CN111404122A - Output open-phase detection and protection method for three-phase inverter - Google Patents
Output open-phase detection and protection method for three-phase inverter Download PDFInfo
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- CN111404122A CN111404122A CN202010420271.8A CN202010420271A CN111404122A CN 111404122 A CN111404122 A CN 111404122A CN 202010420271 A CN202010420271 A CN 202010420271A CN 111404122 A CN111404122 A CN 111404122A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/122—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters
- H02H7/1227—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters responsive to abnormalities in the output circuit, e.g. short circuit
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Abstract
The invention discloses a three-phase inverter output open-phase detection and protection method, which comprises the following steps: normal operation of the S1 inverter: opening an inverter to enable the inverter to be electrified with direct current, converting the direct current into alternating current by the inverter, and presetting a current threshold value for phase-lacking comparison of the inverter; s2 real-time sampling of three-phase currents: sampling negative values of the lower half part of the three-phase alternating current of the inverter in real time, converting the negative values into positive values, namely taking absolute values of the three-phase alternating current, and then performing low-pass filtering processing in real time to convert the three-phase alternating current signals into direct current signals; s3, judging whether the inverter is in phase failure; s4 inverter open-phase protection. The invention has high accuracy of phase failure judgment, is not easy to report by mistake, simultaneously, the output phase failure of any phase inverter can drive the other two phase inverters to be cut off, and simultaneously, the three-phase circuit can be cut off in time when the output end phase failure is caused by the self failure, thereby ensuring that the inverters are not damaged.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to a three-phase inverter output open-phase detection and protection method.
Background
With the continuous development of the modernization process of the society, more and more power electronic products are applied to the daily production and life of people, an inverter is an important application in the power electronic industry, the inverter mainly functions to convert direct current into alternating current, and a variable frequency power supply and an inverter which are widely used at present are applied. Taking the example of converting direct current into three-phase alternating current (three-phase three-wire system), shore power supplies, UPSs and the like are all the applications of the function, the power supply is characterized in that the output characteristic of the power supply is a voltage source and no N-wire output exists, a load carried by the power supply can be a balanced load or an unbalanced load, and in use, due to the fact that the abnormal connection between the power supply and the load can cause the output loss phenomenon of a certain phase, namely, the output phase-loss fault, the phase-loss can cause the input voltage of load equipment to be abnormal, the operation is stopped if the phase is light, and the equipment can be damaged if the phase is serious, so that the common power supply can have the output phase-loss protection function to protect the load equipment.
However, the conventional three-phase inverter is inconvenient to detect when the output phase is short, and cannot effectively protect the output phase of the three-phase inverter, so that the phase-lack protection is easy to fail, and the safety coefficient is low.
Disclosure of Invention
Based on the technical problems in the background art, the invention provides a three-phase inverter output open-phase detection and protection method.
The invention provides a three-phase inverter output open-phase detection and protection method, which comprises the following steps:
normal operation of the S1 inverter:
opening an inverter to enable the inverter to be electrified with direct current, converting the direct current into alternating current by the inverter, and presetting a current threshold value for phase-lacking comparison of the inverter;
s2 real-time sampling of three-phase currents:
sampling negative values of the lower half part of the three-phase alternating current of the inverter in real time, converting the negative values into positive values, namely taking absolute values of the three-phase alternating current, and then performing low-pass filtering processing in real time to convert the three-phase alternating current signals into direct current signals;
s3 judging whether the inverter is in phase failure:
the three-phase direct current signal obtained by conversion is detected by a signal detection unit, the detected three-phase direct current signal is compared with a preset current threshold value, when the three-phase direct current value is larger than the current threshold value, the phase is determined to be in a phase-lacking state, and when the three-phase direct current value is smaller than the current threshold value, the phase is determined to be in a normal state;
s4 inverter open-phase protection: a controller on the inverter is provided with a first control unit, a second control unit and a third control unit, and the first control unit is connected with the phase A of the three-phase inverter and the second control unit; the second control unit is connected with the phase B of the three-phase inverter and the third control unit; the third control unit is connected with the C phase of the three-phase inverter and the first control unit;
s41, when the first control unit detects that the output end of the phase A lacks phase, the second control unit is controlled to separate to disconnect the phase B, and simultaneously the second control unit controls the third control unit to separate to disconnect the phase C;
s42, when the second control unit detects that the output end of the B phase is lack of phase, the third control unit is controlled to separate to disconnect the C phase, and simultaneously the third control unit controls the first control unit to separate to disconnect the A phase;
and S43, when the third control unit detects that the output end of the C phase is lack of phase, the first control unit is controlled to separate to disconnect the A phase, and simultaneously the first control unit controls the second control unit to separate to disconnect the B phase.
Preferably, in the step S2, the processor chip MCU is used to sample the three-phase current of the inverter in real time, and the AD sampling module connected to the signal input terminal of the processor chip MCU converts the real-time current sample three-phase ac current output by the current sensor into a dc current signal and inputs the dc current signal to the processor chip MCU.
Preferably, the signal detection unit in step S3 includes a differential sampling circuit and a comparison circuit connected in series.
According to the method for detecting and protecting the output open-phase of the three-phase inverter, the judgment accuracy of the open-phase is high, false alarm is not easy to occur, meanwhile, the open-phase of the output of any one-phase inverter drives the other two-phase inverter to be cut off, and meanwhile, when the output end is open-phase due to self fault, a three-phase circuit can be cut off in time, so that the inverter is prevented from being damaged.
Drawings
Fig. 1 is a schematic flow chart of a method for detecting and protecting an output open-phase of a three-phase inverter according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Referring to fig. 1, a method for detecting and protecting an output open-phase of a three-phase inverter includes the following steps:
normal operation of the S1 inverter:
opening an inverter to enable the inverter to be electrified with direct current, converting the direct current into alternating current by the inverter, and presetting a current threshold value for phase-lacking comparison of the inverter;
s2 real-time sampling of three-phase currents:
sampling negative values of the lower half part of the three-phase alternating current of the inverter in real time, converting the negative values into positive values, namely taking absolute values of the three-phase alternating current, and then performing low-pass filtering processing in real time to convert the three-phase alternating current signals into direct current signals;
s3 judging whether the inverter is in phase failure:
the three-phase direct current signal obtained by conversion is detected by a signal detection unit, the detected three-phase direct current signal is compared with a preset current threshold value, when the three-phase direct current value is larger than the current threshold value, the phase is determined to be in a phase-lacking state, and when the three-phase direct current value is smaller than the current threshold value, the phase is determined to be in a normal state;
s4 inverter open-phase protection: a controller on the inverter is provided with a first control unit, a second control unit and a third control unit, and the first control unit is connected with the phase A of the three-phase inverter and the second control unit; the second control unit is connected with the phase B of the three-phase inverter and the third control unit; the third control unit is connected with the C phase of the three-phase inverter and the first control unit;
s41, when the first control unit detects that the output end of the phase A lacks phase, the second control unit is controlled to separate to disconnect the phase B, and simultaneously the second control unit controls the third control unit to separate to disconnect the phase C;
s42, when the second control unit detects that the output end of the B phase is lack of phase, the third control unit is controlled to separate to disconnect the C phase, and simultaneously the third control unit controls the first control unit to separate to disconnect the A phase;
and S43, when the third control unit detects that the output end of the C phase is lack of phase, the first control unit is controlled to separate to disconnect the A phase, and simultaneously the first control unit controls the second control unit to separate to disconnect the B phase.
In the present invention, in step S2, the processor chip MCU samples the three-phase current of the inverter in real time, and the AD sampling module connected to the signal input terminal of the processor chip MCU converts the real-time current sample three-phase ac current output by the current sensor into a dc current signal to be input to the processor chip MCU.
In the present invention, the signal detection unit in step S3 includes a differential sampling circuit and a comparison circuit connected in sequence.
The invention comprises the following steps: normal operation of the inverter: opening an inverter to enable the inverter to be electrified with direct current, converting the direct current into alternating current by the inverter, and presetting a current threshold value for phase-lacking comparison of the inverter; sampling three-phase current in real time: sampling negative values of the lower half part of the three-phase alternating current of the inverter in real time, converting the negative values into positive values, namely taking absolute values of the three-phase alternating current, and then performing low-pass filtering processing in real time to convert the three-phase alternating current signals into direct current signals; judging whether the inverter is in phase failure: the three-phase direct current signal obtained by conversion is detected by a signal detection unit, the detected three-phase direct current signal is compared with a preset current threshold value, when the three-phase direct current value is larger than the current threshold value, the phase is determined to be in a phase-lacking state, and when the three-phase direct current value is smaller than the current threshold value, the phase is determined to be in a normal state; inverter open-phase protection: a controller on the inverter is provided with a first control unit, a second control unit and a third control unit, and the first control unit is connected with the phase A of the three-phase inverter and the second control unit; the second control unit is connected with the phase B of the three-phase inverter and the third control unit; the third control unit is connected with the C phase of the three-phase inverter and the first control unit; when the first control unit detects that the output end of the phase A is lack of phase, the second control unit is controlled to separate to disconnect the phase B, and meanwhile, the second control unit controls the third control unit to separate to disconnect the phase C; when the second control unit detects that the output end of the B phase is lack of phase, the third control unit is controlled to separate to disconnect the C phase, and meanwhile, the third control unit controls the first control unit to separate to disconnect the A phase; when the third control unit detects that the output end of the C phase is lack of phase, the first control unit is controlled to separate to disconnect the A phase, and meanwhile, the first control unit controls the second control unit to separate to disconnect the B phase.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (3)
1. The output open-phase detection and protection method of the three-phase inverter is characterized by comprising the following steps:
normal operation of the S1 inverter:
opening an inverter to enable the inverter to be electrified with direct current, converting the direct current into alternating current by the inverter, and presetting a current threshold value for phase-lacking comparison of the inverter;
s2 real-time sampling of three-phase currents:
sampling negative values of the lower half part of the three-phase alternating current of the inverter in real time, converting the negative values into positive values, namely taking absolute values of the three-phase alternating current, and then performing low-pass filtering processing in real time to convert the three-phase alternating current signals into direct current signals;
s3 judging whether the inverter is in phase failure:
the three-phase direct current signal obtained by conversion is detected by a signal detection unit, the detected three-phase direct current signal is compared with a preset current threshold value, when the three-phase direct current value is larger than the current threshold value, the phase is determined to be in a phase-lacking state, and when the three-phase direct current value is smaller than the current threshold value, the phase is determined to be in a normal state;
s4 inverter open-phase protection: a controller on the inverter is provided with a first control unit, a second control unit and a third control unit, and the first control unit is connected with the phase A of the three-phase inverter and the second control unit; the second control unit is connected with the phase B of the three-phase inverter and the third control unit; the third control unit is connected with the C phase of the three-phase inverter and the first control unit;
s41, when the first control unit detects that the output end of the phase A lacks phase, the second control unit is controlled to separate to disconnect the phase B, and simultaneously the second control unit controls the third control unit to separate to disconnect the phase C;
s42, when the second control unit detects that the output end of the B phase is lack of phase, the third control unit is controlled to separate to disconnect the C phase, and simultaneously the third control unit controls the first control unit to separate to disconnect the A phase;
and S43, when the third control unit detects that the output end of the C phase is lack of phase, the first control unit is controlled to separate to disconnect the A phase, and simultaneously the first control unit controls the second control unit to separate to disconnect the B phase.
2. The method according to claim 1, wherein in step S2, the processor chip MCU samples the three-phase current of the inverter in real time, and the AD sampling module connected to the signal input terminal of the processor chip MCU converts the real-time sampled three-phase ac current outputted from the current sensor into a dc current signal for input to the processor chip MCU.
3. The method according to claim 1, wherein the signal detection unit in step S3 comprises a differential sampling circuit and a comparison circuit connected in sequence.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010420271.8A CN111404122A (en) | 2020-05-18 | 2020-05-18 | Output open-phase detection and protection method for three-phase inverter |
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| CN202010420271.8A CN111404122A (en) | 2020-05-18 | 2020-05-18 | Output open-phase detection and protection method for three-phase inverter |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20110084678A (en) * | 2010-01-18 | 2011-07-26 | 엘에스산전 주식회사 | Inverter |
| JP2013106424A (en) * | 2011-11-14 | 2013-05-30 | Hitachi Ltd | Motor controller |
| CN103376409A (en) * | 2012-04-18 | 2013-10-30 | 珠海格力电器股份有限公司 | Phase loss detection method for three-phase motor and detection circuit |
| CN103616572A (en) * | 2013-12-09 | 2014-03-05 | 安徽江淮汽车股份有限公司 | Phase failure diagnosis method of PMSM (permanent magnet synchronous motor) drive system of electric vehicle |
| CN110932236A (en) * | 2019-11-08 | 2020-03-27 | 珠海格力电器股份有限公司 | Overcurrent open-phase detection protection circuit and method and compressor comprising circuit |
| CN110988505A (en) * | 2019-11-20 | 2020-04-10 | 珠海格力电器股份有限公司 | Phase-loss detection circuit and method for compressor and compressor |
| CN110994557A (en) * | 2019-11-07 | 2020-04-10 | 广东尚研电子科技有限公司 | Phase loss detection method and protection mechanism for PMSM motor |
-
2020
- 2020-05-18 CN CN202010420271.8A patent/CN111404122A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20110084678A (en) * | 2010-01-18 | 2011-07-26 | 엘에스산전 주식회사 | Inverter |
| JP2013106424A (en) * | 2011-11-14 | 2013-05-30 | Hitachi Ltd | Motor controller |
| CN103376409A (en) * | 2012-04-18 | 2013-10-30 | 珠海格力电器股份有限公司 | Phase loss detection method for three-phase motor and detection circuit |
| CN103616572A (en) * | 2013-12-09 | 2014-03-05 | 安徽江淮汽车股份有限公司 | Phase failure diagnosis method of PMSM (permanent magnet synchronous motor) drive system of electric vehicle |
| CN110994557A (en) * | 2019-11-07 | 2020-04-10 | 广东尚研电子科技有限公司 | Phase loss detection method and protection mechanism for PMSM motor |
| CN110932236A (en) * | 2019-11-08 | 2020-03-27 | 珠海格力电器股份有限公司 | Overcurrent open-phase detection protection circuit and method and compressor comprising circuit |
| CN110988505A (en) * | 2019-11-20 | 2020-04-10 | 珠海格力电器股份有限公司 | Phase-loss detection circuit and method for compressor and compressor |
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Application publication date: 20200710 |