Integrated motor and integrated motor control method for a six-cylinder engine

Abstract

This invention relates to the field of power control and motor applications, and particularly to an integrated motor and integrated motor control method for a six-cylinder engine. The method includes: starting mode control, where the motor's q-axis current is controlled to output a positive electromagnetic torque, driving the engine crankshaft to idle speed; switching from starting to generator mode, where the motor's q-axis current is switched to switch from electric motor to generator when the engine speed reaches idle speed; and switching from generator to assist mode, where the motor outputs a positive assist torque under specific conditions to assist the engine in increasing speed. The invention also includes energy balance control and other steps. Furthermore, it relates to an integrated motor employing this control method. This application achieves the technical effects of switching between three motor modes (starting, generator, and assist), adjusting motor operation according to different operating conditions, optimizing system efficiency, and meeting the vehicle's electrical load and battery charging requirements.

Description

Technical Field

[0001] This invention relates to the field of power control and electric motor applications, and in particular to an integrated motor for a six-cylinder engine and an integrated motor control method. Background Technology

[0002] With the continuous development of motorcycle engine technology, six-cylinder motorcycle engines, with their smooth operation, strong power output, and excellent performance, have been widely used in the mid-to-large displacement high-end motorcycle market. This has driven the improvement of high-end motorcycle performance, resulting in better performance in terms of power and comfort, providing consumers with a superior riding experience, and propelling the motorcycle industry towards higher-end models.

[0003] In traditional motorcycle six-cylinder engine technology, the starting and power generation systems are arranged independently. (Reference) Figure 2 This means that the system is equipped with an independent starter motor 1 and an independent generator 2. In order to prevent the starter motor from being damaged by reverse drag when the engine is running normally, an overrunning clutch needs to be installed between the starter motor and the engine crankshaft, thus forming a three-section independent structure of "starter motor 1 + overrunning clutch + generator 2".

[0004] However, this traditional structure has serious drawbacks. It is redundant and cumbersome, with the starter motor 1, overrunning clutch, and generator 2 arranged independently, requiring separate mounting brackets and transmission mechanisms. This occupies a large amount of space around the engine block 3, resulting in a large overall engine size, which is not conducive to optimizing the overall layout of the motorcycle, especially for sport motorcycles that aim for a compact body. Moreover, the weight and cost of this structure are relatively high. The three independent components and their matching transmission and bracket structures significantly increase the curb weight of the engine, which not only affects the handling agility of the motorcycle but also increases fuel consumption. At the same time, the independent production and assembly of multiple components also increases manufacturing costs and assembly complexity. Summary of the Invention

[0005] This invention solves the problem of redundant and cumbersome starter generator structure in traditional motorcycle six-cylinder engines. It proposes an integrated motor and integrated motor control method for a six-cylinder engine, which adopts "single P1 motor control to realize multi-mode switching of six-cylinder engine", thus simplifying the structure of the six-cylinder engine starter generator system and improving performance and efficiency.

[0006] To achieve the above objectives, the following technical solution is proposed: An integrated motor control method for a six-cylinder engine, applied to a P1 permanent magnet synchronous motor rigidly connected coaxially to the crankshaft of the six-cylinder engine, the control method comprising the following steps: Step S1, Startup mode control: In response to the start instruction, control the q-axis current \(i_q\) of the motor to be positive, so that the motor outputs a positive electromagnetic torque to drive the engine crankshaft to rotate until the engine speed reaches the idle speed \(n_{idle}\). Step S2, start to power generation mode switching: Monitor the engine speed \(n\) in real time. When \(n\geq n_{idle}\), control the \(i_q\) of the motor to switch from positive to negative, so that the motor is converted from the electric state to the power generation state, and convert the engine mechanical energy into electrical energy. Step S3, power generation to assist mode switching: In the power generation mode, if it is detected that the engine speed \(n < n_{idle}\) and the vehicle demand torque \(T_{req}>0\), then control the \(i_q\) of the motor to switch from negative to positive, so that the motor outputs a positive assist torque to assist the engine to increase the speed.

[0007] By adopting the above technical solution, the switching of the three modes of starting, power generation, and assistance of the P1 permanent magnet synchronous motor can be realized, achieving the dual functions of a single motor. There is no need for an independent starting motor, an independent generator, and an overrunning clutch, which simplifies the structure, reduces the weight, optimizes the layout, and improves the reliability. At the same time, it adapts to the high power and wide speed requirements of the six-cylinder engine, reduces the manufacturing cost and maintenance cost, and improves the handling performance and fuel economy of the motorcycle.

[0008] Preferably, it further includes: Step S4, energy balance control: Monitor the engine output power \(P_{engine}\), the motor electric power \(P_{motor}\), the power generation power \(P_{gen}\), the vehicle load \(P_{load}\), and the system loss \(P_{loss}\) in real time, and satisfy: \(P_{engine}+P_{motor}=P_{load}+P_{gen}+P_{loss}\); And adjust the \(i_q\) value of the motor according to the energy balance to optimize the system efficiency.

[0009] By adopting the above technical solution, monitoring the engine output power, the motor electric power, the power generation power, the vehicle load, and the system loss in real time, satisfying a specific energy balance formula, can clarify the energy relationship of each part of the system; adjusting the q-axis current value of the motor according to this energy balance can achieve the optimization of the system efficiency.

[0010] Preferably, the specific steps of controlling the \(i_q\) of the motor to switch from positive to negative in step S2 include: Fast torque reduction stage: Control the q-axis current \(i_q\) of the motor to rapidly decrease from the current positive value to 0 according to a preset negative gradient \(k1\); \(di_q / d_t=-k1\), \(k1>0\); Power generation setup phase: When i_q drops to 0, control i_q to change from 0 to the negative target power generation current i_q_gen according to the preset negative gradient k2; di_q / d_t = -k2, k2 > 0, and k2 <k1; The motor enters a stable power generation state when i_q reaches the target value i_q_gen; where i_q_gen is calculated based on the energy balance control in S4.

[0011] By adopting the above technical solution, the two-step gradient switching avoids step changes in current and torque, reduces the impact of mode switching on the engine crankshaft and transmission system, and the first step of rapid torque reduction shortens the time to exit the start-up mode. The overall switching process is more controllable and potentially faster than a simple step switching.

[0012] Preferably, the process of switching i_q from a positive value to a negative value also includes the following control steps: Maximum switching time limit: Set the total time T_max from the switching trigger to i_q stabilizing at i_q_gen. If the timeout occurs, an error will be reported and the current state will be maintained or the system will enter safe mode. Abnormal rollback mechanism: If the engine speed n drops sharply below the safety threshold during the switching process, the switching is immediately interrupted and the control i_q is returned to the positive value, and the process proceeds to step S3.

[0013] By adopting the above technical solutions, the added stability time judgment and protection logic improve the system's reliability and fault tolerance under complex operating conditions.

[0014] Preferably, in the start-up mode control, the maximum torque control strategy with i_d=0 is adopted, and the electromagnetic torque T_e=3 / 2n_pψ_fi_q, where n_p is the number of motor pole pairs and ψ_f is the permanent magnet flux linkage.

[0015] By adopting the above technical solution and using the maximum torque control strategy of i_d=0 in the start-up mode control, the electromagnetic torque calculation formula can be simplified, and the motor can output a larger electromagnetic torque, thereby driving the engine crankshaft to rotate more effectively and helping the engine to start reliably.

[0016] Preferably, the conditions for switching from startup to power generation mode also include: after the engine speed n reaches the idle speed n_idle, maintaining a stable operating time Δt or more, the switching of i_q is then performed.

[0017] By adopting the above technical solution, switching i_q after the engine speed reaches the idle speed and maintains a stable operating time Δt or more can ensure that the engine smoothly transitions from the starting mode to the power generation mode in a stable state, thereby improving the stability and reliability of mode switching and avoiding abnormal switching caused by unstable engine conditions.

[0018] Preferably, the conditions for switching from power generation to power assist mode also include: the torque demand signal T_req sent by the vehicle controller is greater than a preset threshold, and the current output torque of the engine is insufficient to maintain idle speed.

[0019] By adopting the above technical solution, when switching from generator to power assist mode, the condition that the torque demand signal sent by the vehicle controller is greater than the preset threshold and the current output torque of the engine is insufficient to maintain the idle speed is added. This allows the motor to switch from generator mode to power assist mode under more precise operating conditions, more effectively assisting the engine to increase its speed, avoiding engine stalling, improving the stability and reliability of the system operation, and further optimizing the power support for the six-cylinder engine.

[0020] Preferably, in the starting mode, the peak torque T_e_max output by the motor is greater than the maximum compression resistance torque T_comp_max of the engine to ensure reliable starting.

[0021] By adopting the above technical solution, the peak torque output by the motor is made greater than the maximum compression resistance torque of the engine in the starting mode, which ensures that the P1 permanent magnet synchronous motor can reliably drive the six-cylinder engine to overcome the maximum compression resistance and start.

[0022] Preferably, in the power generation mode, the power generation power is controlled by adjusting the negative value of i_q to meet the vehicle's electrical load and battery charging requirements.

[0023] By adopting the above technical solution, the negative value of the q-axis current i_q can be adjusted in the power generation mode to control the power generation power and meet the electrical load of the vehicle and the charging needs of the battery.

[0024] An integrated motor for a six-cylinder engine, applicable to the aforementioned integrated motor control method for a six-cylinder engine, employs a P1 permanent magnet synchronous motor. The rotor of the P1 permanent magnet synchronous motor is rigidly connected coaxially to the crankshaft of the six-cylinder engine. The P1 permanent magnet synchronous motor achieves switching between three modes: starting, power generation, and power assist by adjusting the direction and magnitude of the q-axis current.

[0025] By adopting the above technical solution and using the P1 permanent magnet synchronous motor, which is applicable to specific integrated motor control methods, its rotor is rigidly connected to the crankshaft of the six-cylinder engine on the same axis. This eliminates the need for a separate starter motor, a separate generator, and an overrunning clutch, achieving "single motor dual function," simplifying the structure, reducing weight, optimizing the layout, and improving reliability. By adjusting the direction and magnitude of the q-axis current, the three modes of starting, generating electricity, and assisting can be switched, which can adapt to the high power and wide speed requirements of the six-cylinder engine, reduce manufacturing and maintenance costs, and improve the handling performance and fuel economy of the motorcycle.

[0026] The beneficial effects of this invention are: 1. Dual-function engine with simplified structure: A single P1 permanent magnet synchronous motor is used to achieve both starting and power generation functions, eliminating the need for a traditional independent starter motor, generator, and overrunning clutch. This significantly simplifies the engine's surrounding structure, reduces the number of parts, and lowers assembly complexity.

[0027] 2. Weight reduction and optimized layout: Eliminating multiple independent components and their mounting brackets and transmission mechanisms effectively reduces the engine's curb weight, which is conducive to the lightweight design of the motorcycle as a whole, and improves handling agility and fuel economy.

[0028] 3. Improved reliability: The overrunning clutch is eliminated, thus eliminating the risk of failures such as wear, slippage, and jamming; the smooth switching between starting and power generation is achieved through electronic control, avoiding damage to the starter motor by reverse drag and improving system durability.

[0029] 4. Flexible control and smooth mode switching: Based on q-axis current direction control, it can freely switch between start-up mode, generator mode and power assist mode. The switching conditions are clear (based on idle speed and torque demand). It responds quickly and does not require a mechanical clutch. It is especially suitable for the wide speed range and high compression resistance of six-cylinder engines.

[0030] 5. Reduced cost and convenient maintenance: Reduced number of independent motors, clutches and supporting transmission components, reducing manufacturing costs; simplified structure also facilitates later maintenance. Attached Figure Description

[0031] Figure 1 This is a flowchart of the method of the present invention.

[0032] Figure 2 This is a schematic diagram of motor installation using existing technology.

[0033] Figure 3 This is a schematic diagram of the motor installation according to the present invention.

[0034] The components include: 1. Starter motor; 2. Independent generator; 3. Engine block; 4. P1 permanent magnet synchronous motor. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The described embodiments are only possible technical implementations of the present invention, but are not limited thereto. Other embodiments obtained by those skilled in the art in conjunction with the embodiments of the present invention without creative effort are also within the protection scope of the present invention. Example 1:

[0036] An integrated motor control method for a six-cylinder engine, applied to a P1 permanent magnet synchronous motor rigidly connected coaxially to the crankshaft of the six-cylinder engine, referenced. Figure 1The control method includes the following steps: Step S1, Startup mode control: In response to the start command, the q-axis current i_q of the control motor is made positive, so that the motor outputs positive electromagnetic torque, which drives the engine crankshaft to rotate until the engine speed reaches the idle speed n_idle; In the start-up mode control, a maximum torque control strategy with i_d=0 is adopted, and the electromagnetic torque T_e=3 / 2n_pψ_fi_q, where n_p is the number of motor pole pairs and ψ_f is the permanent magnet flux linkage. This embodiment uses a maximum torque control strategy with i_d=0 in the start-up mode control, which simplifies the electromagnetic torque calculation formula and enables the motor to output a larger electromagnetic torque, thereby more effectively driving the engine crankshaft to rotate and contributing to reliable engine start-up.

[0037] In the aforementioned starting mode, the peak torque T_e_max output by the motor is greater than the maximum compression resistance torque T_comp_max of the engine, which ensures that the P1 permanent magnet synchronous motor can reliably drive the six-cylinder engine to overcome the maximum compression resistance and start.

[0038] Step S2, initiate the switch to power generation mode: The engine speed n is monitored in real time. When n ≥ n_idle, the control motor i_q switches from a positive value to a negative value, so that the motor switches from electric motor mode to generator mode, converting the engine's mechanical energy into electrical energy. The conditions for switching from start-up to generator mode also include: after the engine speed n reaches the idle speed n_idle, it maintains a stable operating time Δt or more before switching i_q. This ensures that the engine smoothly transitions from start-up mode to generator mode in a stable state, improving the stability and reliability of mode switching and avoiding switching abnormalities caused by unstable engine conditions.

[0039] The specific steps for controlling the motor's i_q to switch from a positive to a negative value in step S2 include: Rapid torque reduction phase: The q-axis current i_q of the motor is controlled to rapidly decrease from its current positive value (starting torque current i_q_start) to 0 according to the preset negative gradient k1; this process aims to quickly eliminate the driving torque of the motor and prepare for power generation.

[0040] di_q / d_t=-k1, k1>0; Power generation setup phase: When i_q drops to 0, immediately control i_q to change from 0 to the negative target power generation current i_q_gen according to another preset negative gradient k2; di_q / d_t = -k2, k2 > 0, and k2 <k1; Until \(i_q\) reaches the target value \(i_{q\_gen}\), the motor enters a stable power generation state; where \(i_{q\_gen}\) is calculated according to the energy balance control in S4.

[0041] In this embodiment, the two-step gradient switching avoids the step changes in current and torque, reduces the impact of mode switching on the engine crankshaft and transmission system. The first step of rapid torque reduction shortens the time to exit the starting mode, and the overall switching process is more controllable and possibly faster than simple step switching.

[0042] The process of \(i_q\) switching from a positive value to a negative value also has the following control steps: Maximum switching time limit: Set the total time \(T_{max}\) from the switching trigger to \(i_q\) stabilizing at \(i_{q\_gen}\). If it times out, report an error and maintain the current state or enter the safety mode. Abnormal fallback mechanism: During the switching process, if it is detected that the engine speed \(n\) drops sharply to be lower than the safety threshold (such as \(n_{idle}-\Delta n\)), immediately interrupt the switching, control \(i_q\) back to a positive value, and enter step S3 to prevent the engine from stalling.

[0043] The added stable time judgment and protection logic in this embodiment improve the reliability and fault tolerance of the system under complex working conditions.

[0044] Step S3, switching from power generation mode to boosting mode: In the power generation mode, if it is detected that the engine speed \(n < n_{idle}\) and the vehicle demand torque \(T_{req}>0\), control the \(i_q\) of the motor to switch from a negative value to a positive value, so that the motor outputs a positive boosting torque to assist the engine to increase the speed. The conditions for switching from power generation mode to boosting mode also include: the torque demand signal \(T_{req}\) sent by the vehicle controller is greater than the preset threshold, and the current output torque of the engine is not sufficient to maintain idle speed. Adding the condition that the torque demand signal sent by the vehicle controller is greater than the preset threshold and the current output torque of the engine is not sufficient to maintain idle speed during the switching from power generation mode to boosting mode can enable the motor to switch from power generation mode to boosting mode under more accurate working conditions, more effectively assist the engine to increase the speed, avoid engine stalling, improve the stability and reliability of system operation, and further optimize the power support for the six-cylinder engine. Adjusting the negative value of the q-axis current \(i_q\) in the power generation mode can control the power generation power to meet the vehicle electrical load and battery charging requirements.

[0045] Step S4, energy balance control: Real-time monitor the engine output power \(P_{engine}\), motor electric power \(P_{motor}\), power generation power \(P_{gen}\), vehicle load \(P_{load}\) and system loss \(P_{loss}\), satisfying: P_engine+P_motor=P_load+P_gen+P_loss; The system efficiency is optimized by adjusting the i_q value of the motor based on energy balance.

[0046] This embodiment enables the P1 permanent magnet synchronous motor to switch between three modes: starting, generating, and assisting, achieving dual functions with a single motor. It eliminates the need for a separate starter motor, generator, and overrunning clutch, simplifying the structure, reducing weight, optimizing layout, and improving reliability. Simultaneously, it adapts to the high power and wide speed range requirements of a six-cylinder engine, reducing manufacturing and maintenance costs, and improving the motorcycle's handling performance and fuel economy. This embodiment monitors engine output power, motor power, generator power, vehicle load, and system losses in real time, satisfying a specific energy balance formula and clearly defining the energy relationships of each part of the system. Adjusting the q-axis current value of the motor based on this energy balance optimizes system efficiency.

[0047] In this embodiment, the dq axis model of the motor body is as follows: 1. Voltage equation: u_d=R_si_d-ω_rL_qi_q; u_q=R_si_q+ω_rL_di_d+ω_rψ_f; Where: u_d / u_q is the d / q axis voltage; i_d / i_q is the d / q axis current; R_s is the stator phase resistance; L_d / L_q is the d / q axis inductance; ω_r is the rotor mechanical angular velocity; ψ_f is the permanent magnet flux linkage.

[0048] 2. Electromagnetic torque formula (shared by six-cylinder engine starter / generator): T_e=2 / 3n_p[ψ_fi_q+(L_d−L_q)i_di_q]; Where: n_p is the number of pole pairs of the motor; starting mode: T_e is the starting torque of the driving engine; generating mode: T_e is the resistance torque of the motor driven by the engine.

[0049] 3. Mechanical dynamics equations (direct connection without overrunning clutch): T_e−T_L−Bω_r=J(dω_r / d_t); Where: T_L is the engine resistance torque (compression resistance torque of a six-cylinder engine); B is the damping coefficient; J is the total rotational inertia of the motor rotor and engine crankshaft system; this equation is used for the start-up smoothness control of a clutchless rigid direct drive.

[0050] Boot mode formula (replacing a standalone bootloader): Target rotational speed determination: ω_r ≥ ω_idle; Among them: ω_idle is the engine idle angular velocity, and when it reaches, the startup is completed.

[0051] Startup peak torque constraint: T_e_max ≥ T_comp_max; Among them: T_comp_max is the maximum compression resistance torque of the six-cylinder engine.

[0052] Startup power: P_start = T_e⋅n / 9550; Among them: n is the engine speed (rpm); P_start is the motor startup power.

[0053] Power generation mode formula (replacing the independent generator): Back electromotive force: E0 = k_E⋅n; Among them: k_E is the back electromotive force coefficient; n is the engine speed.

[0054] Three-phase power generation power: ; Among them: U is the line voltage; I is the line current; cosφ is the power factor.

[0055] Power generation efficiency: η_gen = P_gen_out / P_mech_in; Among them: P_gen_out is the output electric power; P_mech_in is the engine input mechanical power.

[0056] General conversion of power / torque / speed (full operating conditions): P = Tn / 9550, T = 9550P / n; Among them: P is the power (kW); T is the torque (N・m); n is the speed (rpm).

[0057] Mode switching criterion (the control core for canceling the overrunning clutch): Startup → power generation switching: When n ≥ n_idle, i_q = 0 → i_q < 0, enter power generation.

[0058] Power generation → boost switching: When n < n_idle and T_req > 0, perform the boost mode.

[0059] System energy balance: P_engine + P_motor = P_load + P_gen + P_loss; Among them: P_engine is the engine output power; P_motor: the motor electric power; P_gen: the motor power generation power; P_load is the vehicle electrical load; P_loss is the total system loss.

[0060] The implementation principle of this embodiment is as follows: This embodiment precisely switches between the starting, power generation, and assist modes of the six-cylinder engine and the P1 permanent magnet synchronous motor through a series of orderly control steps. Each step cooperates with the others, flexibly adjusting the motor's operating mode and output power according to different engine operating states and the actual needs of the vehicle. This precise control avoids the redundancy of traditional independent starter motors, independent generators, and overrunning clutches, simplifying the system structure, reducing weight, and optimizing the layout. Simultaneously, through energy balance control and reasonable adjustment of the motor's operating mode, the system's reliability and energy utilization rate are improved, manufacturing and maintenance costs are reduced, and ultimately, the motorcycle's handling performance and fuel economy are enhanced, representing a significant improvement compared to traditional technologies. Example 2:

[0061] This embodiment describes Embodiment 1 in conjunction with a specific application scenario, which is as follows: This example is adapted for a motorcycle with a six-cylinder gasoline engine (1600cc displacement). The P1 motor is a permanent magnet synchronous motor (PMSM), coaxially connected to the engine crankshaft, eliminating the need for a separate starter motor, generator, and overrunning clutch, thus achieving integrated starting and power generation. All parameters below are commonly used values ​​in practical engineering and can be directly used as data for this patented embodiment.

[0062] I. Basic Parameter Settings: Motor parameters: stator phase resistance R_s=0.08Ω, d-axis inductance L_d=0.8mH, q-axis inductance L_q=1.5mH, permanent magnet flux linkage ψ_f=0.12Wb, number of motor pole pairs n_p=8, back electromotive force coefficient k_E=0.015V·min / r.

[0063] Engine parameters: Idle speed n_idle=1200rpm; The corresponding idle angular velocity ω_idle = 2π × 1200 / 60 = 125.66 rad / s; The maximum compressive resistance torque T_comp_max = 110 N·m, the total moment of inertia of the crankshaft system + motor rotor J = 0.15 kg·m², and the damping coefficient B = 0.06 N·m·s / rad.

[0064] Operating parameters: Line voltage U=48V, line current I=18A, power factor cosφ=0.92 in power generation mode; peak torque of motor at startup T_e_max=130N·m.

[0065] II. Step-by-step application and calculation of each formula: Application of the motor body dq axis model (start-up condition): At startup, the motor operates in electric mode, controlling the d-axis current i_d=0 (maximum torque control strategy). At this time, the voltage equation and electromagnetic torque formula are simplified as follows: Electromagnetic torque calculation: T_e=3 / 2n_p[ψ_fi_q+(L_d-L_q)i_di_q], since i_d=0, simplifies to: T_e=3 / 2n_pψ_fi_q; Substituting the parameters: T_e = 3 / 2 × 8 × 0.12 × i_q = 1.44i_q; Given the starting peak torque T_e_max = 130 N·m, the starting peak q-axis current i_q_max = 130 / 1.44 ≈ 90.28 A.

[0066] Voltage equation calculation: u_d=R_si_d-ω_rL_qi_q; u_q=R_si_q+ω_rL_di_d+ω_rψ_f, i_d=0; At the moment of startup, the rotational speed n=0 (ω_r=0), then: u_d=0, u_q=R_s×i_q_max=0.08×90.28≈7.22V; When the rotational speed increases to n = 600 rpm (ω_r = 2π × 600 / 60 = 62.83 rad / s), then: u_d=-62.83×1.5×10⁻³×90.28≈-8.59Vu_q=0.08×90.28+62.83×0.12≈7.22+7.54≈14.76V.

[0067] Application of mechanical dynamics equations: T_e-T_L-Bω_r=Jdω_r / d_t; At the moment of startup (ω_r=0), the engine drag torque is: T_L≈T_comp_max=110N·m, substituting into the equation, we get: 130 - 110 - 0 = 0.15 × dω_r / d_t, therefore dω_r / d_t = 20 / 0.15 ≈ 133.33 rad / s². This indicates that the instantaneous angular acceleration at startup is 133.33 rad / s², which can quickly drive the crankshaft of the 1600cc six-cylinder engine to rotate, meeting the requirements for direct-drive starting without an overrunning clutch.

[0068] Application of Startup Mode Formula: Target speed determination at startup: When ω_r ≥ ω_idle, and the engine speed n = 1200 rpm, ω_r = 125.66 rad / s. Since ω_r ≥ ω_idle (125.66 rad / s) is satisfied, the start-up is determined to be complete, and the system switches to power generation mode.

[0069] Start-up peak torque constraint: T_e_max≥T_comp_max; Given T_e_max = 130 N·m, T_comp_max = 110 N·m, and 130 ≥ 110, which satisfies the constraints, ensure that the motor can reliably drive the 1600cc six-cylinder engine to overcome the maximum compression resistance and start.

[0070] Starting power calculation: P_start=T_e·n / 9550. During the starting process, when the speed n=600rpm and the torque T_e=115N·m, the starting power is: P_start=115×600 / 9550≈7.23kW, which meets the starting power requirements of a 1600cc six-cylinder motorcycle engine.

[0071] Application of power generation mode formula: Back electromotive force calculation: E0 = k_E·n. When the engine speed n = 3000 rpm (normal driving conditions), the back electromotive force is: E0 = 0.015 × 3000 = 45V, which matches the generator line voltage of 48V to ensure the stability of power generation.

[0072] Three-phase power generation calculation: Substitute the parameters: It can meet the electrical load of a 1600cc motorcycle (lights, instruments, ECU, etc., approximately 1000W), and the remaining power can charge the battery.

[0073] The dynamic calculation of i_q_gen in step S2 is a closed-loop control process, based on the general principles of motor control systems and on-board energy management, and involves the following modules: Input monitoring module: The vehicle electrical load (P_load) is a real-time monitoring device that controls the total electrical power consumed by all electrical equipment in the vehicle (such as lights, ECU, air conditioning, entertainment system, etc.).

[0074] Battery status: State of charge (SOC) provides real-time information on the remaining percentage of battery charge.

[0075] Battery State of Health (SOH) and Temperature: Used to determine the battery's maximum safe charging current or power (P_batt_max).

[0076] Decision and Calculation Module: Based on the monitored values, the controller makes decisions and calculates the target power generation (P_gen_target) according to the following logic: Determining charging demand: Based on the SOC value, if the SOC is lower than the target value (e.g., 80%), and the battery temperature and SOH allow it, then charging is determined to be required. The charging power requirement (P_chg_req) can be given by a mapping table or a PID controller based on the SOC difference.

[0077] If the SOC is close to full charge (e.g., above 95%), then P_chg_req=0, and the system enters float charging or stops charging.

[0078] Calculate the total power demand: P_demand = P_load + P_chg_req. This is the total electrical power that the motor needs to provide in real time.

[0079] Calculate the target q-axis current (i_q_gen): Based on the motor model and the current engine speed (n), the following relationship exists: P_gen_target≈f(n,i_q). Here, f is a functional relationship, which is shown in Example 2 of the document (power is calculated by converting torque and speed).

[0080] In a simplified approach, it can be assumed that at a fixed speed, the power generation is proportional to |i_q| (the absolute value of the negative value). Therefore, the controller will calculate the required target value of i_q_gen (a negative value) based on P_gen_target and the current speed, either by looking up a table or by model calculation.

[0081] Closed-loop control and output module: The calculated i_q_gen is sent as an instruction to the motor's current loop controller. The system continuously monitors whether the actual power generation P_gen_actual matches P_gen_target and whether the SOC change meets expectations. It performs closed-loop feedback control by fine-tuning i_q_gen to ensure that the real-time changing load and charging demands are met, while maintaining the system's energy balance.

[0082] Power generation efficiency calculation: η_gen = P_gen_out / P_mech_in; Given that the engine input mechanical power P_mech_in = T_e·n / 9550; During power generation, T_e is the resistance torque, taken as T_e = 12 N·m, n = 3000 rpm: P_mech_in=12×3000 / 9550≈3.77kW; The power output is P_gen_out = 1.34kW, therefore the power generation efficiency is: η_gen = 1.34 / 3.77 ≈ 35.5% (which conforms to the conventional range of 30% - 40% for the power generation efficiency of P1 motor).

[0083] General conversion and application of power / torque / speed: Torque conversion to power: When the motor output torque T_e = 50 N·m and the speed n = 2000 rpm, the power: P = 50 × 2000 / 9550 ≈ 10.47 kW.

[0084] Power conversion to torque: When the motor power generation power P = 1.5 kW and the speed n = 3500 rpm, the resistance torque: T = 9550 × 1.5 / 3500 ≈ 4.09 N·m.

[0085] Application of mode switching criterion (canceling the core of the overrunning clutch): Startup → power generation switching: When n = 1200 rpm (≥ n_idle = 1200 rpm), control i_q to adjust from 90.28 A (positive, electric) to -12 A (negative, power generation), satisfying the switching criterion and completing the smooth switching from startup to power generation (without an overrunning clutch, achieving the working condition conversion through the switching of the current direction).

[0086] Power generation → assistance switching: When the engine speed n = 1000 rpm (< n_idle = 1200 rpm) and the vehicle demand torque T_req = 25 N·m (> 0), control i_q to adjust from -12 A to 35 A (positive, electric), and the motor output assistance torque T_e = 1.44 × 35 ≈ 50.4 N·m to assist the 1600 cc engine to maintain the speed and avoid stalling.

[0087] Application of system energy balance: P_engine + P_motor = P_load + P_gen + P_loss; When the engine output power P_engine = 35 kW, the motor operates in the power generation mode (P_motor = 0, the motor does not output electric power during power generation), the vehicle electrical load P_load = 1.0 kW, and the power generation output P_gen = 1.34 kW, calculate the total system loss P_loss: P_loss = 35 + 0 - 1.0 - 1.34 = 32.66 kW.

[0088] In this embodiment, the independent starter motor, independent generator, and overrunning clutch are canceled, and the P1 motor integrating the startup and power generation functions into one realizes "single motor dual functions", simplifies the structure, reduces the weight, optimizes the layout, improves the reliability, and at the same time adapts to the high power and wide speed requirements of the six-cylinder engine, reduces the manufacturing cost and maintenance cost, and improves the handling performance and fuel economy of the motorcycle. Example 3:

[0089] This embodiment, based on Embodiment 1, proposes an integrated motor for a six-cylinder engine, applicable to the aforementioned integrated motor control method for a six-cylinder engine. (Refer to...) Figure 3 A P1 permanent magnet synchronous motor 4 is used, which is fixed to the outside of the engine block 3. The rotor of the P1 permanent magnet synchronous motor 4 is rigidly connected coaxially to the crankshaft of the six-cylinder engine. The P1 permanent magnet synchronous motor achieves switching between three modes: starting, generating, and assisting by adjusting the direction and magnitude of the q-axis current. This embodiment uses a P1 permanent magnet synchronous motor that is applicable to a specific integrated motor control method. Its rotor is rigidly connected coaxially to the crankshaft of the six-cylinder engine, which can eliminate the need for a separate starter motor, a separate generator, and an overrunning clutch, achieving "single motor dual function". This simplifies the structure, reduces weight, optimizes the layout, and improves reliability. By adjusting the direction and magnitude of the q-axis current to achieve switching between the three modes of starting, generating, and assisting, it can adapt to the high power and wide speed requirements of the six-cylinder engine, reduce manufacturing and maintenance costs, and improve the handling performance and fuel economy of the motorcycle.

Claims

1. An integrated motor control method of a six-cylinder engine, applied to a P1 permanent magnet synchronous motor rigidly connected with a six-cylinder engine crankshaft, characterized in that, The control method includes the following steps: Step S1, startup mode control: In response to a startup instruction, control the q-axis current \(i_q\) of the motor to be positive, so that the motor outputs a positive electromagnetic torque to drive the engine crankshaft to rotate until the engine speed reaches the idle speed \(n_{idle}\). Step S2, startup to power generation mode switching: Monitor the engine speed \(n\) in real time. When \(n\geq n_{idle}\), control the \(i_q\) of the motor to switch from positive to negative, so that the motor changes from the electric state to the power generation state, and converts the engine mechanical energy into electrical energy. Step S3, power generation to assist mode switching: In the power generation mode, if it is monitored that the engine speed \(n < n_{idle}\) and the vehicle demand torque \(T_{req}>0\), then control the \(i_q\) of the motor to switch from negative to positive, so that the motor outputs a positive assist torque to assist the engine in increasing the speed. Step S4, energy balance control: Monitor the engine output power \(P_{engine}\), motor electric power \(P_{motor}\), power generation power \(P_{gen}\), vehicle load \(P_{load}\) and system loss \(P_{loss}\) in real time, and satisfy: \(P_{engine}+P_{motor}=P_{load}+P_{gen}+P_{loss}\); And adjust the \(i_q\) value of the motor according to the energy balance.

2. The integrated motor control method for a six-cylinder engine according to claim 1, characterized in that, The specific steps for controlling the \(i_q\) of the motor to switch from positive to negative in step S2 include: Fast torque reduction stage: Control the q-axis current \(i_q\) of the motor to rapidly decrease from the current positive value to 0 according to a preset negative gradient \(k1\). \(di_q / d_t=-k1\), \(k1>0\); Power generation establishment stage: When \(i_q\) drops to 0, control \(i_q\) to change from 0 to the negative target power generation current \(i_{q\_gen}\) according to a preset negative gradient \(k2\). \(di_q / d_t=-k2\), \(k2>0\), and \(k2 < k1\); Until \(i_q\) reaches the target value \(i_{q\_gen}\), the motor enters a stable power generation state; where \(i_{q\_gen}\) is calculated according to the energy balance control in S4.

3. The integrated motor control method for a six-cylinder engine according to claim 2, characterized in that, The following control steps are also provided in the process of \(i_q\) switching from positive to negative: Maximum switching time limit: Set the total time \(T_{max}\) from the switching trigger to \(i_q\) stabilizing at \(i_{q\_gen}\). If it times out, report an error and maintain the current state or enter the safety mode. Abnormal fallback mechanism: During the switching process, if it is monitored that the engine speed \(n\) drops sharply below the safety threshold, immediately interrupt the switching and control \(i_q\) back to the positive value, and enter step S3.

4. The integrated motor control method for a six-cylinder engine according to claim 1, characterized in that, In the startup mode control, the maximum torque control strategy with \(i_d = 0\) is adopted, and the electromagnetic torque \(T_e = 3 / 2n_p\psi_fi_q\), where \(n_p\) is the number of pole pairs of the motor and \(\psi_f\) is the permanent magnet flux linkage.

5. The integrated motor control method for a six-cylinder engine according to claim 1, characterized in that, The conditions for switching from startup to power generation mode also include: After the engine speed \(n\) reaches the idle speed \(n_{idle}\), maintain stable operation for more than a time interval \(\Delta t\), and then perform the switching of \(i_q\).

6. The integrated motor control method for a six-cylinder engine according to claim 1, characterized in that, The conditions for switching from power generation to assist mode also include: The torque demand signal \(T_{req}\) sent by the vehicle controller is greater than the preset threshold, and the current output torque of the engine is not sufficient to maintain idle speed.

7. The integrated motor control method for a six-cylinder engine according to claim 1, characterized in that, In the aforementioned start-up mode, the peak torque T_e_max output by the motor is greater than the maximum compressive resistance torque T_comp_max of the engine.

8. The integrated motor control method for a six-cylinder engine according to claim 1, characterized in that, In the power generation mode, the power generation capacity is controlled by adjusting the negative value of i_q.

9. An integrated motor for a six-cylinder engine, applicable to the integrated motor control method for a six-cylinder engine as described in any one of claims 1-8, characterized in that, A P1 permanent magnet synchronous motor is adopted. The rotor of the P1 permanent magnet synchronous motor is rigidly connected to the crankshaft of the six-cylinder engine on the same axis. The P1 permanent magnet synchronous motor achieves the switching between three modes: starting, power generation, and power assist by adjusting the direction and magnitude of the q-axis current.

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