A motor state calculation circuit

Abstract

The present invention discloses a motor state calculation circuit, comprising: a voltage acquisition circuit, a current acquisition circuit, a flux observation circuit, a pulse generation circuit and a controller, wherein the controller comprises a current conversion module and a state calculation module. In an embodiment of the present invention, a rotor line flux signal and a pulse signal are obtained by arranging hardware circuits such as a voltage acquisition circuit, a current acquisition circuit, a flux observation circuit, and a pulse generation circuit in the motor state calculation circuit, and the state calculation module in the controller calculates the state of the motor based on the pulse signal. Therefore, the motor state calculation circuit adopts a combination of software and hardware, and will not cause partial data information loss due to the process of digital discretization processing in the data acquisition process or the model approximation process, thereby improving the data accuracy of the rotor line flux signal and making the obtained state information more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a motor state calculation circuit. Background Art

[0002] Permanent magnet synchronous motors are widely used in industrial manufacturing, home appliances, locomotive and electric vehicle drives, aerospace and other industries. In situations where position accuracy is not required (such as fan drives), speed sensorless control methods are more and more widely used than position sensor control methods due to their lower cost and higher reliability.

[0003] At present, the widely used speed sensorless methods include back-EMF method, model reference adaptive method and Kalman filter. Most of these methods use software to build motor models and estimate motor operating parameters to obtain motor rotor state information. Motor rotor state information usually includes rotor position or speed information, and the important state variables involved include voltage, current, motor internal resistance and inductance and other parameters.

[0004] Since the existing technology uses digital methods for modeling and calculation, it has high requirements for the processing MCU and certain cost requirements. In addition, due to the process of digital discretization processing in the data acquisition process or the model approximation process, some data information is lost, thereby reducing the accuracy of the estimated position or speed data to a certain extent. In addition, in some existing technologies, the voltage parameter part driver uses a given voltage. This method saves the voltage sampling circuit and the voltage data processing resources. However, due to the influence of factors such as the dead zone of the PWM converter and the nonlinearity of the power device, there is a deviation between the given value and the feedback value. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a motor state calculation circuit to solve the problem that the motor rotor state information is not accurately calculated by a speed sensorless method.

[0006] The technical solution proposed by the present invention is as follows:

[0007] The embodiment of the present invention provides a motor state calculation circuit, comprising: a voltage acquisition circuit, a current acquisition circuit, a flux observation circuit, a pulse generation circuit and a controller, wherein the controller comprises a current conversion module and a state calculation module;

[0008] The input end of the voltage acquisition circuit is connected to the motor working circuit, and the output end is connected to the flux observation circuit, and is used to collect the line voltage of any two phase lines of the motor working circuit;

[0009] The input end of the current acquisition circuit is connected to the motor working circuit and is used to acquire the phase currents of the two-phase lines of the voltage acquisition circuit that acquires the line voltage;

[0010] The input end of the current conversion module is connected to the output end of the current acquisition circuit, and is used to convert the phase current collected by the current acquisition circuit into a line current, and generate a first current conversion signal and a second current conversion signal to the flux observation circuit based on the line current, the stator line resistance and the stator line inductance;

[0011] The flux observation circuit includes a first conversion circuit, a second conversion circuit and a third conversion circuit, wherein the first conversion circuit is used to convert the first current conversion signal into a first intermediate flux, the second conversion circuit is used to convert the second current conversion signal and the line voltage into a second intermediate flux, and the input end of the third conversion circuit is respectively connected to the output end of the first conversion circuit and the output end of the second conversion circuit, and is used to perform an addition operation on the first intermediate flux and the second intermediate flux to obtain a rotor line flux signal;

[0012] The input end of the pulse generating circuit is connected to the output end of the third conversion circuit, and is used to convert the rotor line flux signal into a pulse signal corresponding to the reverse rotation of the preset rotor angle;

[0013] The input end of the state calculation module is connected to the output end of the pulse generation circuit, and is used to calculate the state of the motor according to the pulse signal.

[0014] Optionally, the first conversion circuit includes a first op amp, a second capacitor, a first resistor, a second resistor and a third resistor, one end of the second capacitor is grounded, and the other end is connected to a first power supply and one end of the second resistor respectively, the other end of the second resistor is respectively connected to an inverting input of the first op amp and one end of the first resistor, the other end of the first resistor is connected to the output of the first op amp, one end of the third resistor is connected to the controller for receiving the first current conversion signal, and the other end is connected to a non-inverting input of the first op amp.

[0015] Optionally, the second conversion circuit includes a second op amp, a third capacitor, a fourth resistor, a fifth resistor and an eighth resistor, one end of the fourth resistor is connected to the output end of the voltage acquisition circuit for receiving the line voltage, the output end of the fourth resistor is respectively connected to one end of the third capacitor, one end of the fifth resistor and the non-inverting input end of the second op amp, the other end of the third capacitor and the other end of the fifth resistor are respectively connected to the output end of the second op amp, one end of the eighth resistor is connected to the controller for receiving the second current conversion signal, the other end is connected to the non-inverting input end of the second op amp, and the inverting input end of the second op amp is grounded.

[0016] Optionally, the third conversion circuit includes a third op amp, a sixth resistor, a seventh resistor, a ninth resistor and a tenth resistor, one end of the sixth resistor is connected to the output end of the first conversion circuit, and the other end is respectively connected to one end of the seventh resistor and the inverting input end of the third op amp, the other end of the seventh resistor is respectively connected to the output end of the third op amp and one end of the tenth resistor, the other end of the tenth resistor is connected to the input end of the pulse generating circuit, one end of the ninth resistor is connected to the second conversion circuit, and the other end is connected to the inverting input end of the third op amp, and the non-inverting input end of the third op amp is grounded.

[0017] Optionally, the pulse generating circuit includes a comparator, an eleventh resistor, a twelfth resistor, a thirteenth resistor and a fourth capacitor, one end of the thirteenth resistor is connected to the output end of the third conversion circuit, and the other end is connected to the non-inverting input end of the comparator, one end of the eleventh resistor is connected to the second power supply, the other end of the eleventh resistor is respectively connected to one end of the twelfth resistor, one end of the fourth capacitor and the inverting input end of the comparator, the other end of the twelfth resistor is connected to the other end of the fourth capacitor and is grounded, and the output end of the comparator is connected to the controller.

[0018] Optionally, the voltage acquisition circuit includes a phase voltage acquisition circuit and a line voltage detection circuit. The input end of the phase voltage acquisition circuit is connected to the motor working circuit, and the output end is connected to the line voltage detection circuit. The phase voltage acquisition circuit is used to collect the phase voltages of any two phase lines of the motor working circuit and transmit them to the line voltage detection circuit. The output end of the line voltage detection circuit is connected to the input end of the second conversion circuit for converting the phase voltage into a line voltage.

[0019] Optionally, the state calculation module includes a differentiator for differentiating the pulse signal to obtain the rotor speed.

[0020] Optionally, the state calculation module further includes an integrator for integrating the rotor speed to obtain the rotor position.

[0021] Optionally, the state calculation module further includes: an actual position calculation unit, configured to obtain the actual position of the rotor according to the rising edge or the falling edge of the pulse signal.

[0022] Optionally, the current conversion module includes: a first conversion module, a second conversion module and a third conversion module.

[0023] The first conversion module is used to convert the phase current collected by the current collection circuit into a line current;

[0024] The second conversion module is used for multiplying the line current and the stator line inductance and performing deviation transformation to obtain a first current conversion signal;

[0025] The third conversion module is used for multiplying the line current and the stator line resistance and then inverting the multiplication to obtain a second current conversion signal.

[0026] The technical solution provided by the present invention has the following effects:

[0027] The motor state calculation circuit of the embodiment of the present invention collects the line voltage of any two phase lines of the motor working circuit through the voltage acquisition circuit, converts the phase current collected by the current acquisition circuit into the line current through the current conversion module and the current acquisition circuit, and generates a first current conversion signal and a second current conversion signal to the flux observation circuit based on the line current, stator line resistance and stator line inductance. The flux observation circuit includes a first conversion circuit, a second conversion circuit and a third conversion circuit. The line voltage, the first current conversion signal and the second current conversion signal are observed by hardware circuits through these three conversion circuits to obtain a rotor line flux signal, and then the rotor line flux signal is converted into a pulse signal corresponding to the reverse of a preset rotor angle through a pulse generation circuit, and the controller calculates the state of the motor according to the pulse signal. The embodiment of the present invention obtains a rotor line flux signal and a pulse signal by setting hardware circuits such as a voltage acquisition circuit, a current acquisition circuit, a flux observation circuit, and a pulse generation circuit in a motor state calculation circuit, and calculates the state of the motor based on the pulse signal through a state calculation module in a controller. Therefore, the motor state calculation circuit adopts a combination of software and hardware, and will not cause partial data information loss during the data acquisition process or the model approximation process due to the digital discretization process, thereby improving the data accuracy of the rotor line flux signal and making the obtained state information more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly express the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 Schematic diagram of the structure of the motor state calculation circuit in an embodiment of the present invention;

[0030] Figure 2 : is a circuit schematic diagram of a flux observation circuit in an embodiment of the present invention;

[0031] Figure 3 is a circuit schematic diagram of a pulse generating circuit in an embodiment of the present invention;

[0032] Figure 4 Schematic diagram of steady-state control process in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] like Figure 1 As shown, an embodiment of the present invention provides a motor state calculation circuit, including: a voltage acquisition circuit 1, a current acquisition circuit 2, a flux observation circuit 3, a pulse generation circuit 4 and a controller 5, wherein the controller 5 includes a current conversion module 52 and a state calculation module 51. Exemplarily, the controller 5 can be a microcontroller unit (MCU), a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components and other chips, or a combination of the above chips.

[0035] The input end of the voltage acquisition circuit 1 is connected to the motor working circuit 6, and the output end is connected to the flux observation circuit 3, which is used to collect the line voltage of any two phase lines of the motor working circuit 6. The motor in this embodiment is a three-phase motor, specifically a three-phase surface-mounted permanent magnet synchronous motor. It works by being powered by a three-phase power supply, and the three-phase power supply has three phase lines. The three-phase motor corresponds to three stators A, B, and C. In this embodiment, the voltage acquisition circuit 1 collects the line voltage of any two phase lines of the motor working circuit 6, that is, collects the line voltage between any two stators. For example, the collected line voltage is the line voltage Uab of stator A and stator B.

[0036] The input end of the current acquisition circuit 2 is connected to the motor working circuit 6, and is used to acquire the phase current of the two-phase line whose line voltage is acquired by the voltage acquisition circuit 1. Correspondingly, when the line voltage acquired by the voltage acquisition circuit 1 is the line voltage Uab of stator A and stator B, the current acquired by the current acquisition circuit 2 is the phase current Ia of stator A and the phase current Ib of stator B.

[0037] The input end of the current conversion module 52 is connected to the output end of the current acquisition circuit 2, and is used to convert the phase current collected by the current acquisition circuit 2 into the line current, and generate a first current conversion signal and a second current conversion signal to the flux observation circuit 3 based on the line current, stator line resistance and stator line inductance. Specifically, compared with the phase voltage, current and flux signals, the maximum values ​​of the line voltage, current and flux are Therefore, the current conversion module 52 only needs to perform a simple multiplication calculation on the phase current to obtain the line current. The stator line resistance and stator line inductance are fixed parameters of the three-phase motor and can be obtained from the motor manual or measurement.

[0038] In one embodiment, the first current conversion signal is obtained by multiplying the line current and the stator line inductance and performing deviation transformation, and the deviation transformation is specifically 1.5 V. In other embodiments, other values ​​such as 3 V may also be selected. The second current conversion signal is obtained by multiplying the line current and the stator line resistance and then inverting it.

[0039] like Figure 2 As shown, the flux observation circuit 3 includes a first conversion circuit 31, a second conversion circuit 32 and a third conversion circuit 33. The first conversion circuit 31 is used to convert the first current conversion signal into a first intermediate flux, the second conversion circuit 32 is used to convert the second current conversion signal and the line voltage into a second intermediate flux, and the input end of the third conversion circuit 33 is respectively connected to the output end of the first conversion circuit 31 and the output end of the second conversion circuit 32, and is used to add the first intermediate flux and the second intermediate flux to obtain a rotor line flux signal.

[0040] Specifically, the first intermediate flux is the product of the stator line inductance and the line current, and the second intermediate flux is the integral of the difference between the line voltage Uab and the product of the stator line resistance and the line current, and then the inverse is taken, that is, the first intermediate flux U omid1 =L s I ab ; The second intermediate flux U omid2 =-∫(U ab -R s i ab )dt. Among them, L s is the stator line inductance, I ab is the line current, R s The stator line resistance is obtained by respectively obtaining the first intermediate flux and the second intermediate flux through the first conversion circuit 31 and the second conversion circuit 32, and then the first intermediate flux and the second intermediate flux are added through the third conversion circuit 33 to obtain the rotor line flux signal, and the AB line flux sinusoidal signal is observed through the hardware circuit, which simplifies the calculation process and retains the original information of the data to the greatest extent.

[0041] The input end of the pulse generating circuit 4 is connected to the output end of the third conversion circuit 33, and is used to convert the rotor line flux signal into a pulse signal corresponding to the reverse of the preset rotor angle. The rotor line flux signal is a sinusoidal AC signal with periodicity. The pulse generating circuit 4 outputs a high level signal when the value of the rotor line flux signal is greater than the preset value, and outputs a low level signal when it is lower than the preset value, thereby forming a pulse signal. The size of the preset value is the size of the rotor line flux signal at the preset rotor line electrical angle. For example, the size of the preset value is set to the size of the rotor line flux signal when the rotor line electrical angle is 30°. When the rotor line electrical angle θ of the rotor line flux signal is greater than 30°, a high level signal that lasts for 90° is formed. When θ>120°, a falling edge is output to form a low level signal that lasts for 90°.

[0042] The input end of the state calculation module 51 is connected to the output end of the pulse generation circuit 4 and is used to calculate the state of the motor according to the pulse signal.

[0043] Specifically, the state of the motor is the rotor speed or rotor position of the motor or a combination of the two. The state calculation module 51 obtains the rotor speed by performing differential calculation on the pulse signal, and obtains the rotor position by performing integral calculation on the rotor speed.

[0044] In the embodiment of the present invention, the voltage acquisition circuit 1 acquires the line voltage of any two phase lines of the motor working circuit 6, and converts the phase current acquired by the current acquisition circuit 2 into the line current through the current conversion module 52 and the current acquisition circuit 2, and generates a first current conversion signal and a second current conversion signal to the flux observation circuit 3 based on the line current, the stator line resistance and the stator line inductance. The flux observation circuit 3 includes a first conversion circuit 31, a second conversion circuit 32 and a third conversion circuit 33. The line voltage, the first current conversion signal and the second current conversion signal are observed by hardware circuits through these three conversion circuits to obtain a rotor line flux signal, and then the rotor line flux signal is converted into a pulse signal corresponding to the reverse of the preset rotor angle through the pulse generation circuit 4, and the controller 5 calculates the state of the motor according to the pulse signal. The embodiment of the present invention obtains a rotor line flux signal and a pulse signal by setting hardware circuits such as a voltage acquisition circuit 1, a current acquisition circuit 2, a flux observation circuit 3, and a pulse generation circuit 4 in a motor state calculation circuit, and calculates the state of the motor based on the pulse signal through a state calculation module 51 in a controller 5. Therefore, the motor state calculation circuit adopts a combination of software and hardware, and will not cause part of the data information to be lost during the data acquisition process or the model approximation process due to the digital discretization process, thereby improving the data accuracy of the rotor line flux signal and making the obtained state information more accurate.

[0045] In one embodiment, if Figure 2As shown, the first conversion circuit 31 includes a first amplifier U1B, a second capacitor C2, a first resistor R1, a second resistor R2 and a third resistor R3, one end of the second capacitor C2 is grounded, and the other end is connected to the first power supply and one end of the second resistor R2 respectively, the other end of the second resistor R2 is connected to the inverting input end of the first amplifier U1B and one end of the first resistor R1 respectively, the other end of the first resistor R1 is connected to the output end of the first amplifier U1B, one end of the third resistor R3 is connected to the controller 5 for receiving the first current conversion signal, and the other end is connected to the non-inverting input end of the first amplifier U1B. In this embodiment, the first current conversion signal is the product of the line current and the stator line inductance plus a deviation of 1.5V, that is, 1.5+L s I ab , the voltage of the first power supply is 3V, R1=R2=R3. At this time, the output signal of the first conversion circuit 31, that is, the vector equation of the first intermediate flux is: U omid1 =2(1.5+L s I ab / 2)-3, which is simplified to U omid| =L s I ab .

[0046] The deviation value, the specific value of the voltage of the first power supply and the magnitude relationship between the resistors in this embodiment are not limited. In other embodiments, the deviation value can also be selected from other values, such as 3V, and the voltage of the first power supply becomes 6V accordingly.

[0047] like Figure 2 As shown, the second conversion circuit 32 includes a second amplifier U1C, a third capacitor C3, a fourth resistor R4, a fifth resistor R5 and an eighth resistor R8. One end of the fourth resistor R4 is connected to the output end of the voltage acquisition circuit 1 for receiving the line voltage Uab. The output end of the fourth resistor R4 is respectively connected to one end of the third capacitor C3, one end of the fifth resistor R5 and the in-phase input end of the second amplifier U1C. The other end of the third capacitor C3 and the other end of the fifth resistor R5 are respectively connected to the output end of the second amplifier U1C. One end of the eighth resistor R8 is connected to the controller 5 for receiving the second current conversion signal, and the other end is connected to the in-phase input end of the second amplifier U1C. The inverting input end of the second amplifier U1C is grounded. In this embodiment, the second current conversion signal is obtained by multiplying the line current and the stator line resistance and then inverting it, that is, the second current conversion signal is -L s I ab , R4=R5=R8. At this time, the output signal of the second conversion circuit 32, that is, the vector equation of the second intermediate flux is: Where ω is the electrical angular frequency of the motor line, and its value is much greater than 1, so R5C3ω>>1, so it can be equivalent to: U omid2=-∫(U ab -R s I ab )dt.

[0048] Further, the third conversion circuit 33 includes a third amplifier U1D, a sixth resistor R6, a seventh resistor R7, a ninth resistor R9 and a tenth resistor R10. One end of the sixth resistor R6 is connected to the output end of the first conversion circuit 31, and the other end is respectively connected to one end of the seventh resistor R7 and the inverting input end of the third amplifier U1D. The other end of the seventh resistor R7 is respectively connected to the output end of the third amplifier U1D and one end of the tenth resistor R10. The other end of the tenth resistor R10 is connected to the input end of the pulse generating circuit 4. One end of the ninth resistor R9 is connected to the second conversion circuit 32, and the other end is connected to the inverting input end of the third amplifier U1D. The in-phase input end of the third amplifier U1D is grounded. In this embodiment, R6=R9=R7, so the third conversion circuit 33 is equivalent to an adding circuit, and the final output value is U in =∫(U ab -R s I ab )dt-L s I ab , whose value is the magnetic flux of rotor AB phase line.

[0049] In order to prove that the output value of the third conversion circuit 33 is U in is the rotor AB phase line flux, and this embodiment performs the following verification:

[0050] Taking the three-phase surface-mounted permanent magnet synchronous motor as an example, its magnetic flux equation is:

[0051]

[0052] Among them, ψ A , B and ψ C are the flux generated by the stator A, B, and C three-phase windings; i A 、i B 、i C are the three-phase stator currents respectively; fA , fB , fC are the three-phase excitation flux of the rotor permanent magnet; L A , L B , L C Three-phase stator self-inductance; L AB , L BA , L AC , L CA , L BC , L CB is the three-phase stator mutual inductance;

[0053] Since it is a surface mounted permanent magnet synchronous motor, there is L A =L B =L C ; L AB =L BA =L AC =L CA =L BC =L CB ; Assuming that the three-phase stator winding is Y-connected and the neutral point is not led out, then i A +i B +i C =0; Substituting into formula (1), we can get:

[0054] ψ A =L S i A +ψ fA (2)

[0055] ψ B =L S i B +ψ fB (3)

[0056] ψ C =L S i C +ψ fC (4)

[0057] Where L S It is the stator line inductance of the motor, also called synchronous inductance.

[0058] Compared with the phase voltage, current and flux linkage signals, the maximum values ​​of line voltage, current and flux linkage are times, and the line signal is used for estimation, especially near the signal zero crossing, which makes it easier to reduce the influence of factors such as zero drift. From equations (2) and (3), the AB line flux equation can be obtained as:

[0059] ψ AB =L s I ab +ψ fAB (5)

[0060] where ψ AB is the stator AB phase line flux, i AB is the stator AB phase line current, ψ fAB is the flux linkage of rotor AB phase line;

[0061] ψ fAB Contains the rotor position information, and can be obtained from formula (5)

[0062] ψ fAB =ψ AB -L s Iab (6)

[0063] Where: L S is a constant, which can be obtained through measurement, calculation or online identification; I ab It can be calculated by sampling the current sensor of controller 5. AB It can be obtained by observing the stator line voltage and line current. The implementation method is:

[0064] ψ AB =∫(U ab -R S I ab )dt (7)

[0065] Where R S is the stator line resistance of the motor, also called the motor synchronous resistance, which is a constant; U ab is the line voltage, which can be obtained by sampling. Therefore, the rotor line flux can be observed by the following formula:

[0066] ψ fAB =∫(U ab -R S I ab )dt-L s I ab (8)

[0067] Compare (8) and U in , found U in That is ψ fAB Therefore, the value output by the third conversion circuit 33 is U in is the magnetic flux of rotor AB phase line.

[0068] In the case of permanent magnet synchronous motor with rotor field orientation and no field weakening control, ψ fAB It is a sine wave with constant amplitude. After the previous stage data processing, its amplitude is ψ fABmax =3.0V, then the rotor line flux signal value is:

[0069] ψ fAB =ψ fABmax Sin(θ) (9)

[0070] Where θ is the electrical angle of the rotor line. The pulse generating circuit 4 is used to convert the rotor line flux signal U in Converted into a pulse signal corresponding to the reverse rotation of the preset rotor angle.

[0071] In one embodiment, if Figure 3As shown, the pulse generating circuit 4 includes a comparator U2D, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a fourth capacitor C4, one end of the thirteenth resistor R13 is connected to the output end of the third conversion circuit 33, and the other end is connected to the non-inverting input end of the comparator U2D, one end of the eleventh resistor R11 is connected to the second power supply, the other end of the eleventh resistor R11 is respectively connected to one end of the twelfth resistor R12, one end of the fourth capacitor C4 and the inverting input end of the comparator U2D, the other end of the twelfth resistor R12 is connected to the other end of the fourth capacitor C2 and grounded, and the output end of the comparator U2D is connected to the controller 5. In this embodiment, the voltage of the first power supply is 3V, R11=R12, and the voltage of the inverting input end of the comparator U2D is 1.5V after voltage division. When the rotor line electrical angle θ>30°, the output end of the comparator U2D outputs a rising edge. Similarly, when θ>120°, the output end of the comparator U2D outputs a falling edge. A high-level signal Uo lasting 90° is formed and sent to the timer capture unit of the controller 5. At the same time, the circuit is equivalent to a low-pass filter, shielding high-frequency interference and avoiding the amplification of noise by directly using feedback current and motor model differential calculation in the traditional way.

[0072] In one embodiment, the voltage acquisition circuit 1 includes a phase voltage acquisition circuit and a line voltage detection circuit. The input end of the phase voltage acquisition circuit is connected to the motor working circuit 6, and the output end is connected to the line voltage detection circuit. The phase voltage acquisition circuit is used to collect the phase voltages of any two phase lines of the motor working circuit 6 and transmit them to the line voltage detection circuit. The output end of the line voltage detection circuit is connected to the input end of the second conversion circuit 32 for converting the phase voltage into the line voltage.

[0073] Exemplarily, the line voltage detection circuit is an amplifier circuit for amplifying the phase voltage The line voltage is obtained after multiplication. In this embodiment, the line voltage is obtained through the phase voltage acquisition circuit and the line voltage detection circuit, and the line voltage is obtained through the hardware circuit, without the need for software algorithm calculation, thereby improving the overall stability of the circuit.

[0074] In one embodiment, the state calculation module 51 includes a differentiator for differentiating the pulse signal to obtain the rotor speed. The high-level phase difference of the pulse signal is fixed at 90°, and the rotor speed is obtained by the differentiator in this embodiment. In addition, calculating the rotor speed by a fixed phase difference of 90° is equivalent to a low-pass filter to shield high-frequency interference.

[0075] In one embodiment, the state calculation module 51 further includes an integrator for integrating the rotor speed to obtain the rotor position. In this embodiment, the rotor position is obtained by integrating the calculated rotor speed, and the speed and position information of the rotor can be obtained simultaneously.

[0076] In one embodiment, the state calculation module 51 further includes: an actual position calculation unit, which is used to obtain the actual position of the rotor according to the rising edge or falling edge of the pulse signal. In this embodiment, the actual position of the rotor can be directly obtained through the rising edge or falling edge of the pulse signal, avoiding the calculation error that may be generated by the integral calculation based on the rotor speed, and the actual position of the rotor is obtained, and the data is more accurate. In some embodiments, the actual position of the rotor can also be used to perform angle correction and compensation on the rotor position obtained by the integral calculation based on the rotor speed to ensure that the Park inverse transformation angle θ s The stator flux leads the rotor by an angle θ r 90°, that is, the electromagnetic torque is maximum under given current.

[0077] In one embodiment, the current conversion module 52 includes: a first conversion module, a second conversion module and a third conversion module. The first conversion module is used to convert the phase current collected by the current acquisition circuit 2 into a line current. The second conversion module is used to multiply the line current and the stator line inductance and then perform a deviation transformation to obtain a first current conversion signal. The third conversion module is used to multiply the line current and the stator line resistance and then invert it to obtain a second current conversion signal.

[0078] In this embodiment, the current conversion module 52 of the controller 5 calculates and processes the collected phase current to obtain an input signal of the flux observation circuit 3, which provides a basis for observing the flux through the hardware circuit.

[0079] This embodiment can realize the traditional steady-state control process. The traditional steady-state control process is as follows: Figure 4 As shown, the controller 5 collects the motor input line voltage and line current, and the flux observation circuit 3 and the pulse generation circuit 4 obtain a pulse signal containing position information. The position observation software part uses the capture unit to perform differential calculation on the Uo high level to obtain the motor speed Vfed. With the Vfed system, the traditional vector control based on rotor magnetic field orientation is carried out, and the process is as follows: Vfed and the given speed Vref form a speed closed loop through the PI regulator to generate the current given Iqref. The torque current Iqfed and the stator flux current Idfed are obtained by collecting the three-phase current through the Clark transformation from the three-phase to the two-phase stationary coordinate system, and the Park transformation from the two-phase stationary coordinate system to the two-phase rotating coordinate system. The torque current Iqfed and the stator flux current Idfed are respectively controlled by the PI regulator closed loop, and the output is subjected to Park inverse transformation and SVPWM modulation to obtain the three-phase voltage required to drive the motor.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A motor state calculation circuit, characterized in that: include: A voltage acquisition circuit, a current acquisition circuit, a flux observation circuit, a pulse generation circuit and a controller, wherein the controller includes a current conversion module and a state calculation module; The input end of the voltage acquisition circuit is connected to the motor working circuit, and the output end is connected to the flux observation circuit, and is used to collect the line voltage of any two phase lines of the motor working circuit; The input end of the current acquisition circuit is connected to the motor working circuit and is used to acquire the phase currents of the two-phase lines of the voltage acquisition circuit that acquires the line voltage; The input end of the current conversion module is connected to the output end of the current acquisition circuit, and is used to convert the phase current collected by the current acquisition circuit into a line current, and generate a first current conversion signal and a second current conversion signal to the flux observation circuit based on the line current, the stator line resistance and the stator line inductance; The flux observation circuit includes a first conversion circuit, a second conversion circuit and a third conversion circuit, wherein the first conversion circuit is used to convert the first current conversion signal into a first intermediate flux, the second conversion circuit is used to convert the second current conversion signal and the line voltage into a second intermediate flux, and the input end of the third conversion circuit is respectively connected to the output end of the first conversion circuit and the output end of the second conversion circuit, and is used to perform an addition operation on the first intermediate flux and the second intermediate flux to obtain a rotor line flux signal; The input end of the pulse generating circuit is connected to the output end of the third conversion circuit, and is used to convert the rotor line flux signal into a pulse signal corresponding to the reverse rotation of the preset rotor angle; The input end of the state calculation module is connected to the output end of the pulse generation circuit, and is used to calculate the state of the motor according to the pulse signal.

2. A motor state calculation circuit according to claim 1, characterized in that: The first conversion circuit includes a first op amp, a second capacitor, a first resistor, a second resistor and a third resistor. One end of the second capacitor is grounded, and the other end is connected to a first power supply and one end of the second resistor respectively. The other end of the second resistor is connected to an inverting input of the first op amp and one end of the first resistor respectively. The other end of the first resistor is connected to the output of the first op amp. One end of the third resistor is connected to the controller for receiving the first current conversion signal, and the other end is connected to the non-inverting input of the first op amp.

3. A motor state calculation circuit according to claim 1, characterized in that: The second conversion circuit includes a second op amp, a third capacitor, a fourth resistor, a fifth resistor and an eighth resistor. One end of the fourth resistor is connected to the output end of the voltage acquisition circuit for receiving the line voltage. The output end of the fourth resistor is respectively connected to one end of the third capacitor, one end of the fifth resistor and the non-inverting input end of the second op amp. The other end of the third capacitor and the other end of the fifth resistor are respectively connected to the output end of the second op amp. One end of the eighth resistor is connected to the controller for receiving the second current conversion signal, and the other end is connected to the non-inverting input end of the second op amp. The inverting input end of the second op amp is grounded.

4. A motor state calculation circuit according to claim 1, characterized in that: The third conversion circuit includes a third operational amplifier, a sixth resistor, a seventh resistor, a ninth resistor and a tenth resistor. One end of the sixth resistor is connected to the output end of the first conversion circuit, and the other end is respectively connected to one end of the seventh resistor and the inverting input end of the third operational amplifier. The other end of the seventh resistor is respectively connected to the output end of the third operational amplifier and one end of the tenth resistor. The other end of the tenth resistor is connected to the input end of the pulse generating circuit. One end of the ninth resistor is connected to the second conversion circuit, and the other end is connected to the inverting input end of the third operational amplifier. The non-inverting input end of the third operational amplifier is grounded.

5. A motor state calculation circuit according to claim 1, characterized in that: The pulse generating circuit includes a comparator, an eleventh resistor, a twelfth resistor, a thirteenth resistor and a fourth capacitor, one end of the thirteenth resistor is connected to the output end of the third conversion circuit, and the other end is connected to the non-inverting input end of the comparator, one end of the eleventh resistor is connected to a second power supply, the other end of the eleventh resistor is respectively connected to one end of the twelfth resistor, one end of the fourth capacitor and the inverting input end of the comparator, the other end of the twelfth resistor is connected to the other end of the fourth capacitor and is grounded, and the output end of the comparator is connected to the controller.

6. A motor state calculation circuit according to claim 1, characterized in that: The voltage acquisition circuit includes a phase voltage acquisition circuit and a line voltage detection circuit. The input end of the phase voltage acquisition circuit is connected to the motor working circuit, and the output end is connected to the line voltage detection circuit. The phase voltage acquisition circuit is used to collect the phase voltages of any two phase lines of the motor working circuit and transmit them to the line voltage detection circuit. The output end of the line voltage detection circuit is connected to the input end of the second conversion circuit for converting the phase voltage into a line voltage.

7. A motor state calculation circuit according to claim 1, characterized in that: The state calculation module includes a differentiator for differentiating the pulse signal to obtain the rotor speed.

8. A motor state calculation circuit according to claim 7, characterized in that: The state calculation module also includes an integrator for integrating the rotor speed to obtain the rotor position.

9. A motor state calculation circuit according to claim 1, characterized in that: The state calculation module also includes: an actual position calculation unit, which is used to obtain the actual position of the rotor according to the rising edge or falling edge of the pulse signal.

10. The motor state calculation circuit according to claim 1, characterized in that: The current conversion module includes: a first conversion module, a second conversion module and a third conversion module. The first conversion module is used to convert the phase current collected by the current collection circuit into a line current; The second conversion module is used for multiplying the line current and the stator line inductance and performing deviation transformation to obtain a first current conversion signal; The third conversion module is used for multiplying the line current and the stator line resistance and then inverting the multiplication to obtain a second current conversion signal.

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