CN112737462B - Method and device for identifying initial state of permanent magnet synchronous motor - Google Patents

Method and device for identifying initial state of permanent magnet synchronous motor Download PDF

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CN112737462B
CN112737462B CN202011605329.2A CN202011605329A CN112737462B CN 112737462 B CN112737462 B CN 112737462B CN 202011605329 A CN202011605329 A CN 202011605329A CN 112737462 B CN112737462 B CN 112737462B
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voltage
phase
time
motor
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CN112737462A (en
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徐晖
姜真军
何原明
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Hangzhou Silan Microelectronics Co Ltd
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Hangzhou Silan Microelectronics 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
    • 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
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/08—Arrangements for controlling the speed or torque of a single motor
    • 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
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/14—Electronic commutators
    • H02P6/16—Circuit arrangements for detecting position
    • H02P6/18—Circuit arrangements for detecting position without separate position detecting elements
    • H02P6/182—Circuit arrangements for detecting position without separate position detecting elements using back-emf in windings
    • 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
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/30—Arrangements for controlling the direction of rotation
    • 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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  • Power Engineering (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)

Abstract

The application discloses a method and a device for identifying the initial state of a permanent magnet synchronous motor, which comprises the steps of sampling the terminal voltage of a detection phase to obtain a sampling voltage, wherein the detection phase is any one of three phases; judging whether the edge jump of the sampling voltage occurs or not; when the edge jump of the sampling voltage does not occur within the preset time, judging that the initial state of the motor is a static state; and when the edge jump of the sampling voltage occurs within the preset time, judging that the initial state of the motor is a rotating state. The invention also provides a device for identifying the initial state of the permanent magnet synchronous motor, which is used for sampling the end voltage of the detection phase to obtain the sampling voltage of the detection phase and analyzing the sampling voltage to judge the initial state of the motor.

Description

Method and device for identifying initial state of permanent magnet synchronous motor
Technical Field
The invention relates to the technical field of motor control, in particular to a method and a device for identifying an initial state of a permanent magnet synchronous motor.
Background
With the development of motor technology, the application range of the permanent magnet synchronous motor is wider and wider. Because of the characteristics of low power consumption and low noise, various household appliances use permanent magnet synchronous motors to replace the prior induction motors, such as compressors, blowers and the like of refrigerators and air conditioners, and in addition, most of the latest electric vehicles also adopt high-power permanent magnet synchronous motors as driving motors thereof.
When the permanent magnet synchronous motor operates, the position of a rotor needs to be detected to realize the commutation of a winding, which is the basis for controlling the permanent magnet synchronous motor. At present, a control method of a permanent magnet synchronous motor adopts a motor-based accurate model method, namely the control of the permanent magnet synchronous motor depends on a mathematical model of the motor.
For some applications, before the permanent magnet synchronous motor is started, the initial state of the motor may be: stationary, forward, or reverse. In order to avoid the problems of current impact, motor vibration and the like when the inverter works, the initial state of the motor before starting needs to be determined, and the initial state comprises information of dq axis counter electromotive force components, rotor position, rotating speed, steering and the like.
The mathematical model of the motor is as follows:
Figure BDA0002873102260000011
if the inverter has no current loop before the motor is started, i d ＝i q ＝di d /dt＝di q /dt＝0
The mathematical model of the motor is then simplified to:
Figure BDA0002873102260000012
wherein, ω is e ψ f The magnitude of the back emf is characterized. The initial state of the motor is therefore generally determined by the following parameters: back electromotive force amplitude E of motor Amp Motor rotor position theta e Motor speed omega e And steering.
The scheme for calculating the initial state of the motor in the prior art comprises the following steps: the parameters are obtained by respectively detecting three-phase back electromotive voltage of the motor and then by means of a phase-locked loop PLL and the like. But the hardware circuit of the scheme is more complex and needs more ADC sampling ports.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a method and an apparatus for identifying an initial state of a permanent magnet synchronous motor, in which a terminal voltage of a detection phase is sampled to obtain a sampling voltage of the detection phase, and the sampling voltage is analyzed to obtain initial state information of the motor, so that a circuit topology is simplified, and a result is accurate without depending on an accurate mathematical model of the motor.
According to a first aspect of the present invention, there is provided a method for identifying an initial state of a permanent magnet synchronous motor, including: sampling terminal voltage of a detection phase to obtain sampling voltage, wherein the detection phase is any one of three phases; judging whether the edge jump of the sampling voltage occurs or not; when the sampling voltage does not jump within the preset time, judging that the initial state of the motor is a static state; and when the sampling voltage jumps within the preset time, judging that the initial state of the motor is a rotating state.
Preferably, the identification method further comprises: when the initial state of the motor is a rotation state, initial state information of the motor is calculated, the initial state information including at least one of a counter electromotive force amplitude, a rotor position, a rotation speed, and a rotation direction.
Preferably, the step of calculating the rotational speed of the motor comprises: comparing the sampled voltage to a voltage threshold; after the sampling voltage is at an effective low level, when the sampling voltage is detected to reach a voltage threshold value for the first time, a timer starts timing from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; when the sampling voltage reaches the voltage threshold value for the third time, a timer counts to obtain the electric period of the motor; and calculating the rotating speed of the motor according to the electric cycle.
Preferably, the step of calculating the steering of the motor comprises: comparing the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampling voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the leading phase for the first time, acquiring the phase current of the leading phase in the first time, and judging the steering of the motor according to the phase current of the leading phase and the first current threshold, wherein the leading phase is a phase with a spatially more leading detection phase.
Preferably, when the phase current of the leading phase is smaller than the first current threshold, the motor rotates forwards;
when the phase current of the leading phase is greater than the first current threshold, the motor is reversed.
Preferably, the step of calculating the steering of the motor comprises: comparing the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampling voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the leading phase for the first time, switching off the lower bridge arm of the leading phase after the lower bridge arm of the leading phase is switched on for the first time, acquiring the bus current, and judging the steering of the motor according to the bus current and the second current threshold.
Preferably, when the bus current is smaller than the second current threshold, the motor rotates forwards; when the bus current is greater than the second current threshold, the motor reverses.
Preferably, the step of calculating the steering of the motor comprises: comparing the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer is used for timing to obtain the duration time of the effective high level of the sampling voltage; and when the sampled voltage reaches the voltage threshold value for the third time, switching on the lower bridge arm of the lag phase for the second time, acquiring the phase current of the lag phase in the second time, and judging the steering of the motor according to the phase current of the lag phase and the third current threshold value, wherein the lag phase is a phase lagging the detection phase in space.
Preferably, when the phase current of the lag phase is greater than the third current threshold, the motor rotates forwards; when the phase current of the lagging phase is less than the third current threshold, the motor is reversed.
Preferably, the step of calculating the steering of the motor comprises: comparing the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampled voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the lag phase for a second time, switching off the lower bridge arm of the lag phase after the lower bridge arm of the lag phase is switched on for the second time, acquiring the bus current, and judging the steering of the motor according to the bus current and a fourth current threshold.
Preferably, when the bus current is greater than the fourth current threshold, the motor rotates forwards; when the bus current is less than the fourth current threshold, the motor reverses.
Preferably, the step of calculating the back emf magnitude and the rotor position of the motor comprises: comparing the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer is used for timing to obtain the duration time of the effective high level of the sampling voltage; when the sampling voltage is detected to reach the voltage threshold value for the third time, the timer counts one half of the duration time of the effective high level of the sampling voltage again to obtain the terminal voltage at the current moment; and calculating the amplitude of the opposite electromotive force of the motor and the position of the rotor according to the terminal voltage at the current moment.
Preferably, the magnitude of the counter electromotive force E of said motor is Amp ＝2V P_t4 /3 wherein V P_t4 Is a terminal voltage at which the sampling voltage continues for one-half of the duration of the active high level of the sampling voltage after reaching a voltage threshold for the third time, where P is the detection phase.
Preferably, the rotor position θ of the motor e And (n =0,1, 2), wherein n =0,1,2 corresponds to the detection phases being U, V, W phases, respectively.
Preferably, the identification method further comprises: and verifying the initial state information according to the counter electromotive force coefficient.
Preferably, the verifying the initial state information according to the back emf coefficient includes: when the difference value between the product of the counter electromotive force coefficient and the rotating speed and the amplitude of the opposite electromotive force is within a preset threshold value range, the initial state information is accurate; and when the difference value between the product of the counter electromotive force coefficient and the rotating speed and the counter electromotive force amplitude is not within the preset threshold range, sampling the terminal voltage of the detection phase again to obtain a sampling voltage, and judging the initial state of the motor according to the sampling voltage.
According to another aspect of the present invention, there is provided an apparatus for identifying an initial state of a permanent magnet synchronous motor, including: the sampling circuit is connected with the phase line of the detection phase and is used for sampling the terminal voltage of the detection phase to obtain a sampling voltage, and the detection phase is any one of the three phases; the identification module is connected with the sampling circuit and used for judging the initial state of the motor according to the sampling voltage, wherein the identification module is used for judging whether the edge jump of the sampling voltage occurs or not; when the edge jump of the sampling voltage does not occur within the preset time, judging that the initial state of the motor is a static state; and when the sampling voltage generates edge jump within the preset time, judging that the initial state of the motor is a rotating state.
Preferably, the identification module comprises: the edge detection unit is used for judging whether the edge jump occurs in the sampling voltage; the identification unit is used for judging that the initial state of the motor is in a static state when the sampling voltage does not generate edge jump within the preset time; and when the edge jump of the sampling voltage occurs within the preset time, judging that the initial state of the motor is in a rotating state.
Preferably, the identification module further comprises: and the calculating unit is used for calculating initial state information of the motor when the initial state of the motor is a rotating state, wherein the initial state information comprises at least one of the amplitude of the reverse electromotive force, the position of the rotor, the rotating speed and the rotating direction.
Preferably, the calculation unit is configured to compare the sampled voltage with a voltage threshold; after the sampling voltage is at an effective low level, detecting that the sampling voltage reaches the voltage threshold value for the first time, and starting timing from an initial value by a timer; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; when the sampling voltage reaches the voltage threshold value for the third time, a timer counts to obtain the electric period of the motor; and calculating the rotating speed of the motor according to the electric cycle.
Preferably, the calculation unit is further configured to compare the sampled voltage with a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer is used for timing to obtain the duration time of the effective high level of the sampling voltage; and when the sampling voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the leading phase for the first time, acquiring the phase current of the leading phase in the first time, and judging the steering of the motor according to the phase current of the leading phase and the first current threshold, wherein the leading phase is a phase with a spatially more leading detection phase.
Preferably, when the phase current of the leading phase is smaller than a first current threshold, the motor rotates forwards; when the phase current of the leading phase is greater than a first current threshold, the motor is reversed.
Preferably, the calculation unit is further configured to compare the sampled voltage with a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampled voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the leading phase for the first time, switching off the lower bridge arm of the leading phase after the lower bridge arm of the leading phase is switched on for the first time, acquiring the bus current, and judging the steering of the motor according to the bus current and the second current threshold.
Preferably, when the bus current is smaller than the second current threshold, the motor rotates forwards; when the bus current is greater than the second current threshold, the motor reverses.
Preferably, the calculation unit is further configured to compare the sampled voltage with a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampled voltage reaches the voltage threshold value for the third time, switching on the lower bridge arm of the lag phase for the second time, acquiring the phase current of the lag phase in the second time, and judging the steering of the motor according to the phase current of the lag phase and the third current threshold value, wherein the lag phase is a phase lagging the detection phase in space.
Preferably, when the phase current of the lag phase is greater than the third current threshold, the motor rotates forwards; when the phase current of the lagging phase is less than the third current threshold, the motor is reversed.
Preferably, the calculation unit is further configured to compare the sampled voltage with a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampled voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the lag phase for a second time, switching off the lower bridge arm of the lag phase after the lower bridge arm of the lag phase is switched on for the second time, acquiring the bus current, and judging the steering of the motor according to the bus current and a fourth current threshold.
Preferably, when the bus current is greater than the fourth current threshold, the motor rotates forwards; when the bus current is less than the fourth current threshold, the motor reverses.
Preferably, the calculation unit is further configured to compare the sampled voltage with a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; when the sampling voltage is detected to reach the voltage threshold value for the third time, a timer counts a half of the duration time of the effective high level of the sampling voltage again to obtain the terminal voltage at the current moment; and calculating the amplitude of the opposite electromotive force and the rotor position of the motor according to the terminal voltage at the current moment.
Preferably, the magnitude of the counter electromotive force E of said motor is Amp ＝2V P_t4 /3 wherein V P_t4 Is a terminal voltage at which the sampling voltage continues for one-half of the duration of the active high level of the sampling voltage after reaching a voltage threshold for the third time, where P is the detection phase.
Preferably, the rotor position θ of the motor e And (n =0,1, 2), wherein n =0,1,2 corresponds to the detection phases being U, V, W phases, respectively.
Preferably, the identification module further comprises: and the checking unit is used for checking the initial state information according to the back electromotive force coefficient.
Preferably, the checking unit is further configured to determine that the initial state information is accurate when a difference between the product of the counter electromotive force coefficient and the rotation speed and the counter electromotive force amplitude is within a preset threshold range; and when the difference value between the product of the counter electromotive force coefficient and the rotating speed and the counter electromotive force amplitude is not within the preset threshold range, sampling the terminal voltage of the detection phase again to obtain a sampling voltage, and judging the initial state of the motor according to the sampling voltage.
The invention provides a method and a device for identifying the initial state of a permanent magnet synchronous motor, wherein the terminal voltage of a detection phase is sampled to obtain the sampling voltage of the detection phase, and the sampling voltage is analyzed to judge the initial state of the motor; and calculates initial state information in a rotating state of the motor. The circuit topology is simplified, the occupied external resources such as an analog-digital converter (ADC) and the like are less, the calculation is simple, the complex parameter adjustment is not needed, the method does not depend on an accurate mathematical model of the motor, and the identification result is more reliable.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:
fig. 1 is a circuit block diagram of an identification device for an initial state of a permanent magnet synchronous motor according to an embodiment of the present invention;
fig. 2 shows a spatial coordinate system diagram of a permanent magnet synchronous machine;
fig. 3 is a schematic diagram showing the relationship between the back electromotive force of the detection phase and the terminal voltage;
fig. 4 shows a three-phase terminal voltage waveform diagram;
fig. 5 is a flowchart illustrating a method for identifying an initial state of a permanent magnet synchronous motor according to an embodiment of the present invention;
FIG. 6 shows a flowchart of step S150 in FIG. 5;
fig. 7 shows a block diagram of the identification module in fig. 1.
Detailed Description
Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
The following detailed description of the present invention is provided in connection with the accompanying drawings and examples.
Fig. 2 is a spatial coordinate system relation diagram of the permanent magnet synchronous motor.
N-S is a permanent magnet of the permanent magnet synchronous motor, the permanent magnet rotor rotates to generate an alternating magnetic field in space, the magnetic field is linked with the three-phase winding in an intersecting manner to induce back electromotive force, and at the moment, the rotor magnetic field synchronously rotates along with the stator rotating magnetic field under the action of the pulling force of the stator magnetic field.
According to fig. 2, the abc coordinate system represents a three-phase stator coordinate system, the axes a, B, and C of the three-phase windings of the three-phase ac motor spatially differ from each other by an electrical angle of 2 pi/3 rad, and the projections of the space vector on the three coordinate axes are represented as components of the space vector on the three windings; the d axis of the horizontal axis of the d-q coordinate system is at the same position with the N magnetic pole of the permanent magnet rotor, the q axis of the vertical axis of the d-q coordinate system leads the d axis of the horizontal axis by 90 electrical degrees anticlockwise, the coordinate system and the permanent magnet rotor rotate synchronously in space, and the d-q coordinate system is also called as a rotating coordinate system.
When the permanent magnet rotor and the stator rotating magnetic field keep synchronous rotation, the included angle between the d axis of the transverse axis of the rotating coordinate system (namely the rotor N pole) and the A axis of the three-phase stator coordinate system ABC is defined as the position angle theta of the rotor e 。
Three-phase winding axes A, B and C of the three-phase alternating current motor respectively correspond to a U phase, a V phase and a W phase of the motor, a counterclockwise direction is defined as a forward rotation direction of the motor, and the U phase, the V phase and the W phase are advanced by 2 pi/3 in sequence on a space phase all the time. Assuming the motor initial state belt speed, if the motor rotates in the forward direction, as shown in fig. 2, the V phase leads the U phase by 2 pi/3 in time phase, and if the motor rotates in the reverse direction, the V phase lags the U phase by 2 pi/3 in time phase.
Fig. 1 is a circuit block diagram of an identification device for an initial state of a permanent magnet synchronous motor according to an embodiment of the present invention. As shown in fig. 1, the permanent magnet synchronous motor 200 is connected to a power supply through a main circuit, and normally operates under power supply of the power supply. The main circuit is a full bridge inverter circuit 300. The permanent magnet synchronous motor initial state identification device 100 is connected with a main circuit of the permanent magnet synchronous motor to sample the terminal voltage of a detection phase to obtain a sampling voltage, and the sampling voltage is analyzed to calculate the initial state of the motor.
The input end of the full-bridge inverter circuit 110 receives the dc voltage VDC and inverts the dc voltage VDC into three-phase ac, and the output end of the full-bridge inverter circuit is connected to the three-phase stator winding L of the pmsm 200 through three-phase lines U, V, and W A 、L B 、L C And (4) connecting.
The device 100 for identifying the initial state of the permanent magnet synchronous motor comprises a sampling circuit 110 and an identification module 120.
The sampling circuit 110 is connected to a phase line of any one of the U, V, and W phase lines, and samples a terminal voltage of the corresponding detection phase to obtain a sampling voltage V PS (where, P is any one of U-phase, V-phase, or W-phase), where the terminal voltage of the detection phase is a terminal voltage of the phase line of the detection phase to ground. For example, the sampling circuit 110 is connected to a U-phase line, and samples a terminal voltage of the U-phase line to obtain a sampling voltage V US 。
The sampling circuit 110 includes a first resistor R1 and a second resistor R2. The first resistor R1 and the second resistor R2 are connected in series between the phase line of any one of the three phases of U, V and W and the ground terminal. A node between the first resistor R1 and the second resistor R2 outputs a sampling voltage V representing a terminal voltage of the detection phase PS 。
The identification module 120 represents the sampling voltage V of the terminal voltage of the detection phase according to the relationship between the counter electromotive force and the sampling voltage representing the terminal voltage of the detection phase PS And analyzing to obtain the initial state of the motor.
In the present embodiment, the initial state of the motor includes a stationary state and a rotating state. When the initial state is the rotation state, the initial state information is also calculated. Wherein the initial state information comprises a back electromotive force amplitude E Amp Rotor position theta e Rotational speed omega e And steering.
The identification device for the initial state of the permanent magnet synchronous motor provided by the embodiment of the invention obtains sampling voltage by sampling the terminal voltage of the sampling detection phase, and analyzes and judges the initial state of the motor; and calculates initial state information in a rotating state of the motor. The circuit topology is simplified, external resources such as an analog-to-digital converter (ADC) and the like are less occupied, the calculation is simple, complex parameter adjustment is not needed, the method does not depend on an accurate mathematical model of the motor, and the identification result is more reliable.
Fig. 3 shows a graph of the relationship of the counter electromotive force to the terminal voltage. As shown in FIG. 3, the waveform 201 is the reverse electromotive force E PN (i.e., neutral voltage, P is any of the U-phase, V-phase, or W-phase), waveform 202 is the signal that characterizes the detection phaseTerminal voltage E PG (P is any one of a U phase, a V phase or a W phase).
Assuming that the initial phase of the back electromotive force is 0, E PN ＝E Amp sin θ, (1); wherein E is Amp Theta is the phase of the opposite potential phasor for the opposite electromotive force magnitude.
From fig. 3, it can be seen that the relationship between the back emf and the terminal voltage in one electrical cycle is as follows:
Figure BDA0002873102260000101
according to equation (1), when θ = π/2, i.e. when the back electromotive force E PN To a maximum value E Amp Accordingly, as can be seen from fig. 3, the terminal voltage E PG ＝3/2E Amp It can be considered that the rotation speed of the motor is not changed in one electrical cycle, and when the electromotive force E is reversed PN To a maximum value E Amp Then the point is just at the midpoint of the active high level of the terminal voltage.
According to the space vector superposition principle, when the counter electromotive force is maximized, the counter electromotive force vector is located on the axis of the corresponding phase. For example when U is opposing electromotive force E UN At maximum, the back emf vector lies on the U-phase axis. Since the back emf vector is always located on the q-axis of the pmsm, i.e. the q-axis of the pmsm coincides with the axis of the respective phase.
Because the d axis of the permanent magnet synchronous motor, namely the rotor position, lags the q axis by pi/2, the rotor position theta can be obtained according to the sampling voltage representing the terminal voltage of the detection phase e 。
When E is UG ＝3E Amp When/2, the back electromotive force of U reaches the maximum value, the back electromotive force vector is located on the axis of U phase, that is, the phase is 0, and the rotor position is delayed by pi/2 from the q axis, it is found that the rotor position θ e And (= 3 pi/2) as shown in fig. 2.
When E is VG ＝3E Amp At/2, the counter electromotive force V reaches a maximum value, and the counter electromotive force vector is located on the V-phase axis, i.e., the phase is 2 pi/3, according to the rotor positionLags the q-axis by pi/2, indicating the rotor position θ e ＝π/6。
When E is WG ＝3E Amp When the W back electromotive force reaches the maximum value at the time of/2, the back electromotive force vector is positioned on the W phase axis, that is, the phase is 4 pi/3, and the rotor position is delayed from the q axis by pi/2, whereby the rotor position theta is known e ＝5π/6。
Fig. 5 is a flowchart illustrating a method for identifying an initial state of a permanent magnet synchronous motor according to an embodiment of the present invention. As shown in fig. 5, the method for identifying the initial state of the permanent magnet synchronous motor includes the following steps.
In step S110, a terminal voltage of a detection phase is sampled to obtain a sampling voltage, where the detection phase is any one of three phases.
In this embodiment, the three phases are U-phase, V-phase, and W-phase.
In step S120, it is determined whether an edge transition occurs in the sampling voltage.
In this embodiment, the sampled voltage is compared with a voltage threshold, and if the sampled voltage crosses the voltage threshold, that is, the sampled voltage rises from a first voltage value smaller than the voltage threshold to a second voltage value larger than the voltage threshold, or the sampled voltage falls from the second voltage value larger than the voltage threshold to the first voltage value smaller than the voltage threshold, it is determined that an edge jump occurs in the sampled voltage; if the sampled voltage does not cross the voltage threshold, that is, the sampled voltage is always smaller than the voltage threshold or always larger than the voltage threshold, it is determined that the edge jump of the sampled voltage does not occur. The rising edge refers to the sample voltage rising from a first voltage value less than the voltage threshold to a second voltage value greater than the voltage threshold; the falling edge refers to the sampled voltage falling from a second voltage value greater than the voltage threshold to a first voltage value less than the voltage threshold.
In step S130, when the edge jump does not occur in the sampling voltage within the preset time, it is determined that the initial state of the motor is a static state.
In this embodiment, the preset time is set by a timer. If the preset time set by the timer is exceeded, no edge jump occurs, namely no rising edge or falling edge occurs, the initial state of the motor is judged to be in a static state.
In step S140, when the edge jump occurs in the sampled voltage within the preset time, it is determined that the initial state of the motor is a rotation state.
In this embodiment, if an edge transition occurs within a preset time, that is, a rising edge or a falling edge occurs, it is determined that the initial state of the motor is in a rotating state.
In step S150, when the initial state of the motor is the rotation state, initial state information of the motor is calculated.
Specifically, step S150 includes steps S151-S156, as shown in FIG. 6.
In step S151, the sampled voltage is compared with a voltage threshold.
In this embodiment, referring to fig. 3, several ADC sampling periods are detected continuously, if the voltage V is sampled PS Are all less than a voltage threshold V TH Consider that the next time the sampled voltage V is detected PS Greater than a voltage threshold V TH For the occurrence of a valid rising edge. If the voltage V is sampled PS Less than voltage threshold V TH Then sample the voltage V PS Active low; if the voltage V is sampled PS Greater than a voltage threshold V TH Then sample the voltage V PS Is active high.
In step S152, the voltage V is sampled PS After being active low, when the sampling voltage V is detected PS First reaching voltage threshold V TH The timer starts counting from the initial value.
In this embodiment, the sampling voltage V PS Rising edges occur after active low levels. Sampling voltage V PS First reaching a voltage threshold V after an active low level TH Is denoted as a first time t1.
In step S153, when the sampling voltage V is detected PS Second reaching voltage threshold V TH The timer counts to obtain the effective high level duration time T HI 。
In the present embodiment, the voltage V is sampled PS Second oneSub-reaching voltage threshold V TH Is denoted as a second time t2. Sampling voltage V PS Gradually rising from the active low level to reach a voltage threshold V for the first time TH Then continuously rising to the peak value, sampling the voltage V PS Jumping from the active low level to the active high level as a rising edge; then decreases from the peak value and reaches the voltage threshold value V for the second time TH Then continuously reducing to effective low level, sampling voltage V PS And jumping from the active high level to the active low level to be a falling edge.
In step S154, when the sampling voltage V is detected PS Third reaching voltage threshold V TH The timer is used for obtaining the electric period T of the motor FL Calculating the rotation speed omega of the motor according to the electric period e 。
In this embodiment, the sampling voltage V PS Third reaching voltage threshold V TH Is denoted as a third time t3. Speed of rotation omega of the motor e ＝(2π)/T FL 。
In step S155, the timer is cleared to restart timing, the lower arm of the leading phase is turned on, the phase current of the leading phase is obtained, and the motor rotation direction is determined according to the phase current of the leading phase and the first current threshold, where the leading phase is a phase ahead of the detection phase in terms of space ratio.
In this embodiment, while the voltage threshold is detected for the third time, the X-phase is defined to spatially advance by 2/3 pi of the detected phase (X is any other phase except the detected phase), the X-phase lower bridge arm (including the power switching device and the freewheeling diode) is turned on for a short time, the turn-on time is a first time Δ t1, and the phase current of the X-phase within the first time Δ t1 is detected in real time, if the phase current of the X-phase is smaller than the first current threshold I, the phase current of the X-phase is determined to be a second time Δ t1, and if the phase current of the X-phase is smaller than the second current threshold I TH1 If not, the motor is considered to rotate reversely.
Or detecting the bus current when the X-phase lower bridge arm is turned off again after the first time delta t is turned on, and if the bus current is less than a second current threshold I TH2 If not, the motor is considered to rotate reversely.
In this embodiment, the three phases U, V, and W are kept spatially unchanged, the waveform 401 in fig. 4 is defined as a U phase, if the motor rotates in the forward direction, the waveforms 402 and 403 correspond to the V phase and the W phase, respectively, the lower arm of the V phase is turned on at time t3, and since the terminal voltage of the V phase is about 0 at this time, no large current is generated, which indicates that the terminal voltages of the three phases U, V, and W sequentially advance by 2 pi/3 in the time phase, that is, the forward speed of the motor.
If the motor rotates reversely, the waveforms 402 and 403 correspond to the W phase and the V phase respectively, the V phase lower bridge arm is switched on at the time t3, and a large current is generated because the voltage of the V phase ground end is large at the moment, which indicates that the voltage of the U phase, the W phase and the V phase end leads by 2 pi/3 in sequence on the time phase, namely the reverse belt speed of the motor.
It should be noted that if the phase current is sampled, the phase current can be sampled when the lower bridge arm of the V phase is turned on, and the sampled phase current is used as a basis for judging the steering of the initial state of the motor. If only the bus current is sampled in the circuit, when the V-phase lower bridge arm is switched on, even if the terminal voltage of the V-phase is larger, the V-phase lower bridge arm and the U-phase and W-phase lower bridge arm freewheeling diodes form a current loop, so that no current is generated in the bus, when the V-phase lower bridge arm is switched off again, the direction of the current cannot be changed suddenly due to the action of an inductor in the motor, the current flows through the bus through the V-phase upper bridge arm freewheeling diode and the U-phase and W-phase lower bridge arm freewheeling diodes, so that larger discharge current exists in the bus, the bus current can be detected as a judgment basis for the initial state steering of the motor, and when the bus current is smaller than a second current threshold I TH2 If not, the motor is considered to rotate reversely.
In a preferred embodiment, in step 155, the timer is cleared to restart timing, the lower arm of the lagging phase is turned on, the phase current of the lagging phase is acquired, and the steering direction of the motor is determined according to the phase current of the lagging phase and the current threshold, where the lagging phase is a phase that is spatially lagged by the detection phase.
In this embodiment, while the voltage threshold is detected for the third time, the Y-phase is defined to lag behind the detection phase by 2/3 pi (Y is any other phase except the detection phase), the lower arm of the Y-phase (including the power switch device and the freewheeling diode) is turned on for a short time, the turn-on time is a second time Δ t2, and the phase current of the Y-phase within the second time Δ t2 is detected in real time, if the Y-phase is detected for the third time, the phase current of the Y-phase is detectedIs greater than a third current threshold I TH3 If not, the motor is considered to rotate reversely.
Or detecting the bus current when the Y-phase lower bridge arm is turned off again after the second time delta t2 is turned on, and if the bus current is greater than a fourth current threshold I TH4 If not, the motor is considered to rotate reversely.
In step S156, the timer starts counting from 0 to half the duration of the active high level of the sampling voltage (i.e., T) HI /2), acquiring the terminal voltage at the current moment; terminal voltage V according to the current time P And calculating the back electromotive force amplitude and the rotor position of the motor.
In this embodiment, the timer is cleared and then counts from 0 to half the duration of the active high level of the sampling voltage (i.e., T) HI /2), which is the fourth time t4 at this time, the terminal voltage V at the current time (i.e., the fourth time t 4) is obtained P When the back electromotive force reaches the maximum value, the back electromotive force amplitude E of the motor can be calculated Amp ，E Amp ＝2V P_t4 [ 3 ] wherein P is one of a U phase, a V phase and a W phase, and V P_t4 Terminal voltage V at time t4 P (can be sampled by a voltage V PS Calculated), and rotor position θ e And = n × 2 pi/3-pi/2 (n =0,1, 2), wherein n =0,1,2 corresponds to the detection phases being U, V, W phases, respectively.
In a preferred embodiment, step S160 is further included.
In step S160, the initial state information is verified based on the back emf coefficient.
In the present embodiment, the rotation speed ω in the initial state information is used e With back emf coefficient psi f The back emf magnitude can be estimated: e' Amp ＝ω e ψ f (ii) a If E Amp And E' Amp If the values are similar, namely the difference value between the two values is within the range of a preset threshold value, the recognized motor initial state information is considered to be correct; if the difference value between the two is not within the preset threshold range, resampling identification is needed. For back emf coefficient psi f The method of obtaining is well known to those skilled in the art, and is not described herein in detail to reduce redundancy.
The method for identifying the initial state of the permanent magnet synchronous motor provided by the embodiment of the invention is characterized in that the terminal voltage of a detection phase is sampled to obtain a sampling voltage representing the terminal voltage of the detection phase, and the sampling voltage is analyzed to judge the initial state of the motor; and calculates initial state information in a rotating state of the motor. The method is simple in calculation, does not need complex parameter adjustment, does not depend on an accurate mathematical model of the motor, and is more reliable in identification result.
Fig. 7 shows a block diagram of the identification module in fig. 1. As shown in fig. 7, the identification module includes an edge detection unit 121, an identification unit 122, a calculation unit 123 and a verification unit 124.
The edge detecting unit 121 is configured to determine whether an edge jump occurs in the sampling voltage.
In the present embodiment, the edge detection unit 121 outputs to the sampling circuit 110 a sampling voltage V representing the terminal voltage of the detection phase PS And carrying out edge detection to judge whether a rising edge or a falling edge occurs.
In this embodiment, the sampled voltage is compared with a voltage threshold, and if the sampled voltage crosses the voltage threshold, that is, the sampled voltage rises from a first voltage value smaller than the voltage threshold to a second voltage value larger than the voltage threshold, or the sampled voltage falls from the second voltage value larger than the voltage threshold to the first voltage value smaller than the voltage threshold, it is determined that an edge jump occurs in the sampled voltage; if the sampled voltage does not cross the voltage threshold, that is, the sampled voltage is always smaller than the voltage threshold or always larger than the voltage threshold, it is determined that the edge jump of the sampled voltage does not occur. The rising edge refers to the rising of the sampling voltage from a first voltage value smaller than the voltage threshold to a second voltage value larger than the voltage threshold; the falling edge refers to the sampled voltage falling from a second voltage value greater than the voltage threshold to a first voltage value less than the voltage threshold.
The edge detection unit 121 includes an ADC sampling module.
The identification unit 122 is configured to determine that the initial state of the motor is in a static state when the edge jump does not occur in the sampling voltage within a preset time; and when the edge jump of the sampling voltage occurs within the preset time, judging that the initial state of the motor is in a rotating state.
In this embodiment, the preset time is set by a timer. If the preset time set by the timer is exceeded, no edge jump occurs, namely no rising edge or falling edge occurs, the initial state of the motor is judged to be in a static state. And if the edge jump occurs within the preset time, namely the rising edge or the falling edge occurs, judging that the initial state of the motor is in a rotating state.
The calculation unit 123 is configured to calculate initial state information of the motor when the initial state of the motor is a rotation state.
In the present embodiment, the calculating unit 123 samples the voltage V PS And a voltage threshold V TH Carrying out comparison; at a sampling voltage V PS After being active low, the sampling voltage V is detected PS First reaching voltage threshold V TH Then, the timer starts timing from the initial value; when the sampling voltage V is detected PS Second reaching voltage threshold V TH The timer counts to obtain the effective high level duration T HI (ii) a When the sampling voltage V is detected PS Third reaching voltage threshold V TH The timer counts to obtain the electric period T of the motor FL Further calculate the rotation speed omega of the motor e Wherein, ω is e ＝(2π)/T FL (ii) a Resetting the timer to restart timing, switching on a lower bridge arm of a phase (subsequently, referred to as a leading phase) which is spatially more leading than a detection phase for a first time delta t1, acquiring phase current of the leading phase within the first time delta t1, and according to the phase current of the leading phase and a first current threshold I TH1 Judging the steering of the motor, or switching on the lower bridge arm of the leading phase for the first time delta t1, switching off the lower bridge arm of the leading phase, acquiring the bus current at the moment of switching off, and according to the bus current and a second current threshold I TH2 Judging the steering of the motor; the timer starts to count from 0 to T again HI At the fourth time t4, the sampling power of the current time is obtainedPressure V PS When the back electromotive force reaches the maximum value, the back electromotive force amplitude E of the motor can be calculated Amp ，E Amp ＝2V P_t4 /3, and rotor position θ e = n × 2 pi/3-pi/2 (n =0,1, 2), where n =0,1,2 corresponds to the detection phases U, V, W, respectively, and V P_t4 Is terminal voltage at time t4 (which may be sampled by voltage V) PS Calculated).
If the phase current of the leading phase is less than the first current threshold I TH1 If not, the motor is considered to rotate reversely. If the bus current is less than the second current threshold I TH2 If not, the motor is considered to rotate reversely.
In a preferred embodiment, the calculation unit 123 samples the voltage V PS And a voltage threshold V TH Comparing; at a sampling voltage V PS After being active low, the sampling voltage V is detected PS First reaching voltage threshold V TH Then, the timer starts timing from the initial value; when the sampling voltage V is detected PS Second reaching voltage threshold V TH The timer counts to obtain the effective high level duration T HI (ii) a When the sampling voltage V is detected PS Third reaching voltage threshold V TH The timer counts to obtain the electric period T of the permanent magnet synchronous motor FL Further calculate the rotation speed omega of the motor e Wherein, ω is e ＝(2π)/T FL (ii) a Resetting the timer to restart timing, opening a lower bridge arm of a phase (hereinafter referred to as a lag phase) lagging in space ratio detection phase for a second time, acquiring phase current of the lag phase within the second time delta t2, and starting timing according to the phase current of the lag phase and a third current threshold I TH3 Judging the steering of the motor or switching on the lower bridge arm of the lag phase for a second time delta t2, switching off the lower bridge arm of the lag phase, acquiring the bus current at the moment of switching off, and switching off the lower bridge arm according to the bus current and a fourth current threshold I TH4 Judging the steering of the motor; the timer starts to count from 0 to T HI At the fourth time t4, the sampling voltage V at the current time is obtained PS When the back electromotive force reaches the maximum value, the back electromotive force of the motor can be calculatedMagnitude of potential E Amp ，E Amp ＝2V P_t4 /3, and rotor position θ e And (3) n × 2 pi/3-pi/2 (n =0,1, 2), wherein n =0,1,2 corresponds to the detection phases being U, V, W phases, respectively.
If the phase current of the lagging phase is greater than the third current threshold I TH3 That is, the motor is considered to rotate forward, otherwise, the motor is considered to rotate reversely. If the bus current is larger than the fourth current threshold I TH4 If not, the motor is considered to rotate reversely.
The verification unit 124 is used for verifying the initial state information according to the back emf coefficient.
In the present embodiment, the rotation speed ω in the initial state information is used e With back emf coefficient psi f The product of (c), the back emf magnitude can be estimated: e' Amp ＝ω e ψ f (ii) a If E Amp And E' Amp If the values are similar, namely the difference value between the two values is within the range of a preset threshold value, the recognized motor initial state information is considered to be correct; if the difference value between the two is not within the preset threshold value range, resampling identification is needed.
The identification device for the initial state of the permanent magnet synchronous motor provided by the embodiment of the invention samples the terminal voltage of a detection phase to obtain a sampling voltage representing the terminal voltage of the detection phase, and analyzes the sampling voltage to judge the initial state of the motor; and calculates initial state information in a rotating state of the motor. The circuit topology is simplified, the occupied external resources such as an analog-digital converter (ADC) and the like are less, the calculation is simple, the complex parameter adjustment is not needed, the method does not depend on an accurate mathematical model of the motor, and the identification result is more reliable.
While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.

Claims (32)

1. A method for identifying the initial state of a permanent magnet synchronous motor is characterized by comprising the following steps:
sampling terminal voltage of a detection phase to obtain sampling voltage, wherein the detection phase is any one of three phases;
judging whether the edge jump of the sampling voltage occurs or not;
when the sampling voltage does not jump within the preset time, judging that the initial state of the motor is a static state;
when the sampling voltage jumps within the preset time, judging that the initial state of the motor is a rotating state;
when the initial state of the motor is a rotating state, calculating initial state information of the motor, wherein the initial state information comprises at least one of a reverse electromotive force amplitude, a rotor position and a steering direction;
wherein the step of calculating the steering of the motor comprises:
comparing the sampled voltage to a voltage threshold;
after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value;
when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage;
and when the sampled voltage reaches the voltage threshold for the third time, switching on a bridge arm of any preceding phase or any lagging phase to acquire the phase current or the bus current of the corresponding phase, and judging the steering of the motor according to the phase current or the bus current of the corresponding phase and the current threshold, wherein the preceding phase is a phase which is spatially more advanced than the detection phase, and the lagging phase is a phase which is spatially more lagging than the detection phase.
2. The identification method of claim 1, wherein the initial state signal further comprises a rotational speed, and wherein the step of calculating the rotational speed of the motor comprises:
comparing the sampled voltage to a voltage threshold;
after the sampling voltage is at an effective low level, when the sampling voltage is detected to reach a voltage threshold value for the first time, a timer starts timing from an initial value;
when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage;
when the sampling voltage reaches the voltage threshold value for the third time, a timer counts to obtain the electric period of the motor;
and calculating the rotating speed of the motor according to the electric cycle.
3. An identification method according to claim 1 or 2, wherein the step of calculating the rotation direction of the motor comprises:
comparing the sampled voltage to a voltage threshold;
after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value;
when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage;
and when the sampling voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the leading phase for the first time, acquiring the phase current of the leading phase in the first time, and judging the steering of the motor according to the phase current of the leading phase and the first current threshold, wherein the leading phase is a phase with a spatially more leading detection phase.
4. An identification method according to claim 3, wherein when the phase current of the leading phase is less than the first current threshold, the motor is rotating forward;
when the phase current of the advanced phase is larger than the first current threshold value, the motor rotates reversely.
5. An identification method according to claim 1 or 2, wherein the step of calculating the rotation direction of the motor comprises:
comparing the sampled voltage to a voltage threshold;
after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value;
when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage;
and when the sampling voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the leading phase for the first time, switching off the lower bridge arm of the leading phase after the lower bridge arm of the leading phase is switched on for the first time, acquiring the bus current, and judging the steering of the motor according to the bus current and the second current threshold.
6. An identification method according to claim 5, wherein when the bus current is less than the second current threshold, the motor is rotating forward; when the bus current is greater than the second current threshold, the motor reverses.
7. An identification method according to claim 1 or 2, wherein the step of calculating the rotation direction of the motor comprises:
comparing the sampled voltage to a voltage threshold;
after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value;
when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage;
and when the sampled voltage reaches the voltage threshold value for the third time, switching on the lower bridge arm of the lag phase for the second time, acquiring the phase current of the lag phase in the second time, and judging the steering of the motor according to the phase current of the lag phase and the third current threshold value, wherein the lag phase is a phase lagging the detection phase in space.
8. The identification method according to claim 7, wherein when the phase current of the lag phase is greater than the third current threshold, the motor rotates forward;
when the phase current of the lagging phase is less than the third current threshold, the motor is reversed.
9. An identification method according to claim 1 or 2, wherein the step of calculating the rotation direction of the motor comprises:
comparing the sampled voltage to a voltage threshold;
after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value;
when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage;
and when the sampled voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the lag phase for a second time, switching off the lower bridge arm of the lag phase after the lower bridge arm of the lag phase is switched on for the second time, acquiring the bus current, and judging the steering of the motor according to the bus current and a fourth current threshold.
10. An identification method according to claim 9, wherein when the bus current is greater than the fourth current threshold, the motor is rotating forward; when the bus current is less than the fourth current threshold, the motor reverses.
11. An identification method according to claim 1 or 2, wherein the step of calculating the back emf magnitude and the rotor position of the motor comprises:
comparing the sampled voltage to a voltage threshold;
after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value;
when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage;
when the sampling voltage is detected to reach the voltage threshold value for the third time, the timer counts one half of the duration time of the effective high level of the sampling voltage again to obtain the terminal voltage at the current moment;
and calculating the amplitude of the opposite electromotive force of the motor and the position of the rotor according to the terminal voltage at the current moment.
12. An identification method according to claim 1, characterized in that the amplitude of the counter electromotive force E of the motor is such that Amp ＝2V P_t4 /3 wherein V P_t4 Is a terminal voltage at which the sampling voltage continues for one-half of the duration of the active high level of the sampling voltage after reaching a voltage threshold for the third time, where P is the detection phase.
13. An identification method according to claim 1, characterised in that the rotor position θ of the electric machine e = n × 2 pi/3-pi/2, where n =0,1,2 corresponds to the detection phases being U, V, W phases, θ e To detect the rotor position at which the magnitude of the back emf of the phases reaches a maximum.
14. The identification method according to claim 1, further comprising:
and verifying the initial state information according to the counter electromotive force coefficient.
15. An identification method according to claim 14, wherein the verifying initial state information according to back emf coefficients comprises:
when the difference value between the product of the counter electromotive force coefficient and the rotating speed and the amplitude value of the counter electromotive force is within a preset threshold value range, the initial state information is accurate;
and when the difference value between the product of the counter electromotive force coefficient and the rotating speed and the counter electromotive force amplitude is not within the preset threshold range, sampling the terminal voltage of the detection phase again to obtain a sampling voltage, and judging the initial state of the motor according to the sampling voltage.
16. The utility model provides an identification device of PMSM initial condition which characterized in that includes:
the sampling circuit is connected with the phase line of the detection phase and is used for sampling the terminal voltage of the detection phase to obtain a sampling voltage, and the detection phase is any one of the three phases;
the identification module is connected with the sampling circuit and used for judging the initial state of the motor according to the sampling voltage,
the identification module judges whether the edge jump of the sampling voltage occurs or not; when the edge jump does not occur to the sampling voltage within the preset time, judging that the initial state of the motor is a static state; when the sampling voltage generates edge jump within the preset time, judging that the initial state of the motor is a rotating state;
when the identification module judges that the initial state of the motor is a rotating state, calculating initial state information of the motor, wherein the initial state information comprises at least one of a reverse electromotive force amplitude, a rotor position and a steering;
wherein the identification module is further configured to compare the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampled voltage reaches the voltage threshold for the third time, switching on a bridge arm of any preceding phase or any lagging phase to acquire the phase current or the bus current of the corresponding phase, and judging the steering of the motor according to the phase current or the bus current of the corresponding phase and the current threshold, wherein the preceding phase is a phase which is spatially more advanced than the detection phase, and the lagging phase is a phase which is spatially more lagging than the detection phase.
17. An identification device according to claim 16 wherein the identification module comprises:
the edge detection unit is used for judging whether the edge jump occurs in the sampling voltage;
the identification unit is used for judging that the initial state of the motor is in a static state when the sampling voltage does not generate edge jump within the preset time; and when the edge jump of the sampling voltage occurs within the preset time, judging that the initial state of the motor is in a rotating state.
18. An identification device according to claim 17 wherein the identification module further comprises:
and the calculating unit is used for calculating the initial state information of the motor when the initial state of the motor is a rotating state.
19. An identification device according to claim 18 wherein the calculation unit is arranged to compare the sampled voltage to a voltage threshold; after the sampling voltage is at an effective low level, detecting that the sampling voltage reaches the voltage threshold value for the first time, and starting timing from an initial value by a timer; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; when the sampling voltage reaches the voltage threshold value for the third time, a timer counts to obtain the electric period of the motor; and calculating the rotating speed of the motor according to the electric cycle.
20. An identification device according to claim 18 or 19 wherein the calculation unit is further arranged to compare the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampling voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the leading phase for the first time, acquiring the phase current of the leading phase in the first time, and judging the steering of the motor according to the phase current of the leading phase and the first current threshold, wherein the leading phase is a phase with a spatially more leading detection phase.
21. An identification device according to claim 20 wherein the motor is rotating forward when the phase current of the leading phase is less than a first current threshold;
when the phase current of the leading phase is greater than a first current threshold, the motor is reversed.
22. An identification device according to claim 18 or 19 wherein the calculation unit is further arranged to compare the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampling voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the leading phase for the first time, switching off the lower bridge arm of the leading phase after the lower bridge arm of the leading phase is switched on for the first time, acquiring the bus current, and judging the steering of the motor according to the bus current and the second current threshold.
23. An identification device according to claim 22 wherein when the bus current is less than the second current threshold, the motor is rotating in the forward direction; when the bus current is greater than the second current threshold, the motor reverses.
24. An identification device according to claim 18 or 19 wherein the calculation unit is further arranged to compare the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampled voltage reaches the voltage threshold value for the third time, switching on the lower bridge arm of the lag phase for the second time, acquiring the phase current of the lag phase in the second time, and judging the steering of the motor according to the phase current of the lag phase and the third current threshold value, wherein the lag phase is a phase lagging the detection phase in space.
25. An identification device according to claim 24 wherein when the phase current of the lagging phase is greater than the third current threshold, the motor is rotating in the forward direction;
when the phase current of the lag phase is less than the third current threshold, the motor is reversed.
26. An identification device according to claim 18 or 19 wherein the calculation unit is further arranged to compare the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; and when the sampled voltage reaches the voltage threshold for the third time, switching on the lower bridge arm of the lag phase for a second time, switching off the lower bridge arm of the lag phase after the lower bridge arm of the lag phase is switched on for the second time, acquiring the bus current, and judging the steering of the motor according to the bus current and a fourth current threshold.
27. An identification device according to claim 26 wherein when the bus current is greater than the fourth current threshold, the motor is rotating in the forward direction; when the bus current is less than the fourth current threshold, the motor reverses.
28. An identification device according to claim 18 or 19 wherein the calculation unit is further arranged to compare the sampled voltage to a voltage threshold; after the sampling voltage is at an active low level, when the sampling voltage is detected to reach the voltage threshold value for the first time, a timer starts to time from an initial value; when the sampling voltage is detected to reach the voltage threshold value for the second time, a timer counts to obtain the duration time of the effective high level of the sampling voltage; when the sampling voltage is detected to reach the voltage threshold value for the third time, the timer counts one half of the duration time of the effective high level of the sampling voltage again to obtain the terminal voltage at the current moment; and calculating the amplitude of the opposite electromotive force and the rotor position of the motor according to the terminal voltage at the current moment.
29. An identification device according to claim 28 wherein the magnitude of the back emf of the motor is E Amp ＝2V P_t4 /3 wherein V P_t4 Is a terminal voltage at which the sampling voltage continues for one-half of the duration of the active high level of the sampling voltage after reaching a voltage threshold for the third time, where P is the detection phase.
30. An identification device according to claim 28 wherein the rotor position θ of the motor e = n × 2 pi/3-pi/2, where n =0,1,2 corresponds to the detection phases being U, V, W phases, θ e To detect the rotor position at which the magnitude of the back emf of the phases reaches a maximum.
31. An identification device according to claim 19 wherein the identification module further comprises:
and the checking unit is used for checking the initial state information according to the back electromotive force coefficient.
32. An identification device according to claim 31 wherein the verification unit is further arranged to determine that the initial state information is accurate when the difference between the product of the back emf coefficient and the speed of rotation and the back emf magnitude is within a predetermined threshold; and when the difference value between the product of the counter electromotive force coefficient and the rotating speed and the counter electromotive force amplitude is not within a preset threshold range, sampling the terminal voltage of the detection phase again to obtain a sampling voltage, and judging the initial state of the motor according to the sampling voltage.
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