DRIVE SYSTEM FOR A VEHICLE WITH ROTOR POSITION ESCTING BY MEANS OF VARIABLE HIGH-FREQUENCY VOLTAGE INJECTION

Abstract

Drive system (100, 200) for a vehicle (102), the drive system (100, 200) comprising: a signal injection module (310) designed to: i) obtain a rotational speed of a motor (106) of the vehicle (102), ii) select a number of stages per cycle of an injection signal and determine an injection frequency of the injection signal based on the rotational speed of the motor (106), the injection signal being injected into a basic voltage signal on the basis of which the motor (106) is driven, and iii) generate the injection signal having the selected number of stages per cycle and the determined injection frequency; and a drive control module (104) designed to: i) sum the basic voltage signal and the injection signal to provide a combined voltage signal, and ii) control the motor (106) on the basis of the combined voltage signal.

Description

INTRODUCTION

[0001] The information contained in this section serves only to provide a general overview of the context of the disclosure. The work of the inventors mentioned herein, as far as it is described in this section, as well as aspects of the description that were not considered prior art at the time of filing, are neither expressly nor implicitly acknowledged as prior art with respect to the present disclosure.

[0002] The present disclosure relates to power sources for electric vehicles.

[0003] Electric and hybrid vehicles comprise one or more power sources to supply electrical energy to one or more electric motors. The electric motors are used for propulsion and can also be used to reduce the vehicle's speed and to recharge, for example, the power source cells. For instance, during regenerative braking, the electric motors can operate as generators to slow the vehicle and / or recharge the power sources. SUMMARY

[0004] A drive system for a vehicle is disclosed, comprising: a signal injection module designed to i) obtain the rotational speed of the vehicle's engine, ii) select a number of stages per cycle of an injection signal and determine an injection frequency of the injection signal based on the engine's rotational speed, the injection signal being injected into a basic voltage signal on the basis of which the engine is driven, and iii) generate the injection signal having the selected number of stages per cycle and the determined injection frequency; and a drive control module designed to i) sum the basic voltage signal and the injection signal to provide a combined voltage signal, and iii) control the engine on the basis of the combined voltage signal.

[0005] According to other features, the drive control module is designed to estimate the speed of the motor based on an output from a current sensor, with the current sensor detecting the current supplied to the motor.

[0006] According to other features, the drive control module is designed to determine the speed of the motor based on an output from a position sensor, where the position sensor detects a rotor position of the motor.

[0007] According to other features, the drive control module is designed to: detect the current supplied to the motor, wherein the supplied current includes a base current and an injection current; and estimate a rotor position of the motor based on the injection current.

[0008] According to other features, the drive control module is designed to: separate the injection current from the base current based on the injection frequency; and estimate the rotor position based on the separated injection current.

[0009] According to other features, the drive control module is designed to: detect the current supplied to the motor and generate a current signal; convert the current signal into a d-axis and q-axis current signal in the stationary reference system; convert the d-axis and q-axis current signal in the stationary reference system into a d-axis and q-axis signal in the rotated reference system; separate a basic torque component and an injection component from the d-axis and q-axis signal in the rotated reference system; estimate a position error based on the injection component; estimate a rotor position based on the position error; generate an output voltage signal based on the estimated rotor position and the combined voltage signal; and control the motor based on the output voltage.

[0010] According to other features, the signal injection module changes the number of stages per cycle of the injection signal in response to a change in the engine speed.

[0011] According to other features, the signal injection module is designed to reduce the number of stages in response to an increase in engine speed.

[0012] According to other features, the drive control module is designed to: detect the current supplied to the motor via a current sensor, where the supplied current includes a base current and an injection current; and estimate a rotor position of the motor based on the injection current. The signal injection module is designed to adjust the number of stages based on one or more sensor characteristics, including i) current sensor gain, ii) current sensor offset accuracy, iii) current sensor output signal signal signal ratio, and iv) current sensor hysteresis.

[0013] According to other features, the signal injection module is designed to inject the injection signal for a direct axis of the engine in response to the engine speed being below a specified threshold, and to refrain from injecting the injection signal in response to the engine speed being above the specified threshold.

[0014] According to other features, the drive control module is designed to: determine the status of a position sensor of the motor, wherein the position sensor generates a signal indicating a position of the motor; inject the injection signal for a direct axis of the motor in response to the determination that the position sensor of the motor has failed; and refrain from injecting the injection signal in response to the determination that the position sensor of the motor has not failed.

[0015] According to other features, a method for controlling a vehicle engine is disclosed. The method comprises: obtaining an engine speed; based on the engine speed, selecting a number of stages per cycle of an injection signal and determining an injection frequency of the injection signal, wherein the injection signal is to be injected into a base voltage signal on the basis of which the engine is driven; generating the injection signal with the selected number of stages per cycle and the determined injection frequency; summing the base voltage signal and the injection signal to provide a combined voltage signal; and controlling the engine on the basis of the combined voltage signal.

[0016] According to other features, the method further includes estimating the speed of the motor based on an output from a current sensor, wherein the current sensor detects the current supplied to the motor.

[0017] According to other features, the method further includes determining the rotational speed of the motor based on an output from a position sensor, wherein the position sensor detects a rotor position of the motor.

[0018] According to other features, the method further comprises: detecting the current supplied to the motor, wherein the supplied current comprises a base current and an injection current; separating the injection current from the base current based on the injection frequency; and estimating a rotor position of the motor based on the injection current.

[0019] According to other features, the method further comprises: detecting the current supplied to the motor and generating a current signal; converting the current signal into a d-axis and q-axis current signal in the stationary reference system; converting the d-axis and q-axis current signal in the stationary reference system into a d-axis and q-axis signal in the rotated reference system; separating a basic torque component and an injection component from the d-axis and q-axis signal in the rotated reference system; estimating a position error based on the injection component; estimating a rotor position based on the position error; generating an output voltage signal based on the estimated rotor position and the combined voltage signal; and controlling the motor based on the output voltage.

[0020] According to other features, the method also includes changing the number of stages per cycle of the injection signal in response to a change in the engine speed.

[0021] According to other features, the method also includes a reduction in the number of stages in response to an increase in the engine speed.

[0022] According to other features, the method further comprises: detecting the current supplied to the motor via a current sensor, wherein the supplied current includes a base current and an injection current; estimating a rotor position of the motor based on the injection current; and adjusting the number of stages based on one or more sensor characteristics, including i) a current sensor gain, ii) an offset accuracy of the current sensor, iii) a signal-to-noise ratio of a current sensor output signal, and iv) a current sensor hysteresis.

[0023] According to other features, the method further comprises: injecting the injection signal for a direct axis of the engine in response to i) determining that the engine speed is less than a specified threshold, and / or ii) determining that a position sensor of the engine has not failed; and refraining from injecting the injection signal in response to i) determining that the engine speed is greater than the specified threshold, and / or ii) determining that the position sensor of the engine has failed.

[0024] Further applications of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and the specific examples serve only for illustration and are not intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present revelation becomes more fully understandable from the detailed description and the accompanying drawings; they show: Fig. 1 a functional block diagram of an example of a drive system comprising a drive control module with a rotor position module, according to the present disclosure; Fig. 2 a functional block diagram of a section of the drive system of Fig. 1; Fig. 3 a functional block diagram of a section of the drive system from Fig. 1 with a signal injection module and a current filter according to the present disclosure; Fig. 4 a functional block diagram of the current filter of Fig. 3, which represents the signal inputs and outputs of the current filter; Fig. 5. A functional block diagram of an example of the current filter from Fig. 4; Fig. 6 an example of a voltage-time diagram of a high-frequency injection signal with 6 stages per cycle; Fig. Figure 7 shows an example of a current-time diagram of the d-axis and q-axis current and the filtered-out high-frequency component resulting from the injection of the high-frequency injection signal with 6 stages per cycle. Fig. 6 are detected; Fig. 8 An example of a position error diagram based on the high-frequency component of Fig. 7; Fig. 9. An example of a diagram of the estimated rotor position based on the position error of Fig. 8; Fig. 10 an example of a high-frequency injection signal with 4 stages per cycle over time; Fig. 11 an example of a high-frequency injection signal with 6 stages per cycle over time; Fig. 12 an example of a high-frequency injection signal with 8 levels per cycle over time; Fig. 13 an example of a high-frequency injection signal with 10 steps per cycle over time; Fig. 14 a method for operating an engine according to the present disclosure; and Fig. 15 an example of an injection frequency as a function of the stages per cycle according to the present disclosure.

[0026] Reference symbols can be used multiple times in the drawings to denote similar and / or identical elements. DETAILED DESCRIPTION

[0027] The rotor position of a vehicle's engine is a factor used to control engine performance. The rotor position can be determined and used to control the engine's operating efficiency. For example, the rotor position can be detected by a position sensor mounted on the rotor shaft. The rotor position is then used to adjust the current supplied to coils on the engine's stator, thereby aligning the magnetic fields of the stator and rotor. The rotor may contain permanent magnets with corresponding magnetic fields that interfere with the magnetic fields generated by the coils. A timing (or phase) of the current applied to the coils is adjusted to optimize the engine's operating efficiency.

[0028] If the motor's position sensor fails, the rotor's position can be estimated. A high-frequency voltage signal can be injected into the voltage generated to drive the motor. The current supplied to the motor is detected by one or more current sensors. The detected current indicates the motor's position. The fundamental and high-frequency components of the detected current are separated. The high-frequency component is then demodulated to provide an estimate of the motor rotor's position error. This position error allows the motor's position to be determined.

[0029] As the engine speed increases, the high-frequency signal injected into the engine's power supply can interfere with the engine's harmonics. As the engine speed increases, the harmonics of the engine's operating frequency become more pronounced. Consequently, the engine's harmonics can align with the high-frequency injection signal. This can lead to noise and torque ripple in the engine, which may manifest as rapid changes in vehicle speed and / or acceleration that are experienced (i.e., felt) by the driver and / or vehicle occupants.

[0030] The examples described herein include a system for estimating the rotor position of a motor based on an injected voltage signal and for adjusting the current supplied to the motor based on the estimated rotor position. The injected voltage signal is generated based on the motor speed and the number of steps per cycle of the injected voltage signal. According to one embodiment, as the motor speed increases, the number of steps per cycle of the injected voltage signal decreases. Reducing the number of steps leads to an increase in the frequency of the injected voltage, which allows for the separation of motor harmonics and the voltage injection.

[0031] The examples described herein enable the restoration of drivability in the event of a rotor position sensor failure during low-speed operation. Low-speed operation may, for example, refer to operating the motor at a speed less than or equal to 10% of its maximum operating speed. Variable high-frequency voltage injection is used to estimate the rotor position by exploiting the motor's inductive slant. The variable frequency injection is achieved through a series of multi-stage injection waveforms, which are employed to mitigate the impact on torque production and minimize the motor's noise, vibration, and harshness (NVH) characteristics.This low-speed estimation can be used together with a high-speed estimation to provide a full speed range for estimation and drivability in the event of a rotor position sensor failure.

[0032] Fig. Figure 1 shows a drive system 100 of a vehicle 102, which includes a drive control module 104 that controls the operation of a motor 106. The drive control module 104 includes a rotor position module 108 that determines and estimates the position of a rotor of the motor 106 as further described herein. This includes estimating the rotor position when the motor 106 is operating at a speed below a threshold (e.g., 10% of the maximum operating speed of the motor 106).

[0033] The drive system 100 further comprises a power source 110 with battery packs 112. The power source 110 can supply power to an inverter 114, which in turn drives the motor 106 (e.g., an internal permanent magnet motor (IPM motor)). Although the motor 106 is shown as an IPM motor, it could be a surface permanent magnet motor or another type of electric motor. The power source 110 can comprise multiple cells, battery modules, and / or battery packs connected in series and / or parallel to provide predetermined voltage outputs.

[0034] The drive system 100 is used to move the vehicle 102 and further comprises a shaft 120, an axle 122, a differential 124, and wheels 126. The inverter 114 converts a direct current voltage into a three-phase alternating current (AC) to supply the motor 106. The motor 106 rotates the shaft 120, which in turn rotates the axle 122 via the differential 124.

[0035] The drive system 100 further comprises a vehicle control module 130, the drive control module 104, and a driver 132. The vehicle control module 130 can generate a torque request signal. The torque request signal can be generated based on a torque command, for example, from an accelerator pedal 134, if present. The drive control module 104 can control the driver 132 based on the torque request signal. The driver 132 can, for example, generate pulse-width modulation (PWM) signals to control the states of transistors of the inverter 114 based on the output of the drive control module 104.

[0036] The drive system 100 can include a battery management module 140 that detects the current and voltage levels of one or more power sources to determine the impedance responses of those power sources. A different frequency signal (or pulse signal) can be received by different cells, battery modules, and / or battery packs based on selective coupling of the cells, battery modules, and / or battery packs to the inverter. For example, each battery module can have a specific chemical composition, size, shape, etc., and thus be assigned to a specific set of one or more frequency signals. Each frequency signal can have a specific duty cycle profile, amplitude profile, and frequency profile. According to one embodiment, an identical set of frequency signals is generated and received by two or more power sources.The application of frequency signals and the monitoring of the impedance responses of the power sources enable an onboard characteristic analysis of the power sources. Impedances can be calculated and stored in memory 143. The battery management module 140 can store the impedance responses and / or impedance values ​​in memory 143.

[0037] The drive control module 104 controls the driver 132 based on output signals from sensors. The sensors can include current sensors (e.g., Hall effect sensors 150), a rotary encoder (or rotor position sensor) 152, a temperature sensor 154, and / or other sensors 156 (e.g., an accelerometer). The current sensors can include sensors other than Hall effect sensors.

[0038] The drive control module 104 converts the current phase signals Ia, Ib, and Ic for the three phases of the motor into current vector signals Id and Iq. The drive control module 104 determines the current flow and the current required (or requested) and modifies the input current levels of the motor 106 by adjusting the output voltage vector signals supplied to the driver 132. This is based on (i) the current vector signals Id and Iq, (ii) the position signal from the rotary encoder 152, and (iv) the torque request signal from the vehicle control module 130.

[0039] A drive system 100 can comprise one or more electric motors. Each electric motor can be used to drive one or more axles and / or one or more wheels of the vehicle 102. For example, an electric motor can be used to drive an axle of the vehicle 102 via a differential. Based on a torque request, the vehicle control module 130 can signal the electric motor to rotate an input gear of the differential and, consequently, the wheels attached to the axle. The vehicle control module 130 can adjust the current, voltage, and / or power level of the electric motor to control the acceleration, deceleration, and / or speed of the vehicle 102.

[0040] The drive system 100 further comprises a telematics module 158 and power source sensors and / or status monitoring devices (referred to as power source sensors 162). The battery management module 140 can configure the power source 110 based on the output signals of the aforementioned sensors, speed requirements, current driving speed, torque requirements, state of charge of the power source 110's battery packs, etc. The power source sensors 162 may include voltage sensors, current sensors, and / or other circuit elements used to monitor the open-circuit voltages (VOCs), states of charge (SOCs), and / or capacities of the battery packs 112 and / or cells and / or modules of the battery packs 112. The power source sensors 162 may be separate from or contained within the battery packs 112 and monitor voltages, current levels, SOCs, VOCs, capacities, etc.The battery management module 140 monitors the cells and / or modules of the battery packs and / or each of the battery packs 112 as a whole. The battery management module 140 can isolate one or more cells and / or battery packs 112 if: they are not functioning properly; they are not charging to a predetermined voltage level; they output a voltage and / or current at one or more levels below one or more predetermined minimum levels; and / or they exhibit another anomaly. The modules 130, 140, 158, 162 and sensors 156 can be interconnected and / or communicate with each other via a network 170 or another form of communication.

[0041] The rotor position module 108 can be configured as any of the rotor position modules described here and can be used in the method of Fig. Execute 14.

[0042] Fig. Figure 2 shows a drive system 200 within the vehicle 102. The vehicle 102 comprises the motor 106 with a stator 204 and a rotor 206, which includes at least one permanent magnet. The rotor 206 can include a first permanent magnet 208 and a second permanent magnet 210 with alternating polarity around the outer circumference of a rotor core 212. The rotor 206 can include any number of permanent magnets; for simplicity, two are shown. The rotor 206 defines an electrical rotor speed (ω). e ) and a mechanical rotor frequency (ω m ), which are related to each other as follows: (ω e =(P / 2)*ω m ), where P is the number of pole pairs. Although the in Fig. Figure 2 shows a three-phase machine with one pole pair (i.e., two poles); it is understood that the number of phases or pole pairs may differ from that shown.

[0043] The stator 204 comprises a stator core 214, which may be cylindrical with a hollow interior. The stator core 214 may have inwardly projecting stator teeth 216A-F, which are separated from one another by gaps or slots 218. According to the embodiment shown, stator windings 220 may be operationally connected to the stator core 214, for example, by being wound around the stator teeth 216A-F. The motor 106 may include synchronous machines, but is not limited to them.

[0044] The stator 204 is designed such that an electric current, referred to here as stator current, flows in the stator windings 220 and generates a rotating magnetic field in the stator 204. The stator windings 220 can comprise six sets of windings, one set for each of the three phases (the first phase through stator windings 220A and 220D, the second phase through stator windings 220B and 220E, and the third phase through stator windings 220C and 220F). Alternatively, slip rings or brushes (not shown) can be used. A quadrature magnet axis 222 (referred to here as q-axis 222) and a direct magnet axis 224 (referred to here as d-axis 224) are shown. The first and second permanent magnets 208, 210 support the generation of a magnetic field and magnetic flux linkage.

[0045] The drive system 200 comprises the drive control module 104, which communicates with the motor 106, for example, electronically. The drive control module 104 can be implemented as a standalone controller or as a module of a vehicle and / or powertrain control module. The drive control module 104 can include an online torque estimation module OE and a torque sensor failure detection module RD. The electric motor 12 is designed to generate torque to drive the vehicle 102. The drive system 200 can include a secondary source 234, for example, an internal combustion engine, which is designed to selectively provide a secondary torque contribution to drive the vehicle 102.

[0046] The drive system 200 includes a position sensor 236, for example, a rotary encoder, a transducer, an inductive sensor, or another type of detector. The signal from the position sensor 236 provides the rotor position information used in many three-phase motor control systems. In the event of a position sensor failure, the motor control cannot maintain torque control capability, and a loss of drive power may occur in the vehicle 102. The drive control module 104 can include one or more processors and memory (or a non-transient, physical, computer-readable storage medium) on which instructions for executing a procedure such as the one described in Fig. The 14 recorded commands are used to determine the rotor position. The memory stores instruction sets executable by a controller, and the one or more processors execute the controller-executable instruction sets stored in the memory.

[0047] System 200 is designed to enable torque control at low speeds, including zero speed, in the event of a sensor failure, by injecting a specific voltage signal V into the motor control system. In the synchronous reference frame, the voltage signal V is essentially injected into the d-axis 224, while essentially zero voltage is injected into the q-axis 222. The injected voltage modifies the shape of the motor phase current according to the rotor position. The rotor position information is then calculated by the drive control module 104.

[0048] To decouple interference between rotor angle detection and basic torque control, it can be useful to increase the frequency of the injected voltage in a scenario where the position sensor 236 is unavailable. System 200 improves the accuracy of rotor position estimation and enhances torque control performance in terms of operating efficiency, maximum torque capability, and torque control dynamics.

[0049] The drive control module 104 can perform the procedure of Fig. The drive system 200 can execute and receive inputs from one or more sensors. It can include a rotor temperature sensor 238, a current sensor 240, and a magnetic flux linkage monitor 242, each of which can measure a corresponding physical factor and send a corresponding signal to the controller 230. As an alternative to physical sensors, virtual software substitutes can be used. Additionally, the drive control module 104 can be programmed to determine the respective physical factors by inputting the respective signals into a model or other available estimation technique. The driver 132 and the inverter 114 can be operationally connected to the drive control module 104 and configured to supply power to the motor 106.

[0050] Fig. Figure 3 shows section 300 of the drive system 100 of Fig. 1, comprising a current generator 302, the drive control module 104, the driver 132, the inverter 114, and the motor 106. The drive control module 104 may include a current controller 304, a first position module R(θ̂) 306, and a first reference system transformer 308. The current generator 302 generates a current signal. idqr^* (303) based on a command torque (or command current signal 301) supplied to the current controller 304, which provides a basic voltage signal vdqfr^* (305) outputs the basic voltage signal. vdqfr^* is equipped with a high-frequency injection signal vdinjr^* (307), generated by a signal injection module 310, is summed via a summing module 312 to provide a combined voltage signal 320, which is supplied to the first position module 306. The signal injection module 310 is designed to determine the number of stages per cycle of the high-frequency injection signal. vdinjr^* based on the rotational speed of the motor 106 and a reference frequency ω e (314) to be amended. The summing unit 312 is used for the injection of low-amplitude high-frequency voltages to excite the motor, resulting in a current response that depends on the inductive legness of the motor and thus on the rotor position.

[0051] The combined voltage signal 320 output by the summing unit 312 is forwarded to the first position module 306, which converts the received signal from a synchronous reference system to a stationary reference system based on the determined or estimated rotor position θ̂ (366). The converted signal vdqs* (322) is passed to the first reference system transformer 308, which converts the signal 322 from a d-axis and q-axis signal in the stationary reference system into an abc reference system signal (or 3-phase reference system signal) v abc(324) converts. The abc reference system signal (or 3-phase reference system signal) v abc The signal is fed to the driver 132, which outputs control signals 326 to the inverter 114. The inverter outputs three AC signals 328 to the motor 106.

[0052] The drive control module 104 also includes a second reference system transformer 330, a second position module R(−θ^) 332, a current filter 334, a demodulator 336, and a position estimation module 338. The second reference system transformer 330 receives a measured current signal i abc (340) from the current sensor 150 and samples the current signal i abc and converts it into a d-axis and q-axis current signal in the stationary reference frame. idqs (342). The second position module 332 converts the d-axis and q-axis current signal in the stationary reference frame. idqs based on the 338 determined or estimated rotor position θ̂ (366) from the position estimation module into a d-axis and q-axis signal in the rotated reference system idqr^ (344) according to one embodiment and when the rotor position sensor 152 of Fig. If the first position module has not failed, the second position module 332 converts the d-axis and q-axis current signal in the stationary reference system. idqs based on the measured and / or estimated rotor position in the d-axis and q-axis signal in the rotated reference system idqr^ An estimated rotor position θ̂ can be used to verify the measured rotor position if the rotor position sensor 152 has not failed, or can be used as a failsafe if the rotor position sensor 152 has failed.

[0053] A sensorless algorithm (i.e., without a rotor position sensor) is implemented jointly by elements 334, 336, and 338. The current filter 334 separates the base current component. idqfr^ (346) and the high-frequency current component iqinjr^ (348) from the d-axis and q-axis signal in the rotated reference system idqr^. The 334 power filter is based on Fig. 4-5 described in more detail. The demodulator 336 estimates the rotor position error θ̃. est (352) based on the high-frequency current component iqinjr^ and the high-frequency injection signal iqinjr^*. The output of the demodulator 336 is proportional to the rotor position.

[0054] According to one embodiment, the radio frequency current is demodulated to provide a signal proportional to the position error, which is then sent to the position estimation module (or observer) 338. The position estimation module 338 estimates the rotor position θ̂ based on the rotor position error θ̃. est .

[0055] Fig. Figure 4 shows the current filter 334. Fig. 3. The current filter 334 receives the d-axis and q-axis signals in the rotated reference system. idqr^ and an injection frequency f inj of the high-frequency injection signal vdinjr^* and generates the base current component used for torque production based on these inputs. idqfr^ and the resulting high-frequency current component iqinjr^ from the current injection. According to one embodiment, the injection frequency f inj equal to a sampling frequency fs of the engine divided by a selected number of stages per cycle of the high-frequency injection signal vdinjr^* The number of stages is selected based on the engine speed. The injection frequency f inj changes depending on the injection method of the high-frequency injection signal vdinjr^*.

[0056] Fig. Figure 5 shows an example of the 334 current filter from Fig. 4. The current filter 334 can comprise a notch filter 500 or a bandpass filter, as shown, and further comprises a summing filter 502. The notch filter 500 filters the d-axis and q-axis signals in the rotated reference frame. idqr^, to the basic current component idqfr^ to supply the basic current component idqfr^ is derived from the d-axis and q-axis signals in the rotated reference system idqr^ subtracted to obtain the resulting high-frequency current component iqinjr^ to supply. According to one embodiment, the filter 500 has a center frequency which is based on the injection frequency of the injection signal 307 of Fig. 3 is fixed and changes dynamically as a function of the shape of the injection signal 307.

[0057] Fig. Figure 6 shows an example of a voltage-time diagram of a high-frequency injection signal with 6 stages per cycle. The injection signal 600 is generally sinusoidal and comprises 6 stages per cycle. This is an example of a high-frequency injection signal 307. Fig. 3.

[0058] Fig. Figure 7 shows an example of a current-time diagram of a d-axis and q-axis current 700 and a filtered-out high-frequency component current 702, which is the result of injecting the high-frequency injection signal with 6 steps per cycle. Fig. 6 can be detected. The current 700 is an example of the d-axis and q-axis signal in the rotated reference frame. idqr^ from Fig. 3. Current 702 is an example of the resulting high-frequency current component. iqinjr^ from Fig. 3.

[0059] Fig. Figure 8 shows an example of a position error diagram based on the high-frequency component current from Fig. 7. The position error of 800 is an example of the rotor position error θ̃. est from Fig. 3.

[0060] Fig. Figure 9 shows an example of a diagram of the estimated rotor position based on the position error of Fig. 8. The estimated rotor position is an example of the estimated rotor position θ̂ of Fig. 3.

[0061] The following Fig. 10-13 are further examples of the high-frequency injection signal 307 from Fig. 3. As disclosed herein, the high-frequency injection signal 307 can be adjusted based on the rotational speed of the corresponding motor. This can include adjusting the number of stages per cycle, the shape, and the frequency of the high-frequency injection signal. Fig. Figure 10 shows an example of a high-frequency injection signal with 4 stages per cycle 1000. Fig. Figure 11 shows an example of a high-frequency injection signal with 6 stages per cycle 1100. Fig. Figure 12 shows an example of a high-frequency injection signal with 8 stages per cycle 1200. Fig. Figure 13 shows an example of a high-frequency injection signal with 6 stages per cycle 1300. Each of the signals 1000, 1100, 1200, 1300 comprises discrete signal stages, with each depicted point representing the start of a new stage sampling. The injection occurs at the level of each point until the next stage sampling, and thus for each stage period. Multi-stage waveforms are possible with the sampling rate of the current from the sensors 150. Fig. 1 linked. The multi-stage waveforms can be selected and / or varied to selectively match high dynamic performance with system characteristics and to avoid speed-dependent motor harmonics.

[0062] Fig. Figure 14 shows a method for operating a motor. The method can be used for fail-safe operation in the event of a rotor position sensor failure and / or for verification purposes when the rotor position sensor is functioning correctly. The following operations can be performed iteratively. Although at least some of the following operations are performed based on the motor's rotational speed, the operations can also be performed based on the motor's output torque, either additionally or alternatively.

[0063] The motor speed is determined at 1400. The motor speed can be determined based on the rotor position sensor 154. Fig. 1 or based on the current signals 150 of Fig. 1. According to one embodiment, the rotational speed is a last rotational speed determined based on the output of the rotor position sensor 152 before a detected failure of the rotor position sensor 152. According to another embodiment, the rotational speed is an estimate based on one or more of the current signals 150 that indicate the rotational speed of the motor.

[0064] At step 1402, the drive control module 104 can determine whether the rotor position is used for verification. If not, step 1404 can be performed; otherwise, step 1406 can be performed.

[0065] At 1404, the drive control module 104 can determine whether the rotor position sensor 152 is Fig. 1 has failed. If so, process 1406 can be carried out; otherwise, process 1414 can be carried out.

[0066] At stage 1406, the drive control module 104 can determine whether the engine speed is less than or equal to a threshold (e.g., 10% of the engine's maximum speed). Stages 1408, 1410, and 1412 can be performed as part of a low-speed procedure implemented from vehicle start until the vehicle speed reaches the threshold. If the vehicle speed is less than or equal to the threshold, stage 1408 is performed; otherwise, stage 1414 can be performed.

[0067] At 1408, the drive control module 104 and / or the signal injection module 310 can select a number of stages for the high-speed injection signal 307 from Fig. 3. This can be done based on the motor speed. The higher the motor speed, the fewer stages are selected. According to one embodiment, the drive control module 104 selects a first number of stages for a first speed range and a second number of stages for a second speed range. The first and second speed ranges are below the threshold used in 1406. For example, the first number of stages is 6 for a speed range of 0 to 7% of the motor's maximum speed, and the second number of stages is 4 for a speed range between 7 and 10% of the motor's maximum speed. Any number of speed ranges and a corresponding number of stages per cycle can be implemented. For example, the four examples of Fig. 10-13 for four respective speed ranges between 0 and the threshold. According to another embodiment, the selected number of steps is reduced when the speed reaches a predetermined speed (e.g., 200 revolutions per minute (rpm)). According to another embodiment, the number of steps is reduced each time one of several speed thresholds (e.g., 200 rpm, 400 rpm, 600 rpm, etc.) is reached. Although this in Fig. Not shown in Figure 14, the drive control module 104 can switch from a low-speed procedure, as described in relation to operations 1406, 1408, 1410, and 1412, to a high-speed procedure. This can occur when the rotational speed reaches a predetermined speed (e.g., 1000 rpm or 2000 rpm).

[0068] For example, a 10 kHz sampling frequency of the motor current with a 6-stage injection signal yields a 1600 Hz signal, and a 10 kHz sampling frequency of the motor current with a 4-stage injection signal yields a 2500 Hz signal. Motor harmonics are multiples of the motor frequency, which is directly related to the motor speed. At a motor speed of 2500 rpm, the fundamental frequency is 160 Hz with harmonics, one of which is at 1600 Hz. This depends on the number of rotor poles in the motor. A fundamental frequency is equal to the product of the number of pole pairs, the motor speed (in rpm), π / 30, and 1 / 2π. Thus, the number of stages can be reduced from 6 to 4 to avoid misalignment between the motor's harmonic and the resulting sampled signal.According to one embodiment, if the cost of the current sensor 150 is not a factor and therefore the accuracy of the current sensor 150 is high, a small number of stages (e.g. 4 or less) is selected and maintained so that the number of stages is not changed when the speed of the motor is increased up to the threshold of the process 1406.

[0069] According to one embodiment, the number of stages can be changed based on the motor's output torque when torque is used instead of speed. For example, if the output torque is less than or equal to a predefined value (e.g., 50% of the motor's maximum output torque), a first number of stages is selected. If the output torque is greater than the predefined value, a second number of stages is selected. The second number of stages is smaller than the first.

[0070] As an alternative or in addition to adjusting the number of stages per cycle of the injection signal based on the vehicle's rotational speed, the number of stages per cycle can be changed based on system and / or sensor characteristics. According to one embodiment, the signal injection module is designed to adjust the number of stages based on one or more sensor characteristics, including i) current sensor gain, ii) current sensor offset accuracy, iii) current sensor output signal-to-noise ratio, and iv) current sensor hysteresis.

[0071] At 1410, the drive control module 104 and / or the signal injection module 310 can control the injection frequency f inj Determine the high-speed injection signal based on the engine speed and the selected number of stages per cycle. Fig. Figure 15 shows an example of a graph of injection frequency as a function of the stages per cycle. The injection frequency f inj can be equal to a sampling frequency f s The sampling frequency can be determined by dividing the selected number of steps. For example, the sampling frequency f s The frequency is 10 kilohertz (kHz). The injection signal is synchronized with the engine speed by changing and adjusting the number of stages based on the engine speed. Fig. Figure 15 shows an example of a diagram of the injection frequency f. injas a function of the number of signal stages per cycle. With an increasing number of signal stages, the associated noise, vibration, and harshness (NVH) characteristics increase (or worsen). With a decreasing number of signal stages, the required accuracy of the current sensor increases, and the probability of engine resonance due to the alignment of engine harmonics with the frequency of the high-speed injection signal decreases. The fewer the selected stages, the higher the injection frequency f. s The aforementioned factors are weighed against each other when selecting the number of stages. The number of stages is chosen so that the injection frequency f s The signal must be high enough to prevent the injection signal from being aligned with the harmonics and thus the frequency content of the engine. Alignment can lead to resonance.

[0072] As an alternative or in addition to changing the injection signal frequency based on engine speed, the frequency can be changed based on system and / or sensor characteristics. For example, the frequency can be changed based on i) the gain of current sensor 150, ii) the offset accuracy of current sensor 150, iii) the signal-to-noise ratio of an output from current sensor 150, and iv) the hysteresis of current sensor 150.

[0073] In the 1412, the drive control module 104 and / or the signal injection module 310 generates and injects a multi-stage voltage injection signal according to specific parameters. These parameters include the frequency, the number of stages, and the shape of the injection signal.

[0074] At 1414, the second reference frame transformer 330 detects Fig. 3 via the current sensor 150 the 3-phase current supplied to the motor i abc .

[0075] At 1416, the second frame transformer 330 converts the 3-phase current i abc into a d-axis and q-axis current signal in the stationary reference frame idqs um.

[0076] In 1418, the second position module 332 is converted from Fig. 3 the d-axis and q-axis current signal in the stationary reference frame idqs based on the measured and / or estimated rotor position into the d-axis and q-axis signal in the rotated (synchronous) reference system idqr^ um.

[0077] At 1420, the current filter 334 separates from Fig. 3 the fundamental frequency component idqfr^ and the high-frequency component iqinjr^ of the d-axis and q-axis current signal idqr^ in the rotating frame of reference. Separation (or filtering) is based on the injection frequency f. sand thus based on the selected number of stages. This allows for a precise determination of the high-frequency component. iqinjr^ and thus a subsequent accurate estimation of the rotor position. The measured current is passed through a filter that is dynamically tuned to the frequency of the injected voltage in order to separate the current used for torque from the high-frequency response to the voltage injection.

[0078] At 1422, the demodulator 336 estimates the position error θ̃. est of the motor's rotor based on the high-frequency component iqinjr^. At 1424, the position estimation module 338 estimates the rotor position θ̂ based on the position error θ̃. est . Operation 1400 can be performed after operation 1424.

[0079] The processes described above are intended as illustrative examples. Depending on the application, the processes can be executed sequentially, synchronously, simultaneously, continuously, during overlapping time periods, or in any other order. Furthermore, each process can be skipped or not executed, depending on the implementation and / or the sequence of events.

[0080] The examples presented herein include a fail-safe procedure that enables continued controlled operation of a motor in the event of a rotor position sensor failure. The procedure includes operations used to control operation at low speeds (e.g., less than or equal to 10% of the motor's maximum speed). These operations can be implemented in combination with operations to control the motor at high speeds (e.g., greater than 10% of the motor's maximum speed). The procedure ensures controlled operation of the motor at low speeds, allowing the motor to run efficiently.

[0081] The examples disclosed herein include varying the shape of a high-frequency injection signal based on the operating point of a motor (e.g., speed or output torque of the motor). This is done to avoid interaction with the fundamental frequency and its harmonics. The injection frequency is linked to the shape of the injected signal. According to one embodiment, the shape is linked to an inverter switching rate and the sampling rate. In other words, the number of stages of the injection signal can be determined based on the switching rate of inverter 114. Fig. 1 and the sampling rate at which the current supplied to the motor is sampled can be selected. The frequency of the injection signal can be increased with increasing motor speed.

[0082] The examples include multi-stage voltage injections with injection signals having an integer number of stages per cycle. The number of stages can be greater than 1. Example numbers of stages are 2, 4, 6, 8, 10, etc. The number of stages is tuned based on the fundamental frequency of the torque supplied by the motor and the corresponding harmonics. The waveform type of the injection signal is determined based on parameters such as the accuracy of the current sensor and the noise characteristics requirements. The disclosed multi-stage waveforms include a discrete pattern for demodulation purposes and are sinusoidal. The amplitudes of the waveforms are kept constant across the stage periods.

[0083] The examples provide drivability in the event of a rotary encoder failure with little or no impact on torque capability. The examples have no impact on the base current control (i.e., torque production).

[0084] The foregoing description serves only for illustration and is not intended in any way to limit the disclosure, its application, or its use. The general teachings of the disclosure can be implemented in a multitude of forms. Although this disclosure includes certain examples, the actual scope of the disclosure is not intended to be limited thereto, since other variations will be apparent upon review of the drawings, the description, and the following claims. It is understood that one or more steps within a process may be carried out in a different order (or concurrently) without altering the principles of the present disclosure.Furthermore, although each of the embodiments described above is characterized by certain features, one or more of these features described in relation to one embodiment of the disclosure may be implemented in features of one of the other embodiments and / or combined with them, even if this combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments among themselves remain within the scope of this disclosure.

[0085] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "interlocking," "coupled," "adjacent," "next to," "on," "above," "below," and "arranged." When a relationship between a first and a second element is described in the preceding disclosure, this relationship may be a direct relationship, in which no other intervening elements exist between the first and the second element, or it may be an indirect relationship, in which one or more intervening elements (either spatial or functional) exist between the first and the second element, unless it is explicitly described as "direct."When used herein, the expression “at least one of A, B and C” shall be interpreted as meaning a logical (A OR B OR C) using a non-exclusive logical OR, and shall not be interpreted as meaning “at least one of A, at least one of B and at least one of C”.

[0086] In diagrams, the direction of an arrow, as indicated by its tip, generally shows the flow of information (e.g., data or commands) relevant to the diagram. For example, if Element A and Element B exchange a variety of information, but the information sent from Element A to Element B is relevant to the diagram, the arrow may point from Element A to Element B. This unidirectional arrow does not mean that no other information is sent from Element B to Element A. Furthermore, Element B may send requests for or acknowledgments of information sent from Element A to Element B.

[0087] In this application, including the definitions below, the term "module" or "controller" may be replaced by the term "circuit." The term "module" may refer to, be part of, or include: an application-specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field-programmable gate array (FPGA); a processor circuit (shared, dedicated, or grouped) that executes code; a memory circuit (shared, dedicated, or grouped) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-a-chip.

[0088] The module may include one or more interface circuits. According to some examples, the interface circuits may include wired or wireless interfaces connected to a local area network (LAN), the internet, a wide area network (WAN), or combinations thereof. The functionality of any module of this disclosure may be distributed across multiple modules connected via interface circuits. For example, multiple modules may enable load balancing. According to another example, a server module (also known as a remote or cloud module) may perform certain functionality on behalf of a client module.

[0089] The term "code" as used above can include software, firmware, and / or microcode, and can refer to programs, routines, functions, classes, data structures, and / or objects. The term "shared processor circuit" refers to a single processor circuit that executes some or all of the code from multiple modules. The term "group processor circuit" refers to a processor circuit that, in combination with additional processor circuits, executes some or all of the code from one or more modules. References to multiple processor circuits include multiple processor circuits on discrete chips, multiple processor circuits on a single chip, multiple cores of a single processor circuit, multiple strands of a single processor circuit, or a combination thereof.The term shared memory circuit refers to a single memory circuit that stores some or all of the code from multiple modules. The term group memory circuit refers to a memory circuit that, in combination with additional memory, stores some or all of the code from one or more modules.

[0090] The term memory circuit is a subset of the term computer-readable medium. The term computer-readable medium used here does not include transitory electrical or electromagnetic signals that propagate through a medium (e.g., on a carrier wave); the term computer-readable medium can therefore be considered material and non-transient. Non-restrictive examples of a non-transient, material computer-readable medium are non-volatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random-access memory circuit or a dynamic random-access memory circuit), magnetic storage media (such as analog or digital magnetic tape or a hard disk drive), and optical storage media (such as CDs, DVDs, or Blu-ray Discs).

[0091] The devices and methods described in this application can be implemented in part or in full by a special-purpose computer created by configuring a general-purpose computer to perform one or more specific functions contained in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications that can be translated into computer programs through the routine work of an experienced technician or programmer.

[0092] The computer programs contain processor-executable instructions stored on at least one non-transient, physical, machine-readable medium. The computer programs may also contain or access stored data. The computer programs may include a basic input / output system (BIOS) that interacts with the hardware of the special-purpose computer, device drivers that interact with specific devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, and so on.

[0093] Computer programs can include: (i) descriptive text to be parsed, such as HTML (Hypertext Markup Language), XML (Extensible Markup Language), or JSON (JavaScript Object Notation); (ii) assembly code; (iii) object code generated from source code by a compiler; (iv) source code for execution by an interpreter; (v) source code for compilation and execution by an on-demand compiler, etc. Source code can be written using the syntax of languages ​​such as C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5th Revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB, and Simulink, by way of example. and written in Python®.

Claims

[1] Propulsion system for a vehicle, wherein the propulsion system comprises: a signal injection module designed to: i) obtain the rotational speed of the vehicle's engine; ii) select, based on the engine's rotational speed, a number of stages per cycle of an injection signal and determine an injection frequency of the injection signal, the injection signal being injected into a base voltage signal on the basis of which the engine is driven; and iii) generate the injection signal having the selected number of stages per cycle and the determined injection frequency; and a drive control module designed to i) sum the base voltage signal and the injection signal to provide a combined voltage signal, and iii) control the motor based on the combined voltage signal. [2] Drive system according to claim 1, wherein the drive control module is designed to estimate the speed of the motor based on an output from a current sensor, wherein the current sensor detects current supplied to the motor. [3] Drive system according to claim 1, wherein the drive control module is designed to determine the speed of the motor based on an output from a position sensor, wherein the position sensor detects a rotor position of the motor. [4] Drive system according to claim 1, wherein the drive control module is designed to: to detect the current supplied to the motor, wherein the supplied current comprises a base current and an injection current; and to estimate the rotor position of the motor based on the injection flow. [5] Drive system according to claim 1, wherein the drive control module is designed to: to detect the current supplied to the motor and generate a current signal; to convert the current signal into a d-axis and q-axis current signal in the stationary reference frame; to convert the d-axis and q-axis current signal in the stationary reference system into a d-axis and q-axis signal in the rotated reference system; to separate a basic torque component and an injection component from the d-axis and q-axis signal in the rotated reference system; to estimate a positional error based on the injection component; to estimate a rotor position based on the position error; to generate an output voltage signal based on the estimated rotor position and the combined voltage signal; and to control the motor based on the output voltage. [6] Drive system according to claim 1, wherein the signal injection module changes the number of stages per cycle of the injection signal in response to a change in the speed of the motor. [7] Drive system according to claim 1, wherein the signal injection module is designed to reduce the number of stages in response to an increase in the speed of the motor. [8] Drive system according to claim 1, wherein the drive control module is designed to to detect the current supplied to the motor via a current sensor, wherein the supplied current comprises a base current and an injection current, and to estimate the rotor position of the engine based on the injection flow; and The signal injection module is designed to adjust the number of stages based on one or more sensor characteristics, including i) current sensor gain, ii) current sensor offset accuracy, iii) current sensor output signal / noise ratio, and iv) current sensor hysteresis. [9] Drive system according to claim 1, wherein the signal injection module is designed to: to inject the injection signal for a direct shaft of the engine in response to the engine speed being less than a specified threshold; and in response to the fact that the engine speed is greater than the specified threshold, to refrain from injecting the injection signal. [10] Drive system according to claim 1, wherein the drive control module is designed to: to determine the status of a position sensor of the motor, wherein the position sensor generates a signal that indicates a position of the motor; to inject the injection signal for a direct axis of the engine in response to a determination that the engine's position sensor has failed; and In response to the determination that the engine position sensor has not failed, to refrain from injecting the injection signal.

Images