Electric vehicle wheel hub three-in-one electric drive assembly integrated architecture and drive control algorithm

Abstract

The application discloses an electric vehicle wheel hub three-in-one electric drive assembly integrated architecture and a drive control algorithm. The architecture comprises a permanent magnet synchronous motor assembly, a motor controller assembly and a two-stage reduction mechanism which are coaxially nested and integrated in a wheel hub. The rotor output end of the permanent magnet synchronous motor assembly is in transmission connection with the input side of the two-stage reduction mechanism, and the output side of the two-stage reduction mechanism is coupled with the wheel rim for widening the motor constant power speed regulation range through speed reduction and torque increase. The power device of the motor controller assembly is arranged close to the stator end of the permanent magnet synchronous motor assembly. The electric vehicle wheel hub three-in-one electric drive assembly integrated architecture and the drive control algorithm solve the problems of low-speed torque deficiency, low full-working-condition efficiency and limited endurance of a traditional direct-drive wheel hub motor, and solve the problems of difficult consideration of full-speed-domain performance of a single angle detection scheme and poor reliability of a mechanical sensor.

Description

Technical Field

[0001] This invention belongs to the field of electric vehicle electric drive technology, specifically relating to an integrated architecture and drive control algorithm for a three-in-one electric drive assembly for electric bicycles and electric mopeds. Background Technology

[0002] Currently, electric bicycles with speeds ≤25km / h and electric mopeds with speeds >25km / h and ≤50km / h generally adopt a direct-drive hub motor solution. This solution is limited by the narrow constant power speed regulation range of the motor itself. Under low-speed, high-torque conditions, the current surges, leading to severe heat generation. Furthermore, a single motor cannot meet the dual requirements of starting, climbing, and high-speed cruising. Therefore, it generally suffers from technical pain points such as insufficient low-speed climbing ability, low efficiency under all operating conditions, and reduced overall vehicle range.

[0003] Meanwhile, the motor control systems of traditional electric bicycles and electric mopeds have long relied on mechanical angle detection components such as Hall sensors, photoelectric encoders, or rotary transformers. In hub motor applications, these sensors face multiple reliability bottlenecks, including high requirements for coaxiality during installation, signal drift caused by alternating high and low temperatures, easy failure of water and dustproof seals, and mechanical wear and wiring harness aging and breakage caused by severe vibration. These bottlenecks not only increase system costs and assembly complexity but also become a key weakness contributing to the high failure rate of the entire vehicle, severely restricting the durability and environmental adaptability of the electric drive system.

[0004] To address the aforementioned issues, sensorless control technology has become a key area for industry upgrades. However, single back-EMF observation schemes suffer from weak back-EMF amplitude and poor signal-to-noise ratio near low and zero speeds, making them prone to observation drift and instability. Meanwhile, single Hall signal schemes have inherent quantization errors, significant commutation jitter at high speeds, and insufficient control precision. Therefore, existing technologies struggle to simultaneously achieve both observation robustness and control precision across the entire speed range. Summary of the Invention

[0005] The main objective of this invention is to provide an integrated architecture and drive control algorithm for a three-in-one electric drive assembly for electric vehicle hubs, which solves the problems of insufficient low-speed torque, low efficiency under all operating conditions, and limited range of traditional direct-drive hub motors. At the same time, it also solves the problems of difficulty in achieving full-speed performance in single-angle detection schemes and poor reliability of mechanical sensors.

[0006] To achieve the above objectives, this invention provides an integrated architecture for a three-in-one electric drive assembly in an electric vehicle wheel hub, comprising a permanent magnet synchronous motor assembly, a motor controller assembly, and a two-stage reduction mechanism coaxially nested and integrated inside the wheel hub, wherein: The rotor output end of the permanent magnet synchronous motor assembly is connected to the input side of the two-stage reduction mechanism, and the output side of the two-stage reduction mechanism is coupled to the hub and rim for transmission, which is used to widen the constant power speed regulation range of the motor by reducing speed and increasing torque. The power devices of the motor controller assembly are arranged close to the stator end of the permanent magnet synchronous motor assembly and are directly electrically connected to the stator winding through a short busbar to shorten the power harness length. The motor controller assembly and the permanent magnet synchronous motor assembly share a common motor housing as a heat dissipation channel to achieve integrated thermal management.

[0007] As a further preferred embodiment of the above technical solution, the two-stage reduction mechanism is a two-stage fixed-axis gear transmission structure, including an input shaft, an intermediate shaft, and an output shaft arranged in parallel along the radial direction, wherein: The input shaft is the rotor output shaft of the permanent magnet synchronous motor assembly, and its end is provided with a single-stage drive gear; The intermediate shaft is provided with a first-stage driven gear and a second-stage driving gear. The first-stage driven gear meshes with the first-stage driving gear to complete the first-stage speed reduction and torque increase. The output shaft is provided with a secondary driven gear, which meshes with the secondary driving gear to complete the second stage of speed reduction and torque amplification. The secondary driven gear also meshes directly with the internal gear ring of the wheel hub rim to output the amplified torque to the wheel hub.

[0008] As a further preferred technical solution of the above technical solution, the input shaft, intermediate shaft and output shaft are all radially loaded and axially limited by ball bearings; the motor housing and the reducer cover are fitted together to form a closed gear chamber; the support shaft coaxially passes through the secondary driven gear through the support shaft ball bearing, the output shaft and the motor housing are fitted with an output oil seal, and the support shaft and the motor housing are fitted with a support shaft oil seal, forming a double sealing structure.

[0009] As a further preferred technical solution of the above technical solution, the motor controller assembly, permanent magnet synchronous motor assembly, two-stage reduction mechanism and rear wheel assembly are arranged sequentially from the inside to the outside along the axial direction inside the wheel hub. The rear wheel assembly includes tires, wheel hub rim and braking system. The braking system includes brake drum cover, brake shoes and brake rocker arm, used to realize driving and parking braking.

[0010] This invention also provides a drive control algorithm for an integrated architecture of a three-in-one electric drive assembly in the wheel hub of an electric vehicle, based on a permanent magnet synchronous motor field-oriented control system, including the following steps: Step S1, Dual-source angular velocity signal acquisition: Two heterogeneous rotor angular velocity signals are acquired respectively. The first signal is obtained by real-time observation of the stator back EMF through an extended back EMF observer in the α-β stationary coordinate system, and the continuous rotor angular velocity estimate is calculated. The second signal is obtained by discrete state transition signals from a three-phase Hall sensor, which are analyzed by a state machine and differentially calculated with adjacent transition times to obtain discrete rotor angular velocity information. Step S2, Adaptive Weighted Fusion: Input the two angular velocity signals into the phase-locked loop (PLL) simultaneously. Based on the real-time rotational speed, back EMF amplitude confidence level, and Hall signal update frequency, the time-varying weighting coefficient is adaptively adjusted to dynamically weight and fuse the two angular velocity signals, and the fused angular velocity is output. Step S3, PLL closed-loop angle correction: The rotor position is estimated by time integration of the fused angular velocity. At the same time, the discrete absolute position corresponding to the Hall signal transition moment is used as the phase reference. The difference between the integrated angle and the Hall reference position is compared by the PLL phase detector. The integrated result is corrected by the output angle compensation amount of the loop filter to eliminate the cumulative angle error. Step S4, Vector Control Drive: Based on the corrected rotor position and fused angular velocity, perform field-oriented control to generate pulse width modulation signals to drive the motor.

[0011] As a further preferred technical solution of the above technical solution, in step S1, the construction process of the extended back EMF observer is as follows: establish the voltage equation of the permanent magnet synchronous motor in the α-β stationary coordinate system, and derive the extended back EMF expression; calculate the back EMF components of the α-axis and β-axis based on the collected stator voltage and current signals; obtain the rotor electrical angle estimation value through arctangent operation, perform differential operation on the electrical angle, and obtain the continuous rotor angular velocity estimation value; In step S1, the process of obtaining discrete rotor angular velocity information is as follows: the times of the six Hall state transition edges within one electrical cycle are collected, and the duration and corresponding angle of each sector are calculated; the angular acceleration is calculated based on the angular velocity difference between adjacent transition times, and the discrete rotor angular velocity and position at any time are obtained by interpolation of the angular acceleration.

[0012] As a further preferred technical solution of the above technical solution, in step S2, the value range of the time-varying weighting coefficient is 0 to 1; when the motor is in low-speed operation, the weighting coefficient approaches 0, and the system prioritizes the angular velocity information output by the three-phase Hall sensor; when the motor is in medium-high speed operation, the weighting coefficient smoothly transitions to approach 1, and the system prioritizes the angular velocity information output by the back EMF observer.

[0013] As a further preferred technical solution of the above technical solution, in step S3, the loop filter is a PI regulator; whenever the Hall state changes, the PI regulator outputs an angle compensation amount according to the phase error, which is superimposed on the integral angle to periodically correct the cumulative error of the back EMF observer caused by parameter temperature drift, inverter nonlinearity and load disturbance.

[0014] As a further preferred technical solution of the above technical solution, in step S4, the field orientation control includes MTPA maximum torque current ratio control, which calculates the optimal d-axis and q-axis current commands based on the stator current vector amplitude and motor parameters to achieve the maximum torque output under unit current. Six drive signals are generated using voltage space vector pulse width modulation (SVPWM) to control the switching on and off of the inverter power devices. Based on the sector where the command voltage vector is located, the action time of adjacent non-zero vectors and zero vectors is allocated according to the volt-second balance principle to synthesize the target voltage vector.

[0015] As a further preferred technical solution to the above technical solution, the solution also includes a dynamic adjustment step for bus voltage: real-time acquisition of battery voltage and target bus voltage; operation in Buck step-down mode when battery voltage is higher than target bus voltage; operation in Boost step-up mode when battery voltage is lower than target bus voltage; and operation in Buck-Boost interleaved mode when voltages are close, thereby achieving stable adjustment of bus voltage.

[0016] The beneficial effects of this invention are as follows: 1. Deep electromechanical integration significantly improves power density and transmission efficiency: This invention integrates a motor, controller, and reducer coaxially within the wheel hub. A two-stage reduction mechanism amplifies torque at low speeds, significantly enhancing climbing and load-bearing capabilities. Simultaneously, it allows the motor to operate in its high-efficiency range at high speeds, broadening the constant power speed regulation range. The integrated layout of the controller and motor shortens the power circuit, reducing line impedance and electromagnetic interference. The shared wheel hub housing enables integrated thermal management. While maintaining the same wheel hub outer diameter, this invention significantly improves power density and torque density, simultaneously enhancing the vehicle's low-speed performance, maximum speed, and driving range.

[0017] 2. Dual-source heterogeneous fusion, balancing full-speed domain control performance and reliability: This invention employs a PLL control algorithm that fuses back EMF observation in an α-β stationary coordinate system with three-phase Hall signals. In the low-speed range, the Hall signals ensure robust observation and avoid the low-speed drift problem of sensorless algorithms. In the medium and high-speed ranges, a smooth transition to the back EMF observer enables high-precision continuous tracking, suppressing Hall quantization noise and jitter. Simultaneously, through PLL closed-loop and periodic calibration of Hall absolute position, the accumulated angle error caused by parameter temperature drift and disturbances is eliminated. This completely eliminates the dependence on high-precision mechanical angle sensors and achieves rotor position observation with low phase lag and no steady-state deviation across the entire speed domain, comprehensively improving the control robustness, environmental adaptability, and operational quality of the electric drive system.

[0018] 3. Wide voltage range adaptability and efficient modulation further enhance system adaptability and energy efficiency: 4. This invention integrates a four-switch synchronous rectification buck-boost circuit, which is compatible with battery packs of different voltage levels, compensates for voltage fluctuations caused by battery SOC, temperature and discharge rate, and maintains the optimal modulation depth of the inverter; combined with MTPA control and SVPWM modulation, it further improves energy conversion efficiency, reduces power device losses, and extends the vehicle's range. Attached Figure Description

[0019] Figure 1 This is a system control block diagram of the present invention.

[0020] Figure 2 This is the driving circuit diagram of the system of the present invention.

[0021] Figure 3 This is a schematic diagram showing the correspondence between the three-phase Hall signals and the motor rotor of the present invention.

[0022] Figure 4 This is a schematic diagram showing the relationship between the Hall sensor angle and the compensated electrical angle of the present invention.

[0023] Figure 5 This invention is based on A schematic diagram of PLL-optimized control of two angular velocities: the estimated angular velocity of the motor rotor in the stationary coordinate system and the angular velocity of the motor rotor estimated based on the three-phase Hall signal.

[0024] Figure 6 This invention relates to a voltage space vector diagram based on the voltage space vector modulation algorithm SVPWM.

[0025] Figure 7A This is a schematic diagram of the integrated architecture of the present invention.

[0026] Figure 7B This is a cross-sectional view of the integrated architecture of the present invention.

[0027] Figure 8A This is a schematic diagram of the overall two-stage deceleration mechanism of the present invention.

[0028] Figure 8B This is a schematic diagram of the two-stage reduction mechanism of the present invention.

[0029] Figure 9A This is an overall cross-sectional view of the two-stage reduction mechanism of the present invention.

[0030] Figure 9B This is a cross-sectional view of the two-stage reduction mechanism of the present invention.

[0031] Figure 10 This is an exploded view of the integrated architecture of the present invention. Detailed Implementation

[0032] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0033] In the preferred embodiments of the present invention, those skilled in the art should note that the electric bicycles and electric mopeds hubs involved in the present invention can be considered as prior art.

[0034] Preferred embodiment.

[0035] This invention discloses an integrated architecture for a three-in-one electric drive assembly in an electric vehicle wheel hub, comprising a permanent magnet synchronous motor assembly, a motor controller assembly, and a two-stage reduction mechanism coaxially nested and integrated inside the wheel hub, wherein: The rotor output end of the permanent magnet synchronous motor assembly is connected to the input side of the two-stage reduction mechanism, and the output side of the two-stage reduction mechanism is coupled to the hub and rim for transmission. This structure, through the speed ratio matching of the reduction mechanism, makes the motor operating point far away from the low-speed, high-torque, inefficient region, and is used to widen the constant power speed regulation range of the motor by reducing speed and increasing torque. The power devices of the motor controller assembly are arranged close to the stator end of the permanent magnet synchronous motor assembly and are directly electrically connected to the stator windings via a short busbar to shorten the power harness length and reduce line impedance and electromagnetic interference. The motor controller assembly and the permanent magnet synchronous motor assembly share a common motor housing as a heat dissipation channel, achieving integrated thermal management. This significantly improves power density and torque density while maintaining the same hub outer diameter, solving the pain points of traditional direct-drive hub motors caused by insufficient low-speed climbing torque, low efficiency under all operating conditions, and limited range due to the single motor. It enables electric bicycles and electric mopeds to achieve high torque output on low-speed, steep inclines and high-efficiency operation during high-speed cruising.

[0036] Specifically, such as Figure 7A and Figure 7B As shown, the wheel hub adopts a highly integrated modular architecture. The internal space is arranged axially from the inside to the outside, including the motor controller assembly, the permanent magnet synchronous motor assembly, the two-stage reduction mechanism, and the rear wheel assembly. The permanent magnet synchronous motor assembly is centrally located, and the three-in-one drive assembly is rigidly connected to the frame through the flat fork assembly. The rotor assembly of the motor assembly is directly coupled to the wheel hub rim through the built-in two-stage reduction mechanism to output torque. The motor controller assembly is embedded close to the end of the motor stator, and the power devices are directly connected to the stator winding through the short busbar. The control board and power board are stacked in layers to compress the axial dimension. The rear wheel assembly includes the tire, wheel hub rim, and braking system. The brake rocker arm, brake drum cover, and output shaft gear are coaxially arranged on the outside of the wheel hub, and parking and service braking are achieved through mechanical linkage. The swingarm assembly not only supports and positions the motor stator and transmits the vehicle load, but also serves as the electrical and mechanical interface between the controller and the frame. This allows the motor, electronic control, transmission, and braking functions to be deeply coupled within a single wheel hub, significantly simplifying the vehicle assembly process, shortening the power circuit, and optimizing the thermal management path, thus achieving the ultimate compactness and lightweighting of the powertrain.

[0037] Specifically, the two-stage reduction mechanism is a two-stage fixed-axis gear transmission structure, including an input shaft, an intermediate shaft, and an output shaft arranged in parallel along the radial direction, wherein: The input shaft is the rotor output shaft of the permanent magnet synchronous motor assembly, and its end is provided with a single-stage drive gear; The intermediate shaft is provided with a first-stage driven gear and a second-stage driving gear. The first-stage driven gear meshes with the first-stage driving gear to complete the first-stage speed reduction and torque increase. The output shaft is equipped with a secondary driven gear (i.e., the output shaft gear). The secondary driven gear meshes with the secondary driving gear to complete the second stage of speed reduction and torque amplification. The secondary driven gear also meshes directly with the internal gear ring of the wheel hub rim to output the amplified torque to the wheel hub.

[0038] More specifically, the input shaft, intermediate shaft, and output shaft all achieve radial bearing and axial limiting through ball bearings; the motor (reducer) housing and reducer cover cooperate to form a closed gear chamber; the support shaft coaxially passes through the secondary driven gear through the support shaft ball bearing; the output shaft and the motor housing mating end face are provided with an output oil seal; the support shaft and the motor housing mating point are provided with a support shaft oil seal, forming a double sealing structure.

[0039] Specifically, such as Figure 8A and Figure 8BAs shown, the reducer mechanism adopts a two-stage fixed-axis gear transmission structure, with the input shaft, intermediate shaft, and output shaft arranged in parallel to achieve a high reduction ratio and compact layout: the input shaft is the output shaft of the motor rotor (motor shaft), and its end gear introduces the high-speed, low-torque power of the motor into the reducer; the intermediate shaft is mounted in the motor (reducer) housing through a driven wheel ball bearing, and two gears are fixedly connected or integrally formed on the shaft. The first-stage driven gear meshes with the input shaft driving gear to complete the first stage of reduction and torque amplification, while the second-stage driving gear forms the second stage of transmission with the output shaft gear; the output shaft is precisely positioned by an output ball bearing, and only one second-stage driven gear is provided at the shaft end. The external spline of this gear directly meshes with the internal spline of the wheel hub rim, and the torque amplified by the two stages is finally transmitted to the wheel rim to drive the entire vehicle. All three shafts rely on ball bearings on the support shaft to achieve radial load bearing and axial limit, ensuring that each gear maintains precise meshing clearance and transmission coaxiality within the narrow space of the hub. The reducer cover and the motor reducer housing cooperate to form a closed gear chamber, which not only provides rigid support for the outer ring of the bearing, but also isolates external mud, water vapor and dust from intrusion through the sealing structure, maintains a clean internal lubrication environment, and ensures the smooth operation and service life of the reducer under long-term vibration and water immersion conditions.

[0040] like Figure 9A and Figure 9B As shown, the cross-sectional structure of the reducer mechanism is arranged along the power transmission path in two stages of meshing pairs: the motor shaft, the driven gear, and the output shaft gear. The driven gear is precisely positioned and rotated by a driven wheel ball bearing, meshing with the input shaft (motor shaft) driving gear to complete the first stage of reduction and torque increase. The output shaft gear is mounted on the motor reducer housing by an output shaft ball bearing, receiving the torque transmitted through the intermediate stages and meshing with the spline inside the hub to achieve the final power output. The support shaft coaxially passes through the output shaft gear via a support shaft ball bearing and is mounted on the motor housing and fixed to the horizontal fork assembly, providing auxiliary rigid support for the transmission components to enhance load-bearing capacity and impact resistance. The output oil seal is located on the mating end face of the output shaft and the motor housing, and the support shaft oil seal is located at the mating point of the support shaft and the output shaft gear. The double oil seal structure forms a labyrinthine sealing barrier, effectively preventing gear lubricating oil leakage, while blocking external mud, water vapor, and dust intrusion, ensuring the lubrication reliability, transmission accuracy, and sealing durability of the reducer under long-term operation, vibration, and water immersion conditions.

[0041] like Figure 10The diagram shown is an exploded view of the integrated architecture of the three-in-one electric drive assembly. The hub motor adopts an axially layered architecture with deep integration of the motor, controller, and reducer, with each functional module stacked from the inside to the outside along the power transmission direction. The motor controller assembly is fastened to the outer end of the motor housing with hexagonal head screws, forming an independent sealed electronic control chamber. The permanent magnet synchronous motor assembly uses the stator assembly pressed into the inner cavity of the motor housing as a fixed reference. The rotor assembly is supported by the front and rear bearings of the motor for coaxial rotation with the stator. Bushings are used for axial positioning and preload adjustment of the bearing inner ring. The motor shaft oil seal is arranged at the shaft extension end to form a rotary dynamic seal. Hall sensors are embedded in the end caps with cross-slot countersunk screws at the stator end to provide the initial position signal of the rotor. The motor (reducer) housing serves as the core load-bearing skeleton and integrates a vent valve to balance the air pressure inside and outside the chamber and an oil drain plug for periodic maintenance and static sealing of the gear oil. Inside the reducer, the driven gear is supported on the motor housing by a driven wheel ball bearing and meshes with the motor rotor shaft gear to complete the first stage of reduction. The support shaft is mounted on the motor housing via a support shaft ball bearing to enhance transmission rigidity and is sealed and isolated by a support shaft oil seal. The output shaft gear is positioned on the motor reducer housing by an output shaft ball bearing, receives the second stage reduction torque, and transmits it outward via an external spline. The reducer cover is circumferentially aligned with the motor housing by a locating pin and is secured with hexagonal head screws to form a closed gear cavity. The support shaft is mounted on the motor housing via a support shaft ball bearing to enhance transmission rigidity and is sealed and isolated on the reducer side by a support shaft oil seal. An O-ring provides a seal with the motor housing. A bushing is used for axial positioning and preload adjustment of the support shaft and the flat fork assembly that are mounted through the motor housing. The braking system is located on the outside of the wheel hub: the lock nut and output gear are threaded together to fix and limit the rear wheel assembly; the brake drum cover is coaxially arranged with the rear wheel assembly, the brake shoes are built into the inner cavity of the brake drum cover, the brake shaft passes through the brake drum cover and is linked to the brake rocker arm, and the waist-shaped shim is used to adjust the brake clearance of the support shaft; the hexagonal flange nut and hexagonal flange lock nut are layered to achieve axial locking and anti-loosening of the brake assembly, rear wheel assembly and swingarm assembly; the swingarm assembly, as the mechanical interface between the vehicle suspension and the wheel hub, passes through the center of the wheel hub and undertakes the transmission of vehicle load and the support and positioning of the motor. The above components are modularly stacked axially and nested radially, achieving a high degree of integration of electric drive, transmission, braking and suspension interfaces within a single wheel hub, significantly shortening the power harness length, simplifying vehicle assembly and improving system reliability.

[0042] This invention also discloses a drive control algorithm for an integrated architecture of a three-in-one electric drive assembly in the wheel hub of an electric vehicle, based on a permanent magnet synchronous motor field-oriented control system, such as... Figure 1The diagram shows the control block diagram of the electric drive system. In the vector control system of the permanent magnet synchronous motor, the continuous rotor angular velocity obtained by observing the back electromotive force in the α-β stationary coordinate system, and the discrete rotor angular velocity obtained by differential analysis of the three-phase Hall signals through a state machine are simultaneously input into the phase-locked loop (PLL). By adaptively adjusting the PLL loop parameters, the system prioritizes the Hall signals to ensure robustness in the low-speed range, and smoothly transitions to the back electromotive force observer to achieve high-precision continuous tracking in the medium and high-speed ranges. This filters out high-frequency noise, eliminates accumulated angle errors, and reduces speed feedback phase lag across the entire speed domain. While completely eliminating the need for high-precision mechanical angle sensors, it comprehensively improves the low-speed heavy-load adaptability and full-speed-domain control robustness of the electric drive system. The algorithm includes the following steps: Step S1, Dual-source angular velocity signal acquisition: Two heterogeneous rotor angular velocity signals are acquired respectively. The first signal is obtained by real-time observation of the stator back EMF through an extended back EMF observer in the α-β stationary coordinate system, and the continuous rotor angular velocity estimate is calculated. The second signal is obtained by discrete state transition signals from a three-phase Hall sensor, which are analyzed by a state machine and differentially calculated with adjacent transition times to obtain discrete rotor angular velocity information. In step S1, the construction process of the extended back EMF observer is as follows: the voltage equation of the permanent magnet synchronous motor is established in the α-β stationary coordinate system, and the extended back EMF expression is derived; the back EMF components of the α-axis and β-axis are calculated based on the collected stator voltage and current signals; the rotor electrical angle is estimated by arctangent operation, and the continuous rotor angular velocity is estimated by differential operation on the electrical angle.

[0043] The specific implementation is as follows: The motor is The voltage equation in the stationary coordinate system is expressed as follows: ; In a stationary coordinate system Shaft motor voltage; In a stationary coordinate system Shaft motor voltage; Motor phase resistance; : Electric angular velocity of the motor rotor; ; ; : D-axis inductance of motor winding; : q-axis inductance of motor winding; : The magnetic flux of the air gap magnetic field generated by the rotor magnet of the motor; Electrical angle of the motor rotor.

[0044] The above equation is transformed into an extended back electromotive force equation: ; Back electromotive force in static coordinate system and This equation contains rotor position angle information and can be used to estimate the rotor position: ; The extended back electromotive force equation is calculated by the following formula: .

[0045] The voltage equation is calculated by the following formula: ; The equations for estimating the electric angle and angular velocity are calculated using the following formula: ; Estimated electrical angle; ; : Estimated angular velocity.

[0046] In step S1, the process of obtaining discrete rotor angular velocity information is as follows: the times of the six Hall state transition edges within one electrical cycle are collected, and the duration and corresponding angle of each sector are calculated; the angular acceleration is calculated based on the angular velocity difference between adjacent transition times, and the discrete rotor angular velocity and position at any time are obtained by interpolation of the angular acceleration.

[0047] The specific implementation is as follows: The relationship between the three-phase Hall signal (i.e., the signal collected by the three-phase Hall sensor) and the electrical angle of the motor rotor position is as follows: Figure 3 As shown: Interval 1: Hall signal 001; electrical angle 270°~330°; Interval 3: Hall signal 011; electrical angle -30° to 30°; Interval 2: Hall signal 010; electrical angle 30°~90°; Interval 6: Hall signal 110; electrical angle 90°~150°; Interval 4: Hall signal 100°; electrical angle 150°~210°; Interval 5: Hall signal 101; electrical angle 270°~330°; like Figure 4 As shown, the Hall sensor angle With compensated electrical angle Relationship. Online signal acquisition is performed on the six signal transition edges of the Hall position sensor within one electrical cycle of 360 degrees, and the corresponding time is recorded. The relative angle of each sector corresponding to the Hall signal can be calculated by the following formula: ; Motor rotor angular position acceleration within the interval Calculated by the following formula: ; : The interval number of the motor rotor position; : The time elapsed within the interval; : The electric angular acceleration at time t; : The electric angular acceleration at time t; At any given moment, the motor rotor The electric angular velocity at time t is calculated by the following formula: ; The electrical angle of the motor rotor in any rotor position range can be calculated by the following formula: ; Last time The calibration position angle at which the Hall signal is triggered at any given moment; Angle compensation; the angular velocity and position information provided by the Hall signal have an absolute position reference, which is highly reliable at low speeds, but there is a fixed effective error of 60° electrical angle, and the jitter is obvious at high speeds.

[0048] Step S2, Adaptive Weighted Fusion: Input the two angular velocity signals into the phase-locked loop (PLL) simultaneously. Based on the real-time rotational speed, back EMF amplitude confidence level, and Hall signal update frequency, the time-varying weighting coefficient is adaptively adjusted to dynamically weight and fuse the two angular velocity signals, and the fused angular velocity is output. In step S2, the time-varying weighting coefficient ranges from 0 to 1. When the motor (i.e., the permanent magnet synchronous motor assembly) is in a low-speed condition, the weighting coefficient approaches 0, and the system prioritizes the angular velocity information output by the three-phase Hall sensor to ensure observation robustness. When the motor is in a medium-to-high-speed condition, the weighting coefficient smoothly transitions to approach 1, and the system prioritizes the angular velocity information output by the back EMF observer to achieve high-precision continuous tracking. This filters out high-frequency noise and eliminates the angle accumulation error caused by parameter temperature drift in the full speed domain, significantly reduces the phase lag of speed feedback, optimizes the current decoupling accuracy in field-oriented control, and completely eliminates the dependence on high-precision mechanical angle sensors while comprehensively improving the low-speed heavy-load adaptability and full-speed domain control robustness of the electric drive system.

[0049] The specific implementation is as follows: like Figure 5 As shown, the optimal motor rotor angle and rotor angular velocity The angular velocity is calculated using the following formula, which is the weighted fusion of angular velocities. The formula for calculating the fused angular velocity is: ; : Weighted values ​​at time points, ; The motor is Estimated value of the angular velocity of the motor rotor in a stationary coordinate system; :exist The estimated value of the motor rotor angular velocity obtained based on the three-phase Hall signals at any time; Step S3, PLL closed-loop angle correction: Integrate the fused angular velocity over time to obtain the rotor position estimate. Meanwhile, the discrete absolute position corresponding to the Hall signal transition moment is used as the phase reference. The difference between the integral angle and the Hall reference position is compared by the PLL phase detector. The integral result is corrected by the output angle compensation amount of the loop filter to eliminate the cumulative angle error. In step S3, the loop filter is a PI regulator; whenever the Hall state changes, the PI regulator outputs an angle compensation amount based on the phase error, which is superimposed on the integral angle to periodically correct the accumulated error of the back EMF observer caused by parameter temperature drift, inverter nonlinearity and load disturbance.

[0050] The PLL uses the discrete absolute position derived from the Hall signal as the phase reference. Whenever a transition occurs in the Hall state, the phase detector integrates the angle. The difference between the position and the Hall reference position is compared to generate a phase error signal; this error is fed back through a loop filter (usually a PI controller) to correct the initial integral value and weighting coefficients, thereby continuously offsetting the error. The observer suffers from cumulative angle errors caused by motor parameter temperature drift, inverter nonlinearity, and load disturbances.

[0051] ; The angle compensation signal error must be consistent with the equation. Addition. The core of the fusion algorithm lies in using time-varying weighting coefficients. Construct the optimal estimate of the dual-source velocity. Depend on The output of the angle observer in the stationary coordinate system has the characteristics of high bandwidth and continuous jitter-free operation, but its observation accuracy is positively correlated with the back electromotive force amplitude, and the signal-to-noise ratio deteriorates sharply at low speed and near zero speed. This is obtained by performing state machine analysis on the three-phase Hall switch signals and time difference analysis of adjacent transition edges. Although there is an inherent quantization error of 60° electrical angle, it can provide reliable speed information with an absolute position reference in the low-speed region. Weighted value It is not constant, but rather adaptively adjusted based on real-time speed, back EMF amplitude confidence level, and Hall signal update frequency: under low-speed, high-torque conditions, The system prioritizes the discrete velocity of the Hall signal to ensure observation robustness and avoids drift instability of the sensorless algorithm in the weak back EMF region; as the rotational speed increases and the back EMF signal-to-noise ratio improves, Smoothly transition to near 1, the system gradually switches to The high-bandwidth continuous estimation of the observer suppresses quantization noise and commutation timing jitter introduced by Hall differential operations. This weighted fusion mechanism essentially constitutes a real-time optimal filter for the noise from the two heterogeneous observations, enabling the fusion of angular velocities. It combines the reliability of low-speed range with the continuity of high-speed range across the entire speed range.

[0052] Furthermore, the equation Rotor position estimation is obtained by time integration of the fused angular velocity. This integration step is not an open-loop accumulation, but a controlled integration embedded in a phase-locked loop (PLL) closed-loop architecture. Therefore, It retains the advantages of continuous high resolution without sensor observation, and eliminates the inherent DC drift and divergence risks of pure integration through periodic calibration of Hall absolute position. It provides accurate rotor position information with small phase lag and no steady-state deviation in the entire speed domain for field-oriented control (FOC), which significantly improves the current decoupling accuracy and torque control quality.

[0053] Step S4, Vector Control Drive: Based on the corrected rotor position and fused angular velocity, perform field-oriented control to generate pulse width modulation signals to drive the motor. In step S4, the field-oriented control includes MTPA maximum torque-current ratio control. Based on the stator current vector amplitude and motor parameters, the optimal d-axis and q-axis current commands are calculated to achieve the maximum torque output per unit current. Six drive signals are generated using voltage space vector pulse width modulation (SVPWM) to control the switching on and off of the inverter power devices. Based on the sector where the command voltage vector is located, the action time of adjacent non-zero vectors and zero vectors is allocated according to the volt-second balance principle to synthesize the target voltage vector.

[0054] The specific implementation is as follows: Based on the corrected rotor position and angular velocity, field-oriented control is performed. The system includes an MTPA (maximum torque-to-current ratio) control module, which calculates the optimal d-axis and q-axis current commands based on the commanded torque, achieving maximum torque output per unit current and reducing copper losses.

[0055] In MTPA control, the stator current vector amplitude is: ; : The magnitude of the stator current vector of the drive motor; The maximum allowable stator phase current vector value for the drive motor; Calculate the value of one of the drive motors in a dual-motor system. d shaft and q The current value of the shaft; ; : The magnitude of the stator current vector of the drive motor; The leading phase angle of the motor phase current; When performing MTPA (Max-Torque-Per-Ampere) control on a drive motor, the lead phase angle of the motor phase current can be calculated using the following formula: ; Calculate the command current along the d-axis in the dq coordinate system: ; Calculate the q-axis command current in the dq coordinate system: ; MTPA control of the drive motor: ; : Maximum permissible stator phase voltage limit of the drive motor Phase voltage limit value without considering the phase resistance of the drive motor Calculate the drive current limiting circle and voltage limiting circle: ; ; ; Terminal voltage in steady state; Voltage limit value; d-axis motor voltage; : q-axis motor voltage; Simplified limiting equation for motor voltage: ; = - ; : Maximum permissible stator phase current limit for drive motor; .

[0056] It is worth mentioning that, such as Figure 6 As shown, the Voltage Space Vector Modulation (SVPWM) algorithm generates a specific pulse width modulation waveform based on the discrete switching state combinations of six IGBT or SiC power devices in a three-phase motor controller. The six switching devices have eight switching states. This includes six non-zero vectors V1

[100] , V2

[110] , V3

[010] , V4

[011] , V5

[001] , and V6

[100] , and two zero vectors V0

[100] and V7

[110] . These eight voltage space vectors are plotted on... , In a stationary coordinate system, they divide the coordinate plane into 6 regions, which are called sectors.

[0057] At any time t, V 0_ref Let V be a sector located in sector 1-6. 0_ref Located in sector 1, if the switching period T s Small enough that it can be approximated as being in T s V within a time period 0_ref If it remains unchanged, then based on the volt-second balance principle, V 0_ref In a switching cycle T s The result of the action can be equivalent to the combined action of two adjacent non-zero vectors V1 and V2, and zero vectors V0 and V7 within the sector, over a certain period of time. Or, in other words... , Any rotating spatial vector on the stationary coordinate plane at any given moment can be considered as the result of two adjacent stationary spatial vectors and the zero vector, which yields: ; In the formula, They are respectively , , , From the duration of action, we can obtain: ; Similarly, we can obtain V 0_ref The voltage vector action time at sectors 2, 3, 4, 5, and 6; generating 6-phase PWM signals to drive 6 groups of IGBTs or SiC power devices to control the drive motor.

[0058] Specifically, it also includes a dynamic adjustment step for the bus voltage: real-time acquisition of battery voltage and target bus voltage. When the battery voltage is higher than the target bus voltage, it operates in Buck mode to reduce the bus voltage and reduce inverter switching losses. When the battery voltage is lower than the target bus voltage, it operates in Boost mode to raise the bus voltage and ensure power output in the high-speed range. When the voltage is close to the target voltage, it operates in Buck-Boost interleaved mode to achieve stable regulation of the bus voltage.

[0059] Specifically, such as Figure 2 The diagram shows the drive circuit of the motor's electric drive system. The motor drive controller uses a three-phase two-level controller. The drive circuit within the MCU controller consists of six Si-based IGBTs or SiC-based MOSFETs, six freewheeling diodes (FWD) power modules, thin-film capacitors, and control circuitry, among other main components, for real-time control of the stator three-phase current. The drive circuit is composed of U... 上 U 下 V 上 V 下 W 上 W 下 The three-phase currents Iu_act, Iv_act, and Iw_act of the drive circuit are obtained by the current sensor of the drive circuit, and the rotor angle signal of the motor is obtained by the resolver Hall sensor; Vdc is the on-board battery voltage, which is connected to the main capacitor. The front end of the motor controller integrates a four-switch synchronous rectifier bridge buck-boost converter. It uses two pairs of complementary power switches to form an H-bridge topology, combined with inductor energy storage and high-frequency PWM modulation, to achieve constant or on-demand adjustment of the bus voltage when the input voltage fluctuates over a wide range: When the battery terminal voltage is higher than the bus voltage required for motor drive, the circuit operates in Buck mode, reducing the bus voltage through chopping by the upper switch and synchronous rectification by the lower switch, thus reducing inverter switching losses; when the battery is deeply discharged or the voltage drops below the motor back EMF at low temperatures, the circuit seamlessly switches to Boost mode, using the inductor boost principle to raise the bus voltage, ensuring the motor can still output sufficient terminal voltage and power in the high-speed range; in the transition range where the battery voltage is close to the target bus voltage, a Buck-Boost interleaved mode is used for smooth connection. This bridge-type step-up / step-down circuit not only effectively compensates for the wide voltage fluctuations caused by changes in SOC, temperature drift, and high-rate discharge of the power battery, enabling the electric drive system to be compatible with battery packs of different voltage levels and always maintain the inverter operating at the optimal modulation depth, but also dynamically maps the high-efficiency range of the motor to the actual driving conditions by actively adjusting the bus voltage, significantly reducing the switching and conduction losses of power devices, improving the energy conversion efficiency and driving range of the whole vehicle, and enhancing the voltage adaptability and power output stability of the system under extreme conditions.

[0060] It is worth mentioning that the technical features of electric bicycles and electric mopeds, such as wheel hubs, involved in this patent application should be regarded as prior art. The specific structure, working principle, and possible control methods and spatial arrangement of these technical features can be adopted using conventional choices in the field, and should not be regarded as the inventive point of this patent. This patent will not be further elaborated in detail.

[0061] For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. An integrated architecture for a three-in-one electric drive assembly in the wheel hub of an electric vehicle, characterized in that, This includes a permanent magnet synchronous motor assembly coaxially nested and integrated inside the wheel hub, a motor controller assembly, and a two-stage reduction gear mechanism, wherein: The rotor output end of the permanent magnet synchronous motor assembly is connected to the input side of the two-stage reduction mechanism, and the output side of the two-stage reduction mechanism is coupled to the hub and rim for transmission, which is used to widen the constant power speed regulation range of the motor by reducing speed and increasing torque. The power devices of the motor controller assembly are arranged close to the stator end of the permanent magnet synchronous motor assembly and are directly electrically connected to the stator winding through a short busbar to shorten the power harness length. The motor controller assembly and the permanent magnet synchronous motor assembly share a common motor housing as a heat dissipation channel to achieve integrated thermal management.

2. The integrated architecture of the electric vehicle wheel hub three-in-one electric drive assembly according to claim 1, characterized in that, The two-stage reduction mechanism is a two-stage fixed-axis gear transmission structure, including an input shaft, an intermediate shaft, and an output shaft arranged in parallel along the radial direction, wherein: The input shaft is the rotor output shaft of the permanent magnet synchronous motor assembly, and its end is provided with a single-stage drive gear; The intermediate shaft is provided with a first-stage driven gear and a second-stage driving gear. The first-stage driven gear meshes with the first-stage driving gear to complete the first-stage speed reduction and torque increase. The output shaft is provided with a secondary driven gear, which meshes with the secondary driving gear to complete the second stage of speed reduction and torque amplification. The secondary driven gear also meshes directly with the internal gear ring of the wheel hub rim to output the amplified torque to the wheel hub.

3. The integrated architecture of a three-in-one electric drive assembly for electric vehicle wheel hubs according to claim 2, characterized in that, The input shaft, intermediate shaft, and output shaft all use ball bearings to achieve radial bearing and axial limiting; the motor housing and reducer cover cooperate to form a closed gear chamber; the support shaft coaxially passes through the secondary driven gear through the support shaft ball bearing; the output shaft and the motor housing mating end face are provided with an output oil seal; the support shaft and the motor housing mating point are provided with a support shaft oil seal, forming a double sealing structure.

4. The integrated architecture of a three-in-one electric drive assembly for electric vehicle wheel hubs according to claim 1, characterized in that, Inside the wheel hub, the motor controller assembly, permanent magnet synchronous motor assembly, two-stage reduction mechanism and rear wheel assembly are arranged sequentially from the inside to the outside along the axial direction. The rear wheel assembly includes tires, wheel hub rims and braking system. The braking system includes brake drum cover, brake shoes and brake rocker arm, used to realize driving and parking braking.

5. A drive control algorithm for an integrated architecture of a three-in-one electric drive assembly in an electric vehicle wheel hub, applied to the integrated architecture of the three-in-one electric drive assembly in an electric vehicle wheel hub as described in any one of claims 1-4, characterized in that, The field orientation control system based on a permanent magnet synchronous motor includes the following steps: Step S1, Dual-source angular velocity signal acquisition: Two heterogeneous rotor angular velocity signals are acquired respectively. The first signal is obtained by real-time observation of the stator back EMF through an extended back EMF observer in the α-β stationary coordinate system, and the continuous rotor angular velocity estimate is calculated. The second signal is obtained by discrete state transition signals from a three-phase Hall sensor, which are analyzed by a state machine and differentially calculated with adjacent transition times to obtain discrete rotor angular velocity information. Step S2, Adaptive Weighted Fusion: Input the two angular velocity signals into the phase-locked loop (PLL) simultaneously. Based on the real-time rotational speed, back EMF amplitude confidence level, and Hall signal update frequency, the time-varying weighting coefficient is adaptively adjusted to dynamically weight and fuse the two angular velocity signals, and the fused angular velocity is output. Step S3, PLL closed-loop angle correction: The rotor position is estimated by time integration of the fused angular velocity. At the same time, the discrete absolute position corresponding to the Hall signal transition moment is used as the phase reference. The difference between the integrated angle and the Hall reference position is compared by the PLL phase detector. The integrated result is corrected by the output angle compensation amount of the loop filter to eliminate the cumulative angle error. Step S4, Vector Control Drive: Based on the corrected rotor position and fused angular velocity, perform field-oriented control to generate pulse width modulation signals to drive the motor.

6. The drive control algorithm for the integrated architecture of a three-in-one electric drive assembly in an electric vehicle wheel hub according to claim 5, characterized in that, In step S1, the construction process of the extended back EMF observer is as follows: the voltage equation of the permanent magnet synchronous motor is established in the α-β stationary coordinate system, and the extended back EMF expression is derived; based on the collected stator voltage and current signals, the back EMF components of the α-axis and β-axis are calculated; the rotor electrical angle is estimated by arctangent operation, and the electrical angle is differentiated to obtain the continuous rotor angular velocity estimate. In step S1, the process of obtaining discrete rotor angular velocity information is as follows: the times of the six Hall state transition edges within one electrical cycle are collected, and the duration and corresponding angle of each sector are calculated; the angular acceleration is calculated based on the angular velocity difference between adjacent transition times, and the discrete rotor angular velocity and position at any time are obtained by interpolation of the angular acceleration.

7. The drive control algorithm for the integrated architecture of a three-in-one electric drive assembly in an electric vehicle wheel hub according to claim 5, characterized in that, In step S2, the time-varying weighting coefficient ranges from 0 to 1; when the motor is in low-speed operation, the weighting coefficient approaches 0, and the system prioritizes the angular velocity information output by the three-phase Hall sensor. When the motor is operating at medium to high speed, the weighting coefficient smoothly transitions to close to 1, and the system prioritizes the angular velocity information output by the back EMF observer.

8. The drive control algorithm for the integrated architecture of a three-in-one electric drive assembly in an electric vehicle wheel hub according to claim 5, characterized in that, In step S3, the loop filter is a PI regulator; whenever the Hall state changes, the PI regulator outputs an angle compensation amount based on the phase error, which is superimposed on the integral angle to periodically correct the accumulated error of the back EMF observer caused by parameter temperature drift, inverter nonlinearity and load disturbance.

9. The drive control algorithm for the integrated architecture of a three-in-one electric drive assembly in an electric vehicle wheel hub according to claim 5, characterized in that, In step S4, the field-oriented control includes MTPA maximum torque-current ratio control. Based on the stator current vector amplitude and motor parameters, the optimal d-axis and q-axis current commands are calculated to achieve the maximum torque output per unit current. Six drive signals are generated using voltage space vector pulse width modulation (SVPWM) to control the switching on and off of the inverter power devices. Based on the sector where the command voltage vector is located, the action time of adjacent non-zero vectors and zero vectors is allocated according to the volt-second balance principle to synthesize the target voltage vector.

10. The drive control algorithm for the integrated architecture of a three-in-one electric drive assembly in an electric vehicle wheel hub according to claim 5, characterized in that, It also includes a dynamic bus voltage adjustment step: real-time acquisition of battery voltage and target bus voltage; when the battery voltage is higher than the target bus voltage, it operates in Buck step-down mode; when the battery voltage is lower than the target bus voltage, it operates in Boost step-up mode; and when the voltages are close, it operates in Buck-Boost interleaved mode to achieve stable adjustment of the bus voltage.

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