CN115932573A - Detection device and detection method for power conversion unit - Google Patents
Detection device and detection method for power conversion unit Download PDFInfo
- Publication number
- CN115932573A CN115932573A CN202211682501.3A CN202211682501A CN115932573A CN 115932573 A CN115932573 A CN 115932573A CN 202211682501 A CN202211682501 A CN 202211682501A CN 115932573 A CN115932573 A CN 115932573A
- Authority
- CN
- China
- Prior art keywords
- power conversion
- conversion unit
- bridge arm
- switch tube
- current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention discloses a detection device and a detection method of a power conversion unit, wherein the detection device comprises: the current equalizing device comprises a heating current source, a measuring current source, switch tube control units, a conduction voltage drop measuring unit and a signal processing unit, wherein the signal processing unit controls the switch tube control units to conduct all switch tubes in a bridge arm to be measured, heating current is input to all the switch tubes within a preset time period, the switch tube control units are controlled to conduct all the switch tubes in sequence, the measuring current is input during the conduction period of each switch tube, the conduction voltage drop is collected at the same time, and whether the current equalizing characteristic of the power conversion unit to be measured reaches the standard or not is determined based on the conduction voltage drops corresponding to all the switch tubes. The invention can realize off-line detection of the power conversion unit, and can detect the condition that the current sharing characteristic of the power conversion unit does not reach the standard due to the abnormal parameters of the welding resistance, the stray inductance and the like of each branch circuit connected in parallel of the power conversion unit at one time.
Description
Technical Field
The present invention relates to the field of power conversion unit technologies, and in particular, to a detection apparatus and a detection method for a power conversion unit.
Background
The existing power conversion unit is formed by connecting discrete devices in parallel, and the power conversion unit has the obvious advantages of flexible specification change, stable supply chain and the like, so the power conversion unit is widely applied to the fields of new energy automobile motor drive and the like, for example, the common motor controller system comprises the power conversion unit.
In the power conversion unit, each bridge arm is formed by connecting n switching tubes (namely, a switching tube 1 to a switching tube n) in parallel. Due to the fact that performance parameters of the switch tubes connected in parallel and parameters such as welding resistance and stray inductance of the branch circuits connected in parallel are different, current flowing through each switch tube is not uniform, if the non-uniform current condition is serious, the switch tubes connected in parallel are uneven in heating, and therefore the reliability of the whole power conversion unit and even a product is affected.
Therefore, how to detect whether the current sharing characteristic of the power conversion unit meets the standard becomes a technical problem that needs to be solved urgently by those skilled in the art.
Disclosure of Invention
In view of this, the present invention discloses a detection apparatus and a detection method for a power conversion unit, so as to detect whether a current sharing characteristic of the power conversion unit meets a standard.
A detection apparatus of a power conversion unit, comprising:
the output end of the heating current source is connected with the input end of a bridge arm of a tested bridge arm in the tested power conversion unit, and the input end of the heating current source is connected with the output end of the bridge arm of the tested bridge arm and used for providing heating current for the tested power conversion unit;
the output end of the measuring current source is connected with the input end of the bridge arm, and the output end of the measuring current source is connected with the output end of the bridge arm, so that the detecting device provides the heating current for the power conversion unit to be measured and then provides the measuring current for the power conversion unit to be measured, wherein the measuring current is smaller than the heating current;
the switching tube control unit is connected with the control end of each switching tube in the bridge arm to be tested and is used for controlling the switching tubes to be conducted when the detection device provides the heating current and the measuring current;
the conduction voltage drop measuring unit is connected with the input end and the output end of each switching tube in the bridge arm to be measured and is used for measuring the conduction voltage drop of the power conversion unit to be measured when the power conversion unit to be measured flows through the measuring current;
and the signal processing unit is respectively connected with the control end of the heating current source, the control end of the measuring current source, the switch tube control unit and the conduction voltage drop measurement unit, and is used for controlling the switch tube control unit to conduct each switch tube in the tested bridge arm, so that the heating current is input to each switch tube for a preset time period, controlling the switch tube control unit to sequentially conduct each switch tube, controlling the measuring current source to input the measuring current to a conducted target switch tube during the conduction period of each switch tube, controlling the conduction voltage drop measurement unit to collect the conduction voltage drop of the target switch tube, and determining whether the current sharing characteristic of the tested power conversion unit tube reaches the standard or not based on the conduction voltage drop corresponding to all the switch tubes.
Optionally, when the tested bridge arm is an upper bridge arm, a bus connected to the input end of the bridge arm is used as a positive bus of the tested power conversion unit, and the output end of the bridge arm is used as an alternating current output end of the tested power conversion unit;
and when the tested bridge arm is a lower bridge arm, the bus connected with the input end of the bridge arm is used as the alternating current output end of the tested power conversion unit, and the output end of the bridge arm is used as a negative bus of the tested power conversion unit.
Optionally, the switching tube control unit includes: controllable voltage sources with the same quantity as that of each switching tube in the bridge arm to be tested;
and the positive terminal of each controllable voltage source is used as a control pin of the switch tube control unit and is used for being connected with a control end of a target switch tube, and the negative terminal of each controllable voltage source is used for being connected with an output end of the target switch tube, wherein the target switch tube is any one switch tube in the bridge arm to be tested, and different controllable voltage sources are connected with different target switch tubes.
Optionally, the conduction voltage drop measuring unit includes: a voltmeter;
and a first measurement pin of the voltmeter is used for being connected with the input end of each switching tube in the bridge arm to be tested, and a second measurement pin of the voltmeter is used for being connected with the output end of each switching tube in the bridge arm to be tested.
Optionally, the heating current source and the measuring current source are both direct current sources.
A method for detecting a power conversion unit, applied to a signal processing unit in the detection device, the method comprising:
controlling a switch tube control unit to conduct each switch tube in a bridge arm to be tested, and enabling heating current to be input to each switch tube for a preset time period;
controlling the switch tube control unit to sequentially conduct the switch tubes;
controlling a measuring current source to input measuring current to a conducted target switch tube during the conduction period of each switch tube, and controlling a conduction voltage drop measuring unit to collect the conduction voltage drop of the target switch tube;
and determining whether the current sharing characteristic of the tested power conversion unit tube reaches the standard or not based on the conduction voltage drop corresponding to all the switch tubes.
Optionally, determining whether the current sharing characteristic of the tested power conversion unit tube reaches the standard based on the conduction voltage drops corresponding to all the switch tubes includes:
calculating the average value of the conduction voltage drops corresponding to all the switch tubes to obtain the average value of the conduction voltage drops;
respectively calculating a first voltage drop difference value of each conduction voltage drop and the mean value of the conduction voltage drops;
judging whether a first target pressure drop difference value exceeding a first preset threshold exists in all the first pressure drop difference values or not;
if yes, determining that the current sharing characteristic of the tested power conversion unit does not meet the standard;
if not, determining that the current sharing characteristic of the tested power conversion unit reaches the standard.
Optionally, determining whether the current sharing characteristic of the tested power conversion unit tube reaches the standard based on the conduction voltage drops corresponding to all the switch tubes includes:
calculating a second voltage drop difference value of any two conduction voltage drops in all the conduction voltage drops corresponding to the switch tubes;
judging whether a second target pressure drop difference value exceeding a second difference threshold exists in all the second pressure drop difference values;
if yes, determining that the current sharing characteristic of the tested power conversion unit does not meet the standard;
if not, determining that the current sharing characteristic of the tested power conversion unit reaches the standard.
Optionally, the magnitude of the heating current is related to the conducting current capability of the switching tube.
As can be seen from the foregoing technical solutions, the present invention discloses a detection apparatus and a detection method for a power conversion unit, wherein the detection apparatus includes: the current-sharing characteristic detection device comprises a heating current source, a measuring current source, switch tube control units, a conduction voltage drop measurement unit and a signal processing unit, wherein the signal processing unit controls the switch tube control units to conduct all switch tubes in a bridge arm to be detected, heating current is input to all the switch tubes for a preset time period, then the switch tube control units are controlled to conduct all the switch tubes in sequence, the measuring current source is controlled to input measuring current to a conducted target switch tube during the conduction period of each switch tube, meanwhile, the conduction voltage drop measurement unit is controlled to collect the conduction voltage drop of the target switch tube, and whether the current-sharing characteristic of the power conversion unit to be detected reaches the standard or not is determined based on the conduction voltage drops corresponding to all the switch tubes. The invention can realize off-line detection of the power conversion unit, can detect the condition that the current sharing characteristic of the power conversion unit does not reach the standard due to the abnormal and unbalanced parameters of the welding resistance, the stray inductance and the like of each parallel branch of the power conversion unit at one time, and has high automation degree and short time consumption in the whole process.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the disclosed drawings without creative efforts.
FIG. 1 is a system architecture diagram of a typical motor controller disclosed in the prior art;
fig. 2 is a schematic diagram of a parallel power conversion unit disclosed in the prior art;
fig. 3 is a schematic diagram of a detection apparatus of a power conversion unit according to an embodiment of the disclosure;
fig. 4 is a schematic diagram of a connection relationship between a detection apparatus of a power conversion unit and a power conversion unit under test according to an embodiment of the present invention;
fig. 5 is a schematic diagram illustrating a detection principle of a power conversion unit detection apparatus according to an embodiment of the present invention;
fig. 6 is a flowchart of a method for detecting a power conversion unit according to an embodiment of the present invention.
Detailed Description
To facilitate understanding of the internal structure of the power conversion unit, the following description will take the power conversion unit in the motor controller as an example, and specifically includes the following steps:
referring to fig. 1, a system architecture diagram of a typical motor controller disclosed in the prior art is shown, the motor controller is composed of six three-phase arms, and the upper and lower arms of each phase constitute a parallel power conversion unit (see fig. 2 for details), so that there are three power conversion units in the motor controller, and the three power conversion units respectively perform U-phase ac output, V-phase ac output and W-phase ac output to the motor.
Referring to fig. 2, a schematic diagram of a parallel power conversion unit disclosed in the prior art includes: each bridge arm is formed by connecting n switching tubes in parallel, and the n switching tubes are respectively from switching tube 1 to switching tube n. Due to the fact that performance parameters of the switch tubes connected in parallel and parameters such as welding resistance and stray inductance of the branch circuits connected in parallel are different, current flowing through each switch tube is not uniform, if the non-uniform current condition is serious, the switch tubes connected in parallel are uneven in heating, and therefore the reliability of the whole power conversion unit and even a product is affected. Based on the above, the invention provides a detection method and a detection method for a power conversion unit, so as to detect the condition of uneven current of a switch tube in the power conversion unit.
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. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The embodiment of the invention discloses a detection device and a detection method of a power conversion unit, wherein the detection device comprises: the current-sharing characteristic testing device comprises a heating current source, a measuring current source, a switch tube control unit, a conduction voltage drop measurement unit and a signal processing unit, wherein the signal processing unit controls the switch tube control unit to conduct each switch tube in a tested bridge arm, so that the heating current is input to each switch tube for a preset time period, then controls the switch tube control unit to conduct each switch tube in sequence, controls the measuring current source to input measuring current to a conducted target switch tube during the conduction period of each switch tube, controls the conduction voltage drop measurement unit to collect the conduction voltage drop of the target switch tube, and determines whether the current-sharing characteristic of the tested power conversion unit reaches the standard or not based on the conduction voltage drop size corresponding to all the switch tubes. The invention can realize off-line detection of the power conversion unit, can detect the condition that the current sharing characteristic of the power conversion unit does not reach the standard due to the abnormal and unbalanced parameters of the welding resistance, the stray inductance and the like of each parallel branch of the power conversion unit at one time, and has high automation degree and short time consumption in the whole process.
Referring to fig. 3, a schematic diagram of a detection apparatus for a power conversion unit according to an embodiment of the present invention includes: a heating current source 11, a measurement current source 12, a switching tube control unit 13, a conduction voltage drop measurement unit 14, and a signal processing unit 15.
The output end of the heating current source 11 is connected to the bridge arm input end of the bridge arm to be tested in the power conversion unit 10 to be tested, and the input end of the heating current source 11 is connected to the bridge arm output end of the bridge arm to be tested, so as to provide heating current to the power conversion unit 10 to be tested.
The heating current may be a current when the power conversion unit normally operates.
In addition, the measured bridge arm in the measured power conversion unit 10 includes: an upper bridge arm and a lower bridge arm. And when the tested bridge arm is an upper bridge arm, the bus connected with the input end of the bridge arm is used as a positive bus of the tested power conversion unit, and the output end of the bridge arm is used as an alternating current output end of the tested power conversion unit. And when the tested bridge arm is a lower bridge arm, the bus connected with the input end of the bridge arm is used as the alternating current output end of the tested power conversion unit, and the output end of the bridge arm is used as the negative bus of the tested power conversion unit.
Taking the measured bridge arm as an upper bridge arm as an example, the connection relationship between the detection device of the power conversion unit and the measured power conversion unit 10 is as shown in fig. 4, the output end of the heating current source 11 is connected to the positive bus of the measured power conversion unit 10, the input end of the heating current source 11 is connected to the ac output end of the measured power conversion unit 10, and the heating current source 11 is used for inputting heating current to each switching tube in the measured bridge arm.
Wherein, the magnitude of the heating current is related to the conducting current capability of the switch tube.
The output end of the measurement current source 12 is connected to the input end of the bridge arm, and the output end of the measurement current source 12 is connected to the output end of the bridge arm, so that the detection device provides the heating current to the measured power conversion unit 10 and then provides the measurement current to the measured power conversion unit 10, where the measurement current is smaller than the heating current.
Taking the measured bridge arm as an upper bridge arm as an example, the output end of the measurement current source 12 is connected to the positive bus of the measured power conversion unit 10, the input end of the measurement current source 12 is connected to the alternating current output end of the measured power conversion unit 10, and the measurement current source 12 is used for inputting measurement current to each switching tube in the measured bridge arm.
The measurement current is smaller than the heating current, and the value of the measurement current needs to enable a single switch tube to be conducted so as to measure the conduction voltage drop of the switch tube and avoid the excessive temperature rise of the switch tube.
The switching tube control unit 13 is connected to the control end of each switching tube in the bridge arm to be measured, and is configured to control the switching tube to be turned on when the detection device provides the heating current and the measurement current.
In practical application, the switch tube may be a triode or a MOS tube.
When the switch tube is a triode, the control end of the switch tube is a base electrode, the input end of the switch tube is a collector electrode, and the output end of the switch tube is an emitter electrode.
When the switch tube is an MOS tube, the control end of the MOS tube is a grid electrode, the input end of the switch tube is a drain electrode, and the output end of the switch tube is a source electrode.
The conduction voltage drop measuring unit 14 is connected to the input end and the output end of each switching tube in the bridge arm to be measured, and is used for measuring the conduction voltage drop of the power conversion unit 10 to be measured when the power conversion unit 10 to be measured flows the measurement current.
The signal processing unit 15 is respectively connected to the heating current source 11, the measurement current source 12, the switching tube control unit 13, and the conduction voltage drop measurement unit 14, and the signal processing unit 15 is configured to control the switching tube control unit 13 to turn on each switching tube in the detected bridge arm, so that the heating current is input to each switching tube for a preset time period, control the switching tube control unit 13 to turn on each switching tube in sequence, control the measurement current source 12 to input the measurement current to the turned-on target switching tube during the turn-on period of each switching tube, control the conduction voltage drop measurement unit 14 to collect the conduction voltage drop of the target switching tube, and determine whether the current sharing characteristic of the detected power conversion unit 10 reaches the standard or not based on the conduction voltage drops corresponding to all the switching tubes.
The value of the preset time period is determined based on the junction temperature of the switching tube reaching a preset temperature threshold, and the value of the preset temperature threshold is determined according to actual needs, which is not limited herein.
Specifically, taking the connection relationship between the detection device of the power conversion unit shown in fig. 4 and the power conversion unit 10 to be tested as an example, assuming that the bridge arm to be tested is an upper bridge arm, the bridge arm to be tested includes: the n switching tubes are respectively a switching tube 1-a switching tube n, the detection principle is shown in fig. 5, and the whole detection process is as follows:
when the detection is started at the time t0, the signal processing unit 15 sends a switching tube control signal to the switching tube control unit 13, so that the switching tube control unit 13 controls gate voltages of n switching tubes (switching tubes 1 to n) in the upper bridge arm to be far higher than gate-level turn-on thresholds of the switching tubes, and all the switching tubes 1 to n are in a turn-on state. The signal processing unit 15 controls the heating current source 11 to output heating current, and the heating current passes through the switching tube 1 to the switching tube n to heat the n switching tubes, so that the junction temperature of the switching tube 1 to the switching tube n can rise rapidly. Due to the existence of imbalance factors such as device characteristics, loop impedance and the like, the currents from the switch tube 1 to the switch tube n are imbalanced, and junction temperature deviation is caused.
At the time t1, when the junction temperature of each switching tube reaches a preset temperature threshold value, so that the junction temperature can be measured more accurately, the signal processing unit 15 controls the heating current source 11 to stop outputting the heating current, and the measurement stage is started.
In the measurement phase, the signal processing unit 15 controls the gate-level voltages of the switching tubes 1 to n to be higher than the gate-level turn-on threshold of the switching tubes through the switching tube control unit 13, so that the switching tubes 1 to n are in the on state respectively, and controls the measurement current source 12 to input the measurement current into the switching tube turned on in the n switching tubes when the switching tubes 1 to n are turned on, and measures and records the on voltage drops of the switching tubes 1 to n respectively.
Specifically, the switching tube control unit 13 controls the gate level of the switching tube 1 to be a high level at the time t2, so that the switching tube 1 is in a conducting state, other switching tubes are in an off state, and the measurement current is output through the measurement current source 12 at the time t2, at this time, the measurement current completely flows through the switching tube 1, and the conducting voltage drop Vce1 of the switching tube 1 is tested and recorded through the conducting voltage drop measurement unit 14.
And when the measurement on the switching tube 1 is finished at the time t3, the measurement current source 12 stops outputting the measurement current, and the switching tube control unit 13 controls the switching tube 1 to be switched off.
At the time of t4, the switching tube control unit 13 controls the gate level of the switching tube 2 to be a high level, so that the switching tube 2 is in a conducting state, other switching tubes are in a turn-off state, and the measurement current is output through the measurement current source 12 at the time of t4, at this time, the measurement current completely flows through the switching tube 2, and the conduction voltage drop Vce2 from the testing of the switching tube 2 is recorded through the conduction voltage drop measurement unit 14.
At time t5, the measurement of the switching tube 2 is finished, the measurement current source 12 stops outputting the measurement current, and the switching tube control unit 13 controls the switching tube 2 to be disconnected.
And repeating the process until the conduction voltage Vcen of the switching tube n is measured at the time of tn + 1.
It should be noted that, since the junction temperature of each switching tube decreases slowly after the heating current stops, the measurement stage must be completed quickly, so as to effectively reduce the influence of the junction temperature of the switching tube decreasing naturally on the measurement result.
Finally, whether each switch tube in the power conversion unit 10 to be tested is not current-sharing is determined based on the conduction voltage drop Vce1, the conduction voltage drop Vce2, and the conduction voltage drop ….
In practical application, the conduction voltage drops corresponding to the n switching tubes can be compared, and if the conduction voltage drops are different greatly, it is indicated that the current-sharing characteristic of the measured power conversion unit 10 does not reach the standard; on the contrary, if the difference of the conduction voltage drops is not large, it indicates that the current sharing characteristic of the measured power conversion unit 10 reaches the standard.
In summary, the present invention discloses a detection device for a power conversion unit, the detection device comprising: the current-sharing characteristic testing device comprises a heating current source 11, a measuring current source 12, a switch tube control unit 13, a conduction voltage drop measurement unit 14 and a signal processing unit 15, wherein the signal processing unit 15 controls the switch tube control unit 13 to conduct each switch tube in a tested bridge arm, so that heating current is input to each switch tube for a preset time period, then controls the switch tube control unit 13 to conduct each switch tube in sequence, controls the measuring current source 12 to input measuring current to a conducted target switch tube during the conduction period of each switch tube, controls the conduction voltage drop measurement unit 14 to collect the conduction voltage drop of the target switch tube, and determines whether the current-sharing characteristic of the tested power conversion unit 10 reaches the standard or not based on the conduction voltage drop sizes corresponding to all the switch tubes. The invention can realize off-line detection of the power conversion unit, can detect the condition that the current sharing characteristic of the power conversion unit does not reach the standard due to the abnormal and unbalanced parameters of the welding resistance, the stray inductance and the like of each parallel branch of the power conversion unit at one time, and has high automation degree and short time consumption in the whole process.
Preferably, the heating current source 11 and the measuring current source 12 can be both direct current sources.
To further optimize the above embodiment, referring to fig. 3 and 4, the switching tube control unit 13 may include: a controllable voltage source.
The number of the controllable voltage sources is the same as that of each switching tube in the bridge arm to be tested, for example, if the bridge arm to be tested includes n switching tubes, the number of the controllable voltage sources is also n. Compared with the condition that only one controllable voltage source is connected with all the switching tubes, the invention can realize that each switching tube is controlled by the only corresponding controllable voltage source, so that the number of the conducted switching tubes is one or more according to actual needs.
A positive terminal of each controllable voltage source is used as a control pin of the switch tube control unit 13 and is used for being connected with a control end of a target switch tube, and a negative terminal of each controllable voltage source is used for being connected with an output end of the target switch tube, wherein the target switch tube is any one switch tube in the bridge arm to be tested, and different controllable voltage sources are connected with different target switch tubes.
Each controllable voltage source controls the on and off of one switching tube. The controllable voltage source outputs a gate voltage higher than the switching threshold of the switching tube gate machine to the connected switching tube to control the conduction of the switching tube.
To further optimize the above embodiment, referring to fig. 3 and 4, the conducting voltage drop measuring unit 14 may include: a voltmeter;
and a first measurement pin of the voltmeter is used for being connected with the input end of each switching tube in the bridge arm to be tested, and a second measurement pin of the voltmeter is used for being connected with the output end of each switching tube in the bridge arm to be tested.
The voltmeter is used for collecting the conduction voltage drop of the switch tube when the switch tube is conducted and the measuring current is input into the switch tube, and uploading the conduction voltage drop to the signal processing unit 15.
Corresponding to the embodiment of the device, the invention also discloses a detection method of the power conversion unit.
Referring to fig. 6, a flowchart of a detection method for a power conversion unit according to an embodiment of the present invention is applied to a signal processing unit in a detection apparatus, and the detection method includes:
and S101, controlling a switch tube control unit to conduct each switch tube in a bridge arm to be tested, and enabling heating current to be input to each switch tube for a preset time period.
Specifically, the signal processing unit sends a switching tube control signal to the switching tube control unit, so that the switching tube control unit controls gate voltages of n switching tubes (switching tubes 1 to n) in the upper bridge arm to be far higher than gate-level turn-on thresholds of the switching tubes, and the switching tubes 1 to n are all in a turn-on state.
Heating current passes through the switching tubes 1 to n to heat the n switching tubes, so that junction temperatures of the switching tubes 1 to n rise rapidly.
Wherein, the magnitude of the heating current is related to the conducting current capability of the switch tube.
In practical applications, when the detection apparatus further includes a heating current source, the signal processing unit may control the heating current source to input the heating current to each of the switch tubes after each of the switch tubes is turned on.
And S102, controlling the switching tube control unit to sequentially conduct the switching tubes.
And S103, controlling a measuring current source to input measuring current to a conducted target switch tube during the conduction period of each switch tube, and controlling a conduction voltage drop measuring unit to collect the conduction voltage drop of the target switch tube.
In the measurement phase, the signal processing unit 15 controls the gate-level voltages of the switching tubes 1 to n to be higher than the gate-level turn-on threshold of the switching tubes through the switching tube control unit 13, so that the switching tubes 1 to n are in the on state respectively, and controls the measurement current source 12 to input the measurement current into the switching tube turned on in the n switching tubes when the switching tubes 1 to n are turned on, and measures and records the on voltage drops of the switching tubes 1 to n respectively.
And step S104, determining whether the current sharing characteristic of the tested power conversion unit tube reaches the standard or not based on the conduction voltage drop corresponding to all the switch tubes.
In practical application, the conduction voltage drops corresponding to the n switching tubes can be compared, and if the conduction voltage drops have larger difference, it indicates that the current sharing characteristic of the tested power conversion unit 10 does not reach the standard; on the contrary, if the difference of the conduction voltage drops is not large, it indicates that the current sharing characteristic of the measured power conversion unit 10 reaches the standard.
In summary, the invention discloses a detection method of a power conversion unit, wherein a signal processing unit controls a switch tube control unit to conduct each switch tube in a bridge arm to be detected, so that heating current is input to each switch tube for a preset time period, then the switch tube control unit is controlled to conduct each switch tube in sequence, a measurement current source is controlled to input measurement current to a conducted target switch tube during the conduction period of each switch tube, meanwhile, a conduction voltage drop measurement unit is controlled to collect conduction voltage drop of the target switch tube, and whether the current sharing characteristic of the power conversion unit to be detected reaches the standard is determined based on the conduction voltage drop corresponding to all the switch tubes. The invention can realize off-line detection of the power conversion unit, can detect the condition that the current sharing characteristic of the power conversion unit does not reach the standard due to the abnormal and unbalanced parameters of the welding resistance, the stray inductance and the like of each parallel branch of the power conversion unit at one time, and has high automation degree and short time consumption in the whole process.
To further optimize the above embodiment, step S104 may specifically include:
calculating the average value of the conduction voltage drops corresponding to all the switch tubes to obtain the average value of the conduction voltage drops;
respectively calculating a first voltage drop difference value of each conduction voltage drop and the mean value of the conduction voltage drops;
judging whether a first target pressure drop difference exceeding a first preset threshold exists in all the first pressure drop difference values or not;
if yes, the current sharing characteristic of the measured power conversion unit is determined not to meet the standard.
If not, determining that the current sharing characteristic of the tested power conversion unit reaches the standard.
It should be noted that the failure of the current sharing characteristic of the measured power conversion unit to reach the standard is mainly caused by the difference between the performance parameters of each switching tube and the parameters of the welding resistance, the stray inductance and the like of each parallel branch.
The value of the first difference threshold depends on actual needs, and the invention is not limited herein.
To further optimize the above embodiment, step S104 may specifically include:
calculating a second voltage drop difference value of any two conduction voltage drops in all the conduction voltage drops corresponding to the switch tubes;
judging whether a second target pressure drop difference value exceeding a second difference threshold exists in all the second pressure drop difference values;
if yes, the current sharing characteristic of the measured power conversion unit is determined not to meet the standard.
If not, determining that the current sharing characteristic of the power measurement conversion unit reaches the standard.
The value of the second difference threshold depends on actual needs, and the invention is not limited herein.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, 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 process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. A detection apparatus for a power conversion unit, comprising:
the output end of the heating current source is connected with the input end of a bridge arm of a tested bridge arm in the tested power conversion unit, and the input end of the heating current source is connected with the output end of the bridge arm of the tested bridge arm and used for providing heating current for the tested power conversion unit;
the output end of the measuring current source is connected with the input end of the bridge arm, and the output end of the measuring current source is connected with the output end of the bridge arm, so that the measuring current is provided for the measured power conversion unit after the heating current is provided for the measured power conversion unit by the detection device, wherein the measuring current is smaller than the heating current;
the switching tube control unit is connected with the control end of each switching tube in the bridge arm to be tested and is used for controlling the switching tubes to be conducted when the detection device provides the heating current and the measuring current;
the conduction voltage drop measuring unit is connected with the input end and the output end of each switching tube in the bridge arm to be measured and is used for measuring the conduction voltage drop of the power conversion unit to be measured when the power conversion unit to be measured flows through the measuring current;
and the signal processing unit is respectively connected with the control end of the heating current source, the control end of the measuring current source, the switch tube control unit and the conduction voltage drop measurement unit, and is used for controlling the switch tube control unit to conduct each switch tube in the tested bridge arm, so that the heating current is input to each switch tube for a preset time period, controlling the switch tube control unit to sequentially conduct each switch tube, controlling the measuring current source to input the measuring current to a conducted target switch tube during the conduction period of each switch tube, controlling the conduction voltage drop measurement unit to collect the conduction voltage drop of the target switch tube, and determining whether the current sharing characteristic of the tested power conversion unit tube reaches the standard or not based on the conduction voltage drop corresponding to all the switch tubes.
2. The detection device according to claim 1, wherein when the bridge arm to be detected is an upper bridge arm, a bus connected to the input end of the bridge arm is used as a positive bus of the power conversion unit to be detected, and the output end of the bridge arm is used as an alternating current output end of the power conversion unit to be detected;
and when the tested bridge arm is a lower bridge arm, the bus connected with the input end of the bridge arm is used as the alternating current output end of the tested power conversion unit, and the output end of the bridge arm is used as a negative bus of the tested power conversion unit.
3. The detection apparatus according to claim 1, wherein the switching tube control unit includes: controllable voltage sources with the same quantity as that of each switching tube in the bridge arm to be tested;
and the positive terminal of each controllable voltage source is used as a control pin of the switch tube control unit and is used for being connected with a control end of a target switch tube, and the negative terminal of each controllable voltage source is used for being connected with an output end of the target switch tube, wherein the target switch tube is any one switch tube in the bridge arm to be tested, and different controllable voltage sources are connected with different target switch tubes.
4. The detecting device according to claim 1, wherein the conduction voltage drop measuring unit includes: a voltmeter;
and a first measurement pin of the voltmeter is used for being connected with the input end of each switching tube in the bridge arm to be tested, and a second measurement pin of the voltmeter is used for being connected with the output end of each switching tube in the bridge arm to be tested.
5. The detection device according to claim 1, wherein the heating current source and the measuring current source are both direct current sources.
6. A method for detecting a power conversion unit, the method being applied to a signal processing unit in the detection apparatus according to any one of claims 1 to 5, the method comprising:
controlling a switch tube control unit to conduct each switch tube in a bridge arm to be tested, and enabling heating current to be input to each switch tube for a preset time period;
controlling the switch tube control unit to sequentially conduct the switch tubes;
controlling a measuring current source to input measuring current to a conducted target switch tube during the conduction period of each switch tube, and controlling a conduction voltage drop measuring unit to collect the conduction voltage drop of the target switch tube;
and determining whether the current sharing characteristic of the tested power conversion unit tube reaches the standard or not based on the conduction voltage drops corresponding to all the switch tubes.
7. The method according to claim 6, wherein the determining whether the current sharing characteristics of the tested power conversion unit tubes meet the requirements based on the conduction voltage drops of all the switch tubes comprises:
calculating the average value of the conduction voltage drops corresponding to all the switch tubes to obtain the average value of the conduction voltage drops;
respectively calculating a first voltage drop difference value of each conduction voltage drop and the mean value of the conduction voltage drops;
judging whether a first target pressure drop difference value exceeding a first preset threshold value exists in all the first pressure drop difference values or not;
if yes, determining that the current sharing characteristic of the tested power conversion unit does not meet the standard;
if not, determining that the current sharing characteristic of the tested power conversion unit reaches the standard.
8. The method according to claim 6, wherein the determining whether the current sharing characteristics of the tested power conversion unit tubes meet the requirements based on the conduction voltage drops of all the switch tubes comprises:
calculating a second voltage drop difference value of any two conduction voltage drops in all the conduction voltage drops corresponding to the switch tubes;
judging whether a second target pressure drop difference value exceeding a second difference threshold value exists in all the second pressure drop difference values or not;
if yes, determining that the current sharing characteristic of the tested power conversion unit does not meet the standard;
if not, determining that the current sharing characteristic of the tested power conversion unit reaches the standard.
9. The detection method according to claim 6, wherein the magnitude of the heating current is related to the on-current capability of the switching tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211682501.3A CN115932573A (en) | 2022-12-26 | 2022-12-26 | Detection device and detection method for power conversion unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211682501.3A CN115932573A (en) | 2022-12-26 | 2022-12-26 | Detection device and detection method for power conversion unit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115932573A true CN115932573A (en) | 2023-04-07 |
Family
ID=86650599
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211682501.3A Pending CN115932573A (en) | 2022-12-26 | 2022-12-26 | Detection device and detection method for power conversion unit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115932573A (en) |
-
2022
- 2022-12-26 CN CN202211682501.3A patent/CN115932573A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106291303B (en) | The determination of the aging of power semiconductor in power-driven system | |
| JP6017481B2 (en) | Motor drive device having insulation resistance detection function and motor insulation resistance detection method | |
| CN101142493B (en) | Apparatus and method for measuring the amount of the current in battery cells using a plurality of sensing resistors | |
| CN102841284B (en) | On-line insulated monitoring method for high voltage of electromobile | |
| CN102830283A (en) | Insulating detection device and detection method for direct-current power supply | |
| CN105305780A (en) | Semiconductor apparatus and power conversion apparatus | |
| CN103185850B (en) | For detecting the apparatus and method of switching device fault in inverter | |
| CN102193066A (en) | Method and apparatus to monitor loss of ground isolation of an electric motor drive circuit | |
| CN112904255B (en) | Fault determination method and device for current sensor | |
| WO2020173200A1 (en) | Power conversion apparatus, and method controlling output impedance of power conversion apparatus | |
| CN111505409B (en) | Online detection method and device for bus capacitor of frequency converter | |
| JP2019095395A (en) | Motor drive device and measurement method | |
| CN102466749B (en) | A kind of method and multimeter automatically determining suitable range | |
| CN107872173B (en) | Motor drive with insulation resistance detection function | |
| CN115932573A (en) | Detection device and detection method for power conversion unit | |
| CN109443573A (en) | A kind of power tube kernel system for detecting temperature and method | |
| CN104836462A (en) | Detection method of frequency and phase of input alternating current of air conditioning system and device | |
| JP2018098922A (en) | Inspection apparatus and inspection method for photovoltaic power generation system | |
| CN116068318A (en) | Intelligent power component reliability verification system and verification method | |
| JP5369818B2 (en) | Inverter device failure detection method | |
| CN112595948B (en) | Testing system and method of IGCT phase module | |
| CN211856709U (en) | Current detection circuit | |
| JP6428396B2 (en) | Inspection method and inspection apparatus for photovoltaic power generation system | |
| Cardoso et al. | Converter fault diagnosis in variable speed DC drives, by Park's vector approach | |
| CN108267663A (en) | Detection device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |