure early warning apparatus may refer to the contents described in the embodiment of the compressor failure early warning method, and are not repeated here.
It will be understood by those skilled in the art that all or part of the flow of the method according to the above-described embodiment may be implemented by a computer program, which may be stored in a computer-readable storage medium and used to implement the steps of the above-described embodiments of the method when the computer program is executed by a processor. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying said computer program code, media, usb disk, removable hard disk, magnetic diskette, optical disk, computer memory, read-only memory, random access memory, electrical carrier wave signals, telecommunication signals, software distribution media, etc. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.
Further, it should be understood that, since the configuration of each module is only for explaining the functional units of the apparatus of the present invention, the corresponding physical devices of the modules may be the processor itself, or a part of software, a part of hardware, or a part of a combination of software and hardware in the processor. Thus, the number of individual modules in the figures is merely illustrative.
Those skilled in the art will appreciate that the various modules in the apparatus may be adaptively split or combined. Such splitting or combining of specific modules does not cause the technical solutions to deviate from the principle of the present invention, and therefore, the technical solutions after splitting or combining will fall within the protection scope of the present invention.
So far, the technical solution of the present invention has been described with reference to one embodiment shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.
Claims (10)
1. A compressor fault warning method, wherein the compressor is connected to an inverter, and the inverter is configured to convert an input power to output a driving current to the compressor to drive the compressor to operate, and the method comprises:
responding to a received frequency converter starting instruction, and carrying out driving current detection on the frequency converter;
judging whether the three-phase driving current output by the frequency converter is unbalanced or not according to the detection result;
if yes, judging that the three-phase imbalance fault occurs after the compressor is started in advance and giving an alarm.
2. The compressor fault early warning method according to claim 1, wherein the frequency converter comprises a three-phase full-bridge inverter, an alternating current side of the three-phase full-bridge inverter is connected with the compressor, the three-phase full-bridge inverter comprises three-phase bridge arms, each phase of bridge arm comprises an upper bridge arm and a lower bridge arm, and the step of detecting the driving current of the frequency converter specifically comprises the following steps:
for each phase of bridge arm, respectively carrying out drive current detection through the following steps to obtain current detection results of three times of drive current detection:
setting the current phase bridge arm as a main phase detection bridge arm, and setting other two phase bridge arms as phase detection bridge arms;
driving an upper bridge arm of the main phase detection bridge arm and a lower bridge arm of each phase detection bridge arm to be conducted according to a preset PWM signal so as to enable the input power supply to be transmitted through a conducting loop formed by the upper bridge arm, the compressor and one lower bridge arm and enable the input power supply to be transmitted through a conducting loop formed by the upper bridge arm, the compressor and the other lower bridge arm; the preset PWM signal is a PWM signal generated according to a driving current given value;
and acquiring the actual value of the driving current transmitted on each detected phase bridge arm to obtain the current detection result of the current driving current detection.
3. The compressor fault early warning method according to claim 2, wherein the step of determining whether the three-phase driving current output by the frequency converter is unbalanced according to the detection result specifically comprises:
respectively judging whether the currents transmitted on two bridge arms to be detected in the current detection result of each driving current detection are balanced;
and if the currents transmitted by the two detected phase bridge arms in the current detection result of at least one driving current detection are unbalanced, judging that the three-phase driving current output by the frequency converter is unbalanced.
4. The compressor fault early warning method according to claim 3, wherein the step of respectively judging whether the currents transmitted by the two detected phase bridge arms in the current detection result of each driving current detection are balanced specifically comprises:
and judging whether the currents transmitted on the two detected phase bridge arms in the current detection results are balanced or not by the following steps respectively according to the current detection results of each driving current detection:
and respectively calculating the current deviation of the actual value of the driving current transmitted on each detected phase bridge arm in the current detection result by adopting a deviation calculation function shown as the following formula:
wherein d represents the current deviation degree, IrRepresenting the actual value of the driving current, wherein I represents the given value of the driving current;
judging whether each current deviation degree is smaller than a preset deviation degree threshold value;
if so, judging that the currents transmitted on the two detected phase bridge arms are balanced; and if not, judging that the currents transmitted on the two detected phase bridge arms are unbalanced.
5. The compressor fault warning method as claimed in claim 3, wherein after the step of determining that the three-phase driving currents output from the inverter are unbalanced, the method further comprises:
and calculating the unbalance of the three-phase driving current output by the frequency converter by adopting a three-phase unbalance calculation method according to the current detection result of the three times of driving current detection.
6. A compressor fault warning device, wherein the compressor is connected to an inverter, and the inverter is configured to convert an input power to output a driving current to the compressor to drive the compressor to operate, the device comprising:
a current detection module configured to perform drive current detection on the frequency converter in response to a received frequency converter start instruction;
a fault pre-judging module configured to judge whether the three-phase driving current output by the frequency converter is unbalanced according to the detection result; if yes, judging that the three-phase imbalance fault occurs after the compressor is started in advance and giving an alarm.
7. The compressor fault early warning device according to claim 6, wherein the frequency converter comprises a three-phase full-bridge inverter, an alternating current side of the three-phase full-bridge inverter is connected with the compressor, the three-phase full-bridge inverter comprises three-phase bridge arms, each phase of bridge arm comprises an upper bridge arm and a lower bridge arm, and the current detection module is further configured to perform drive current detection on each phase of bridge arm respectively through the following steps to obtain current detection results of three drive current detections:
setting the current phase bridge arm as a main phase detection bridge arm, and setting other two phase bridge arms as phase detection bridge arms;
driving an upper bridge arm of the main phase detection bridge arm and a lower bridge arm of each phase detection bridge arm to be conducted according to a preset PWM signal so as to enable the input power supply to be transmitted through a conducting loop formed by the upper bridge arm, the compressor and one lower bridge arm and enable the input power supply to be transmitted through a conducting loop formed by the upper bridge arm, the compressor and the other lower bridge arm; the preset PWM signal is a PWM signal generated according to a driving current given value;
and acquiring the actual value of the driving current transmitted on each detected phase bridge arm to obtain the current detection result of the current driving current detection.
8. The compressor fault pre-warning device according to claim 7, wherein the fault pre-judging module comprises a current analyzing unit configured to perform the following operations:
respectively judging whether the currents transmitted on two bridge arms to be detected in the current detection result of each driving current detection are balanced;
and if the currents transmitted by the two detected phase bridge arms in the current detection result of at least one driving current detection are unbalanced, judging that the three-phase driving current output by the frequency converter is unbalanced.
9. The compressor fault warning device according to claim 8, wherein the current analyzing unit is further configured to perform the following operations:
and judging whether the currents transmitted on the two detected phase bridge arms in the current detection results are balanced or not by the following steps respectively according to the current detection results of each driving current detection:
and respectively calculating the current deviation of the actual value of the driving current transmitted on each detected phase bridge arm in the current detection result by adopting a deviation calculation function shown as the following formula:
wherein d represents the current deviation degree, IrRepresenting the actual value of the driving current, wherein I represents the given value of the driving current;
judging whether each current deviation degree is smaller than a preset deviation degree threshold value;
if so, judging that the currents transmitted on the two detected phase bridge arms are balanced; and if not, judging that the currents transmitted on the two detected phase bridge arms are unbalanced.
10. The compressor fault pre-warning device according to claim 8, wherein the fault pre-judging module includes an unbalance degree calculating unit configured to calculate the unbalance degree of the three-phase driving current output by the inverter by using a three-phase unbalance degree calculating method and according to current detection results of three times of driving current detection.
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