Method, device, motor driver and household appliance for estimating a motor rotor position

Abstract

The embodiment of the application discloses a method and device for estimating the rotor position of a motor, a motor driver and a household appliance. The method comprises: injecting a square wave voltage signal in a set frequency range into the d-axis of the motor; and estimating the rotor position of the motor based on the corresponding response current of the square wave voltage signal and based on the related parameters of the square wave voltage signal, the d-axis inductance of the motor and the q-axis inductance of the motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of variable frequency drives, and in particular to a method and device for estimating rotor position of a motor, a motor driver and a household appliance. BACKGROUND

[0002] In the related art, the position angle of the rotor of the motor is estimated based on the back electromotive force of the motor when the back electromotive force of the motor reaches a set value. However, when the motor is stationary or running at a low speed, the back electromotive force of the motor cannot reach the set value, resulting in the inability to estimate the position angle of the rotor of the motor. SUMMARY

[0003] In view of this, the embodiments of the present application aim to provide a method and device for estimating rotor position of a motor, a motor driver and a household appliance, to solve the technical problem in the related art that the position angle of the rotor of the motor cannot be estimated when the motor is running at a low speed because the back electromotive force of the motor cannot reach a set value.

[0004] To achieve the above-mentioned purpose, the technical solution of the present application is as follows:

[0005] The embodiments of the present application provide a method for estimating rotor position of a motor, comprising:

[0006] injecting a square wave voltage signal in a set frequency range into the d-axis of the motor;

[0007] estimating the rotor position of the motor based on the response current corresponding to the square wave voltage signal, and based on the related parameters of the square wave voltage signal, the d-axis inductance of the motor and the q-axis inductance of the motor.

[0008] In the above-mentioned solution, the estimation of the rotor position of the motor based on the response current corresponding to the square wave voltage signal, and based on the related parameters of the square wave voltage signal, the d-axis inductance of the motor and the q-axis inductance of the motor, comprises:

[0009] filtering the first α-axis response current and the first β-axis response current corresponding to the square wave voltage signal based on the frequency range of power grid fluctuations, to obtain the second α-axis response current and the second β-axis response current after filtering;

[0010] estimating the rotor position of the motor based on the related parameters of the square wave voltage signal, the d-axis inductance of the motor, the q-axis inductance of the motor, the second α-axis response current and the second β-axis response current.

[0011] In the above-mentioned solution, the filtering of the first α-axis response current and the first β-axis response current corresponding to the square wave voltage signal based on the frequency range of power grid fluctuations to obtain the second α-axis response current and the second β-axis response current after filtering, comprises:

[0012] The first alpha-axis response current corresponding to the square wave voltage signal is band-pass filtered based on the power grid fluctuation frequency range to obtain a third alpha-axis response current.

[0013] The first beta-axis response current corresponding to the square wave voltage signal is band-pass filtered based on the power grid fluctuation frequency range to obtain a third beta-axis response current.

[0014] In the above scheme, the filtering processing of the first alpha-axis response current and the first beta-axis response current corresponding to the square wave voltage signal based on the power grid fluctuation frequency range to obtain the filtered second alpha-axis response current and the filtered second beta-axis response current comprises:

[0015] The first alpha-axis response current corresponding to the square wave voltage signal is band-pass filtered based on the power grid fluctuation frequency range to obtain a third alpha-axis response current.

[0016] The difference between the first alpha-axis response current and the third alpha-axis response current is determined as the filtered second alpha-axis response current.

[0017] The first beta-axis response current corresponding to the square wave voltage signal is band-pass filtered based on the power grid fluctuation frequency range to obtain a third beta-axis response current.

[0018] The difference between the first beta-axis current and the third beta-axis response current is determined as the filtered second beta-axis response current.

[0019] In the above scheme, the square wave voltage signal at the set frequency range is injected into the d-axis of the motor, comprising:

[0020] The square wave voltage signal at the set frequency range is injected into the d-axis of the motor based on a set function; wherein,

[0021] The expression of the set function is: u inj = Asgn (sin (2πf hf t) ) ;

[0022] The A represents the voltage amplitude of the square wave voltage signal; and the f hf represents the frequency of the square wave voltage signal.

[0023] In the above scheme, the set frequency range is greater than or equal to 100 Hz and less than or equal to 20 kHz.

[0024] The application also provides a device for estimating the rotor position of a motor, comprising:

[0025] a signal injection unit configured to inject a square-wave voltage signal in a set frequency range to a d-axis of the motor;

[0026] a rotor position estimation unit configured to estimate a rotor position of the motor based on a response current corresponding to the square-wave voltage signal, and based on a related parameter of the square-wave voltage signal, a d-axis inductance of the motor, and a q-axis inductance of the motor.

[0027] The embodiment of the present application further provides a motor driver, comprising a processor and a memory for storing a computer program capable of running on the processor,

[0028] The processor is configured to execute the computer program, and perform the steps of the method for estimating the rotor position of the motor.

[0029] The embodiment of the present application further provides a household appliance, comprising a motor driver, a motor, a processor and a memory for storing a computer program capable of running on the processor,

[0030] The processor is configured to execute the computer program, and perform the steps of the method for estimating the rotor position of the motor.

[0031] The embodiment of the present application further provides a storage medium having a computer program stored thereon, the computer program being executed by a processor to implement the steps of the method for estimating the rotor position of the motor.

[0032] The embodiment of the present application injects a square-wave voltage signal in a set frequency range to a d-axis of the motor; utilizes the salient pole characteristic of the motor, estimates a rotor position of the motor based on a response current corresponding to the square-wave voltage signal, and based on a related parameter of the square-wave voltage signal, a d-axis inductance of the motor, and a q-axis inductance of the motor. In the above scheme, the rotor position of the motor is tracked based on the characteristics that the d-axis inductance and the q-axis inductance of the motor are not equal, so that the back electromotive force of the motor is not needed, and thus the rotor position of the motor can be estimated when the motor is at rest or running at a low speed. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A topology structure diagram of a motor driving device without an electrolytic capacitor is provided for related technologies;

[0034] Figure 2 An implementation flowchart of a method for estimating a rotor position of a motor is provided for the embodiment of the present application;

[0035] Figure 3 A schematic diagram of a position relationship between an estimated rotating coordinate system of a rotor and an actual rotating coordinate system of the rotor is provided for the embodiment of the present application;

[0036] Figure 4 A schematic diagram of an implementation procedure of estimating a rotor position of a motor according to an embodiment of the present application is provided in the method of estimating the rotor position of the motor;

[0037] Figure 5 A schematic diagram of filtering a response current corresponding to a square wave voltage signal according to an embodiment of the present application is provided in the method of estimating the rotor position of the motor;

[0038] Figure 6 A schematic diagram of filtering a response current corresponding to a square wave voltage signal according to another embodiment of the present application is provided in the method of estimating the rotor position of the motor;

[0039] Figure 7 A schematic diagram of an implementation procedure of estimating a rotor position of a motor according to an application embodiment of the present application is provided in the method of estimating the rotor position of the motor;

[0040] Figure 8 A schematic diagram of a motor driver controlling a motor according to an embodiment of the present application is provided in the method of estimating the rotor position of the motor;

[0041] Figure 9 A schematic diagram of a structure of a device of estimating a rotor position of a motor according to an embodiment of the present application is provided in the method of estimating the rotor position of the motor;

[0042] Figure 10 A schematic diagram of a hardware component structure of a household appliance according to an embodiment of the present application is provided in the method of estimating the rotor position of the motor. DETAILED DESCRIPTION

[0043] In the related art, a motor is usually driven to operate by using a motor driving device without electrolytic capacitor. Referring to Figure 1 The motor driving device without electrolytic capacitor includes a motor driver including a filter module, a rectifier module, a direct current bus energy storage module, an inverter module, and a control module. The filter module is composed of an inductor Lg, the rectifier module is composed of diodes D1-D4, the direct current bus energy storage module is composed of a thin film capacitor C1, and the inverter module is composed of power switching tubes (IGBT, Insulated Gate Bipolar Transistor) S1-S6.

[0044] The control module is configured to output a pulse width modulation (PWM) signal to the inverter module based on given parameters of the motor, such as a given speed of the motor an input voltage u in a direct current bus voltage u dc of the motor, and a three-phase symmetrical sinusoidal alternating current i abc of the motor, to drive the motor to operate, so as to realize the field weakening control of the motor. The motor is a permanent-magnet synchronous motor (PMSM).

[0045] In the related art, the position angle of the rotor of the motor is estimated based on the back electromotive force of the motor when the back electromotive force of the motor reaches a set value. However, when the motor is at rest or operates at a low speed, the back electromotive force of the motor cannot reach the set value, so that the position angle of the rotor of the motor cannot be estimated.

[0046] To solve the above technical problem, the embodiment of the present application provides a method for estimating the position of the rotor of a motor, injecting a square wave voltage signal in a set frequency range into the d-axis of the motor, and estimating the position of the rotor of the motor based on the response current corresponding to the square wave voltage signal and based on the related parameters of the square wave voltage signal, the d-axis inductance and the q-axis inductance of the motor. In this scheme, the position of the rotor of the motor is tracked based on the characteristics that the d-axis inductance and the q-axis inductance of the motor are not equal, and the process is independent of the back electromotive force of the motor. Therefore, the position of the rotor of the motor can be estimated when the motor is at rest or operates at a low speed.

[0047] It should be noted that, since the frequency of the square wave voltage signal injected into the d-axis of the motor is high, the square wave voltage signal does not change the method for driving the motor to operate, and the square wave voltage signal is only used as a detection signal for detecting the position of the rotor of the motor. That is, in the embodiment of the present application, the method for estimating the position of the rotor of the motor is improved, and the method for driving the motor to operate is not improved.

[0048] The technical scheme of the present application is further described in detail below in combination with the drawings and specific embodiments of the present application.

[0049] Figure 2 An implementation flowchart of a method for estimating the position of the rotor of a motor provided by the embodiment of the present application is shown. In the embodiment of the present application, the execution subject of the method for estimating the position of the rotor of the motor is a motor driver, or a household appliance including the motor driver and the motor, and the household appliance includes an air conditioner. The motor driver includes various modules as shown in Figure 1

[0050] Referring to Figure 2 , the method for estimating the position of the rotor of the motor provided by the embodiment of the present application includes:

[0051] S201: injecting a square wave voltage signal in a set frequency range into the d-axis of the motor.

[0052] For reference Figure 3 , to accurately estimate the position of the rotor of the motor, an estimated rotation coordinate system of the rotor and an actual rotation coordinate system of the rotor are established as shown in Figure 3 Figure 3 ​​As shown, the αβ coordinate system is the stationary coordinate system of the motor stator; the dq coordinate system is the actual rotating coordinate system of the motor rotor; and the d′q′ coordinate system is the estimated rotating coordinate system of the motor rotor. Among these,

[0053] Both the dq coordinate system and the d′q′ coordinate system rotate synchronously with the rotor of the motor. The d-axis of the dq coordinate system represents the direction of the N pole (rotor permanent magnet flux linkage) of the motor rotor; the d′ axis of the d′q′ coordinate system represents the estimated direction of the N pole of the motor rotor; the rotational speed of the d′q′ coordinate system is consistent with the estimated flux linkage speed.

[0054] The angle between the d-axis and the axis of the α-phase winding is θ, which represents the actual rotor position; the angle between the d′-axis and the axis of the α-phase winding is θ', which represents the estimated rotor position; the angle between the d′-axis and the d-axis (the actual rotor flux linkage position) is Δθ, which represents the rotor position estimation error angle; Δθ = θ - θ'.

[0055] A square wave voltage signal within a set frequency range is injected onto the d′ axis of the d′q′ coordinate system, while no signal is injected onto the q′ axis of the d′q′ coordinate system.

[0056] It should be noted that the injected square wave voltage signal represents a high-frequency voltage signal.

[0057] In some embodiments, injecting a square wave signal within a set frequency range into the d-axis of the motor includes:

[0058] Based on a defined function, a square wave signal within a defined frequency range is injected into the d-axis of the motor; where,

[0059] The expression for the setting function is: u inj =Asgn(sin(2πf) hf t));

[0060] A represents the voltage amplitude of the square wave voltage signal; f hf Characterizing the frequency of the square wave voltage signal; sgn(sin(2πf) hf t)) characterizes sin(2πf hf The step function of t). When t is greater than or equal to 0 and less than or equal to πf hf At that time, sgn(sin(2πf) hf t))=1; when t is greater than πf hf And less than or equal to 2πf hf At that time, sgn(sin(2πf) hf t))=-1.

[0061] Here, a corresponding square wave signal is generated based on a set function, and a square wave signal within a set frequency range is injected into the d-axis of the motor. The frequency f of the square wave voltage signal...hf It is within the set frequency range.

[0062] In some embodiments, the set frequency range is greater than or equal to 100 Hz and less than or equal to 20 kHz.

[0063] S202: Based on the response current corresponding to the square wave voltage signal, and based on the relevant parameters of the square wave voltage signal, the d-axis inductance of the motor and the q-axis inductance of the motor, the rotor position of the motor is estimated.

[0064] Here, the square wave voltage signal injected into the d′ axis of the d′q′ coordinate system of the motor generates a first response current on the d′ axis and a second response current on the q′ axis. After the first response current and the second response current undergo Park inverse transform, Clark inverse transform and Clark transform, the response currents corresponding to the α axis and β axis of the injected square wave voltage signal in the αβ coordinate system are obtained, that is, the α axis response current and the β axis response current.

[0065] In practical applications, since no signal is injected onto the q′ axis of the d′q′ coordinate system, the first response current generated along the d′ axis in the d′q′ coordinate system is zero. At this point, the rotor position of the motor is estimated based on the second response current along the q′ axis, relevant parameters based on the square wave voltage signal, and the motor's d-axis and q-axis inductances. The expression for the second response current along the q′ axis is as follows:

[0066]

[0067] Among them, U f The voltage amplitude characterizes the injected square wave voltage signal; ω f The angular frequency characterizing the injected square wave voltage signal; L d The d-axis inductance of the motor, L q Characterizes the q-axis inductance of the motor.

[0068] Here, since the second response current of the q′ axis can be detected, the voltage amplitude, angular frequency, d-axis inductance of the motor, and q-axis inductance of the injected square wave voltage signal can be substituted into formula (1) to obtain the estimation error Δθ; while the actual rotor position θ is known, θ' can be calculated based on Δθ=θ-θ' to obtain the estimated rotor position.

[0069] It should be noted that, based on the set function u inj =A sgn(sin(2πf) hf When a square wave voltage signal is injected into the d-axis, ω f =2πfhf When t is greater than or equal to 0 and less than or equal to πf hf At that time, U f The voltage amplitude A, i.e., U, is equal to the injected square wave voltage signal. f =A; when t is greater than πf hf And less than or equal to 2πf hf At that time, U f =-A.

[0070] In practical applications, the rotor position of the motor can also be estimated based on the α-axis response current and β-axis response current, as well as the relevant parameters based on the square wave voltage signal, the d-axis inductance and q-axis inductance of the motor.

[0071] The expressions for the α-axis response current and the β-axis response current are as follows:

[0072]

[0073] Here, as can be seen from the above formula (2), the α-axis response current and the β-axis response current are related to the estimation error Δθ. When Δθ≈0, θ=θ'. Since sinΔθ=0, the α-axis response current corresponds to the cosine value of the actual rotor position θ, and the β-axis response current corresponds to the sine value of the actual rotor position θ. Solving the corresponding trigonometric functions will yield the actual rotor position θ, and then the estimated rotor position θ'.

[0074] It should be noted that, given the estimated rotor position of the motor, the estimated speed of the motor can be obtained by differentiating the estimated rotor position.

[0075] In this embodiment, a square wave voltage signal within a set frequency range is injected into the d-axis of the motor. Utilizing the salient pole characteristics of the motor, the rotor position is estimated based on the response current corresponding to the square wave voltage signal, as well as related parameters of the square wave voltage signal, and the d-axis and q-axis inductances of the motor. This solution uses the unequal d-axis and q-axis inductances of the motor to track its rotor position. This process is independent of the motor's back electromotive force; therefore, the rotor position can be estimated even when the motor is stationary or running at low speed.

[0076] As another embodiment of this application, Figure 4 This illustration shows a schematic diagram of the implementation process for estimating the rotor position of a motor, as provided in an embodiment of this application. For example... Figure 4 As shown, based on the response current corresponding to the square wave voltage signal, and based on the relevant parameters of the square wave voltage signal, the d-axis inductance of the motor, and the q-axis inductance of the motor, the rotor position of the motor is estimated, including:

[0077] S401: Based on the power grid fluctuation frequency range, the square wave voltage signal corresponding to the first α-axis response current and the first β-axis response current is filtered to obtain the filtered second α-axis response current and the second β-axis response current.

[0078] Here, based on the power grid fluctuation frequency range, the first α-axis response current and the first β-axis response current are filtered to remove signals in the first α-axis response current and the first β-axis response current that are within the power grid fluctuation frequency range, so as to obtain the filtered second α-axis response current and the second β-axis response current.

[0079] In related technologies, when the bus ripple voltage of the motor is twice the frequency of the power grid, the estimated rotor position of the motor has a large error. Therefore, in practical applications, signals with a frequency twice the frequency of the power grid response current and the first α-axis response current can be filtered out based on the power grid fluctuation frequency to reduce the influence of the twice-frequency signal on the rotor position estimation result and improve the accuracy of the estimated rotor position of the motor.

[0080] S402: Based on the relevant parameters of the square wave voltage signal, the d-axis inductance of the motor, the q-axis inductance of the motor, the second α-axis response current, and the second β-axis response current, the rotor position of the motor is estimated.

[0081] Here, the process of estimating the rotor position of the motor is described in S202, which is based on the α-axis response current and β-axis response current corresponding to the square wave voltage signal. It will not be repeated here.

[0082] In the solution provided in this embodiment, based on the frequency range of power grid fluctuations, the first α-axis response current and the first β-axis response current corresponding to the square wave voltage signal are filtered to remove signals within the power grid fluctuation range from the first α-axis response current and the first β-axis response current, resulting in filtered second α-axis response current and second β-axis response current. Based on the obtained filtered second α-axis response current and second β-axis response current, the rotor position of the motor is estimated. Therefore, the influence of power grid fluctuation signals on the rotor position estimation result can be reduced, improving the accuracy of the estimated rotor position of the motor.

[0083] In some embodiments, S401 may include:

[0084] Based on the power grid fluctuation frequency range, the first α-axis response current corresponding to the square wave voltage signal is subjected to notch filtering to obtain the filtered second α-axis response current.

[0085] Based on the power grid fluctuation frequency range, the first β-axis response current corresponding to the square wave voltage signal is subjected to notch filtering to obtain the filtered second β-axis response current.

[0086] Here, based on the power grid fluctuation frequency range, the first α-axis response current and the first β-axis response current are subjected to at least one notch filter process to filter out signals in the first α-axis response current and the first β-axis response current whose frequencies are within the power grid fluctuation frequency range.

[0087] In practical applications, when performing a single notch filter on the first α-axis response current and the first β-axis response current, the center frequency of the notch filter is twice the grid fluctuation frequency. When using at least two notch filters connected in series to perform at least two notch filters on the first α-axis response current and the first β-axis response current, the center frequency of each notch filter is different, and the center frequency is always a multiple of the grid fluctuation frequency. For example, the center frequency of the notch filter is f0 = nf. g , where n represents a positive integer determined based on the power grid fluctuation frequency range. Here, f0 represents the center frequency of the notch filter; f g Characterizes the frequency of the power grid.

[0088] In practical applications, the power grid frequency is typically 50Hz. n is an integer greater than or equal to 1.

[0089] Reference Figure 5 In practical applications, the first α-axis response current and the first β-axis response current corresponding to the square wave voltage signal can be subjected to high-pass filtering, first-order hysteresis processing, and low-pass filtering to obtain the processed first α-axis response current and the processed first β-axis response current. Then, based on the power grid fluctuation frequency range, the processed first α-axis response current and the processed first β-axis response current are subjected to at least one notch filter processing to obtain the filtered second α-axis response current and the second β-axis response current.

[0090] In some embodiments, S401 includes:

[0091] Based on the power grid fluctuation frequency range, the first α-axis response current corresponding to the square wave voltage signal is bandpass filtered to obtain the third α-axis response current.

[0092] The difference between the first α-axis response current and the third α-axis response current is determined as the filtered second α-axis response current.

[0093] Based on the power grid fluctuation frequency range, the first β-axis response current corresponding to the square wave voltage signal is bandpass filtered to obtain the third β-axis response current.

[0094] The difference between the first β-axis current and the third β-axis response current is determined as the filtered second β-axis response current.

[0095] Here, based on the power grid fluctuation frequency range, parallel bandpass filters are used to perform at least one bandpass filtering process on the first α-axis response current and the first β-axis response current, respectively, so as to allow signals in the first α-axis response current and the first β-axis response current that are in the power grid fluctuation frequency range to pass through, thereby obtaining the corresponding third α-axis response current and the third β-axis response current.

[0096] Given the third α-axis response current, the difference between the first α-axis response current and the third α-axis response current is calculated to remove signals in the first α-axis response current whose frequency falls within the grid fluctuation frequency range, thus obtaining the second α-axis response current.

[0097] Given the third β-axis response current, the difference between the first β-axis response current and the third β-axis response current is calculated. This allows the removal of signals in the first β-axis response current whose frequencies fall within the grid fluctuation frequency range, thus obtaining the second β-axis response current.

[0098] Reference Figure 6 In practical applications, the first α-axis response current and the first β-axis response current corresponding to the square wave voltage signal can be subjected to high-pass filtering, first-order hysteresis processing, and low-pass filtering to obtain the processed first α-axis response current and the processed first β-axis response current. Then, based on the power grid fluctuation frequency range, the processed first α-axis response current and the processed first β-axis response current are subjected to at least one band-pass filtering to obtain the filtered second α-axis response current and the second β-axis response current.

[0099] As another embodiment of this application, Figure 7 This diagram illustrates the implementation flow of a method for estimating the rotor position of a motor according to an embodiment of this application. (Refer to...) Figure 7 The method for estimating the rotor position of a motor provided in this application includes:

[0100] S701: Determine the q-axis and d-axis given voltages of the motor.

[0101] Here, the q-axis given current of the motor is determined based on the phase of the input voltage, the given speed of the motor, and the estimated speed of the motor; the q-axis given voltage of the motor is determined based on the given current of the motor and the actual current of the motor's q-axis; and the d-axis given voltage of the motor is determined based on the given current of the motor's d-axis and the given current of the motor's d-axis.

[0102] It should be noted that the estimated speed of the motor is the rotor speed estimated most recently using the motor's back electromotive force.

[0103] The following details the process of determining the q-axis given current, d-axis given current, q-axis given voltage, and d-axis given voltage of the motor:

[0104] like Figure 8 As shown, after obtaining the three-phase symmetrical sinusoidal alternating current i of the motor abc In the case of the three-phase symmetrical sinusoidal alternating current i of the motor abc Perform a Clark transformation to obtain the α-axis current i of the motor. α and the β-axis current i of the motor β For the α-axis current i α and β-axis current i β Perform the Park transformation to obtain the actual d-axis current i of the motor. d and the actual q-axis current i of the motor q .

[0105] Using the back electromotive force of the motor and based on relevant motor parameters, the estimated angle of the motor rotor can be estimated. and estimated rotational speed The relevant parameters of the motor include: the α-axis current i. α The β-axis current i of the motor β α-axis voltage u of the motor α β-axis voltage u of the motor β The permanent magnet flux linkage ψ of the motor f The actual d-axis current i of the motor d The actual q-axis current i of the motor q And the resistance of the motor, etc.

[0106] Using a phase-locked loop, based on the input voltage u in Determine the phase θ of the input voltage. g Using a current waveform generator based on the phase θ of the input voltage g The first current W is generated. f Among them, W f =|sin(θ) g )|.

[0107] For the given speed of the motor and estimated rotational speed Perform proportional-integral (PI) control to obtain the first proportional-integral calculation result T. p The result T of the first proportional integral operation e and the first current W f Perform multiplication to obtain the given torque T of the motor. e Among them, T e =T p ×W f ;

[0108] Here, K P Characterized by the proportional control coefficient, K p =Jω asr / p;K i Characterizing the integral control coefficient, J represents the moment of inertia of the motor; p represents the number of pole pairs of the motor; ω asr Characterizes the bandwidth of the current loop; The damping coefficient characterizes the motor. In practical applications, the bandwidth of the current loop is set to 20 Hz.

[0109] After obtaining the given torque T of the motor e In this case, based on the calculation formula for the q-axis given current and the given torque of the motor, the q-axis given current of the motor is determined; through the formula... Determine the q-axis setpoint voltage u of the motor. q .

[0110] The formula for calculating the q-axis current setting is as follows:

[0111] i q_ref Characterizes the given q-axis current; T e The given torque of the motor is represented by p; the number of pole pairs of the motor is represented by k. T Characterizing the back electromotive force of the motor; i d Characterized by the actual d-axis current of the motor; L d Characterizing the d-axis inductance of the motor; L q ψ represents the q-axis inductance of the motor. f This refers to the permanent magnet flux linkage of the motor.

[0112] Based on the calculation formula for the motor's d-axis setpoint current, and based on the output voltage amplitude and maximum output voltage of the inverter circuit, the motor's d-axis setpoint current i is determined. d_ref ; through formula Determine the d-axis setpoint voltage u of the motor. d The formula for calculating the d-axis current setting is as follows:

[0113] Here, K id Characterizes the set integral control coefficient; Characterization pairs Integrate points; The output voltage amplitude, u, represents the inverter circuit. dref The most recently determined d-axis given voltage, u qref U represents the most recently determined q-axis given voltage; max Characterizes the maximum output voltage of the inverter circuit. u dc Characterizes the DC bus voltage of the motor.

[0114] It should be noted that, in the k-th determination of the given d-axis current i d_ref At that time, u dref Given the d-axis voltage determined in the (k-1)th iteration, u qref The given voltage for the q-axis is determined in the (k-1)th iteration.

[0115] S702: Inject a square wave voltage signal within a set frequency range into the d-axis of the motor.

[0116] Here, S702 is the same as S201 in the previous embodiment. Please refer to the relevant description in S201.

[0117] S703: Control the motor based on the square wave voltage signal, the estimated angle of the motor, the q-axis given voltage of the motor, and the d-axis given voltage of the motor.

[0118] Here, after determining the estimated angle of the motor... The q-axis given voltage u of the motor q and the given voltage u on the d-axis d In this case, the estimated angle based on the motor Perform an inverse Park transform on the determined q-axis and d-axis voltages to obtain the α-axis voltage u. α and β-axis voltage u β ; for the α-axis voltage u α and β-axis voltage u β The Clark inverse transform is performed to obtain the three-phase voltage command. Based on the three-phase voltage command and the DC bus voltage of the motor, space vector modulation (SVM) is performed to determine the duty cycle control signal. Based on the duty cycle control signal, a PWM signal is output to the inverter module to drive the motor through the PWM signal.

[0119] A square wave voltage signal injected into the d′ axis of the d′q′ coordinate system of the motor generates a first response current on the d′ axis and a second response current on the q′ axis. After passing through the Park inverse transform, Clark inverse transform, and Clark transform, the first and second response currents are used to obtain the response currents corresponding to the α axis and β axis of the injected square wave voltage signal in the αβ coordinate system, respectively, namely, the α-axis response current and the β-axis response current.

[0120] S704: Based on the response current corresponding to the square wave voltage signal, and based on the relevant parameters of the square wave voltage signal, the d-axis inductance of the motor, and the q-axis inductance of the motor, the rotor position of the motor is estimated.

[0121] For the process of estimating the rotor position of the motor, please refer to the relevant description in S202, which will not be repeated here.

[0122] It should be noted that the rotor position of the motor can also be estimated based on S401 to S402.

[0123] In the solution provided in this embodiment, the q-axis and d-axis given voltages of the motor are determined; a square wave voltage signal within a set frequency range is injected into the d-axis of the motor; the motor is controlled based on the square wave voltage signal, the estimated angle of the motor, the q-axis given voltage, and the d-axis given voltage; the rotor position of the motor is estimated based on the response current corresponding to the square wave voltage signal, as well as related parameters of the square wave voltage signal, the d-axis inductance, and the q-axis inductance. Because the d-axis and q-axis inductances of the motor are not equal (the salient pole characteristic of the motor), the rotor position of the motor is tracked, eliminating the need for back electromotive force. Therefore, the rotor position of the motor can be estimated when the motor is stationary or running at low speed.

[0124] To implement the method of the embodiments of this application, the embodiments of this application also provide a device for estimating the position of a motor rotor, which is installed on a motor driver, or on a household appliance including a motor driver and a motor, such as... Figure 9 As shown, the device for estimating the position of the motor rotor includes:

[0125] The signal injection unit 91 is used to inject a square wave voltage signal within a set frequency range into the d-axis of the motor.

[0126] The rotor position estimation unit 92 is used to estimate the rotor position of the motor based on the response current corresponding to the square wave voltage signal, and based on the relevant parameters of the square wave voltage signal, the d-axis inductance of the motor and the q-axis inductance of the motor.

[0127] In some embodiments, the rotor position estimation unit 92 is used for:

[0128] Based on the power grid fluctuation frequency range, the square wave voltage signal is filtered to obtain the filtered second α-axis response current and second β-axis response current.

[0129] Based on the relevant parameters of the square wave voltage signal, the d-axis inductance of the motor, the q-axis inductance of the motor, the second α-axis response current, and the second β-axis response current, the rotor position of the motor is estimated.

[0130] In some embodiments, the rotor position estimation unit 92 is used for:

[0131] Based on the power grid fluctuation frequency range, the first α-axis response current corresponding to the square wave voltage signal is subjected to notch filtering to obtain the filtered second α-axis response current.

[0132] Based on the power grid fluctuation frequency range, the first β-axis response current corresponding to the square wave voltage signal is subjected to notch filtering to obtain the filtered second β-axis response current.

[0133] In some embodiments, the rotor position estimation unit 92 is used for:

[0134] Based on the power grid fluctuation frequency range, the first α-axis response current corresponding to the square wave voltage signal is bandpass filtered to obtain the third α-axis response current.

[0135] The difference between the first α-axis response current and the third α-axis response current is determined as the filtered second α-axis response current.

[0136] Based on the power grid fluctuation frequency range, the first β-axis response current corresponding to the square wave voltage signal is bandpass filtered to obtain the third β-axis response current.

[0137] The difference between the first β-axis current and the third β-axis response current is determined as the filtered second β-axis response current.

[0138] In some embodiments, the signal injection unit 91 is used to inject a square wave voltage signal within a set frequency range into the d-axis of the motor, including:

[0139] Based on a set function, a square wave voltage signal within a set frequency range is injected into the d-axis of the motor; wherein, the expression of the set function is: u inj =A sgn(sin(2πf) hf t));

[0140] A represents the voltage amplitude of the square wave voltage signal; f hf The frequency of the square wave voltage signal is characterized.

[0141] In some embodiments, the set frequency range is greater than or equal to 100 Hz and less than or equal to 20 kHz.

[0142] In practical applications, the various units included in the device for estimating the motor rotor position can be implemented by the processor within that device. Of course, the processor needs to run programs stored in memory to implement the functions of each of the aforementioned program modules.

[0143] It should be noted that the above embodiments of the device for estimating the rotor position of a motor are only illustrated by the division of the above-described program modules. In practical applications, the above processing can be assigned to different program modules as needed, that is, the internal structure of the device for estimating the rotor position of a motor can be divided into different program modules to complete all or part of the processing described above. Furthermore, the device for estimating the rotor position of a motor provided in the above embodiments and the method embodiments for estimating the rotor position of a motor belong to the same concept; the specific implementation process is detailed in the method embodiments and will not be repeated here.

[0144] Based on the hardware implementation of the above program modules, and in order to implement the method of the embodiments of this application, the embodiments of this application also provide a home appliance. Figure 10 This is a schematic diagram of the hardware composition structure of the home appliance provided in the embodiments of this application, such as... Figure 10 As shown, the home appliances include:

[0145] Communication interface 1 enables information exchange with other devices, such as remote controls;

[0146] Processor 2, connected to communication interface 1, enables information exchange with other devices and, when running a computer program, executes the method for estimating the motor rotor position provided by one or more of the above-mentioned technical solutions. The computer program is stored in memory 3.

[0147] Motor driver 4 is used to drive motor 5.

[0148] Of course, in practical applications, the various components in a household appliance are coupled together through bus system 6. It can be understood that bus system 6 is used to achieve communication and connection between these components. In addition to the data bus, bus system 6 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in... Figure 10 The general will label all buses as Bus System 6.

[0149] The memory 3 in this embodiment is used to store various types of data to support the operation of home appliances. Examples of such data include any computer programs used to operate the home appliances.

[0150] It is understood that memory 3 can be volatile memory or non-volatile memory, or both. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), ferromagnetic random access memory (FRAM), flash memory, magnetic surface memory, optical disc, or compact disc read-only memory (CD-ROM); magnetic surface memory can be disk storage or magnetic tape storage. Volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Synchronous Static Random Access Memory (SSRAM), Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDRSDRAM), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM), Sync Link Dynamic Random Access Memory (SLDRAM), and Direct Rambus Random Access Memory (DRRAM).The memory 3 described in the embodiments of this application is intended to include, but is not limited to, these and any other suitable types of memory.

[0151] The methods disclosed in the embodiments of this application can be applied to processor 2, or implemented by processor 2. Processor 2 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the integrated logic circuit of the hardware in processor 2 or by instructions in the form of software. The processor 2 may be a general-purpose processor, DSP, or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. Processor 2 can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the methods disclosed in the embodiments of this application can be directly manifested as being executed by a hardware decoding processor, or being executed by a combination of hardware and software modules in the decoding processor. The software modules may be located in a storage medium, which is located in memory 3. Processor 2 reads the program in memory 3 and completes the steps of the aforementioned method in combination with its hardware.

[0152] When processor 2 executes the program, it implements the process corresponding to the multi-core processor in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0153] In an exemplary embodiment, this application also provides a storage medium, namely a computer storage medium, specifically a computer-readable storage medium, such as a memory 3 that stores a computer program, which can be executed by a processor 2 to complete the steps described in the foregoing embodiments. The computer-readable storage medium may be a memory such as FRAM, ROM, PROM, EPROM, EEPROM, Flash Memory, magnetic surface memory, optical disc, or CD-ROM.

[0154] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0155] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected to achieve the purpose of this embodiment according to actual needs.

[0156] Furthermore, in the various embodiments of this application, all functional units can be integrated into one processing module, or each unit can be a separate unit, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in a combination of hardware and software functional units. Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as mobile storage devices, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0157] It should be noted that the technical solutions described in the embodiments of this application can be combined arbitrarily without conflict.

[0158] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method of estimating a position of a rotor of an electrical machine, characterized by, The method comprises: injecting a square wave voltage signal in a set frequency range to a d-axis of the motor; estimating a rotor position of the motor based on a corresponding response current of the square wave voltage signal, and based on a related parameter of the square wave voltage signal, a d-axis inductance of the motor, and a q-axis inductance of the motor; the injecting a square wave voltage signal in a set frequency range to a d-axis of the motor comprises: injecting a square wave voltage signal in a set frequency range to a d-axis of the motor based on a set function; wherein, The expression of the set function is: ; characterizing the step function with respect to ; The A represents a voltage amplitude of the square wave voltage signal; the The A represents a voltage amplitude of the square wave voltage signal; the The method for estimating the rotor position of the motor based on the corresponding response current of the square wave voltage signal and based on the related parameters of the square wave voltage signal, the d-axis inductance of the motor and the q-axis inductance of the motor comprises: filtering a first alpha-axis response current and a first beta-axis response current corresponding to the square wave voltage signal based on a power grid fluctuation frequency range, to obtain a filtered second alpha-axis response current and a filtered second beta-axis response current; estimating a rotor position of the motor based on a related parameter of the square wave voltage signal, a d-axis inductance of the motor, a q-axis inductance of the motor, the second alpha-axis response current, and the second beta-axis response current.

2. The method of claim 1, wherein, the filtering a first alpha-axis response current and a first beta-axis response current corresponding to the square wave voltage signal based on a power grid fluctuation frequency range, to obtain a filtered second alpha-axis response current and a filtered second beta-axis response current, comprises: notch filtering the first alpha-axis response current corresponding to the square wave voltage signal based on a power grid fluctuation frequency range, to obtain the filtered second alpha-axis response current; notch filtering the first beta-axis response current corresponding to the square wave voltage signal based on a power grid fluctuation frequency range, to obtain the filtered second beta-axis response current.

3. The method of claim 1, wherein, the filtering a first alpha-axis response current and a first beta-axis response current corresponding to the square wave voltage signal based on a power grid fluctuation frequency range, to obtain a filtered second alpha-axis response current and a filtered second beta-axis response current, comprises: band-pass filtering the first alpha-axis response current corresponding to the square wave voltage signal based on a power grid fluctuation frequency range, to obtain a third alpha-axis response current; determining a difference between the first alpha-axis response current and the third alpha-axis response current as the filtered second alpha-axis response current; band-pass filtering the first beta-axis response current corresponding to the square wave voltage signal based on a power grid fluctuation frequency range, to obtain a third beta-axis response current; determining a difference between the first beta-axis response current and the third beta-axis response current as the filtered second beta-axis response current.

4. The method of claim 1, wherein, The set frequency range is greater than or equal to 100 Hz and less than or equal to 20 kHz.

5. An apparatus for estimating a rotor position of an electric machine, characterized by The method comprises: a signal injection unit configured to inject a square wave voltage signal in a set frequency range to a d-axis of the motor; a rotor position estimation unit configured to estimate a rotor position of the motor based on a corresponding response current of the square wave voltage signal, and based on a related parameter of the square wave voltage signal, a d-axis inductance of the motor, and a q-axis inductance of the motor; the injecting a square wave voltage signal in a set frequency range to a d-axis of the motor comprises: injecting a square wave voltage signal in a set frequency range to a d-axis of the motor based on a set function; wherein, The expression of the set function is: ; characterizing the step function with respect to ; The A characterizes a voltage amplitude of the square wave voltage signal; the characterizes a frequency of the square wave voltage signal; The rotor position of the motor is estimated based on the response current corresponding to the square wave voltage signal, and based on the related parameters of the square wave voltage signal, the d-axis inductance of the motor, and the q-axis inductance of the motor, including: The first alpha-axis response current and the first beta-axis response current corresponding to the square wave voltage signal are filtered based on the power grid fluctuation frequency range to obtain filtered second alpha-axis response current and second beta-axis response current; The rotor position of the motor is estimated based on the related parameters of the square wave voltage signal, the d-axis inductance of the motor, the q-axis inductance of the motor, the second alpha-axis response current, and the second beta-axis response current.

6. An electric motor drive, characterized by It includes: a processor and a memory for storing a computer program capable of running on the processor, wherein the processor is configured to execute the steps of the method of any one of claims 1 to 4 when running the computer program.

7. A domestic appliance characterized in that, It includes: a motor driver, a motor, a processor, and a memory for storing a computer program capable of running on the processor, wherein the processor is configured to execute the steps of the method of any one of claims 1 to 4 when running the computer program.

8. A storage medium having stored thereon a computer program, characterized in that The computer program is executed by the processor to implement the steps of the method of any one of claims 1 to 4.

Images