CN116505832B - Device, system and method for measuring inductance and core saturation coefficient of permanent magnet motor - Google Patents

Device, system and method for measuring inductance and core saturation coefficient of permanent magnet motor Download PDF

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Publication number
CN116505832B
CN116505832B CN202310725745.3A CN202310725745A CN116505832B CN 116505832 B CN116505832 B CN 116505832B CN 202310725745 A CN202310725745 A CN 202310725745A CN 116505832 B CN116505832 B CN 116505832B
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current
inductance
winding
value
control unit
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CN116505832A (en
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杨运海
王宇
张涛
张荣亮
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Shenzhen Farwide Electric Co ltd
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Shenzhen Farwide Electric Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
    • H02P23/14—Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
    • G01R27/2611—Measuring inductance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/34—Testing dynamo-electric machines
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/64—Electric machine technologies in electromobility

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Control Of Ac Motors In General (AREA)

Abstract

The invention discloses a device, a system and a method for measuring inductance and core saturation coefficient of a permanent magnet motor, wherein the device comprises: three-phase full-bridge IGBT inverter, hall current sensor, control unit. The method comprises the following steps: in response to the measurement instruction, the control unit turns on the three-phase full-bridge IGBT inverter, the Hall current sensor obtains a feedback value of the current of the first winding of the three-phase permanent magnet motor, and the current value is acquired according to a preset acquisition frequency and stored in the control unit. The control unit calculates an inductance curve through analyzing the change rate of the current curve and a preset current inductance conversion strategy, and finally calculates the core saturation coefficient according to the initial inductance value and the attenuation inductance value in the inductance curve. The inductance value and the current core saturation coefficient at each moment are accurately mastered, and the precision of closed-loop control and the precision of operation adjustment of the motor are improved.

Description

Device, system and method for measuring inductance and core saturation coefficient of permanent magnet motor
Technical Field
The invention relates to the field of new energy motor control, in particular to an inductance and core saturation coefficient measuring device, system and method of a permanent magnet motor.
Background
The three-phase permanent magnet motor is used as new energy supply equipment and is widely applied to industrial production. In the operation process of the three-phase permanent magnet motor, open-loop control or closed-loop control can be performed. The accuracy and response rigidity of the motor model are closely related to the inductance value of the inductance in each phase coil winding and the core saturation coefficient of each phase coil winding in the motor, whether in open loop control or closed loop control, so that the inductance value and the core saturation coefficient of each phase coil winding need to be mastered when the motor operates. In an ideal situation, the inductance value is a constant value, but in the actual operation process, the inductance value has a saturation effect, that is, the inductance value will decrease with the increase of the current when the current reaches a certain threshold value. Therefore, it is necessary to accurately grasp the inductance value at different timings. The existing inductance value identification is to determine an inductance value based on an ac injected current value, which cannot determine a true inductance value in a case where the current value reaches around or above a rated current of the motor. Meanwhile, the iron core saturation of the motor also affects the normal operation, and the iron core saturation degree, namely the iron core saturation coefficient, also lacks a direct and accurate measurement mode. Further, the problem of low response frequency of closed loop control of motor current and low operation adjustment accuracy of the motor is easily caused.
Disclosure of Invention
The embodiment of the invention provides a device, a system and a method for measuring inductance and core saturation coefficients of a permanent magnet motor, and aims to solve the problems of low closed-loop control precision and low operation adjustment precision of the motor caused by incapability of accurately measuring inductance values and core saturation coefficients of the permanent magnet motor in the method in the prior art.
In a first aspect, an embodiment of the present invention provides an inductance and core saturation coefficient measurement device of a permanent magnet motor, including a three-phase full-bridge IGBT inverter, a hall current sensor, and a control unit; the three-phase full-bridge IGBT inverter is connected to a three-phase permanent magnet motor as a measurement object; the Hall current sensor is connected to the first winding of the three-phase permanent magnet motor and the control unit; the control unit is connected to the three-phase full-bridge IGBT inverter; the control unit is used for responding to the measurement instruction and sending an opening instruction to the three-phase full-bridge IGBT inverter; the three-phase full-bridge IGBT inverter is used for responding to the starting instruction to start and transmitting direct-current pulse current to the three-phase permanent magnet motor; the Hall current sensor is used for acquiring a current value in a first winding of the three-phase permanent magnet motor according to a preset current acquisition frequency, and sending the current value in the first winding to the control unit until the current value in the first winding is monitored to reach a preset acquisition stopping condition, and stopping acquiring the current value in the first winding; the control unit is further used for determining a current curve based on the current values in the first windings which are stored according to time sequence; correspondingly converting the current curve into an inductance curve based on a preset current inductance conversion strategy; acquiring an initial inductance value in the inductance curve and an attenuation inductance value corresponding to a rated current value of the first winding; and determining the current core saturation coefficient of the first winding according to the initial inductance value and the attenuation inductance value.
In a second aspect, the embodiment of the invention also provides a system for measuring the saturation coefficient of the inductance and the iron core of the permanent magnet motor, which comprises a three-phase permanent magnet motor and the device for measuring the saturation coefficient of the inductance and the iron core of the permanent magnet motor according to the first aspect; the three-phase permanent magnet motor comprises three motor windings, wherein the three motor windings are a first winding, a second winding and a third winding respectively; the first winding comprises a first resistor and a first inductor, and one end of the first resistor is connected to one end of the first inductor; the second winding comprises a second resistor and a second inductor, and one end of the second resistor is connected to one end of the second inductor; the third winding comprises a third resistor and a third inductor, and one end of the third resistor is connected to one end of the third inductor; the other end of the first resistor is connected to the three-phase full-bridge IGBT inverter and the Hall current sensor, and the other end of the first inductor is connected to the other end of the second inductor and the other end of the third inductor; the other end of the second resistor is connected to the three-phase full-bridge IGBT inverter; and the other end of the third resistor is connected to the three-phase full-bridge IGBT inverter.
In a third aspect, an embodiment of the present invention further provides a method for determining an inductance and an iron core saturation coefficient of a permanent magnet motor, which is applied to the device for determining an inductance and an iron core saturation coefficient of a permanent magnet motor according to the first aspect, where the method includes: the control unit responds to the measurement instruction and sends an opening instruction to the three-phase full-bridge IGBT inverter; the three-phase full-bridge IGBT inverter is started in response to the starting instruction and transmits direct-current pulse current to the three-phase permanent magnet motor; the Hall current sensor acquires a current value in a first winding of the three-phase permanent magnet motor according to a preset current acquisition frequency, and sends the current value in the first winding to the control unit until the current value in the first winding is monitored to reach a preset acquisition stopping condition, and the acquisition of the current value in the first winding is stopped; the control unit determines a current curve based on the current values in the first windings which have been stored in time sequence; the control unit correspondingly converts the current curve into an inductance curve based on a preset current inductance conversion strategy; the control unit obtains an initial inductance value in the inductance curve and an attenuation inductance value corresponding to a rated current value of the first winding; and the control unit determines the current core saturation coefficient of the first winding according to the initial inductance value and the attenuation inductance value.
Based on the device, the system and the method provided by the embodiment of the invention, the method for measuring the inductance and the iron core saturation coefficient of the permanent magnet motor provided by the embodiment of the invention obtains a larger current value by applying the direct current pulse voltage, further obtains the corresponding inductance value when rated current, converts the current curve into a continuous inductance curve, obtains the current iron core saturation coefficient based on the inductance curve, realizes accurate grasp of the inductance value and the current iron core saturation coefficient at each moment, and improves the precision of closed-loop control and the precision of operation adjustment of the motor.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of an inductance and core saturation coefficient measuring device of a permanent magnet motor according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an inductance and core saturation coefficient measurement system of a permanent magnet motor according to an embodiment of the present invention;
fig. 3 is a schematic flow chart of a method for measuring inductance and core saturation coefficient of a permanent magnet motor according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a current curve in a method for measuring inductance and core saturation coefficient of a permanent magnet motor according to an embodiment of the present invention;
fig. 5 is a schematic diagram of an inductance curve in a method for measuring inductance and core saturation coefficient of a permanent magnet motor according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a first sub-flow of a method for determining an inductance and core saturation coefficient of a permanent magnet motor according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a second sub-flow of a method for determining an inductance and a core saturation coefficient of a permanent magnet motor according to an embodiment of the present invention;
fig. 8 is a schematic diagram of a third sub-flowchart of a method for determining an inductance and a core saturation coefficient of a permanent magnet motor according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
Referring to fig. 1, as shown in fig. 1, an embodiment of the present invention provides an apparatus for determining an inductance and an iron core saturation coefficient of a permanent magnet motor, including a three-phase full-bridge IGBT inverter INV, a hall current sensor HECS, and a control unit Uc; the three-phase full-bridge IGBT inverter INV is connected to a three-phase permanent magnet motor as a measurement object; the Hall current sensor HECS is connected to the first winding of the three-phase permanent magnet motor and the control unit Uc; the control unit Uc is connected to the three-phase full-bridge IGBT inverter INV; the control unit Uc is used for responding to the measurement instruction and sending an opening instruction to the three-phase full-bridge IGBT inverter INV; the three-phase full-bridge IGBT inverter INV is used for responding to the starting instruction to start and transmitting direct-current pulse current to the three-phase permanent magnet motor; the Hall current sensor HECS is used for acquiring a current value in a first winding of the three-phase permanent magnet motor according to a preset current acquisition frequency, and sending the current value in the first winding to the control unit Uc until the current value in the first winding is monitored to reach a preset acquisition stopping condition, and stopping acquiring the current value in the first winding; the control unit Uc is also configured to determine a current curve based on the current values in the first windings that have been stored in time sequence; correspondingly converting the current curve into an inductance curve based on a preset current inductance conversion strategy; acquiring an initial inductance value in the inductance curve and an attenuation inductance value corresponding to a rated current value of the first winding; and determining the current core saturation coefficient of the first winding according to the initial inductance value and the attenuation inductance value.
A three-phase permanent magnet motor is an induction motor that requires ac power for driving during normal operation. The three-phase permanent magnet motor comprises a stator and a rotor, wherein three motor windings are arranged on the stator. The three-phase full-bridge IGBT inverter INV is an inverter provided with a dc voltage power supply and six IGBTs (Insulated Gate Bipolar Transistor, insulated gate bipolar transistors) alone, which can generate and deliver a dc pulse current to a three-phase permanent magnet motor. When three windings of the three-phase full-bridge IGBT inverter INV are connected with three-phase symmetrical direct current pulse currents, a rotating magnetic field is generated, and then a rotor is driven to rotate, so that the motor is driven. The control unit Uc comprises a processor and a memory, is connected with the three-phase full-bridge IGBT inverter INV, and can specifically control the on and off of a direct-current voltage power supply and each IGBT monomer in the three-phase full-bridge IGBT inverter INV so as to realize the generation and the stop of direct-current pulse voltage. The hall current sensor HECS is connected with a first winding in the three-phase permanent magnet motor, and can induce current change based on hall effect generated by current, and collect current values. In particular, there is no electrical connection between the hall current sensor HECS and the first winding, which is simply a device that is sleeved on the first winding. After the current value of the first winding is collected, the hall current sensor HECS may send the current value of the first winding to the control unit Uc, and the memory of the control unit Uc may store the current value of the first winding and perform subsequent processing on the current value of the first winding in the processor.
Referring to fig. 2, as shown in fig. 2, an embodiment of the present invention provides a system for measuring an inductance and an iron core saturation coefficient of a permanent magnet motor, including a three-phase permanent magnet motor and an inductance and an iron core saturation coefficient measuring device of the permanent magnet motor as described above; the three-phase permanent magnet motor comprises three motor windings, wherein the three motor windings are a first winding, a second winding and a third winding respectively; the first winding comprises a first resistor R1 and a first inductor L1, and one end of the first resistor R1 is connected to one end of the first inductor L1; the second winding comprises a second resistor R2 and a second inductor L2, and one end of the second resistor R2 is connected to one end of the second inductor L2; the third winding comprises a third resistor R3 and a third inductor L3, and one end of the third resistor R3 is connected to one end of the third inductor L3; the other end of the first resistor R1 is connected to the three-phase full-bridge IGBT inverter INV and the Hall current sensor HECS, and the other end of the first inductor L1 is connected to the other end of the second inductor L2 and the other end of the third inductor L3; the other end of the second resistor R2 is connected to the three-phase full-bridge IGBT inverter INV; the other end of the third resistor R3 is connected to the three-phase full-bridge IGBT inverter INV.
In this embodiment, each motor winding includes its own resistor and an inductor, which can be regarded as each motor winding includes a resistor and an inductor connected in series with each other. Specifically, the first winding includes a first resistor R1 and a first inductor L1, the second winding includes a second resistor R2 and a second inductor L2, and the third winding includes a third resistor R3 and a third inductor L3. The system for measuring the inductance and the core saturation coefficient of the permanent magnet motor provided by the embodiment of the invention is actually a system which is independently used for measuring the inductance value and the core saturation coefficient, has a difference between the working principle of the system and the working principle of the three-phase permanent magnet motor, and does not influence the operation of the three-phase permanent magnet motor. Specifically, the direct current pulse voltage is applied to the three-phase full-bridge IGBT inverter INV, and is different from the alternating current voltage in the normal operation of the three-phase permanent magnet motor, the direct current pulse voltage can enable the current value in the winding to reach the rated current value, and effective measurement of the inductance is achieved.
The first inductor L1 in the first winding is connected to the second inductor L2 and the third inductor L3 at the same time, and the second winding and the third winding are actually in a parallel connection state. In practice, the system is used for measuring the inductance value of the first inductor L1 located in the first winding of the main circuit and the corresponding core saturation coefficient. The current generated by the direct current pulse voltage applied by the three-phase full-bridge IGBT inverter INV flows through the first winding, then branches into the second winding and the third winding, and finally flows to the three-phase full-bridge IGBT inverter INV to form a loop. The first winding can be one of a U-end winding, a V-end winding or a W-end winding in the three-phase permanent magnet motor, and a specific winding can be optionally arranged in a main circuit as the first winding so as to measure an inductance value. The hall current sensor HECS is disposed in the first winding and between the first resistor R1 and the three-phase full-bridge IGBT inverter INV, which can know the current value in the main circuit (i.e., the current value of the first inductor L1). Specifically, the hall current sensor HECS is a device sleeved on the first winding, and there is no electrical connection between the hall current sensor HECS and the first winding. The control unit Uc may obtain a real-time dc bus voltage value (i.e., a real-time value of a dc pulse voltage) through connection with the three-phase full-bridge IGBT inverter INV, and includes a processor and a memory therein, and further, the control unit Uc has a function of performing calculation processing and storage on the obtained data. The system can realize the measurement of the inductance value and the core saturation coefficient of a single winding in the three-phase permanent magnet motor, and simultaneously the control unit Uc can also feed back and adjust the closed-loop control of the motor in real time according to the measured value.
Referring to fig. 3, as shown in fig. 3, the embodiment of the invention further provides a method for measuring the inductance and the core saturation coefficient of a permanent magnet motor, which is applied to the device for measuring the inductance and the core saturation coefficient of the permanent magnet motor, and the method comprises the following steps S110-S170:
and S110, the control unit Uc responds to a measurement instruction and sends an opening instruction to the three-phase full-bridge IGBT inverter INV.
The measurement instruction may be a measurement instruction for the inductance and the core saturation coefficient of the three-phase permanent magnet motor manually input by a user, and when the control unit Uc receives the measurement instruction, an opening instruction is sent to the three-phase full-bridge IGBT inverter INV to start measurement.
And S120, the three-phase full-bridge IGBT inverter INV is started in response to the starting instruction, and direct-current pulse voltage is applied to the three-phase permanent magnet motor.
When the three-phase full-bridge IGBT inverter INV receives the starting instruction from the control unit Uc, the self direct-current voltage power supply is started to generate direct-current pulse voltage, and the direct-current pulse voltage is applied to the three-phase permanent magnet motor.
S130, the Hall current sensor HECS acquires a current value in a first winding of the three-phase permanent magnet motor according to a preset current acquisition frequency, and sends the current value in the first winding to the control unit Uc until the current value in the first winding is monitored to reach a preset acquisition stopping condition, and the acquisition of the current value in the first winding is stopped.
In this embodiment, the control unit Uc may learn in real time the voltage change of the dc bus in the three-phase full-bridge IGBT inverter INV, and learn in real time the current value of the first winding in the three-phase permanent magnet motor through the hall current sensor HECS. When the control unit Uc knows that the direct current bus voltage in the three-phase full-bridge IGBT inverter INV is suddenly changed, for example, when the direct current bus voltage is increased from zero, it can be determined that the three-phase full-bridge IGBT inverter INV is turned on at this time, and the three-phase permanent magnet motor adds the direct current bus voltage. The direct current bus voltage can enable current to exist in the system, meanwhile, because the voltage output by the three-phase full-bridge IGBT inverter INV is direct current pulse voltage, the current in the system is also direct current pulse current, and the current value of the current can gradually rise along with the time. The hall current sensor HECS can acquire trunk current according to a preset current acquisition frequency, namely, acquire a current value in the first winding, and send the current value of the first winding to the control unit Uc for storage in real time. The preset current acquisition frequency may be set to acquire at a high frequency (e.g., 500 kHz) to obtain current data that is relatively continuous over the acquisition time. When the hall current sensor HECS collects the current value, the control unit Uc can acquire and monitor the current value in the first winding in real time, and when the current value reaches the preset collection stopping condition, the control unit Uc controls the hall current sensor HECS to stop collecting the current value in the first winding, and meanwhile, the control unit uic also sends a closing signal to the three-phase full-bridge IGBT inverter INV so as to stop the generation of direct current pulse current.
In an embodiment, the preset stop acquisition condition in step S110 is that the current value in the first winding reaches the rated current value of the first winding.
In this embodiment, after the current value in the first winding reaches the rated current value of the first winding, the control unit Uc knows that the current value in the current first winding has reached the rated current value of the first winding, determines that the preset stop acquisition condition has been reached at this time, and controls the hall current-sensor HECS to stop acquiring the current value. The preset stopping and collecting condition is set to be that the current value in the first winding reaches the rated current value of the first winding, so that the calculation and the acquisition of the real inductance value corresponding to the rated current value are carried out later. Since the rated current value takes a certain time to reach, the control unit Uc may continuously acquire the current value for a certain period of time before the current value of the first winding reaches the rated current value, for subsequent calculation processing. The rated current value is determined according to the attribute of the three-phase permanent magnet motor, and can be adjusted, so that acquisition stopping conditions can be preset and adjusted.
S120, the control unit Uc determines a current curve based on the current values in the first windings that have been stored in time sequence.
In this embodiment, the control unit Uc has first obtained the current value in the first winding through the hall current sensor HECS according to the preset current collection frequency, and has obtained the current value in each first winding corresponding to each collection time. Subsequently, the control unit Uc may make a determination of the current profile based on the time-sequentially stored current values in the first winding. In the figure I n The rated current value is obtained.
In an embodiment, step S120 may be preceded by step a:
A. the control unit Uc stores the current values in each first winding into a current data set according to time sequence; the current value of each first winding in the current data set is correspondingly stored with the acquisition time.
In this embodiment, the current data set may be a current data set in a table form, where the current value in each first winding corresponds to a self-collection time, and represents that the current value corresponding to a certain collection time is a unique current value. In the current data set, the storage mode of each current value is stored according to time sequence, namely, each current value is orderly arranged according to the sequence of the acquisition time of the current value, and the current value with the later acquisition time is arranged at the position of the current data set, which is closer to the end. Further, the current data set may exhibit a change in current value over time.
In one embodiment, referring to fig. 4 and 6, step S120 may specifically include steps S121-S122:
s121, the control unit Uc determines a first right-angle coordinate system taking the acquisition time as an abscissa and taking a current value as an ordinate;
and S122, the control unit Uc maps the current values in the first windings to the first right-angle coordinate system according to the acquisition time corresponding to the current values in the first windings to obtain a current curve.
In this embodiment, the abscissa of the first rectangular coordinate system is the acquisition time of the current value, and the ordinate is the current value. Because the current values in each first winding stored according to time sequence correspond to the acquisition time of the current values, each current value can be marked in a first right-angle coordinate system in the form of a coordinate point. When all the current values are calibrated to the first right-angle coordinate system in the form of coordinate points, mapping of all the current values is completed, and a continuous current curve is formed after all the current values are mapped to the first right-angle coordinate system. When the acquisition time in the current curve is zero, the three-phase full-bridge IGBT inverter INV is not started, at the moment, pulse current is not generated, and the instantaneous value of the current is zero; over time, the current value gradually rises at a stable rate of change, the rate of change of the current value suddenly increases before reaching the rated current value, and an inflection point is formed on the current curve, and then the rated current value is reached, because the inductance value of the first inductor L1 suddenly decays along with the current change, and the acquisition time of the sudden change of the inductance value is the time when the inflection point appears in the current curve. Through the current curve, the change rate of the control current value and the acquisition time of the current value can be quickly and accurately calculated, and the conversion of the inductance value can be conveniently carried out subsequently.
And S130, the control unit Uc correspondingly converts the current curve into an inductance curve based on a preset current inductance conversion strategy.
In this embodiment, the current value in the first winding may correspondingly convert the current curve into the inductance curve according to a preset current-inductance conversion strategy. The preset current-inductance switching strategy is determined by the circuit characteristics of the system itself in combination with the properties of the electronic component itself. Because the current value in the first winding is the current value of the first inductor L1, each current value can be converted into the inductance value of the first inductor L1 according to the preset current-to-inductance conversion strategy. Specifically, after each inductance value is converted, an inductance curve corresponding to each current value may be formed.
In one embodiment, the preset current-inductance conversion strategy in step S130 is as follows:
L=(U-1.5·IR) / (1.5·SlopeI)；
wherein L is an inductance value in the inductance curve, U is a bus voltage provided by the three-phase full-bridge IGBT inverter INV, R is the same resistance value of the first resistor R1, the second resistor R2 and the third resistor R3, and SlopeI is an instantaneous change rate of a current value corresponding to the current acquisition time.
In this embodiment, the preset current-inductance switching strategy is represented by the formula:
L=(U-1.5·IR) / (1.5·SlopeI)；
wherein L is an inductance value in the inductance curve, that is, an inductance value of the first inductor L1 at a corresponding acquisition time; u is the bus voltage provided by the three-phase full-bridge IGBT inverter INV; i is a current value in the current curve; r is the same resistance value of the first resistor R1, the second resistor R2 and the third resistor R3; slopeI is the instantaneous rate of change of the current value corresponding to the current acquisition time, which is actually the slope corresponding to a certain acquisition time in the current curve, specifically slopei=di/dt, where dI is the change value of the current value, and dt is the change time of the current value. Essentially, the voltage across any inductor U 0 And inductance value L 0 Current value I 0 The following relationship exists itself:
U 0 = L 0 ·SlopeI 0 ；
that is, any inductance value L 0 Can be calculated by the inductance value corresponding to the voltage division U 0 Instantaneous rate of change SlopeI of voltage and current values 0 The calculation results are that:
L 0 = U 0 / SlopeI 0 ；
in the method, however, the DC bus is electricThe voltage is divided by the first winding, the second winding and the third winding, and the first winding, the second winding and the third winding have the same equivalent resistance R 0 According to the calculation principle of the resistance value, the equivalent resistance value of the second winding and the third winding which are connected in parallel is as follows:
R 0 · R 0 / (R 0 + R 0 )=0.5 R 0 ；
namely, the equivalent resistance of the branch circuit formed by the second winding and the third winding occupies 2/3 of the total equivalent resistance, and further, the branch circuit has the equivalent resistance R according to the voltage division principle 0 Partial voltage U of the first winding 1 The method comprises the following steps:
U 1 =2/3·U=U/1.5；
then, the voltage U of the first inductor L1 can be known 0 For the partial voltage U of the first winding 1 Subtracting the partial voltage of the first resistor R1, namely:
U 0 =U 1 -IR==U/1.5-IR=(U-1.5·IR) / 1.5；
further, an inductance value L can be obtained 0 The calculation formula of (2) is as follows:
L 0 =(U-1.5·IR) / (1.5·SlopeI 0 )；
namely, the preset current inductance conversion formula in the present embodiment. Through a preset current inductance conversion formula, an inductance curve can be obtained through direct conversion according to the current value in the current curve and the instantaneous change rate of the current value, and then the inductance value of the first inductor L1 in the state corresponding to each current value can be accurately obtained, so that data support is provided for follow-up click closed-loop control.
In one embodiment, referring to fig. 5 and 7, step S130 may specifically include steps S131-S133:
s131, the control unit Uc obtains the instantaneous change rate of the current value in the first winding corresponding to each acquisition time in the current curve and the current value in the first winding corresponding to each acquisition time;
s132, the control unit Uc inputs the instantaneous change rate of the current value in the first winding corresponding to each acquisition time in the current curve and the current value in the first winding corresponding to each acquisition time into the preset current inductance conversion strategy, and obtains and stores the inductance value of the first inductance L1 corresponding to each acquisition time;
s133, the control unit Uc determines an inductance curve based on the inductance values of the first inductances L1 stored according to time sequences; the inductance curve is marked in a second rectangular coordinate system taking the current value as an abscissa and the inductance value as an ordinate.
In this embodiment, based on a preset current-inductance conversion strategy, a current value corresponding to each collection time may be obtained first, and then an instantaneous rate of change of the current value at each collection time may be obtained. Specifically, the instantaneous change rate of the current value may be calculated by a least square method, or may be calculated by substituting each acquisition time into a derivative function of the current curve corresponding function. After the current value and the corresponding instantaneous change rate of the current value at each acquisition time are obtained, the current value and the instantaneous change rate of the current value can be substituted into a preset current inductance conversion strategy to obtain the current inductance value corresponding to each current value. Each inductance value corresponds to one current value, so that a second rectangular coordinate system with the current value as an abscissa and the inductance value as an ordinate can be constructed, and each inductance value which is arranged according to the collection time (the essence is also arranged according to the current value) is calibrated into the second rectangular coordinate system as a coordinate point, so that a continuous inductance curve is formed. After the inductance curve is obtained, inductance values under different current conditions can be obtained, and further feedback of current and voltage can be provided, so that the response frequency of closed-loop control of motor current is optimal.
And S140, the control unit Uc obtains an initial inductance value in the inductance curve and an attenuation inductance value corresponding to the rated current value of the first winding.
In this embodiment, after the inductance curve is constructed, the initial inductance value in the inductance curve and the attenuation inductance value corresponding to the rated current value of the first winding may be obtained, so as to calculate the core saturation coefficient.
In one embodiment, referring to fig. 8, step S140 may specifically include steps S141-S142:
s141, the control unit Uc obtains an initial inductance value when the current value in the first winding is zero based on the inductance curve;
s142, the control unit Uc obtains, based on the inductance curve, a decaying inductance value when the current value in the first winding is a rated current value.
In this embodiment, when the current value of the inductance curve is small, a constant value is often maintained, and when the current is gradually increased, the inductance value will dip at a certain time to form an inflection point on the inductance curve. The initial inductance value when the current value is zero in the inductance curve can be preferentially obtained, and the rated current value I can be obtained n The attenuation inductance value in the case is taken as two reference points. Meanwhile, the control unit Uc stops collecting when the current value is the rated current value, and the current curve and the end point of the inductance curve are both rated current values respectively, so that in the inductance curve, the attenuation inductance value is actually the minimum value of the inductance value in the inductance curve, and the initial inductance value is the maximum value of the inductance value in the inductance curve.
And S150, the control unit Uc determines the current core saturation coefficient of the first winding according to the initial inductance value and the attenuation inductance value.
In this embodiment, core saturation refers to the fact that the magnetization of the core of the three-phase permanent magnet motor in the magnetic field reaches a maximum value, and at this time, if a larger magnetic field is continuously applied to the core (a larger current is applied to the winding), the magnetic induction intensity of the core will not increase. The magnetic field strength around the core and the magnetic induction strength of the core itself can be represented by a B-H curve, where B represents the magnetic induction strength and H represents the magnetic field strength. When H rises, B will also rise, and when H rises to a certain value, B will not change anymore, at which point the core is saturated. The slope of each point in the B-H curve represents the permeability at that time, and the permeability is proportional to the inductance value. When the iron core approaches saturation, the slope of B-H decreases with the increase of the current value, the magnetic permeability decreases with the increase of the current value, and the inductance value decreases with the decrease of the magnetic permeability. The attenuation inductance value and the initial inductance value under the condition of the rated current value are measured, so that the influence degree of the inductance value by the change of the current value can be measured, a current iron core saturation coefficient is obtained, the occurrence condition of iron core saturation is measured, and support is provided for operation adjustment of the motor.
In one embodiment, the calculation formula of the current core saturation coefficient in step S150 is satcoef=l min /L max The method comprises the steps of carrying out a first treatment on the surface of the Wherein SatCoef is the current core saturation coefficient, L min To attenuate the inductance value, L max Is the initial inductance value. Step S150 may specifically include step B:
B. and the control unit Uc inputs the initial inductance value and the attenuation inductance value into a calculation formula of the current iron core saturation coefficient to obtain the current iron core saturation coefficient.
In this embodiment, the calculation formula of the current core saturation coefficient is:
SatCoef=L min /L max ；
wherein SatCoef is the current core saturation coefficient, L min To attenuate the inductance value, L max Is the initial inductance value. The ratio of the attenuation inductance value to the initial inductance value is used as the core saturation coefficient, so that the difference of the inductance values between the working state and the initial working state of the motor under the condition of rated current can be measured, whether the iron core tends to be saturated under the condition of rated current or not can be further obtained, the current core saturation coefficient can early warn for the occurrence of the core saturation condition, and accurate basis is provided for the adjustment of the running state of the motor.
In an embodiment, step S150 may further include:
the control unit Uc stores the current iron core saturation coefficient and the inductance curve as feedback data;
and the control unit Uc generates an operation adjustment strategy of the three-phase permanent magnet motor based on the feedback data.
In this embodiment, after the current core saturation coefficient and the inductance curve are obtained, the control unit Uc may store the current core saturation coefficient and the inductance curve as feedback data, and then may generate an operation adjustment policy of the three-phase permanent magnet motor according to the feedback data, so as to accurately adjust the operating state of the three-phase permanent magnet motor.
In summary, the method for measuring the inductance and the core saturation coefficient of the permanent magnet motor provided by the embodiment of the invention obtains a larger current value by applying the direct current pulse voltage, further obtains the corresponding inductance value when rated current, converts the current curve into a continuous inductance curve, and obtains the current core saturation coefficient based on the inductance curve, thereby realizing accurate grasp of the inductance value and the current core saturation coefficient at each moment, and improving the precision of closed-loop control and the precision of operation adjustment of the motor.
While the invention has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.

Claims (10)

1. The device for measuring the saturation coefficient of the inductance and the iron core of the permanent magnet motor is characterized by comprising a three-phase full-bridge IGBT inverter, a Hall current sensor and a control unit; the three-phase full-bridge IGBT inverter is connected to a three-phase permanent magnet motor as a measurement object; the Hall current sensor is connected to the first winding of the three-phase permanent magnet motor and the control unit; the control unit is connected to the three-phase full-bridge IGBT inverter;
the control unit is used for responding to the measurement instruction and sending an opening instruction to the three-phase full-bridge IGBT inverter;
the three-phase full-bridge IGBT inverter is used for responding to the starting instruction to start and applying direct-current pulse voltage to the three-phase permanent magnet motor;
the Hall current sensor is used for acquiring a current value in a first winding of the three-phase permanent magnet motor according to a preset current acquisition frequency, and sending the current value in the first winding to the control unit until the current value in the first winding is monitored to reach a preset acquisition stopping condition, and stopping acquiring the current value in the first winding;
the control unit is further used for determining a current curve based on the current values in the first windings which are stored according to time sequence; correspondingly converting the current curve into an inductance curve based on a preset current inductance conversion strategy;
acquiring an initial inductance value in the inductance curve and an attenuation inductance value corresponding to a rated current value of the first winding; and determining the current core saturation coefficient of the first winding according to the initial inductance value and the attenuation inductance value.
2. The system for measuring the inductance and the core saturation coefficient of the permanent magnet motor is characterized by comprising a three-phase permanent magnet motor and the device for measuring the inductance and the core saturation coefficient of the permanent magnet motor according to claim 1; the three-phase permanent magnet motor comprises three motor windings, wherein the three motor windings are a first winding, a second winding and a third winding respectively; the first winding comprises a first resistor and a first inductor, and one end of the first resistor is connected to one end of the first inductor; the second winding comprises a second resistor and a second inductor, and one end of the second resistor is connected to one end of the second inductor; the third winding comprises a third resistor and a third inductor, and one end of the third resistor is connected to one end of the third inductor;
the other end of the first resistor is connected to the three-phase full-bridge IGBT inverter and the Hall current sensor, and the other end of the first inductor is connected to the other end of the second inductor and the other end of the third inductor; the other end of the second resistor is connected to the three-phase full-bridge IGBT inverter; and the other end of the third resistor is connected to the three-phase full-bridge IGBT inverter.
3. A method for measuring inductance and core saturation coefficient of a permanent magnet motor, applied to the device for measuring inductance and core saturation coefficient of a permanent magnet motor according to claim 1, characterized in that the method comprises the following steps:
the control unit responds to the measurement instruction and sends an opening instruction to the three-phase full-bridge IGBT inverter;
the three-phase full-bridge IGBT inverter is started in response to the starting instruction, and direct-current pulse voltage is applied to the three-phase permanent magnet motor;
the Hall current sensor acquires a current value in a first winding of the three-phase permanent magnet motor according to a preset current acquisition frequency, and sends the current value in the first winding to the control unit until the current value in the first winding is monitored to reach a preset acquisition stopping condition, and the acquisition of the current value in the first winding is stopped;
the control unit determines a current curve based on the current values in the first windings which have been stored in time sequence;
the control unit correspondingly converts the current curve into an inductance curve based on a preset current inductance conversion strategy;
the control unit obtains an initial inductance value in the inductance curve and an attenuation inductance value corresponding to a rated current value of the first winding;
and the control unit determines the current core saturation coefficient of the first winding according to the initial inductance value and the attenuation inductance value.
4. The method for determining the saturation coefficient of an inductor and a core of a permanent magnet motor according to claim 3, wherein the preset stop acquisition condition is that the current value in the first winding reaches the rated current value of the first winding.
5. The method for measuring inductance and core saturation coefficient of permanent magnet motor according to claim 3, wherein the control unit determines the current curve based on the current values in the first windings each stored in time series, before comprising:
the control unit stores the current value in each first winding into a current data set according to time sequence; the current value in each first winding in the current data set is correspondingly stored with the acquisition time.
6. The method of measuring inductance and core saturation coefficient of a permanent magnet motor according to claim 3, wherein the control unit determines a current curve based on the current values in the first windings each stored in time series, comprising:
the control unit determines a first right-angle coordinate system taking the acquisition time as an abscissa and taking a current value as an ordinate;
and the control unit maps the current value in each first winding to the first right-angle coordinate system according to the acquisition time corresponding to the current value in each first winding to obtain a current curve.
7. The method for determining the inductance and core saturation coefficient of a permanent magnet motor according to claim 3, wherein the preset current-inductance switching strategy is represented by formula l= (U-1.5·ir)/(1.5·slopei);
wherein L is an inductance value in the inductance curve, U is a bus voltage provided by the three-phase full-bridge IGBT inverter, I is a current value in the current curve, R is the same resistance value of the first resistor, the second resistor, and the third resistor in the three-phase permanent magnet motor, and SlopeI is an instantaneous change rate of the current value in the current curve corresponding to the current acquisition time.
8. The method for determining the saturation coefficient of an inductor and an iron core of a permanent magnet motor according to claim 7, wherein the control unit correspondingly converts the current curve into an inductance curve based on a preset current-inductor conversion strategy, and the method comprises:
the control unit obtains the instantaneous change rate of the current value in the first winding corresponding to each acquisition time in the current curve and the current value in the first winding corresponding to each acquisition time;
the control unit inputs the instantaneous change rate of the current value in the first winding corresponding to each acquisition time in the current curve and the current value in the first winding corresponding to each acquisition time into the preset current-inductance conversion strategy to obtain and store the inductance value of the first inductor in the first winding corresponding to each acquisition time;
the control unit determines an inductance curve based on the inductance values of the first inductors which are stored according to time sequence; the inductance curve is marked in a second rectangular coordinate system taking the current value as an abscissa and the inductance value as an ordinate.
9. The method for measuring an inductance and core saturation coefficient of a permanent magnet motor according to claim 3, wherein the control unit obtains an initial inductance value in the inductance curve and an attenuation inductance value corresponding to a rated current value of the first winding, comprising:
the control unit obtains an initial inductance value when the current value in the first winding is zero based on the inductance curve;
the control unit obtains a decaying inductance value when a current value in the first winding is a rated current value based on the inductance curve.
10. The method for determining the inductance and core saturation coefficient of a permanent magnet machine according to claim 3, wherein the calculation formula of the current core saturation coefficient is satcoef=l min /L max The method comprises the steps of carrying out a first treatment on the surface of the The control unit determines a current core saturation coefficient of the first winding according to the initial inductance value and the attenuation inductance value, and includes:
the control unit inputs the initial inductance value and the attenuation inductance value into a calculation formula of the current iron core saturation coefficient to obtain the current iron core saturation coefficient; wherein SatCoef is the current core saturation coefficient, L min To attenuate the inductance value, L max Is the initial inductance value.
CN202310725745.3A 2023-06-19 2023-06-19 Device, system and method for measuring inductance and core saturation coefficient of permanent magnet motor Active CN116505832B (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108966682A (en) * 2016-02-18 2018-12-07 株式会社电装 Control device for inverter
CN110492816A (en) * 2018-05-07 2019-11-22 华中科技大学 A kind of electric excitation synchronous motor parameter saturation coefficient on-line identification method
CN113708342A (en) * 2021-08-18 2021-11-26 南方电网数字电网研究院有限公司 Transformer excitation inrush current identification method and device, computer storage medium and terminal
CN113809971A (en) * 2021-09-29 2021-12-17 深圳弘远电气有限公司 Permanent magnet motor inductance identification method and device, motor driver and storage medium

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108966682A (en) * 2016-02-18 2018-12-07 株式会社电装 Control device for inverter
CN110492816A (en) * 2018-05-07 2019-11-22 华中科技大学 A kind of electric excitation synchronous motor parameter saturation coefficient on-line identification method
CN113708342A (en) * 2021-08-18 2021-11-26 南方电网数字电网研究院有限公司 Transformer excitation inrush current identification method and device, computer storage medium and terminal
CN113809971A (en) * 2021-09-29 2021-12-17 深圳弘远电气有限公司 Permanent magnet motor inductance identification method and device, motor driver and storage medium

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