A range extender control method

Abstract

Embodiments of the application disclose a range extender control method. The method comprises the following steps: S1, detecting a speed deviation and a speed change rate of a generator in real time; S2, judging whether the range extender is currently in a transient state or a steady state according to the speed deviation and the speed change rate; S3, when it is judged that the range extender is in the transient state, a positive feedforward torque is superimposed on a PI closed-loop output torque by an MCU motor control unit to compensate for a speed drop caused by a sudden change in load; and S4, when it is judged that the range extender is in the steady state, a negative feedforward torque is superimposed on the PI closed-loop output torque by the MCU motor control unit, and the range extender can switch between the transient state and the steady state, wherein when switching from the transient state to the steady state, the MCU motor control unit controls the feedforward torque to smoothly transit from the positive feedforward torque to the negative feedforward torque through a preset transition function. The range extender control method of the embodiments of the application can dynamically judge the working condition and realize polarity switching of positive and negative feedforward values.

Description

Technical Field

[0001] This invention relates to the field of range extender technology, and more specifically to a range extender control method. Background Technology

[0002] A range extender is a device used in electric or hybrid vehicles to extend their driving range. It typically consists of a small internal combustion engine (such as a gasoline or diesel engine) and a generator connected coaxially. The engine's torque is controlled by the ECU (Engine Control Unit), while the generator's speed is controlled by the MCU (Motor Control Unit) via a PI (Pilot-Induced) closed-loop control. The two are coordinated and managed through the RCU (Range Control Unit). The main function of the range extender is to adjust the generator's operation in real time based on the battery's state of charge (SOC) to meet the vehicle's power requirements.

[0003] In actual operation, the range extender faces two typical operating conditions: Transient operating conditions (sudden load changes): During vehicle acceleration, hill climbing, and other scenarios, the load suddenly increases, causing the generator speed to drop rapidly, requiring a quick response to restore the speed. Steady-state operating conditions: The range extender operates stably near the target speed, requiring suppression of engine torque fluctuations that disturb the speed and ensure smooth output. However, related technologies have not achieved polarity switching between transient and steady-state feedforward values, and cannot simultaneously meet the two objectives of "rapid response" and "stable disturbance suppression". Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a range extender control method that can dynamically determine the operating conditions and realize the polarity switching of positive and negative feedforward values.

[0006] The range extender control method of this invention includes the following steps: S1, real-time detection of generator speed deviation and speed change rate; S2, determining whether the range extender is currently in transient or steady-state operation based on the speed deviation and speed change rate; S3, when determined to be in transient operation, the MCU motor control unit uses a positive feedforward torque superimposed on the PI closed-loop output torque to compensate for the speed drop caused by sudden load changes; S4, when determined to be in steady-state operation, the MCU motor control unit uses a negative feedforward torque superimposed on the PI closed-loop output torque to suppress the engine torque fluctuation's disturbance to the speed. The range extender can switch between transient and steady-state operation. When switching from transient to steady-state operation, the MCU motor control unit controls the feedforward torque to smoothly transition from the positive feedforward torque to the negative feedforward torque through a preset transition function.

[0007] The range extender control method of this invention solves the contradiction between "fast response" and "stable disturbance suppression" that traditional PI closed-loop control cannot simultaneously achieve by dynamically judging the operating conditions and switching the polarity of positive and negative feedforward values. Under transient conditions, positive feedforward significantly improves the speed recovery speed during sudden load changes, enhancing the power response during vehicle acceleration and hill climbing. Under steady-state conditions, negative feedforward effectively suppresses speed disturbances caused by engine torque fluctuations, ensuring power generation quality and power supply stability. Furthermore, the smooth transition mechanism avoids shocks during operating condition switching, improving reliability and driving smoothness.

[0008] In some embodiments, the positive feedforward torque is proportional to the real-time engine torque and the direction of the positive feedforward torque is the same as the direction of the engine torque; the negative feedforward torque is proportional to the real-time engine torque and the direction of the negative feedforward torque is opposite to the direction of the engine torque.

[0009] In some embodiments, the positive feedforward torque T ff,trans =+k1·T eng Where k1 is greater than zero, T eng For real-time engine torque; and / or, the negative feedforward torque T ff,steady =-k2·T eng Where k2 is greater than zero, T eng This refers to the real-time engine torque.

[0010] In some embodiments, the feedforward value smoothly transitions from positive to negative values ​​between transient and steady states via a transition function f(t):

[0011] The transition function f(t) is a monotonically decreasing function. At the beginning of the transient state, f(t0) = 1, and the feedforward torque is all positive. After the steady state is established, f(t_∞) = 0, and the feedforward torque is all negative.

[0012] In some embodiments, the transition function f(t) is any one of an exponential decay function, a first-order low-pass filter function, or a piecewise linear function based on operating conditions.

[0013] In some embodiments, the criteria for determining the transient operating condition are: the absolute value of the speed deviation is greater than the transient speed deviation threshold, and the absolute value of the speed change rate is greater than the transient speed change rate threshold.

[0014] In some embodiments, the determination condition of the steady-state operating condition is: the absolute value of the speed deviation is less than or equal to the steady-state speed deviation threshold, and the absolute value of the speed change rate is less than or equal to the steady-state speed change rate threshold.

[0015] In some embodiments, the transient speed deviation threshold is equal to or different from the steady-state speed deviation threshold, and the transient speed change rate threshold is equal to or different from the steady-state speed change rate threshold.

[0016] In some embodiments, the range extender control method of the present invention further includes an ECU engine control unit, wherein the real-time engine torque is sent by the ECU engine control unit to the MCU motor control unit via a CAN bus, and the PI closed-loop output torque is calculated by the MCU motor control unit.

[0017] In some embodiments, the range extender control method of the present invention further includes an RCU range extender control unit, which is used to send a target torque command and operating mode to the ECU engine control unit, and to send a target speed command and operating status flag to the MCU motor control unit, so as to coordinate the working timing of the ECU engine control unit and the MCU motor control unit. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the range extender control method according to an embodiment of the present invention. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] like Figure 1 As shown, the range extender control method of this embodiment includes the following steps: S1, real-time detection of generator speed deviation and speed change rate. S2, based on the speed deviation and speed change rate, determining whether the range extender is currently in transient or steady-state operation. S3, when determined to be in transient operation, the MCU motor control unit uses a positive feedforward torque superimposed on the PI closed-loop output torque to compensate for the speed drop caused by sudden load changes. S4, when determined to be in steady-state operation, the MCU motor control unit uses a negative feedforward torque superimposed on the PI closed-loop output torque to suppress the engine torque fluctuation's disturbance to the speed. The range extender can switch between transient and steady-state operation. When switching from transient to steady-state operation, the MCU motor control unit uses a preset transition function to control the feedforward torque to smoothly transition from a positive feedforward torque to a negative feedforward torque.

[0021] For example, by first detecting the generator's speed deviation and speed change rate in real time, it is determined whether the range extender is currently in a transient condition (such as a sudden load change) or a steady-state condition. In a transient condition, the MCU motor control unit uses a positive feedforward torque superimposed on the PI closed-loop output torque, utilizing feedforward compensation to quickly respond to speed drops and compensate for the lag in the PI closed-loop response. In a steady-state condition, it switches to a negative feedforward torque to actively suppress engine torque fluctuations that disturb speed and maintain stable output. When switching from transient to steady-state, a preset transition function achieves a smooth transition of the feedforward torque, avoiding speed oscillations caused by sudden changes in torque polarity.

[0022] Compared to related technologies, this method resolves the contradiction between "rapid response" and "stable disturbance suppression" that traditional PI closed-loop control cannot simultaneously achieve by dynamically judging operating conditions and switching the polarity of positive and negative feedforward values. Under transient conditions, positive feedforward significantly improves the speed recovery speed during sudden load changes, enhancing the vehicle's power response during acceleration and hill climbing. Under steady-state conditions, negative feedforward effectively suppresses speed disturbances caused by engine torque fluctuations, ensuring power generation quality and power supply stability. Furthermore, the smooth transition mechanism avoids shocks during operating condition switching, improving reliability and driving smoothness.

[0023] In some embodiments, the positive feedforward torque is proportional to the real-time engine torque and the direction of the positive feedforward torque is the same as the direction of the engine torque; the negative feedforward torque is proportional to the real-time engine torque and the direction of the negative feedforward torque is opposite to the direction of the engine torque.

[0024] For example, positive feedforward torque is proportional to the real-time torque of the engine and is in the same direction. This means that under transient conditions, the MCU motor control unit will actively output an auxiliary torque in the same direction as the engine output torque, thereby directly enhancing the torque of the drive generator and quickly compensating for the speed drop caused by sudden load changes. Negative feedforward torque is also proportional to the real-time torque of the engine, but in the opposite direction. Under steady-state conditions, the MCU motor control unit outputs a suppression torque in the opposite direction to the engine torque, thereby offsetting the disturbance of engine torque fluctuations on speed and maintaining stable speed.

[0025] The range extender control method of this invention establishes a linear proportional relationship between the feedforward torque and the real-time engine torque, enabling the compensation or suppression magnitude to adapt to the actual output state of the engine. This avoids the overcompensation or undercompensation problems that occur when the engine load changes due to a fixed feedforward value. Simultaneously, the positive and negative directions are clearly separated—that is, compensation in the same direction and suppression in the opposite direction—making the physical meaning of the feedforward function clear and the control logic simple. This reduces the computational complexity of the MCU and the difficulty of parameter tuning, improving the balance between transient response speed and steady-state suppression accuracy.

[0026] In some embodiments, the positive feedforward torque Tff,trans =+k1·T eng Where k1 is greater than zero, T eng For real-time engine torque. And / or, negative feedforward torque T. ff,steady =-k2·T eng Where k2 is greater than zero, T eng This refers to the real-time engine torque.

[0027] For example, the range extender control method of this embodiment of the invention distinguishes between transient and steady-state operating conditions by detecting generator speed deviation and rate of change. Under transient operating conditions, the MCU uses a positive feedforward torque T. ff,trans =+k1·T eng Its direction is related to the engine's real-time torque T. eng Similarly, it directly compensates for the speed drop caused by sudden load changes. Under steady-state conditions, it switches to a negative feedforward torque T. ff,steady =-k2·T eng Direction and real-time torque T eng Conversely, it actively suppresses the disturbance of engine speed caused by engine torque fluctuations, and achieves a smooth transition of feedforward torque through a preset transition function when switching between the two operating conditions.

[0028] The range extender control method of this invention establishes a linear proportional relationship between the feedforward torque and the real-time engine torque, allowing the compensation or suppression amplitude to be adaptively adjusted according to the load, thus avoiding overcompensation or undercompensation problems caused by a fixed feedforward value. Only two independent parameters, k1 and k2, need to be adjusted to optimize transient response speed and steady-state suppression accuracy respectively, significantly reducing calibration complexity. Furthermore, the clear separation of positive and negative directions provides a clear physical meaning for the control logic, facilitating engineering implementation and parameter tuning. This solves the contradiction between "fast response" and "stable disturbance suppression" inherent in traditional PI control, improving the overall performance of the range extender under all operating conditions.

[0029] In some embodiments, the feedforward value smoothly transitions from positive to negative values ​​between transient and steady states via a transition function f(t):

[0030] The transient function f(t) is a monotonically decreasing function. At the beginning of the transient state, f(t0) = 1, and the feedforward torque is all positive. After the steady state is established, f(t_∞) = 0, and the feedforward torque is all negative.

[0031] For example, the range extender control method of this embodiment of the invention adopts a weighted combination form of the transition function. At the transient start time t0, f(t0)=1, at which time the feedforward torque is completely composed of the positive feedforward torque T. ff,trans =+k1·T engThe decision is made to quickly compensate for the speed drop caused by sudden load changes. As time progresses, f(t) monotonically decreases, the weight of positive feedforward gradually decreases, while the weight of negative feedforward T... ff,steady =-k2·T eng The weight 1-f(t) increases synchronously until f(t_∞)=0 when steady state is established. The feedforward torque is completely dominated by the negative feedforward torque, thus achieving steady-state disturbance suppression.

[0032] The range extender control method of this invention achieves a continuous and smooth transition of feedforward torque from positive to negative values ​​during the transient-to-steady-state switching process through a dynamic weighted combination transition method. This avoids speed shocks and mechanical oscillations that may be caused by sudden changes in feedforward polarity, ensuring a smooth transfer between electromagnetic torque and engine torque. Simultaneously, the monotonically decreasing characteristic of the transition function f(t) makes the control logic intuitive and the parameters easy to tune. Only the rate of decrease of f(t) needs to be adjusted to flexibly adapt to the switching response requirements of different power systems, significantly improving the operational stability and driving smoothness of the range extender during operating condition switching.

[0033] In some embodiments, the transition function f(t) is any one of an exponential decay function, a first-order low-pass filter function, or a piecewise linear function based on operating conditions.

[0034] For example, the transition function f(t) can be any of the following: an exponential decay function, a first-order low-pass filter function, or a piecewise linear function based on operating conditions. These three transition functions are suited to different implementation scenarios. The exponential decay function is suitable for analog or continuous systems, the first-order low-pass filter is easy to implement with digital control, and the piecewise linear function is easy to calibrate using lookup tables, providing a flexible control scheme. Regardless of the function used, the monotonically decreasing characteristic ensures a smooth and gradual change in feedforward torque, avoiding speed shocks caused by sudden polarity changes. By adjusting the corresponding parameters, the response speed and transition smoothness can be flexibly balanced, significantly improving the stability and engineering practicality of the range extender during operating condition switching.

[0035] In some embodiments, the criteria for determining transient operating conditions are: the absolute value of the speed deviation is greater than the transient speed deviation threshold, and the absolute value of the speed change rate is greater than the transient speed change rate threshold.

[0036] Specifically, the criteria for determining transient operating conditions are: the absolute value of the speed deviation is greater than the transient speed deviation threshold, and the absolute value of the speed change rate is greater than the transient speed change rate threshold. The range extender control method of this embodiment detects in real time the difference between the actual and target values ​​of the generator speed (speed deviation) and the rate of speed change (speed change rate). When both indicators exceed their respective preset thresholds, it indicates a significant load change or dynamic disturbance, and the system is determined to be in a transient operating condition. It then switches to positive feedforward torque for rapid compensation. Conversely, if the speed deviation or speed change rate does not simultaneously exceed the threshold, it is considered to be in or gradually approaching a steady-state operating condition, and the system switches to negative feedforward torque for fluctuation suppression.

[0037] The range extender control method of this invention avoids the false triggering problem that may be caused by a single threshold judgment by using a dual threshold judgment method of "speed deviation" and "speed change rate". For example, under steady-state conditions, if a large occasional disturbance occurs but the speed change rate is small, the deviation exceeding the threshold alone will not be judged as transient, preventing false switching of feedforward polarity. However, when the load changes suddenly, both indicators change significantly at the same time, which can quickly identify transient demands, improve the system's adaptability to complex operating environments, ensure the precise timing of feedforward torque polarity switching, and thus ensure the coordinated realization of the two control objectives of "fast response" and "stable disturbance suppression".

[0038] In some embodiments, the determination criteria for steady-state operating conditions are: the absolute value of the speed deviation is less than or equal to the steady-state speed deviation threshold, and the absolute value of the speed change rate is less than or equal to the steady-state speed change rate threshold.

[0039] For example, the determination condition for steady-state operation is specifically as follows: the absolute value of the speed deviation is less than or equal to the steady-state speed deviation threshold, and the absolute value of the speed change rate is less than or equal to the steady-state speed change rate threshold. The range extender control method of this embodiment monitors the difference between the actual value and the target value of the generator speed (speed deviation) and the rate of change of the speed (speed change rate). When both indicators are less than or equal to their respective preset steady-state thresholds, it means that the speed has approached the target value and the fluctuation is smooth, without drastic dynamic disturbances. It is determined that the current condition is steady-state, and then negative feedforward torque is activated to suppress the interference of engine torque fluctuations on the speed, maintaining stable output.

[0040] The range extender control method of this invention provides clear boundary conditions for operating condition switching by setting a specific steady-state threshold, forming a complementary and symmetrical logical system with the transient judgment conditions. The steady-state threshold can be set independently, allowing engineers to define the "stable" state in an engineering manner based on the characteristics of the range extender, such as mechanical inertia and generator inertia, avoiding frequent exits from steady state due to an overly strict threshold or premature intervention of steady-state disturbances due to an overly loose threshold.

[0041] In some embodiments, the transient speed deviation threshold is equal to or different from the steady-state speed deviation threshold, and the transient speed change rate threshold is equal to or different from the steady-state speed change rate threshold.

[0042] For example, the range extender control method of this invention determines transient and steady-state conditions through two independent threshold groups. If the absolute values ​​of the speed deviation and the speed change rate both exceed the transient threshold, the system enters transient mode. If they are both less than or equal to the steady-state threshold, the system enters steady-state mode. In the region between the two (e.g., the deviation exceeds the transient threshold but the change rate does not, or vice versa), a smooth switching is achieved through a transition function to avoid frequent oscillations between the two modes.

[0043] The range extender control method of this invention allows for differentiated threshold settings, enhancing the flexibility of operating condition judgment and engineering adaptability. For example, setting the transient threshold slightly higher than the steady-state threshold (i.e., forming a hysteresis interval) can prevent the system from frequently switching between two modes due to minor noise or fluctuations in the critical region, thus improving stability. The two sets of thresholds are independently adjustable, allowing engineers to optimize the sensitivity of transient triggering and the tolerance of steady-state exit according to the actual system's mechanical inertia, sensor accuracy, and control requirements, thereby achieving a more refined balance between rapid dynamic response and steady-state disturbance rejection accuracy.

[0044] In some embodiments, the range extender control method of the present invention further includes an ECU engine control unit, wherein the real-time engine torque is sent by the ECU engine control unit to the MCU motor control unit via a CAN bus, and the PI closed-loop output torque is calculated by the MCU motor control unit.

[0045] For example, the range extender control method of the present invention also includes an ECU engine control unit. The real-time engine torque is sent by the ECU engine control unit to the MCU motor control unit via a CAN bus, while the PI closed-loop output torque is calculated independently by the MCU motor control unit. The ECU engine control unit collects or estimates the engine output torque in real time during engine operation and transmits it to the MCU motor control unit in the form of periodic messages via the CAN bus. After receiving this information, the MCU motor control unit calculates the required real-time engine torque Teng by combining it with its own generator speed PI closed-loop algorithm, and then generates positive and negative feedforward torques respectively, which are then superimposed with the PI closed-loop output to drive the generator.

[0046] The range extender control method of this invention realizes real-time sharing of torque information between the ECU engine control unit and the MCU motor control unit through the CAN bus, so that the feedforward torque can be adaptively compensated or suppressed based on the current real output of the engine, avoiding inaccurate control caused by missing information.

[0047] In some specific embodiments, when a sudden load change is detected (speed deviation exceeds a set threshold and speed change rate exceeds a set threshold), the MCU motor control unit receives the engine torque signal T transmitted from the ECU engine control unit via the CAN bus. eng The positive feedforward torque T ff,trans =+k1·T eng (k1>0) is superimposed on the PI closed-loop output torque T PI Up, T out =T PI +T ff,trans .

[0048] Positive feedforward is equivalent to command feedforward, which actively applies an additional torque command to the generator in the same direction as the engine torque to counteract the speed drop trend, accelerate the speed recovery response speed, and reduce the dynamic speed drop amplitude.

[0049] In some specific embodiments, when the system enters a steady state (the speed deviation is less than a set threshold and the rate of change approaches zero), the feedforward switches to the negative value T of the engine torque. ff,steady =-k2·T eng (k2>0) is superimposed on the PI closed-loop output. T out =T PI +T ff,steady =T PI -k2T eng .

[0050] Engine torque fluctuations are the main source of disturbance to generator speed. Negative feedforward is equivalent to disturbance feedforward compensation, which cancels out the impact of disturbances before they enter the closed loop, reduces the regulation burden of the PI regulator, improves steady-state speed accuracy and disturbance rejection capability, and avoids integral saturation.

[0051] In some embodiments, the range extender control method of the present invention further includes an RCU range extender control unit, which is used to send target torque commands and operating modes to the ECU engine control unit and target speed commands and operating status flags to the MCU motor control unit, so as to coordinate the working timing of the ECU engine control unit and the MCU motor control unit.

[0052] The range extender control method of this invention also includes a Range Extender Control Unit (RCU). The RCU sends target torque commands and operating modes to the Engine Control Unit (ECU) and target speed commands and operating status flags to the Motor Control Unit (MCU) to coordinate their timing. As an upper-level coordinating controller, the RCU generates target torque commands for the engine and the desired operating modes (e.g., idling, generator, shutdown) based on vehicle energy management requirements (e.g., battery SOC, driving power requests), and sends these to the ECU via the CAN bus. Simultaneously, the RCU generates target speed commands for the generator and flags indicating the current operating status (e.g., transient / steady-state), and sends these to the MCU. The ECU adjusts the engine output according to the target torque commands, and the MCU selects the appropriate feedforward strategy based on the target speed commands and operating status flags, thereby completing the coordinated operation of the engine and generator in the time sequence.

[0053] This invention's range extender control method introduces the RCU (Range Extender Control Unit) as a unified coordination node, realizing the control of both the engine and generator. This avoids control conflicts caused by the ECU (Engine Control Unit) and MCU (Motor Control Unit) responding in isolation due to a lack of global information. The RCU simultaneously issues target torque and target speed commands, ensuring physical matching between engine output and generator load, thus reducing the risk of oscillations caused by torque-speed coupling.

[0054] In some specific embodiments, the MCU motor control unit detects the generator speed N and its rate of change dN / dt in real time, and determines the speed deviation (the set speed N of the generator controlled by the MCU motor control unit) based on this deviation. des The absolute value of the difference between the actual speed N and the actual speed N (|ΔN|) and the absolute value of the rate of change of speed (|dN / dt|) determine the current operating condition of the range extender: (1) Transient condition judgment condition: When |ΔN|>N threshold (Speed ​​deviation threshold) and |dN / dt|>K threshold When the (speed change rate threshold) is reached, it is determined to be a transient operating condition (load change condition).

[0055] (2) Steady-state condition judgment condition: When |ΔN|≤N Threshold And |dN / dt|≤K threshold When this condition is reached, it is determined to be a steady-state condition. Where N... threshold The typical value range is 50-150 rpm, K threshold The typical range is 20-50 rpm / s, and the specific value is determined based on the calibration of the range extender system characteristics.

[0056] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0058] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0060] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0061] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A range extender control method, characterized in that, Includes the following steps: S1, real-time detection of generator speed deviation and speed change rate; S2, Based on the speed deviation and the speed change rate, determine whether the range extender is currently in transient or steady-state operation; S3, when the condition is determined to be transient, the MCU motor control unit uses a positive feedforward torque to be superimposed on the PI closed-loop output torque to compensate for the speed drop caused by sudden load changes; S4, When the condition is determined to be steady-state, the MCU motor control unit uses a negative feedforward torque to superimpose onto the PI closed-loop output torque to suppress the disturbance of engine torque fluctuations on the speed. The range extender can switch between transient and steady-state conditions. Specifically, when switching from the transient operating condition to the steady-state operating condition, the MCU motor control unit controls the feedforward torque to smoothly transition from the positive feedforward torque to the negative feedforward torque through a preset transition function. The positive feedforward torque is proportional to the real-time engine torque and its direction is the same as the engine torque direction. The negative feedforward torque is proportional to the real-time engine torque and its direction is opposite to the engine torque direction.

2. The range extender control method according to claim 1, characterized in that, The positive feedforward torque T ff,trans =+k1·T eng Where k1 is greater than zero, T eng For real-time engine torque; and / or, The negative feedforward torque T ff,steady =-k2·T eng Where k2 is greater than zero, T eng This refers to the real-time engine torque.

3. The range extender control method according to claim 1, characterized in that, Between transient and steady states, the feedforward value achieves a smooth transition from positive to negative values ​​through the transition function f(t): The transition function f(t) is a monotonically decreasing function. At the beginning of the transient state, f(t0) = 1, and the feedforward torque is all positive. After the steady state is established, f(t_∞) = 0, and the feedforward torque is all negative.

4. The range extender control method according to claim 3, characterized in that, The transition function f(t) is any one of the following: an exponential decay function, a first-order low-pass filter function, or a piecewise linear function based on operating conditions.

5. The range extender control method according to claim 1, characterized in that, The criteria for determining the transient operating condition are: the absolute value of the speed deviation is greater than the transient speed deviation threshold, and the absolute value of the speed change rate is greater than the transient speed change rate threshold.

6. The range extender control method according to claim 1, characterized in that, The conditions for determining the steady-state operating condition are: the absolute value of the speed deviation is less than or equal to the steady-state speed deviation threshold, and the absolute value of the speed change rate is less than or equal to the steady-state speed change rate threshold.

7. The range extender control method according to claim 6, characterized in that, The transient speed deviation threshold is equal to or different from the steady-state speed deviation threshold, and the transient speed change rate threshold is equal to or different from the steady-state speed change rate threshold.

8. The range extender control method according to any one of claims 1-7, characterized in that, It also includes an ECU engine control unit, whose real-time engine torque is sent to the MCU motor control unit via a CAN bus, and whose PI closed-loop output torque is calculated by the MCU motor control unit.

9. The range extender control method according to claim 8, characterized in that, It also includes an RCU range extender control unit, which is used to send target torque commands and operating modes to the ECU engine control unit, and to send target speed commands and operating status flags to the MCU motor control unit, so as to coordinate the working timing of the ECU engine control unit and the MCU motor control unit.

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