Method for determining resolver offset

Abstract

The invention relates to a method for determining resolver offset. A computer system (100) is provided. The computer system comprises processing circuitry (160, 402) configured to: for each of a preset positive speed value ([omega] ref) and a preset negative speed value (-[omega] ref): control the speed of the electric machine (10) to the preset speed value ([omega] ref,-[omega] ref), short-circuit the electric machine (10), and control the speed of the electric machine (10) to the preset negative speed value (-[omega] ref). And determining a d-current, q-current (id, iq) and an angular velocity (omega) of a rotor (14) of the electric machine (10) during deceleration from the preset velocity value (omega ref,-omega ref), and wherein the processing circuit (160, 402) is further configured to determine a resolver offset (theta off, k omega) based on the determined d-current, q-current (id, iq) and the determined angular velocity (omega) of the rotor (14).

Description

Technical Field

[0001] The present disclosure generally relates to electric machines. In particular aspects, the present disclosure relates to a method for determining a resolver offset. The present disclosure may be applicable to heavy vehicles such as trucks, buses, and construction equipment, as well as other vehicle types. Although the present disclosure may be described with respect to a particular vehicle, the present disclosure is not limited to any particular vehicle. Background Art

[0002] Electric motors are used in a wide variety of applications. By applying position control to electric motors, many benefits are gained.

[0003] Particularly in electric vehicle applications, position control will allow improved efficiency by enabling precise control of the motor's speed and torque. As a result, the motor can be operated at optimal efficiency for a given speed and load, extending the vehicle's range and improving the overall energy efficiency of the electric vehicle.

[0004] Another benefit involves improved performance and driving experience. Accurate information about the rotor position will enable precise control of the motor's position, speed and torque, allowing for faster acceleration, smoother operation and better handling.

[0005] Another benefit of position control is related to reduced wear on the motor, thereby extending the motor's service life because the motor can be driven at optimal efficiency.

[0006] Precise control of the moving parts of a motor can be achieved through a variety of different devices, such as encoders, Hall effect sensors, linear variable differential transformers, and laser displacement sensors. However, when factors such as accuracy, resolution, reliability, immunity to electromagnetic interference, size, and complexity are considered, resolvers are often the first choice.

[0007] A resolver is a type of sensor used to determine the position and speed of a rotating shaft of an electric motor. A resolver operates by converting the mechanical motion of the shaft into an electrical signal that indicates the position and speed of the motor.

[0008] A resolver consists of a stator and a rotor. The stator has multiple sets of coils that are usually positioned at specific angles. The rotor is a rotating component that also contains multiple sets of coils that are positioned around the rotor at specific angles to match the positions of the stator coils. The stator is a stationary component, while the rotor is connected to the rotating shaft of the motor.

[0009] As the rotor rotates with the motor running, voltages are induced in the stator coils that are proportional to the sine and cosine of the angle between the rotor and stator coils of the resolver. These voltages are then processed to determine the position and speed of the rotating shaft.

[0010] From the above background, it can be seen that in order to benefit from precise position control, correct positioning of the resolver is critical.

[0011] Inadequate calibration of the resolver position can lead to degraded performance and can compromise control of the electric machine. Accurate calibration of the resolver, i.e., knowledge of any current resolver offset, is therefore very important to ensure satisfactory performance of the electric machine and, in particular, where applicable, to ensure the desired performance of electric vehicles.

[0012] Therefore, there is a need for improvements in the calibration of resolvers of electric machines, and in particular for improved methods for determining resolver offset. Summary of the invention

[0013] According to a first aspect of the present disclosure, a computer system is provided. The computer system includes a processing circuit, which is configured to: control the speed of the motor to a preset speed value, short-circuit the motor, and determine the d current, q current and angular velocity of the rotor of the motor during deceleration from the preset speed value for each of a preset positive speed value and a preset negative speed value. The processing circuit is also configured to determine a resolver offset based on the determined d current, q current and the determined angular velocity of the rotor. Technical benefits may include the ability to determine a constant resolver offset and a speed-dependent resolver offset in a very efficient manner, thereby achieving improved calibration of the resolver position for more accurate control of the motor.

[0014] Optionally, in some examples, including at least one preferred example, short-circuiting the motor is performed by short-circuiting each phase winding of the motor.

[0015] Optionally, in some examples, including at least one preferred example, the absolute value of the negative speed value is equal to the absolute value of the positive speed value.Technical benefits may include a simpler process for determining resolver offset.

[0016] Optionally, in some examples, including at least one preferred example, the processing circuit is further configured to disconnect the motor from an associated load before controlling the speed of the motor to the preset speed value. Technical benefits may include tracking the induced voltage of the motor to align the resolver with a rotating coordinate system (i.e., dq frame).

[0017] Optionally, in some examples, including at least one preferred example, the processing circuit is further configured to calculate a correct resolver position by subtracting the resolver offset from the estimated resolver position. Technical benefits may include a more accurate resolver position, thereby allowing improved control of the motor.

[0018] Optionally, in some examples, including at least one preferred example, the processing circuit is further configured to control the operation of the motor based on the correct resolver position. Technical benefits may include improved operation of the motor. In particular, in vehicle applications, this may allow for better performance and efficiency of the associated vehicle.

[0019] Optionally, in some examples, including at least one preferred example, the processing circuit is further configured to determine the resolver offset as a constant angular resolver offset and a speed-dependent angular resolver offset. Technical benefits may include resolving misalignment caused by speed-independent and speed-dependent phenomena, thereby allowing the computer system to be particularly suitable for resolver signal demodulation using a delta-sigma A / D converter when obtaining cosine and sine signals from a resolver.

[0020] Optionally, in some examples, including at least one preferred example, the processing circuit is further configured to determine the constant resolver angular offset as Technical benefits may include a more efficient routine for determining a constant resolver angular offset when the motor is short-circuited and when data is available for both positive and negative angular velocities when parameters of the motor are known.

[0021] Optionally, in some examples, including at least one preferred example, the processing circuit is further configured to determine the speed-dependent resolver angular offset as kω, where

[0022]

[0023] Technical benefits may include a more efficient routine for determining a constant resolver angular offset when the motor is short-circuited and when data is available for both positive and negative angular velocities when parameters of the motor are known.

[0024] Optionally, in some examples, including at least one preferred example, the absolute value of the negative speed value is equal to the absolute value of the positive speed value, and the processing circuit is further configured to: disconnect the motor from the associated load before controlling the speed of the motor to the preset speed value; calculate the correct resolver position by subtracting the resolver offset from the estimated resolver position; control the operation of the motor based on the correct resolver position; determine the resolver offset as a constant resolver angular offset and a speed-dependent resolver angular offset; determine the constant resolver angular offset as And determine the speed-dependent resolver angular offset () as kω, where

[0025]

[0026] According to a second aspect of the disclosure, a vehicle is provided. The vehicle comprises a computer system according to the first aspect. The second aspect of the disclosure may seek to allow for better performance and efficiency of the vehicle. Technical benefits may include improved control of an electric motor of the vehicle.

[0027] Optionally, in some examples, including at least one preferred example, the vehicle includes an electric machine, the electric machine including a resolver and at least one load connected to the electric machine. The computer system is configured to determine the constant resolver angular offset and the speed-dependent resolver angular offset of the resolver of the electric machine. As previously described, technical benefits can include resolving misalignment caused by speed-independent and speed-dependent phenomena, thereby allowing the computer system to be particularly suitable for resolver signal demodulation using a delta-sigma A / D converter when obtaining cosine and sine signals from a resolver.

[0028] According to a third aspect of the present disclosure, a computer-implemented method is provided. The method includes, for each of a preset positive speed value and a preset negative speed value: controlling, by a processing circuit, the speed of a motor to a preset speed value, short-circuiting, by the processing circuit, the motor, and determining, by the processing circuit, a d current, a q current, and an angular velocity of a rotor of the motor during deceleration from the preset speed value. The method also includes determining, by the processing circuit, a resolver offset based on the determined d current, q current, and the determined angular velocity of the rotor.

[0029] Optionally, in some examples, including at least one preferred example, the method further comprises allowing the motor to free spin during deceleration from the preset speed value. Technical benefits may include less complex calculation of resolver offsets because the d current and q current will not depend on any load characteristics.

[0030] Optionally, in some examples, including at least one preferred example, the method further comprises short-circuiting, by the processing circuit, a winding of the motor. Technical benefits may include reducing time-dependent ripple on phase currents because an associated inverter does not need to turn transistors on and off. Thus, the measurement of current gives a very accurate value about the average value of the current over a sampling period.

[0031] Optionally, in some examples, including at least one preferred example, the method further comprises determining, by the processing circuit, the resolver offset based on the determined d current, q current for the positive speed value and the negative speed value and based on the determined angular velocity of the rotor for the positive speed value and the negative speed value. Technical benefits may include efficient acquisition of all necessary parameters to accurately determine the resolver offset.

[0032] Optionally, in some examples, including at least one preferred example, the method further comprises determining, by the processing circuit, the d current, q current by estimating the steady-state d voltage, q voltage as zero. Technical benefits may include a simpler model for determining resolver offset.

[0033] Optionally, in some examples, including at least one preferred example, the method further comprises calculating a correct resolver position by subtracting the resolver offset from the estimated resolver position. Technical benefits may include a more accurate resolver position, thereby allowing improved control of the motor.

[0034] Optionally, in some examples, including at least one preferred example, the method further comprises disconnecting the motor from an associated load by the processing circuit before controlling the speed of the motor to the preset speed value, and calibrating the resolver position by the processing circuit based on the resolver offset. As previously mentioned, technical benefits may include improved operation of the motor. In particular, in vehicle applications, this may allow for better performance and efficiency of the associated vehicle.

[0035] According to a fourth aspect of the present disclosure, a computer program product is provided, wherein the computer program product comprises program code, and the program code is used to perform the method according to the third aspect of the present disclosure when executed by a processing circuit.

[0036] According to a fifth aspect of the present disclosure, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium comprises instructions, which, when executed by a processing circuit, cause the processing circuit to perform the method according to the third aspect of the present disclosure.

[0037] The disclosed aspects and / or examples (including any preferred examples) can be appropriately combined with each other, which is obvious to any person skilled in the art. Additional features and advantages are disclosed in the detailed description and the accompanying drawings, and in part will be obvious to those skilled in the art or recognized by practicing the present disclosure as described herein.

[0038] Also disclosed herein are computer systems, control units, code modules, computer-implemented methods, computer-readable media, and computer program products associated with the technical benefits discussed above. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a side view of a vehicle including a computer system according to an example.

[0040] Figure 2 is an exemplary system diagram of a computer system according to an example.

[0041] Figure 3A is a graph showing the dq current as a function of rotation speed in the absence of resolver offset.

[0042] Figure 3B is a graph showing the current load angle as a function of rotational speed in the absence of resolver offset.

[0043] Figure 4A is a graph showing the current load angle as a function of rotational speed in the presence of a time-independent resolver offset.

[0044] Figure 4B is a graph showing the current load angle as a function of rotational speed in the presence of a time-dependent resolver offset.

[0045] Figure 4C is a graph showing current load angle as a function of rotational speed in the presence of time-independent resolver offset and time-dependent resolver offset.

[0046] Figure 5 is a flow chart of an exemplary method for determining resolver error according to an example.

[0047] Figure 6 is a flow chart of an exemplary method for determining resolver error according to an example.

[0048] Figure 7 is a schematic diagram of an exemplary computer system for implementing the examples disclosed herein, according to an example. DETAILED DESCRIPTION

[0049] The detailed description set forth below provides information and examples of the disclosed technology in sufficient detail to enable those skilled in the art to practice the disclosure.

[0050] Before describing the specific details of the techniques of the present disclosure, some general comments on motor control will be given.

[0051] The dq framework is a mathematical tool used to simplify the analysis and control of electrical machines such as electric motors or generators.

[0052] The dq frame is a coordinate system that rotates with the rotor of the motor, where the d-axis is aligned with the magnetic field (i.e., magnetizing field) from the permanent magnets in the rotor and the q-axis is 90 degrees ahead of the d-axis. By transforming the three-phase electrical quantities (i.e., voltage and current) of the motor from a stationary orthogonal frame to a rotating dq frame, the behavior of the motor can be represented as a set of two variables, namely, the direct axis (d-axis) component and the quadrature axis (q-axis) component.

[0053] The d-axis component and the q-axis component may represent any electrical or magnetic quantity (such as current, voltage, or magnetic flux) that changes in a three-phase system when the phase is shifted 120 degrees in space and time.

[0054] Using the dq framework, the behavior of the motor in terms of speed and torque output can be controlled by manipulating the d-axis and q-axis components of the voltage and current.

[0055] A common way to control a motor is called field-oriented control (FOC). FOC involves adjusting the d-axis component and the q-axis component to control the motor's magnetic field. By adjusting these components in real time, the desired speed or torque output from the motor can be maintained.

[0056] FOC requires the position of the rotor as input. For this purpose, a resolver can be arranged at the rotor shaft, thereby providing a resolver signal indicating the position of the rotor. However, due to unbalances in mechanical tolerances during assembly of the resolver on the rotor shaft, there may be a speed-independent mechanical resolver offset.

[0057] Another issue that may be associated with resolvers is related to the analog-to-digital conversion of resolver signals. A common method when performing analog-to-digital conversion of resolver signals is to use delta-sigma modulation, which typically includes initial encoding of the analog signal using high-frequency delta-sigma modulation and subsequent digital filtering to form a high-resolution / low sampling frequency digital output. This conversion technique is often accompanied by an inherent delay that results in a speed-dependent offset in the resolver signal.

[0058] The speed-independent offset and the speed-dependent offset will result in errors that may cause inaccurate determination of the rotor position, which may have a negative impact on the control and efficiency of the motor.

[0059] Figure 1 is an exemplary system diagram of a vehicle 1 according to an example. The vehicle 1 may be any type of vehicle, such as a heavy vehicle or a light vehicle. The vehicle 1 includes an electric machine arrangement 5. The electric machine arrangement 5 includes an electric machine 10 having a rotary transformer 12, and a computer system 100 configured to determine a rotary transformer offset of the electric machine 10, as will be further explained below. Figure 1 In FIG. 5 , an electric machine arrangement 5 and the components it comprises are schematically shown.

[0060] It should be emphasized that the computer system 100 described herein is not specifically designed to operate with the vehicle 1 , but rather the computer system 100 may be used in any suitable application, such as mobile or fixed applications, embedded or standalone applications, etc., as long as it is connected to the motor 10 and forms part of the motor arrangement 5 .

[0061] Figure 2 is an exemplary system diagram of an electric machine arrangement 5 . The electric machine arrangement 5 comprises an electric machine 10 . The electric machine 10 is provided with a resolver 12 configured to transmit a resolver signal RS indicating a current position of a rotor 14 of the electric machine 10 .

[0062] The electric machine arrangement 5 further comprises a computer system 100. The computer system 100 is programmed to determine the resolver offset of the resolver 12. The computer system 100 is further configured to allow field oriented control (FOC) of the electric machine 10. The computer system 100 comprises a transformation circuit 110 configured to measure the motor phase current and transform the motor phase current to a dq frame, thereby generating a measured dq frame current I d and I q The regulators 120a and 120b convert these converted currents I d and I q With reference current I dref and I qref (i.e., flux reference and torque reference) are compared to output a reference voltage V in the dq frame dref and V qref The inverse conversion circuit 130 is configured to convert the reference voltage V dref and V qref Inverted into the voltage component V of the stator vector voltage in the stationary orthogonal reference frame αref and V βref These reference voltages are input to a space vector pulse width modulator 140 which is configured to provide a drive signal to an inverter 150 .

[0063] Each of the conversion circuit 110 and the inverse conversion circuit 130 requires a rotor flux position θ, which depends on the position of the rotor. Although the rotor flux position can be provided from the signal of the rotary transformer 12, any built-in error in the rotary transformer 12 will result in a control error that may have a negative impact on the operation of the motor 10.

[0064] To this end, computer system 100 is configured to determine these built-in errors of resolver 12 according to general principles that will be explained further below.

[0065] The electric machine arrangement 5 comprises a disconnect clutch 20 arranged to allow the electric machine 10 to be disconnected from any load 30 connected thereto. In vehicle applications, such a load may typically be a wheel, a reduction gear or a differential mechanism.

[0066] The computer system 100 is configured to control the disengagement of the disconnect clutch 20 so that the motor 10 can rotate freely without driving any load 30 .

[0067] The computer system 100 includes a computing and / or processing circuit 160 configured to calculate and / or process the Figure 5 Method 200 is generally described for determining resolver offset.

[0068] It should be noted that computing circuit 160 and any processing circuitry programmed to perform method 200 may be implemented as embedded software and / or hardware with computer system 100 configured to control operation of electric machine 10. However, computing circuit 160 and any processing circuitry programmed to perform method 200 may be implemented as a standalone application in other examples. Thus, calculation of the offset of resolver 12 may be performed as part of normal operational control of electric machine 10, or only once during production (preferably at the end of a production line), for example.

[0069] The general idea is to perform measurements of the phase currents in the armature windings and the angular position of the rotor of the motor. Using the measurement of the angular position of the rotor given by the resolver, the winding currents are converted into a rotating reference frame that is synchronous with the rotor. During data acquisition, the phase windings of the motor are short-circuited when the motor rotates in different directions. Both speed-dependent and speed-independent angular offsets are derived from the above measurements.

[0070] The technical concept provides many advantages. First, due to the motor short circuit, the inverter 150 does not turn on or off the transistors. Therefore, there is no time-dependent ripple in the phase current. Therefore, the measurement of the current gives a very accurate value about the average value of the current within one sampling period.

[0071] Secondly, the method addresses misalignment caused by speed-independent and speed-dependent phenomena by taking into account the constant angular offset and speed-dependent delay of the resolver signal input. This makes the method particularly suitable for resolver signal demodulation using a delta-sigma A / D converter when obtaining cosine and sine signals from the resolver.

[0072] Figure 3A A diagram is shown in which the dq currents are plotted for a short-circuited electric machine 10 with a perfect resolver 12 position, ie both the constant resolver angular offset and the speed-dependent resolver angular offset are equal to zero.

[0073] Figure 3B A similar diagram is shown where the dq current load angle is plotted for a short-circuited motor 10 with a perfect resolver 12 position (ie, both the constant resolver angular offset and the speed-dependent resolver angular offset are equal to zero).

[0074] Figure 4A Another diagram is shown in which the dq current load angle is plotted for a short-circuited motor 10 with an uncalibrated resolver 12 position (in this case, the constant resolver angle offset is non-zero, while the speed-dependent resolver angle offset is equal to zero).

[0075] Figure 4B A similar diagram is shown where the dq current load angle is plotted for a short-circuited motor 10 with an uncalibrated resolver 12 position (in this case, the constant resolver angle offset is equal to zero, while the speed-dependent resolver angle offset is non-zero).

[0076] Figure 4C Another diagram is shown in which the dq current load angle is plotted for a short-circuited electric machine 10 with an uncalibrated resolver 12 position (in this case, both the constant resolver angular offset and the speed-dependent resolver angular offset are non-zero).

[0077] like Figure 5 As shown, the method 200 operates by initially controlling 202 the disconnect clutch 20 to a disengaged state. The method 200 then applies 204 FOC, such as speed control or torque control, to the motor 10 so that the motor 10 is accelerated 206 to a preset high speed value ω ref , such as 10000rpm.

[0078] When the motor 10 has reached its target speed, the stator windings of the motor 10 are short-circuited 208. Due to braking torque, friction and losses, the motor 10 will begin to accelerate from the target speed ω ref Slow down 210.

[0079] During deceleration from a higher speed to a lower speed, ie, during a speed interval, method 200 acquires 212 a measured current i of motor 10 d (ω),i q (ω) and the rotation speed ω of the motor 10. The speed interval may be, for example, 10000 rpm to 6000 rpm, or the speed interval may be indirectly set by a preset deceleration time amount.

[0080] When the preset high speed value ω ref Determine the current i of the motor 10 during deceleration d (ω), q current i q (ω) and the rotational speed ω of the motor 10, the method 200 performs the operation by resetting 214 the high speed value to −ω. ref For this new reference value, the method repeats itself by applying 216 FOC to the motor 10, causing the motor 10 to accelerate 218 to a new preset high speed value -ω ref When the new preset high speed value -ω is reached ref Afterwards, the motor 10 is short-circuited 220 , whereby the motor 10 starts to decelerate 222 .

[0081] During deceleration 222 from high speed to low speed, ie, during a speed interval, method 200 acquires 224 a measured current i of motor 10 d (ω),i q (ω) and the rotation speed ω of the motor 10. As for the previous acquisition 212 of data, the speed interval may be, for example, -10000 rpm to -6000 rpm, or the speed interval may be indirectly set by a preset deceleration time amount.

[0082] Once the d-current, q-current are obtained for the positive and negative rotational speeds ω, the method 200 proceeds to post-processing 226 the acquired data. This produces a calculated constant resolver angular offset θ off and the speed-dependent resolver angular offset k.

[0083] Optionally, method 200 further includes using a calibrated resolver position θ cal To control 228 motor 10, where θ cal =θ meas -θ off -kω.

[0084] The calibration method 200 described above begins by transforming the measured phase currents into an orthogonal coordinate system (ie, dq frame or dq coordinate system) that is aligned with the magnetic flux from the permanent magnets in the rotor. Mathematically, the transformation is defined as:

[0085]

[0086] The steady-state voltage in the dq system is defined as:

[0087]

[0088] Where L d and L q is the inductance in the d and q directions, R is the stator resistance, ψ PM is the link flux from the permanent magnets, and ω is the angular velocity of the rotor multiplied by the number of pole pairs. If the motor is short-circuited, the voltage is zero. Under this condition, the dq currents can be estimated by:

[0089] and

[0090]

[0091] Assuming that all variables except angular velocity in the above equation are constant, the short-circuit current can be estimated for all speeds. The above equation shows that for a certain angular velocity, regardless of the direction of rotation, i d The current is the same. In addition, i q The magnitude of the current will be the same, but the sign will be different depending on the sign of the velocity. The above two equations also show that i d is always negative, and i q Approaches zero as speed increases. Again, refer to Figure 3A and Figure 3B , Figure 3A shows the simulated current of a short-circuited motor 10 with perfect resolver angle over the entire speed range, while Figure 3B shows the load angle of the current, which is defined as arctan2(i q ,i d ). As expected, in Figure 3A and Figure 3B In the figure, the current and load angle are symmetrical about the d-axis over the entire speed range.

[0092] The error offset of the resolver angle can be advantageously divided into two parts, a constant offset over the entire speed range (usually a misalignment of the resolver relative to the motor) and an offset that depends linearly on the angular velocity (usually a time delay, e.g. imposed by a filter). Mathematically, the error angular position is defined as:

[0093] θ e =θ+θ off + kω,

[0094] where θ offis the constant angular offset, k is the time delay constant and θ is the actual angular position of the rotor. Therefore, kω represents the time-dependent resolver angular offset. If the rotor angle is offset, the short-circuit dq current is no longer symmetrical about the d-axis. Therefore, an insufficiently calibrated resolver angle can be tracked by analyzing the load angle of the dq current. Again, refer to FIG. 4A to FIG. 4C , shows three examples of short-circuit current load angles over the entire speed range. Figure 4A In the resolver, the angle has a constant offset over the entire speed range; in Figure 4B In, there is a time delay; in Figure 4C In the example, there is both a constant offset and a time delay. The constant angle offset produces a constant offset in the current load angle throughout the speed sequence ( Figure 4A ), while the time delay produces a load angle ( Figure 4B ). Since these two phenomena are independent, they can be separated when finding the offset for arbitrary speeds.

[0095] For the correct angle, considering that 0≤θ<2π, the following equation should be satisfied:

[0096] and

[0097]

[0098] Therefore, the offset or time delay for a specific speed can be estimated by:

[0099] and

[0100]

[0101] Therefore, method 200 is programmed to determine 226 a constant resolver angular offset θ off , and determine 226 the time-dependent resolver angular offset kω. Thus, if data is available for positive and negative angular velocities when the motor is short-circuited and when the motor parameters are known, the constant angular offset and time delay can be estimated.

[0102] When these parameters are known, a more accurate value for the rotor position can be obtained, thereby improving control of the electric machine 10 .

[0103] Figure 6 is a flow chart of a method 300 for determining a resolver error according to an example. The method 300 is configured to determine a predetermined positive speed value ω ref and the preset negative speed value -ω ref Each of: controlling 302 the speed of the motor 10 to a preset speed value ω ref 、-ωref , short-circuiting the motor 10 304, and determining 306 that the rotor 12 of the motor 10 is moving from a preset speed value ω ref 、-ω ref Current i during deceleration d ,q current i q and angular velocity ω. The method 300 also includes determining the current i based on the rotor d ,q current i q and the determined angular velocity ω to determine 308 the resolver offset θ off and the time delay constant k of the time-dependent resolver angular offset kω.

[0104] Figure 7 4 is a schematic diagram of a computer system 400 for implementing the examples disclosed herein. The computer system 400 is suitable for executing instructions from a computer-readable medium to perform these and / or any functions or processes described herein. The computer system 400 can be connected (e.g., networked) to other machines in a LAN, an intranet, an extranet, or the Internet. Although only a single device is shown, the computer system 400 may include any device collection that executes an instruction set (or multiple instruction sets) individually or jointly to perform any one or more of the methods discussed herein. Therefore, any reference to a computer system, a computing system, a computer device, a computing device, a control system, a control unit, an electronic control unit (ECU), a processor device, a processing circuit, etc. in the present disclosure includes a reference to one or more such devices to execute an instruction set (or multiple instruction sets) individually or jointly to perform any one or more of the methods discussed herein. For example, the control system may include a single control unit or multiple control units connected to each other or otherwise communicatively coupled, so that any executed function can be distributed between the control units as needed. In addition, such devices can communicate with each other or with other devices through various system architectures (such as directly or via a controller area network (CAN) bus, etc.).

[0105] Computer system 400 may include at least one computing device or electronic device that can include firmware, hardware and / or execute software instructions to implement the functionality described herein. Computer system 400 may include processing circuitry 402 (e.g., a processing circuit that includes one or more processor devices or control units), memory 404, and system bus 406. Computer system 400 may include at least one computing device with processing circuitry 402. System bus 406 provides interfaces for system components including, but not limited to, memory 404 and processing circuitry 402. Processing circuitry 402 may include any number of hardware components for performing data or signal processing or for executing computer code stored in memory 404. Processing circuitry 402 may include, for example, a general purpose processor, a special purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a circuit containing a processing component, a group of distributed processing components, a group of distributed computers configured for processing, or other programmable logic devices designed to perform the functions described herein, discrete gate or transistor logic, discrete hardware components, or any combination thereof. Processing circuitry 402 may also include computer executable code that controls the operation of a programmable device.

[0106] The system bus 406 can be any of several types of bus structures, which can also be interconnected to a memory bus (with or without a memory controller), a peripheral bus, and / or a local bus using any of a variety of bus architectures. The memory 404 can be one or more devices for storing data and / or computer code to complete or facilitate the methods described herein. The memory 404 can include a database component, an object code component, a script component, or other types of information structures for supporting various activities herein. Any distributed or local memory device can be utilized with the systems and methods of the present specification. The memory 404 can be communicatively connected to the processing circuit 402 (e.g., via a circuit or any other wired, wireless, or network connection) and can include computer code for performing one or more processes described herein. The memory 404 may include nonvolatile memory 408 (e.g., read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.) and volatile memory 410 (e.g., random access memory (RAM)), or any other medium that can be used to carry or store desired program code in the form of machine-executable instructions or data structures and that can be accessed by a computer or other machine having the processing circuit 402. A basic input / output system (BIOS) 412 may be stored in the nonvolatile memory 408 and may include the basic routines that help to transfer information between elements within the computer system 400.

[0107] The computer system 400 may also include or be coupled to non-transitory computer-readable storage media such as storage device 414, which may include, for example, an internal or external hard disk drive (HDD) (e.g., enhanced integrated drive electronics (EIDE) or serial advanced technology attachment (SATA)), a HDD for storage (e.g., EIDE or SATA), flash memory, etc. The storage device 414 and other drives associated with computer-readable and computer-usable media may provide non-volatile storage of data, data structures, computer-executable instructions, etc.

[0108] The hard-coded or soft-coded computer code can be provided in the form of one or more modules. The module can be implemented as software and / or hard-coded in the circuit to implement the functions described herein in whole or in part. The module can be stored in a storage device 414 and / or a volatile memory 410 that can include an operating system 416 and / or one or more program modules 418. All or part of the examples disclosed herein can be implemented as a computer program 420 stored on a temporary or non-temporary computer-usable or computer-readable storage medium (e.g., a single medium or multiple media) such as a storage device 414, which includes complex programming instructions (e.g., complex computer-readable program code) that enable the processing circuit 402 to implement the actions described herein. Therefore, the computer-readable program code of the computer program 420 may include software instructions for implementing the functionality of the examples described herein when executed by the processing circuit 402. In some examples, storage device 414 may be a computer program product (e.g., a readable storage medium) having computer program 420 stored thereon, wherein at least a portion of computer program 420 may be loadable (e.g., loaded into a processor) for implementing the functionality of the examples described herein when executed by processing circuit 402. Processing circuit 402 may serve as a controller or control system of computer system 400 for implementing the functionality described herein.

[0109] The computer system 400 may include an input device interface 422 configured to receive input and selections to be transmitted to the computer system 400 when executing instructions, such as from a keyboard, mouse, touch-sensitive surface, etc. Such input devices may be connected to the processing circuit 402 through the input device interface 422 coupled to the system bus 406, but may be connected through other interfaces such as a parallel port, an Institute of Electrical and Electronics Engineers (IEEE) 1394 serial port, a universal serial bus (USB) port, an IR interface, etc. The computer system 400 may include an output device interface 424 configured to forward output to a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)). The computer system 400 may include a communication interface 426 suitable for communicating with a network as appropriate or as needed.

[0110] Operational actions described in any of the exemplary aspects of this document are described to provide examples and discussions. The actions may be performed by hardware components, may be embodied in machine executable instructions to cause a processor to perform the actions, or may be performed by a combination of hardware and software. Although a specific order of method actions may be shown or described, the order of the actions may be different. In addition, two or more actions may be performed concurrently or partially concurrently.

[0111] Example 1: A computer system (100), the computer system comprising a processing circuit (160, 402), the processing circuit being configured to: for a preset positive speed value (ω ref ) and the preset negative speed value (-ω ref ) in each of which: controlling the speed of the motor (10) to the preset speed value (ω ref 、-ω ref ), short-circuiting the motor (10), and determining that the rotor (14) of the motor (10) is moving from the preset speed value (ω ref 、-ω ref )D current and q current during deceleration (i d 、i q ) and angular velocity (ω), and wherein the processing circuit (160, 402) is further configured to: based on the determined d current, q current (i d 、i q ) and the determined angular velocity (ω) to determine the resolver offset (θ off , kω).

[0112] Example 2: The computer system of Example 1, wherein the negative velocity value (-ω ref ) is equal to the positive velocity value (ω ref )’s absolute value.

[0113] Example 3: A computer system as described in any one of Examples 1 to 2, wherein the processing circuit is further configured to: when controlling the speed of the motor (10) to the preset speed value (ω ref 、-ω ref ), disconnecting the motor (10) from the associated load (30) before.

[0114] Example 4: A computer system as described in any of Examples 1 to 3, wherein the processing circuit is further configured to: meas ) minus the resolver offset (θ off , kω) to calculate the correct resolver position (θ cal ).

[0115] Example 5: The computer system of Example 4, wherein the processing circuit is further configured to: based on the correct resolver position (θ cal ) to control the operation of the motor (10).

[0116] Example 6: A computer system as described in any of Examples 1 to 5, wherein the processing circuit is further configured to: determine the resolver offset (θ off , kω) is the constant resolver angular offset (θ off ) and the speed-dependent resolver angular offset (kω).

[0117] Example 7: The computer system of Example 6, wherein the processing circuit is further configured to: determine the constant resolver angular offset (θ off )for

[0118]

[0119] Example 8: The computer system of any of Examples 6 to 7, wherein the processing circuit is further configured to: determine the speed-dependent resolver angular offset as kω, wherein

[0120]

[0121] Example 9: The computer system of Example 1, wherein the negative velocity value (-ω ref ) is equal to the positive velocity value (ω ref ), and wherein the processing circuit is further configured to: meas ) minus the resolver offset (θ off , kω) to calculate the correct resolver position (θ cal); Based on the correct resolver position (θ cal ) to control the operation of the motor (10); determining the rotary transformer offset (θ off , kω) is the constant resolver angular offset (θ off ) and the speed-dependent resolver angular offset (kω); determining the constant resolver angular offset (θ off )for The speed-dependent resolver angular offset is determined to be kω, where

[0122]

[0123] Example 10: A vehicle (1), comprising a computer system (100, 400) as described in any one of Examples 1 to 9.

[0124] Example 11: The vehicle of Example 10, further comprising: an electric machine (10), the electric machine comprising a rotary transformer (12) and at least one load (30) connected to the electric machine (10), wherein the computer system (100, 400) is configured to determine the constant rotary transformer angular offset (θ off ) and the speed-dependent resolver angular offset (kω).

[0125] Example 12: A computer-implemented method (200, 300), the method comprising: for a preset positive speed value (ω ref ) and the preset negative speed value (-ω ref ) in each of which: the processing circuit controls the speed of the motor (10) (206, 218, 302) to the preset speed value (ω ref 、-ω ref ), the processing circuit short-circuits the motor (10) (208, 220, 304), and the processing circuit determines (212, 224, 306) that the rotor (14) of the motor (10) is moving from the preset speed value (ω ref ,-ω ref )D current and q current during deceleration (i d (ω),i q (ω)) and angular velocity (ω), wherein the method further comprises: calculating, by the processing circuit, based on the determined d current, q current (i d (ω),i q (ω)) and the determined angular velocity (ω) to determine (226, 308) the resolver offset (θ off , kω).

[0126] Example 13: The method described in Example 12 further includes: the processing circuit controls the speed of the motor (10) to the preset speed value (ω ref 、-ω ref ), disconnecting (202) the motor (10) from an associated load (30), and determining, by the processing circuit, based on the resolver offset (θ off , kω) to calibrate the resolver position.

[0127] Example 14: A computer program product comprising program code for performing the method as described in any of Examples 12 to 13 when executed by a processing circuit.

[0128] Example 15: A non-transitory computer-readable storage medium comprising instructions that, when executed by a processing circuit, cause the processing circuit to perform the method of any of Examples 12 to 13.

[0129] The terms used herein are only for the purpose of describing specific aspects and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "a kind of" and "the" are intended to also include plural forms. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It should also be understood that the term "comprises, comprising, includes and / or including" when used herein indicates the presence of stated features, integers, actions, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components and / or their groups.

[0130] It should be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0131] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element to another element, as shown in the figures. It should be understood that these terms and those discussed above are intended to cover different device orientations in addition to the orientations depicted in the figures. It should be understood that when an element is referred to as being "connected" or "coupled" to another element, the element may be directly connected or coupled to the other element, or there may be intermediate elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intermediate elements.

[0132] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. It should also be understood that, unless otherwise clearly defined herein, the terms used herein should be interpreted as meanings consistent with their meanings in the context of this specification and the relevant art, and should not be interpreted in an idealized or overly formal sense.

[0133] It should be understood that the present disclosure is not limited to the aspects described above and shown in the accompanying drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and the appended claims. In the drawings and description, various aspects have been disclosed for illustrative purposes only and not for limiting purposes, and the scope of the present disclosure is set forth in the appended claims.

Claims

1. A computer system (100), the computer system comprising a processing circuit (160, 402), the processing circuit being configured to: For the preset positive speed value (ω ref ) and the preset negative speed value (-ω ref ) in each of: The speed of the motor (10) is controlled to be the preset speed value (ω ref 、-ω ref ), short-circuiting the motor (10), and Determine the rotor (14) of the motor (10) at a speed from the preset speed value (ω ref 、-ω ref )D current and q current during deceleration (i d 、i q ) and angular velocity (ω), and The processing circuit (160, 402) is further configured to: Based on the determined d current and q current (i d 、i q ) and the determined angular velocity (ω) to determine the resolver offset (θ off , kω).

2. The computer system of claim 1, wherein the negative velocity value (-ω ref ) is equal to the positive velocity value (ω ref )’s absolute value.

3. The computer system of any one of claims 1 to 2, wherein the processing circuit is further configured to: When the speed of the motor (10) is controlled to be the preset speed value (ω ref 、-ω ref ), disconnecting the motor (10) from the associated load (30) before.

4. The computer system of any one of claims 1 to 3, wherein the processing circuit is further configured to: By using the measured resolver position (θ meas ) minus the resolver offset (θ off , kω) to calculate the correct resolver position (θ cal ).

5. The computer system of claim 4, wherein the processing circuit is further configured to: Based on the correct resolver position (θ cal ) to control the operation of the motor (10).

6. The computer system of any one of claims 1 to 5, wherein the processing circuit is further configured to: Determine the resolver offset (θ off , kω) is the constant resolver angular offset (θ off ) and the speed-dependent resolver angular offset (kω).

7. The computer system of claim 6, wherein the processing circuit is further configured to: Determine the constant resolver angular offset (θ off )for 8. The computer system of any one of claims 6 to 7, wherein the processing circuit is further configured to: The speed-dependent resolver angular offset is determined to be kω, where 9. The computer system of claim 1, wherein the negative velocity value (-ω ref ) is equal to the positive velocity value (ω ref ), and wherein the processing circuit is further configured to: When the speed of the motor (10) is controlled to be the preset speed value (ω ref 、-ω ref ), disconnecting the motor (10) from the associated load (30); By using the estimated resolver position (θ meas ) minus the resolver offset (θ off , kω) to calculate the correct resolver position (θ cal ); Based on the correct resolver position (θ cal ) to control the operation of the motor (10); Determine the resolver offset (θ off , kω) is the constant resolver angular offset (θ off ) and speed-dependent resolver angular offset (kω); Determine the constant resolver angular offset (θ off )for as well as The speed-dependent resolver angular offset is determined to be kω, where 10. A vehicle (1) comprising a computer system (100, 400) as claimed in any one of claims 1 to 9.

11. The vehicle of claim 10, further comprising: An electric machine (10) comprising a rotary transformer (12) and at least one load (30) connected to the electric machine (10), wherein the computer system (100, 400) is configured to determine the constant rotary transformer angular offset (θ off ) and the speed-dependent resolver angular offset (kω).

12. A computer-implemented method (200, 300), the method comprising: For the preset positive speed value (ω ref ) and the preset negative speed value (-ω ref ) in each of: The processing circuit controls (206, 218, 302) the speed of the motor (10) to the preset speed value (ω ref 、-ω ref ), short-circuiting (208, 220, 304) the motor (10) by the processing circuit, and The processing circuit determines (212, 224, 306) that the rotor (14) of the motor (10) is moving from the preset speed value (ω) ref 、-ω ref )D current and q current during deceleration (i d (ω),i q (ω)) and angular velocity (ω), The method further comprises: The processing circuit is based on the determined d current and q current (i d (ω),i q (ω)) and the determined angular velocity (ω) to determine (226, 308) the resolver offset (θ off , kω).

13. The method of claim 12, further comprising: The processing circuit controls the speed of the motor (10) to the preset speed value (ω ref 、-ω ref ), disconnecting (202) the motor (10) from an associated load (30), and The processing circuit is based on the resolver offset (θ off , kω) to calibrate the resolver position.

14. A computer program product comprising program code for performing the method of any one of claims 12 to 13 when executed by a processing circuit.

15. A non-transitory computer-readable storage medium comprising instructions which, when executed by a processing circuit, cause the processing circuit to perform the method of any one of claims 12 to 13.

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