Identification and classification of current gain errors and resistance imbalances in synchronous motor drivers under feedback current control

Abstract

A method for detecting and differentiating current measurement gain errors and resistance imbalances in a motor drive system includes determining a first voltage command signal, a first motor position signal, and a first quadrature axis current command when a motor is rotated at a first speed; calculating a first demodulated voltage signal based on the first voltage command and the motor position signal; determining a second voltage command signal, a second motor position signal, and a second quadrature axis current command when the motor rotates at a second speed different from the first speed; calculating a second demodulated voltage signal based on the second voltage command and the motor position signal; and calculating a resistance imbalance flag indicative of the resistance imbalance and a current gain error flag indicative of the current sense gain error.

Description

Technical Field

[0001] The present disclosure relates to motor drives, and more particularly to detection and differentiation between current measurement scaling errors and resistance imbalance in a synchronous motor drive system operating under feedback current control. Background Art

[0002] Vehicles (such as cars, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable forms of transportation) typically include a steering system, such as an electric power steering (EPS) system, a steer-by-wire (SbW) steering system, a hydraulic steering system, or other suitable steering system. The steering system and / or other features of the vehicle may include one or more electric motors. Such electric motors may include synchronous motors, such as permanent magnet synchronous motors (PMSMs).

[0003] Safety-critical, high-performance, and fault-tolerant applications that employ PMSM drives (such as electric steering and automotive traction, to name a few) require intelligent diagnostic algorithms that are able to distinguish between different non-ideal conditions or faults that may have similar characteristics, in addition to detecting problems in different parts of the motor drive system.

[0004] Synchronous motors under feedback current control operation generate current and voltage harmonics at twice the synchronous frequency in response to phase-to-phase resistance unbalance and current sensor gain (scaling) errors. The similarity in the characteristics of these two non-ideal conditions creates difficulties in developing algorithms that utilize different signals to detect the presence of or distinguish between the two problems, especially when the two problems occur simultaneously. Summary of the invention

[0005] The present disclosure generally relates to the control of electric machines.

[0006] One aspect of the disclosed embodiment includes a method for detecting and distinguishing between current measurement gain error and resistance imbalance in a motor drive system. The method includes: determining a first voltage command signal, a first motor position signal, and a first quadrature-axis current command for the motor when the motor rotates at a first speed; calculating a first demodulated voltage signal based on the first voltage command signal and the first motor position signal; determining a second voltage command signal, a second motor position signal, and a second quadrature-axis current command when the motor rotates at a second speed different from the first speed; calculating a second demodulated voltage signal based on the second voltage command signal and the second motor position signal; and calculating each of a resistance imbalance flag and a current gain error flag based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command. The resistance imbalance flag has a non-zero value responsive to the resistance imbalance in the motor and is not affected by the current sensing gain error. The current gain error flag has a non-zero value responsive to the current sensing gain error and is not affected by the resistance imbalance in the motor.

[0007] Another aspect of the disclosed embodiment includes an electronic controller. The electronic controller includes a processor and a memory. The memory includes instructions that, when executed by the processor, cause the processor to perform the following operations: when the motor rotates at a first speed, determine a first voltage command signal, a first motor position signal, and a first quadrature-axis current command for the motor; calculate a first demodulated voltage signal based on the first voltage command signal and the first motor position signal; when the motor rotates at a second speed different from the first speed, determine a second voltage command signal, a second motor position signal, and a second quadrature-axis current command; calculate a second demodulated voltage signal based on the second voltage command signal and the second motor position signal; and calculate each of a resistance imbalance flag and a current gain error flag based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command. The resistance imbalance flag has a non-zero value responsive to a resistance imbalance in the motor and is not affected by a current sensing gain error. The current gain error flag has a non-zero value responsive to a current sensing gain error and is not affected by a resistance imbalance in the motor.

[0008] Another aspect of the disclosed embodiment includes a system for detecting and distinguishing between current measurement gain error and resistance imbalance in a motor drive system. The system includes a controller configured to: determine a first voltage command signal, a first motor position signal, and a first quadrature-axis current command for the motor when the motor rotates at a first speed; calculate a first demodulated voltage signal based on the first voltage command signal and the first motor position signal; determine a second voltage command signal, a second motor position signal, and a second quadrature-axis current command when the motor rotates at a second speed different from the first speed; calculate a second demodulated voltage signal based on the second voltage command signal and the second motor position signal; and calculate each of a resistance imbalance flag and a current gain error flag based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command. The resistance imbalance flag has a non-zero value responsive to the resistance imbalance in the motor and is not affected by the current sensing gain error. The current gain error flag has a non-zero value responsive to the current sensing gain error and is not affected by the resistance imbalance in the motor.

[0009] These and other aspects of the present disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present disclosure will be best understood from the following detailed description in conjunction with the accompanying drawings. It should be emphasized that, according to common practice, the various features of the drawings are not drawn to scale. On the contrary, the sizes of the various features are arbitrarily enlarged or reduced for clarity.

[0011] Figure 1 A motor drive system under feedback current control with a non-ideal operation detector according to the principles of the present disclosure is generally shown.

[0012] Figure 2 A synchronous motor drive system under feedback current control in the presence of both current sensor gain error and resistance imbalance according to the principles of the present disclosure is shown.

[0013] Figure 3 A block diagram showing hardware components of a motor drive system according to aspects of the present disclosure is shown.

[0014] Figure 4 A flow chart generally illustrates a method for detecting and distinguishing between current measurement gain error and resistance imbalance in a motor drive system in accordance with the principles of the present disclosure. DETAILED DESCRIPTION

[0015] The following discussion is directed to various embodiments of the present disclosure. Although one or more of these embodiments may be preferred, the disclosed embodiments should not be interpreted or otherwise used to limit the scope of the present disclosure (including the claims). In addition, it will be understood by those skilled in the art that the following description has a wide range of applications, and the discussion of any embodiment is only meant as an example of that embodiment, and is not intended to imply that the scope of the present disclosure (including the claims) is limited to that embodiment.

[0016] This disclosure uses ^ (corner hat) to indicate estimated parameters, * (asterisk) to indicate command parameters, and ˉ (overscore) to indicate vector parameters.

[0017] The present disclosure provides a detailed mathematical model for a synchronous motor drive that considers both of the above issues simultaneously, and explains the specific impact of each issue and their relative dominance on the signal in different operating ranges so that they can be identified and distinguished. The present disclosure also provides a strategy for distinguishing different types of errors (current gain / resistance imbalance / both) over the entire range of operating conditions.

[0018] The present disclosure provides an algorithm for detecting the presence of resistance imbalance and / or current measurement gain error during vehicle operation. The systems and methods of the present disclosure can be used as diagnostics to take necessary actions after an error is detected, such as generating a corresponding error message, and / or utilizing a fallback or redundant set of motor windings and / or current sensors depending on the type of error identified.

[0019] Figure 1 A synchronous motor drive system 100 with feedback current control according to the principles of the present disclosure is generally shown. The system 100 may include a current command generator 112, a current regulator 114, a commutation controller 106, a gate driver 107, an inverter 104, a motor 102, a current sensor 110, a current estimator 118, a position estimator 116, and a position sensor 108.

[0020] In some embodiments, the current regulator 114, the commutation controller 106, the gate driver 107, the inverter 104, the motor 102, the current sensor 110, and the current estimator 118 form a closed-loop current control system. It should be noted that fewer or more components may be included in the system 100 as needed to perform the techniques disclosed herein, and the depicted components are for explanation purposes.

[0021] In some embodiments, the synchronous motor drive system 100 can operate as follows. The current regulator 114 receives a command or reference current and outputs a corresponding voltage command signal. The position sensor 108 can be configured to sense the position of the motor 102. The position sensor 108 can communicate the sensed position to the position estimator 116. The position estimator 116 can estimate one or more positions of the motor 102 based on the position sensed by the position sensor 108.

[0022] Based on the foregoing, additional details and operation of the system 100 will now be discussed. The motor 102 can generate rotational or linear forces that are used to power a machine, such as the machine described herein. The motor 102 can include a synchronous motor, such as a PMSM or other suitable motor. The system 100 can selectively control the electrical energy provided to the motor 102. The system 100 can provide electrical energy to the motor 102 in varying amounts and varying frequencies, thereby indirectly controlling the speed and torque of the motor 102.

[0023] The current sensor 110 may include any suitable current sensor configured to sense or measure current in a circuit. The current sensor 110 may provide a signal indicative of the current to the current estimator 118. The current sensor 110 may be configured to receive the signal indicative of the current and measure the amount of current output by the motor 102 (e.g., based on the current indicated by the signal). The current estimator 118 may be configured to send the stationary frame current of the motor 102 or transform the measured current into a synchronous reference frame using a position estimate from a position estimator 116 of the motor 102.

[0024] The current command generator 112 may receive a torque command The current command generator 112 can generate a command current based on the torque command Current command I * Can be made of straight shaft Current Components and Quadrature Axis The current regulator 114 receives the command current and sends a voltage command signal to the commutation controller 106 The voltage command V* can be composed of the direct axis component and quadrature axis The commutation controller 106 can control the proportion of time that the output voltage signal is high compared to low in a continuous period of time, which can control the direction and speed of the motor 102. The gate driver 107 receives one or more signals from the commutation controller 106 and uses the one or more signals to control the conductive state of one or more switches in the inverter 104. The inverter 104 can include a voltage source inverter or other suitable inverter, and can be configured to change the frequency of the supply power provided to the motor 102 to control the speed of the motor 102. The motor 102 can receive the output voltage signal V abc As an input (for example, the output voltage signal may include V a 、V b , and V c ). The motor 102 can use this input to generate a certain amount of current I abc As an output (for example, a current may include I a ,I b and I c ), which current can be equal to the command current or different from the command current (for example, when current harmonics are present).

[0025] The current I output from the motor 102 abc The current sensor 110 may sense the current to determine the measured current. The current estimator 118 may receive the measured current and determine the estimated current. The current estimator 118 estimates the current The output is to the current regulator 114. Thus, as depicted, the system 100 uses a closed loop. However, as discussed, in some cases, the measured current may not be correct due to circuit degradation, drift, etc.

[0026] The current regulator 114 may receive the estimated current and compare the estimated current to the commanded current. If there is any change, the current regulator 114 can send an output voltage command signal The output voltage command signal will cause the estimated current With command current Therefore, due to the command current is constant (or slowly varying), and since the estimated current Equal to the command current Therefore, the estimated current When current harmonics exist in the current measurement system, the current regulator 114 can output the voltage command signal The pulsating component is included.

[0027] In some embodiments, Figure 1As shown, the synchronous motor drive system 100 also includes a non-ideal operation detector 122, which is configured to determine one or more of a resistance imbalance in the motor 102 and / or a current sensing gain error of the current sensor 110. The non-ideal operation detector 122 uses the output voltage command signal from the current regulator 114 to As input, the non-ideal operation detector 122 may generate one or more output signals indicating the presence and / or characteristics of a resistance imbalance and / or a current sensing gain error.

[0028] Figure 2 A mathematical model 200 for closed-loop current control in the presence of both current gain error and resistance imbalance is shown in FIG. The mathematical model 200 includes a first subtractor 202 that obtains a command current having a direct-axis component and a quadrature-axis component. and provides a differential signal to the forward path current controller 204, which is also labeled The forward path current controller 204 may implement the transfer function The transfer function can be defined as:

[0029]

[0030] The mathematical model 200 also includes a BEMF compensator 206 (also labeled ), the BEMF compensator generates a back-EMF compensation voltage signal that compensates for the back-EMF generated in the motor 102. The BEMF compensator 206 may generate a back-EMF compensation voltage signal having a direct-axis component and a quadrature-axis component and may be defined as: The mathematical model 200 also includes a first adder 208 that adds the output of the forward path current controller 204 to the back EMF compensation voltage signal to generate a voltage command signal having a direct-axis component and a quadrature-axis component and representing a voltage command for the inverter 104.

[0031] The mathematical model 200 also includes an inverter model 210, which is also labeled The inverter model is based on the voltage command signal Calculate the actual voltage signal and models the delay caused by the operation of the inverter 104. The voltage generation model 210 may be defined as: Where T p Represents the propagation delay.

[0032] Mathematical model 200 also includes plant models 212, 214, 216, 218, 220, which together model the operation of motor 102 based on actual voltage signals. Determine the actual current signal The plant models 212, 214, 216, 218, 220 include a resistance unbalance model 212, which is also referred to as The resistance imbalance model generates a signal representative of the noise caused by the imbalance in the resistance of the stator windings of the motor 102. The resistance imbalance model 212 may be defined as: Where K r is the magnitude of resistance unbalance, Φ r K is the resistance unbalance angle representing the angle of resistance unbalance error. r can be used to indicate one or more specific stator windings that have resistance imbalance. The plant models 212, 214, 216, 218, 220 also include a second subtractor 214 that subtracts the actual voltage signal from the actual voltage signal The output of the resistance unbalance model 212 is subtracted from the output of the resistance unbalance model 212

[0033] The plant models 212, 214, 216, 218, 220 also include a BEMF model 216 that models the back EMF effects of the motor 102. The BEMF model 216 may be defined as: The plant model 212 , 214 , 216 , 218 , 220 also includes a third subtractor 218 that subtracts the output of the BEMF model 216 from the output of the second subtractor 214 .

[0034] The plant models 212, 214, 216, 218, 220 also include a plant winding model 220, which is also labeled The object winding model 220 takes the output of the third subtractor 218 as input and calculates the actual current signal The object winding model 220 can realize the transfer function The transfer function can be defined as:

[0035]

[0036] The mathematical model 200 also includes current measurement models 222, 224, 226, which together model the operation of the current sensor to generate a current signal based on the actual current signal. Determine the measured current signal The current measurement models 222, 224, 226 include the position-independent model 222, which is also labeled Position-independent sensor model 222 obtains actual current signal And calculate a position-independent measured current signal that does not vary with the position of the motor 102. The position-independent sensor model 222 may be defined as: The current measurement models 222, 224, 226 also include a position-dependent sensor model 224, which is also labeled Position-dependent sensor model 224 obtains actual current signal and calculates a position-dependent measured current signal that varies with the position of the motor 102. The position-dependent sensor model 224 may be defined as: The position-dependent sensor model uses the current sensing gain error Φ gp The current measurement models 222, 224, 226 also include a second adder 226 that adds the position-independent measured current signal and the position-dependent measured current signal from the position-independent sensor model 222 and the position-dependent sensor model 224, respectively, to generate a measured current signal.

[0037] In some embodiments, the system of the present disclosure may include a controller 150, such as Figure 3 . The controller 150 may include any suitable controller, such as an electronic control unit or other suitable controller. The controller 150 may be configured to control various functions of, for example, a steering system and / or various functions of a vehicle. The controller 150 may include a processor 152 and a memory 154. The processor 152 may include any suitable processor, such as the processor described herein. Additionally or alternatively, in addition to or different from the processor 152, the controller 150 may include any suitable number of processors. The memory 154 may include a single disk or multiple disks (e.g., a hard disk drive), and include a storage management module that manages one or more partitions within the memory 154. In some embodiments, the memory 154 may include a flash memory, a semiconductor (solid-state) memory, and the like. The memory 154 may include a random access memory (RAM), a read-only memory (ROM), or a combination thereof. The memory 154 may include instructions that, when executed by the processor 152, cause the processor 152 to control at least various aspects of the vehicle. Additionally or alternatively, the memory 154 may include instructions that, when executed by the processor 152, cause the processor 152 to perform functions associated with the systems and methods described herein.

[0038] The controller 150 may be operably connected to the electric actuator 156. The electric actuator 156 may include the motor 102 and the inverter 104. The controller 150 may be configured to command the inverter to drive the motor 102 to rotate at a given speed or to generate a given amount of torque. The controller 150 may receive one or more signals from the electric actuator 156, for example, a signal indicating a voltage applied to the motor 102. In some embodiments, the electric actuator 156 may include a position sensor 108, which may be configured to measure the rotational position of the motor 102.

[0039] Alternatively or additionally, the electric actuator 156 may include a current sensor 110 that can measure a phase current of one or more conductors between the inverter 104 and the motor 102. In some embodiments, the electric actuator 156 may include one or more other sensors, such as one or more torque sensors or devices, one or more steering wheel position sensors or devices, one or more motor position sensors or devices, one or more position sensors or devices, other suitable sensors or devices, or combinations thereof.

[0040] In some embodiments, the controller 150 may perform the methods described herein. However, the methods described herein as performed by the controller 150 are not meant to be limiting, and any type of software executed on a controller or processor may perform the methods described herein without departing from the scope of the present disclosure. For example, the methods described herein may be performed by a controller, such as a processor executing software within a computing device.

[0041] In order to understand and differentiate between them, and then develop and implement appropriate detection and mitigation techniques in a robust manner, it is beneficial to develop a detailed mathematical model of the simultaneous occurrence of current measurement gain error and resistance imbalance.

[0042] Analytical Modeling - Resistance Unbalance

[0043] The mathematical model for the resistance unbalance in a PMSM in the synchronous or dq reference frame is given in equation system (1):

[0044]

[0045] Where V represents the actual voltage applied to the stator winding of the motor 102, which can also be written as P -1 is the inverse object model; I is the actual current signal, which can also be written as E is a BEMF model representing the voltage generated by the back electromotive force in the motor 102; N is a noise transfer function that describes the effect of the unbalance of the phase resistance in the motor 102; Ld and L q are the direct-axis inductance and the quadrature-axis inductance respectively; R is the nominal winding resistance of the motor 102, ω e is the electrical rotation speed, s is the derivative operator, which can be discretized based on the implementation of the control loop; ω e and θ e are the electrical velocity and electrical position respectively, λ m is the PM magnetic flux, K r Indicates the magnitude of the voltage command error caused by phase resistance unbalance; Φ r Indicates the phase of the error introduced due to the unbalanced phase resistance; △R x represents the deviation (imbalance) of the resistance of phase x relative to the nominal winding resistance R of the motor 102; ΔR y represents the deviation (imbalance) of the resistance of phase y relative to the nominal winding resistance R of the motor 102. The subscripts x, y, and z may refer to phase a, phase b, and phase c of the motor 120, respectively.

[0046] Analytical Modeling - Current Measurement Gain (Scaling) Error

[0047] The measured motor phase current with only gain error in the current measurement (ie, without any phase resistance unbalance) can be written as follows:

[0048] I am =(1+ΔK ga )I a

[0049] I bm =(1+ΔK gb )I b

[0050] I cm =(1+ΔK gc )I c

[0051] Among them, I x and I xm Indicates the actual current and measured current of phase x, ΔK gx Represents the gain error in the measurement.

[0052] According to the gain error K of phase x gx The synchronous frame current estimate of the actual motor current is modeled as shown in equation (2):

[0053]

[0054] in, is the measured dq current matrix; I is the actual dq current matrix, Φ gprepresents the phase of the error due to the current sensing gain error; K gp represents the magnitude of the error due to current sensing gain error; and M s and M p The inverse matrix of .

[0055] Combination Analysis

[0056] When feedback current regulation is used, current measurement gain errors and resistor imbalances are modulated and manifest themselves in different signals in a (mathematically) complex way. Assuming high bandwidth current regulation, the estimated current can be approximated to the command current to obtain the actual current as given in equation set (3):

[0057]

[0058] in, is the estimated current, is the current command, is the actual current, is the transfer matrix of the static (i.e., position-independent) terms, is the transfer matrix of position-dependent items.

[0059] The voltage command (which can be assumed to be equal to the actual voltage signal) can be calculated as shown in equation (4):

[0060]

[0061] in, is the voltage command, is the actual voltage applied to the windings of the motor 102, is the inverse object model, For the BEMF model 216, is the noise transfer function due to the resistance unbalance model 212.

[0062] Expanding equation (4), the voltage signal can be separated into three separate terms, as shown in equation group (5):

[0063]

[0064] Among them, V DC is a constant voltage term, V θ is a position-dependent voltage term that varies with the position θ of the motor 102, V θω is a position and speed related voltage term, which varies with both the position θ and the speed ω of the motor 102, Δ g It is defined in equation (2).

[0065] Ripple Content in the Demodulated Voltage Equation :

[0066] By demodulating the dq voltage waveform, the ripple components characteristic of the unbalance and current measurement gain error can be separated. An inverse coordinate transformation from the synchronous coordinate system to the two-phase stationary coordinate system is used with an appropriate frequency of two transformations per electrical revolution, as stated in equation group (6):

[0067]

[0068] Among them, V u and V v is the demodulated diagnostic voltage, θ e For electrical position.

[0069] Fault Detection Strategy

[0070] Based on equation group (6), the resistance imbalance symbol A and the current gain error symbol B are defined as listed in equation group (7):

[0071]

[0072] The resistance imbalance flag A and the current gain error flag B respectively provide corresponding errors to be identified separately. The resistance imbalance flag A has a non-zero value responsive to the resistance imbalance in the motor 102 and is not affected by the current sensing gain error, and the current gain error flag B has a non-zero value responsive to the current sensing gain error and is not affected by the resistance imbalance in the motor 102.

[0073] To determine the type of error in the system, the system and method of the present disclosure considers two operating conditions, one operating condition is at a low speed ω m1 Another operating condition is at high speed ω m2 hour.

[0074] At speed ω m1＝ ω e1 When the direct-axis current command is very low (ie, in the first region where the motor 102 produces torque that does not vary with speed), the direct-axis current command With the first speed ω e1 The corresponding first demodulated voltage V u1 、V v1 It can be defined by equation group (8):

[0075]

[0076] Among them, ω m1 represents the first mechanical motor speed, ω e1is the corresponding first electric motor speed. Typically, in a torque-speed curve, the torque is plotted as a function of the mechanical speed, whereas in the equation, both the mechanical speed term and the electrical speed term may be used. Conversion to ω e = number of pole pairs * ω m .

[0077] At high speed m2 =ω e2 When (ie, than the first mechanical motor speed ω m1 High speed and direct axis current command ), and the second speed ω e2 The corresponding second demodulated voltage V u2 、V v2 It can be defined by equation group (9):

[0078]

[0079] Solving the four equations of equations (8) and (9) provides four unknown variables (i.e., resistance unbalance sign A, current gain error sign B, current gain error angle Φ gp and resistance unbalance angle Φ r ) as listed in equation (10):

[0080]

[0081] Once the values ​​of the resistance imbalance flag A and the current gain error flag B are determined, the type of error can be determined based on Table 1 below:

[0082] Table 1

[0083] Resistance unbalance sign A Current gain error flag B Types of Error 0 0 No error Non-zero 0 Resistance unbalance error 0 Non-zero Current Sense Gain Error Non-zero Non-zero Both resistor imbalance error and current sensing gain error

[0084] As shown in Table 1, the values ​​of the resistance imbalance flag A and the current gain error flag B are both zero, indicating that neither the resistance imbalance error nor the current gain error exists. A non-zero value of the resistance imbalance flag A and a zero value of the current gain error flag B indicate that only the resistance imbalance error exists. A zero value of the resistance imbalance flag A and a non-zero value of the current gain error flag B indicate that only the current gain error exists. A non-zero value of the resistance imbalance flag A and a non-zero value of the current gain error flag B indicate that both the resistance imbalance error and the current gain error exist.

[0085] Figure 41 is a flow chart generally illustrating a method 500 for detecting and distinguishing between current measurement gain error and resistance imbalance in a motor drive system according to the principles of the present disclosure. The method 500 may be performed as part of a dedicated fault diagnostic program. Alternatively, the steps of the method 500 may be performed during normal operation of a vehicle or other system.

[0086] At 502, method 500 determines a first voltage command signal, a first motor position signal, and a first quadrature-axis current command for the motor when the motor is rotating at a first speed. m1 When rotating, the processor 152 can execute instructions to implement the following operations: the current regulator 114 calculates the first voltage command The controller 150 can also determine a first motor position signal θ1. For example, when the motor 102 is moving at a first speed ω m1 When rotating, the processor 152 can execute instructions to implement the following operations: the position estimator 116 based on the estimated position To determine the first motor position signal θ1. In some embodiments, the processor 152 can execute instructions to cause the controller 150 to command the inverter 104 to drive the motor 102 at a first speed ω m1 Rotation, the first speed is a relatively low speed. In the case where method 500 is executed during normal operation, the system can wait until the motor 102 is operated to rotate at the first speed ω m1 Rotation, and then the execution depends on the motor 102 at a first speed ω m1 Next steps to be driven.

[0087] At 504, method 500 calculates a first demodulated voltage signal based on the first voltage command signal and the first motor position signal. For example, processor 152 may execute instructions to calculate a first demodulated voltage signal based on the first motor position signal θe and the corresponding first voltage command signal V d1 、V q1 , the first demodulated voltage signal V is calculated based on the following equation u1 、V v1 : As listed in equation (7).

[0088] At 506, method 500 determines a second voltage command signal, a second motor position signal, and a second quadrature-axis current command for the motor when the motor is rotating at a second speed different from the first speed. m2 When rotating, the processor 152 can execute instructions to implement the following operations: the voltage command is determined by the current regulator 114 The controller 150 can also determine a second motor position signal θ2. For example, when the motor 102 is moving at a second speed ω m2 When rotating, the processor 152 can execute instructions to implement the following operations: the position estimator 116 based on the estimated position To determine the second motor position signal θ2. In some embodiments, the processor 152 can execute instructions to selectively command the inverter 104 to drive the motor 102 at a speed higher than the first speed ω m1 The second speed ω m2 In the case where the method 500 is executed during normal operation, the system may wait until the motor 102 is commanded to rotate at the second speed ω m2 Rotation is then performed depending on the motor 102 at the second speed ω m2 Next steps to be driven.

[0089] At 508, method 500 calculates a second demodulated voltage signal based on the second voltage command signal and the second motor position signal. For example, processor 152 may execute instructions to calculate a second demodulated voltage signal based on the second motor position signal θ e and the corresponding second voltage command signal V d2 、V q2 , based on the equation To calculate the second demodulated voltage signal V u2 、V v2 , as listed in equation (7).

[0090] At 510, the method 500 calculates each of a resistance imbalance flag and a current gain error flag based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command. The resistance imbalance flag has a non-zero value responsive to the resistance imbalance in the motor and is not affected by the current sensing gain error, and the current gain error flag has a non-zero value responsive to the current sensing gain error and is not affected by the resistance imbalance in the motor. For example, the processor 152 can execute instructions to solve each of the four equations in the set of equations (9) and (10) to calculate the value of each of the following: resistance imbalance flag A, current gain error flag B, current gain error angle Φ gp and resistance unbalance angle Φ r .

[0091] The present disclosure provides a method for detecting and distinguishing current measurement gain error and resistance imbalance in a motor drive system. The method includes: when the motor rotates at a first speed, determining a first voltage command signal, a first motor position signal, and a first quadrature-axis current command for the motor; calculating a first demodulated voltage signal based on the first voltage command signal and the first motor position signal; when the motor rotates at a second speed different from the first speed, determining a second voltage command signal, a second motor position signal, and a second quadrature-axis current command; calculating a second demodulated voltage signal based on the second voltage command signal and the second motor position signal; and calculating each of a resistance imbalance flag and a current gain error flag based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command. In some embodiments, the resistance imbalance flag has a non-zero value in response to the resistance imbalance in the motor and is not affected by the current sensing gain error, and the current gain error flag has a non-zero value in response to the current sensing gain error and is not affected by the resistance imbalance in the motor.

[0092] In some embodiments, the first speed corresponds to the motor producing a torque that does not vary with speed, and the second speed is greater than the first speed and corresponds to a direct axis current command

[0093] In some embodiments, each of the first demodulated voltage signal and the second demodulated voltage signal includes two components V u 、V v , these two components V u 、V v Calculated as: Among them, θ e is a corresponding one of the first motor position signal or the second motor position signal indicating the electrical position of the motor, V d 、V q are the direct-axis component and the quadrature-axis component of a corresponding one of the first voltage command signal or the second voltage command signal.

[0094] In some embodiments, calculating the resistance imbalance flag includes calculating the resistance imbalance flag according to the following equation:

[0095]

[0096] Among them, A is the resistance unbalance mark, V u1 and V v1 are the two components of the first demodulated voltage signal, V u2 and V v2 are the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, B is the current gain error sign, R is the nominal winding resistance of the motor, Φ gp is the current gain error angle.

[0097] In some embodiments, calculating the current gain error flag includes calculating the current gain error flag according to the following equation:

[0098] Where B is the current gain error flag, V u1 and V v1 are the two components of the first demodulated voltage signal, V u2 and V v2 are the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, L is the nominal synchronous inductance of the motor.

[0099] In some embodiments, the method further includes: calculating a current gain error angle based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command; and in some embodiments, the current gain error angle indicates that a particular one or more current sensors have a current sensing gain error.

[0100] In some embodiments, calculating the current gain error angle includes calculating the current gain error angle according to the following equation:

[0101] Among them, Φ gp is the current gain error angle, V u1 and V v1 are the two components of the first demodulated voltage signal, V u2 and V v2 are the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 Second quadrature-axis current command during rotation.

[0102] In some embodiments, the method further includes calculating a resistance imbalance angle based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command, and in some embodiments, the resistance imbalance angle indicates that a resistance imbalance exists in one or more specific windings of the motor.

[0103] In some embodiments, calculating the resistance imbalance angle includes calculating the resistance imbalance angle according to the following equation:

[0104] Among them, Φ r is the resistance unbalance angle, V u1 and V v1 are the two components of the first demodulated voltage signal, V u2 and V v2 are the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, B is the current gain error sign, R is the nominal winding resistance of the motor, Φ gp is the current gain error angle.

[0105] The present disclosure provides an electronic controller. The electronic controller includes a processor and a memory, and the memory includes instructions. When the instructions are executed by the processor, the processor performs the following operations: when the motor rotates at a first speed, a first voltage command signal, a first motor position signal, and a first quadrature-axis current command are determined for the motor; a first demodulated voltage signal is calculated based on the first voltage command signal and the first motor position signal; when the motor rotates at a second speed different from the first speed, a second voltage command signal, a second motor position signal, and a second quadrature-axis current command are determined; a second demodulated voltage signal is calculated based on the second voltage command signal and the second motor position signal; and each of a resistance imbalance flag and a current gain error flag is calculated based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command. In some embodiments, the resistance imbalance flag has a non-zero value in response to the resistance imbalance in the motor and is not affected by the current sensing gain error, and the current gain error flag has a non-zero value in response to the current sensing gain error and is not affected by the resistance imbalance in the motor.

[0106] In some embodiments, the first speed corresponds to the motor producing a torque that does not vary with speed, and the second speed is greater than the first speed and corresponds to a direct-axis current command.

[0107] In some embodiments, each of the first demodulated voltage signal and the second demodulated voltage signal includes two components V u 、V v , these two components V u 、V v is calculated as:

[0108] Among them, θ eis a corresponding one of the first motor position signal or the second motor position signal indicating the electrical position of the motor, V d 、V q are the direct-axis component and the quadrature-axis component of a corresponding one of the first voltage command signal or the second voltage command signal.

[0109] In some embodiments, the instructions cause the processor to calculate the resistance imbalance flag according to the following equation:

[0110]

[0111] Among them, A is the resistance unbalance mark, V u1 and V v1 are the two components of the first demodulated voltage signal, V u2 and V v2 are the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, B is the current gain error sign, R is the nominal winding resistance of the motor, Φ gp is the current gain error angle.

[0112] In some embodiments, the instructions cause the processor to calculate the current gain error flag according to the following equation: Where B is the current gain error flag, V u1 and V v1 are the two components of the first demodulated voltage signal, V u2 and V v2 are the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, L is the nominal synchronous inductance of the motor.

[0113] In some embodiments, the instructions further cause the processor to perform the following operations: calculate a current gain error angle based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command; and in some embodiments, the current gain error angle indicates that a particular one or more current sensors have a current sensing gain error.

[0114] In some embodiments, the instructions cause the processor to calculate the current gain error angle according to the following equation: Among them, Φ gpis the current gain error angle, V u1 and V v1 are the two components of the first demodulated voltage signal, V u2 and V v2 are the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 Second quadrature-axis current command during rotation.

[0115] In some embodiments, the instructions cause the processor to perform the following operations: calculate a resistance imbalance angle based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command; and in some embodiments, the resistance imbalance angle indicates that a resistance imbalance exists in one or more specific windings of the motor.

[0116] In some embodiments, the instructions cause the processor to calculate the resistance imbalance angle according to the following equation:

[0117] Among them, Φ r is the resistance unbalance angle, V u1 and V v1 are the two components of the first demodulated voltage signal, V u2 and V v2 are the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, B is the current gain error sign, R is the nominal winding resistance of the motor, Φ gp is the current gain error angle.

[0118] The present disclosure provides a system for detecting and distinguishing current measurement gain error and resistance imbalance in a motor drive system. The system includes an inverter and a controller, the inverter is operably connected to the motor, and the controller is operably connected to the inverter. The controller is configured to: when the motor rotates at a first speed, determine a first voltage command signal, a first motor position signal, and a first quadrature axis current command for the motor; calculate a first demodulated voltage signal based on the first voltage command signal and the first motor position signal; when the motor rotates at a second speed different from the first speed, determine a second voltage command signal, a second motor position signal, and a second quadrature axis current command; calculate a second demodulated voltage signal based on the second voltage command signal and the second motor position signal; and calculate each of a resistance imbalance flag and a current gain error flag based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature axis current command, and the second quadrature axis current command. In some embodiments, the resistance imbalance flag has a non-zero value in response to the resistance imbalance in the motor and is not affected by the current sensing gain error, and the current gain error flag has a non-zero value in response to the current sensing gain error and is not affected by the resistance imbalance in the motor.

[0119] In some embodiments, the first speed corresponds to the motor producing a torque that does not vary with speed, and the second speed is greater than the first speed and corresponds to a direct-axis current command that is substantially equal to zero.

[0120] The above discussion is intended to illustrate the principles and various embodiments of the present invention. Once the above disclosure is fully understood, many changes and modifications will become apparent to those skilled in the art. It is intended that the appended claims be interpreted as covering all such changes and modifications.

[0121] The word "example" is used herein to indicate use as an example, instance or illustration. Any aspect or design described herein as an "example" is not necessarily to be interpreted as being preferred or advantageous over other aspects or designs. On the contrary, the use of the word "example" is intended to present the concept in a specific way. As used in this application, the term "or" is intended to represent an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clearly visible from the context, "X includes A or B" is intended to represent any one of the natural inclusive arrangements. That is, in any of the aforementioned examples, if X includes A; X includes B; or X includes both A and B, then "X includes A or B" is satisfied. In addition, the articles "one" and "an" as used in this application and the appended claims should generally be interpreted as meaning "one or more", unless otherwise specified or clearly from the context to refer to the singular form. In addition, the use of the term "one embodiment" or "an embodiment" throughout the text is not intended to represent the same embodiment or embodiment, unless described as such.

[0122] Unless the context clearly dictates otherwise, as used herein, "a", "an", and "the" refer to both the singular and the plural. By way of example, a "processor" programmed to perform various functions refers to one processor programmed to perform each of the functions, or more than one processor that are collectively programmed to perform each of the various functions.

[0123] The specific implementation of the systems, algorithms, methods, instructions, etc. described herein can be implemented in hardware, software, or any combination thereof. The hardware may include, for example, a computer, an intellectual property (IP) core, an application specific integrated circuit (ASIC), a programmable logic array, an optical processor, a programmable logic controller, microcode, a microcontroller, a server, a microprocessor, a digital signal processor, or any other suitable circuit. In the claims, the term "processor" should be understood to include any of the foregoing hardware, either alone or in combination. The terms "signal" and "data" are used interchangeably.

[0124] As used herein, the term module may include: a packaged functional hardware unit designed to be used with other components, an instruction set executable by a controller (e.g., a processor executing software or firmware), a processing circuit configured to perform a specific function, and an independent hardware or software component that interfaces with a larger system. For example, a module may include an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a circuit, a digital logic circuit, an analog circuit, a combination of discrete circuits, a gate, and other types of hardware or combinations thereof. In other embodiments, a module may include a memory that stores instructions that can be executed by a controller to implement module features.

[0125] Furthermore, in one aspect, for example, a general purpose computer or general purpose processor with a computer program can be used to implement the system described herein, which when executed implements any of the corresponding methods, algorithms and / or instructions described herein. Additionally or alternatively, for example, a special purpose computer / processor can be utilized, which can include other hardware for implementing any of the methods, algorithms or instructions described herein.

[0126] In addition, all or part of the embodiments of the present disclosure may take the form of a computer program product accessible from, for example, a computer usable medium or a computer readable medium. A computer usable medium or a computer readable medium may be any device that can, for example, tangibly contain, store, transmit, or transfer a program for use by or in conjunction with any processor. The medium may be, for example, an electronic, magnetic, optical, electromagnetic, or semiconductor device. Other suitable media are also available.

[0127] The above embodiments, implementations and various aspects have been described to allow easy understanding of the present invention without limiting the present invention. On the contrary, the present invention is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, and its scope should be given the broadest interpretation to cover all such modifications and equivalent structures permitted by law.

Claims

1. A method for detecting and distinguishing between current measurement gain error and resistance imbalance in a motor drive system, comprising: determining a first voltage command signal, a first motor position signal, and a first quadrature-axis current command for the motor when the motor rotates at a first speed; calculating a first demodulated voltage signal based on the first voltage command signal and the first motor position signal; determining a second voltage command signal, a second motor position signal, and a second quadrature-axis current command when the motor rotates at a second speed different from the first speed; calculating a second demodulated voltage signal based on the second voltage command signal and the second motor position signal; as well as calculating each of a resistance imbalance flag and a current gain error flag based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command, wherein the resistance imbalance flag has a non-zero value responsive to a resistance imbalance in the motor and is not affected by a current sensing gain error, and Wherein the current gain error flag has a non-zero value responsive to a current sensing gain error and is not affected by a resistance imbalance in the motor.

2. The method according to claim 1, wherein: The first speed corresponds to the electric machine producing a torque that does not vary with speed, and the second speed is greater than the first speed and corresponds to a direct-axis current command that is substantially equal to zero.

3. The method according to claim 1, wherein: Each of the first demodulated voltage signal and the second demodulated voltage signal includes two components V u 、V v , the two components V u 、V v is calculated as: Among them, θ e is a corresponding one of the first motor position signal or the second motor position signal indicating the electrical position of the motor, V d 、V q are the direct-axis component and the quadrature-axis component of a corresponding one of the first voltage command signal or the second voltage command signal.

4. The method according to claim 1, wherein: Calculating the resistance imbalance flag includes calculating the resistance imbalance flag according to the following equation: Where A is the resistance unbalance mark, V u1 and V v1 For the two components of the first demodulated voltage signal, V u2 and V v2 for the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, B is the current gain error flag, R is the nominal winding resistance of the motor, Φ gp is the current gain error angle.

5. The method according to claim 1, wherein: Calculating the current gain error flag includes calculating the current gain error flag according to the following equation: Wherein, B is the current gain error flag, V u1 and V v1 For the two components of the first demodulated voltage signal, V u2 and V v2 for the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, L is the nominal synchronous inductance of the motor.

6. The method according to claim 1, further comprising: calculating a current gain error angle based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command, The current gain error angle indicates that a specific one or more current sensors have a current sensing gain error.

7. The method according to claim 6, wherein: Calculating the current gain error angle includes calculating the current gain error angle according to the following equation: Among them, Φ gp is the current gain error angle, V u1 and V v1 For the two components of the first demodulated voltage signal, V u2 and V v2 for the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation.

8. The method according to claim 1, further comprising: calculating a resistance unbalance angle based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command, The resistance imbalance angle indicates that resistance imbalance exists in one or more specific windings of the motor.

9. The method according to claim 8, wherein: Calculating the resistance unbalance angle includes calculating the resistance unbalance angle according to the following equation: Among them, Φ r is the resistance unbalance angle, V u1 and V v1 For the two components of the first demodulated voltage signal, V u2 and V v2 for the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, B is the current gain error flag, R is the nominal winding resistance of the motor, Φ gp is the current gain error angle.

10. An electronic controller comprising: processor; as well as a memory comprising instructions that, when executed by the processor, cause the processor to: determining a first voltage command signal, a first motor position signal, and a first quadrature-axis current command for the motor when the motor rotates at a first speed; calculating a first demodulated voltage signal based on the first voltage command signal and the first motor position signal; determining a second voltage command signal, a second motor position signal, and a second quadrature-axis current command when the motor rotates at a second speed different from the first speed; calculating a second demodulated voltage signal based on the second voltage command signal and the second motor position signal; as well as calculating each of a resistance imbalance flag and a current gain error flag based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command, wherein the resistance imbalance flag has a non-zero value responsive to a resistance imbalance in the motor and is not affected by a current sensing gain error, and Wherein the current gain error flag has a non-zero value responsive to a current sensing gain error and is not affected by a resistance imbalance in the motor.

11. The electronic controller according to claim 10, wherein: The first speed corresponds to the electric machine producing a torque that does not vary with speed, and the second speed is greater than the first speed and corresponds to a direct-axis current command that is substantially equal to zero.

12. The electronic controller according to claim 10, wherein: Each of the first demodulated voltage signal and the second demodulated voltage signal includes two components V u 、V v , the two components V u 、V v is calculated as: Among them, θ e is a corresponding one of the first motor position signal or the second motor position signal indicating the electrical position of the motor, V d 、V q are the direct-axis component and the quadrature-axis component of a corresponding one of the first voltage command signal or the second voltage command signal.

13. The electronic controller according to claim 10, wherein: The instructions cause the processor to calculate the resistance imbalance flag according to the following equation: Where A is the resistance unbalance mark, V u1 and V v1 For the two components of the first demodulated voltage signal, V u2 and V v2 for the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, B is the current gain error flag, R is the nominal winding resistance of the motor, Φ gp is the current gain error angle.

14. The electronic controller according to claim 10, wherein: The instructions cause the processor to calculate the current gain error flag according to the following equation: Wherein, B is the current gain error flag, V u1 and V v1 For the two components of the first demodulated voltage signal, V u2 and V v2 for the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, L is the nominal synchronous inductance of the motor.

15. The electronic controller according to claim 10, wherein: The instructions further cause the processor to calculate a current gain error angle based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command, The current gain error angle indicates that a specific one or more current sensors have a current sensing gain error.

16. The electronic controller according to claim 15, wherein: The instructions cause the processor to calculate the current gain error angle according to the following equation: Among them, Φ gp is the current gain error angle, V u1 and V v1 For the two components of the first demodulated voltage signal, V u2 and V v2 for the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation.

17. The electronic controller according to claim 10, wherein: The instructions cause the processor to calculate a resistance imbalance angle based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command, The resistance imbalance angle indicates that resistance imbalance exists in one or more specific windings of the motor.

18. The electronic controller of claim 17, wherein: The instructions cause the processor to calculate the resistance imbalance angle according to the following equation: Among them, Φ r is the resistance unbalance angle, V u1 and V v1 For the two components of the first demodulated voltage signal, V u2 and V v2 for the two components of the second demodulated voltage signal, When the motor is at the first speed ω e1 The first quadrature-axis current command during rotation, When the motor is at the second speed ω e2 The second quadrature-axis current command during rotation, B is the current gain error flag, R is the nominal winding resistance of the motor, Φ gp is the current gain error angle.

19. A system for detecting and distinguishing between current measurement gain error and resistance imbalance in a motor drive system, comprising: A controller, the controller being configured to: determining a first voltage command signal, a first motor position signal, and a first quadrature-axis current command for the motor when the motor rotates at a first speed; calculating a first demodulated voltage signal based on the first voltage command signal and the first motor position signal; determining a second voltage command signal, a second motor position signal, and a second quadrature-axis current command when the motor rotates at a second speed different from the first speed; calculating a second demodulated voltage signal based on the second voltage command signal and the second motor position signal; as well as calculating each of a resistance imbalance flag and a current gain error flag based on the first demodulated voltage signal, the second demodulated voltage signal, the first quadrature-axis current command, and the second quadrature-axis current command, wherein the resistance imbalance flag has a non-zero value responsive to a resistance imbalance in the motor and is not affected by a current sensing gain error, and Wherein the current gain error flag has a non-zero value responsive to a current sensing gain error and is not affected by a resistance imbalance in the motor.

20. The system of claim 19, wherein: The first speed corresponds to the electric machine producing a torque that does not vary with speed, and the second speed is greater than the first speed and corresponds to a direct-axis current command that is substantially equal to zero.

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