Energy conversion driving method of hybrid vehicle and controller of hybrid vehicle

Abstract

The invention provides an energy conversion driving method of a hybrid power vehicle and a controller of the hybrid power vehicle. The energy conversion driving method of the hybrid power vehicle comprises the steps that the expected bus voltage and the expected rotating speed of an engine are set according to the hardware condition of the hybrid power vehicle; calculating and predicting the output power of the motor in a future time period according to the power demand, and obtaining the feed-forward expected negative torque of the generator according to the output power of the motor; according to the actual bus voltage, the voltage difference value between the expected bus voltage and the actual bus voltage, the current difference value between the motor end bus current and the power generation end bus current and the capacitance value of the bus capacitor, outputting a feedback expected negative torque; the sum of the feedforward expected negative torque and the feedback expected negative torque serves as the expected input negative torque of the generator, and the actual torque of the generator is controlled to follow the expected input negative torque; based on the expected bus voltage, controlling the actual bus voltage to follow the expected bus voltage; controlling the actual rotating speed of the engine to follow the expected rotating speed.

Description

Technical Field

[0001] The present invention relates to the technical field of hybrid new energy vehicles, and particularly to an energy conversion driving method for a hybrid vehicle and a controller for a hybrid vehicle. Background Art

[0002] The integration of the energy and power domain controllers of hybrid new energy vehicles has significantly reduced the cost of electronic hardware, improved product integration, optimized energy conversion and transmission efficiency, NVH experience, etc. However, when the power battery of a hybrid new energy vehicle experiences power reduction conditions such as overheating, overcooling, too low SOC, hardware failures, or even failure conditions where it stops working, the power generation and electric drive systems cannot participate in the vehicle drive.

[0003] Common hybrid new energy vehicles include plug-in hybrid vehicles and range-extended electric vehicles. For plug-in hybrid models, when the power battery is in a power reduction condition or a failure condition, although the engine can be directly driven, the direct driving of the engine reduces the driving experience, the acceleration performance is limited, the fuel consumption level increases, and the NVH deteriorates. For range-extended electric vehicle models, when the power battery is in a power reduction condition or a failure condition, it will directly cause the energy and power systems to fail, making the vehicle unable to drive. Summary of the Invention

[0004] The purpose of the present invention is to provide an energy conversion driving method for a hybrid vehicle and a controller for a hybrid vehicle to solve the problems existing in existing hybrid vehicles when the power battery is in a power reduction condition or a failure condition.

[0005] To solve the above technical problems, the present invention provides an energy conversion driving method for a hybrid vehicle, which includes:

[0006] Setting the desired bus voltage and the desired engine speed according to the hardware conditions of the hybrid vehicle;

[0007] Calculating and predicting the output power of the motor in a future time period according to the power demand, and obtaining the feedforward desired negative torque of the generator according to the output power of the motor;

[0008] Outputting a feedback desired negative torque according to the actual bus voltage, the voltage difference between the desired bus voltage and the actual bus voltage, the current difference between the motor-side bus current and the power generation-side bus current, and the capacitance value of the bus capacitor;

[0009] Taking the sum of the feedforward desired negative torque and the feedback desired negative torque as the desired input negative torque of the generator, and controlling the actual torque of the generator to follow the desired input negative torque;

[0010] Based on the desired bus voltage, controlling the actual bus voltage to follow the desired bus voltage;

[0011] Control the actual speed of the engine to follow the desired speed.

[0012] Optionally, the actual output torque of the engine is configured to follow the feedforward desired negative torque of the generator.

[0013] Optionally, the step of obtaining the feedforward desired negative torque of the generator according to the output power of the motor includes:

[0014] Obtain the power generation power pwr of the generator according to the output power of the motor Gene ;

[0015] Obtain the current speed n of the engine FlyW ;

[0016] The feedforward desired negative torque torq GeneFF (t) = pwr Gene (t) / n FlyW .

[0017] Optionally, the desired speed of the engine is also configured to be set to one of multiple gears according to the feedforward desired negative torque of the generator.

[0018] Optionally, the feedback desired negative torque torq GeneFB =(f(Δu, Δi, u dc , C)*u dc ) / n FlyW ;

[0019] where Δu is the voltage difference between the desired bus voltage and the actual bus voltage, Δi is the current difference between the motor-side bus current and the power generation-side bus current, u dc is the actual bus voltage, C is the capacitance value of the bus capacitor, and n FlyW is the current speed of the engine.

[0020] Optionally, the motor-side bus current and the power generation-side bus current are estimated based on a controller.

[0021] Optionally, the energy conversion driving method of the hybrid vehicle is used for the power reduction condition or the failure condition of the power battery of the hybrid vehicle.

[0022] Optionally, the power demand is obtained based on the throttle request or the predicted trajectory of the ADS;

[0023] The output power pwr of the motor within the future time period t mtr (t) = torq mtr (t)*n mtr (t)+pwr loss1 ;

[0024] wherein, torq mtr is the output torque of the motor, n mtr is the output speed of the motor, pwr loss1 is the power loss of the driveline.

[0025] Optionally, the actual bus voltage following the desired bus voltage and the actual speed of the engine following the desired speed are both configured for closed-loop control.

[0026] To solve the above technical problems, the present invention further provides a controller for a hybrid vehicle, which is configured to control the engine, the generator and the motor to operate according to the energy conversion driving method of the hybrid vehicle as described above, so as to enable the electric energy generated by the engine driving the generator to supply the motor, and the motor drives the whole vehicle to travel.

[0027] In summary, in the energy conversion driving method of the hybrid vehicle and the controller of the hybrid vehicle provided by the present invention, the energy conversion driving method of the hybrid vehicle includes: setting a desired bus voltage and a desired speed of the engine according to the hardware conditions of the hybrid vehicle; calculating and predicting the output power of the motor in a future time period according to the power demand, and obtaining a feedforward desired negative torque of the generator according to the output power of the motor; outputting a feedback desired negative torque according to the actual bus voltage, the voltage difference between the desired bus voltage and the actual bus voltage, the current difference between the bus current at the motor end and the bus current at the generator end, and the capacitance value of the bus capacitor; taking the sum of the feedforward desired negative torque and the feedback desired negative torque as the desired input negative torque of the generator, and controlling the actual torque of the generator to follow the desired input negative torque; controlling the actual bus voltage to follow the desired bus voltage based on the desired bus voltage; controlling the actual speed of the engine to follow the desired speed.

[0028] With such a configuration, through the planned control of the bus voltage, the torque of the generator, and the speed of the engine, the power matching between the power output of the whole vehicle and the power output of the power generation is ensured, and the joint control of the engine, the generator and the motor to drive the whole vehicle to travel is realized in the case of the power battery being in a power reduction working condition or a failure working condition. When the power battery fails, the motor can still participate in driving the whole vehicle, especially ensuring the driving reliability of the range-extended vehicle model. When the power battery is in a power reduction working condition, the energy conversion driving method of the hybrid vehicle provided by the present invention can at least partially replace the power output of the power battery, realize the voltage stabilization function, ensure the normal driving of the whole vehicle while protecting the power battery, and reduce or prevent the occurrence of adverse conditions that affect the battery life, such as overheating and catching fire of the power battery, lithium precipitation at low temperature, and over-discharge. Description of the Drawings

[0029] Those of ordinary skill in the art will understand that the provided drawings are for better understanding of the present invention and do not constitute any limitation to the scope of the present invention.

[0030] Figure 1 It is the hardware topology diagram of the hybrid vehicle according to an embodiment of the present invention.

[0031] Figure 2 It is the functional topology diagram of the energy conversion driving method of the hybrid vehicle according to an embodiment of the present invention.

[0032] Figure 3 It is the schematic diagram of the composition of the bus system according to an embodiment of the present invention.

[0033] Figure 4 It is the schematic diagram of the bus voltage control and the torque control of the generator according to an embodiment of the present invention.

[0034] Figure 5 It is the schematic diagram of the engine speed control according to an embodiment of the present invention.

[0035] In the drawings: 1 - controller; 2 - generator; 21 - power generation inverter; 3 - motor; 31 - motor inverter; 4 - engine; 5 - bus capacitor; 6 - flywheel. Detailed Embodiments

[0036] To make the objectives, advantages and features of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be noted that the drawings are all in very simplified forms and are not drawn to scale, only for conveniently and clearly assisting in explaining the objectives of the embodiments of the present invention. In addition, the structures shown in the drawings are often part of the actual structures. In particular, the emphasis that each drawing needs to show is different, and sometimes different scales are used.

[0037] As used in the present invention, the singular forms "a", "an", "one" and "the" include plural referents, the term "or" is generally used in the sense of including "and / or", the term "several" is generally used in the sense of including "at least one", the term "at least two" is generally used in the sense of including "two or more", in addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", "third" may explicitly or implicitly include one or at least two of such features, "one end" and "the other end" and "proximal end" and "distal end" generally refer to two corresponding parts, which include not only the endpoints. In addition, as used in the present invention, "mounted", "connected", "coupled", an element "disposed" on another element should be understood in a broad sense, generally only indicating that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the two elements can be directly or indirectly connected, coupled, cooperated or transmitted through an intermediate element, and cannot be construed as indicating or implying the spatial position relationship between the two elements, that is, an element can be in any orientation such as inside, outside, above, below or on one side of another element, unless the content clearly indicates otherwise. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, directional terms such as above, below, up, down, upward, downward, left, right are used relative to the exemplary embodiments as shown in the figures, the upward or upward direction is towards the top of the corresponding figure, and the downward or downward direction is towards the bottom of the corresponding figure.

[0038] The object of the present invention is to provide an energy conversion driving method for a hybrid vehicle and a controller of the hybrid vehicle to solve the problems existing in the prior hybrid vehicle when the power battery is in a power reduction working condition or a failure working condition. The following is described with reference to the accompanying drawings.

[0039] Please refer to Figure 1 , which shows a hardware topology diagram of a hybrid vehicle, which mainly includes components such as a controller 1, a power generation inverter 21, a generator 2, a motor inverter 31, a motor 3, an engine 4, a bus capacitor 5, etc. It should be noted that Figure 1 In the shown hardware topology diagram, the power battery is not included. That is to say, it can be equivalent to the application scenario of the hybrid vehicle when the power battery is in a failure working condition.

[0040] Taking an extended-range vehicle model as an example, the only driving force source of the whole vehicle is the motor 3, and the motor 3 must have a matching power supply to achieve driving. In the prior art extended-range vehicle models, the control logic of the engine 4 works according to its rated high-efficiency working condition, drives the generator 2 to generate electricity, charges the power battery and supplies power to the motor 3 at the same time.

[0041] After the power battery fails, if the engine 4 is simply controlled to operate at its rated working condition to directly drive the generator 2 to generate electricity, it will obviously cause a mismatch between the power generation power of the generator 2 and the output power of the motor 3. When the output power of the motor 3 is small, it will cause excessive power generation, resulting in unnecessary fuel consumption and causing the bus voltage to exceed the overvoltage threshold that the bus capacitor 5 cannot withstand.

[0042] Based on this, please refer to Figure 2 , an energy conversion driving method for a hybrid vehicle provided by an embodiment of the present invention includes:

[0043] Step S1: Set the expected bus voltage and the expected speed of the engine according to the hardware conditions of the hybrid vehicle;

[0044] Step S2: Calculate and predict the output power of the motor 3 in a future time period according to the power demand, and obtain the feedforward expected negative torque of the generator 2 according to the output power of the motor 3;

[0045] Step S3: Output a feedback expected negative torque according to the actual bus voltage, the voltage difference between the expected bus voltage and the actual bus voltage, the current difference between the bus current at the motor end (i.e., the bus current at one end of the motor inverter 31) and the bus current at the power generation end (i.e., the bus current at one end of the power generation inverter 21), and the capacitance value of the bus capacitor;

[0046] Step S4: Use the sum of the feedforward expected negative torque and the feedback expected negative torque as the expected input negative torque of the generator 2, and control the actual torque of the generator 2 to follow the expected input negative torque;

[0047] Step S5: Based on the expected bus voltage, control the actual bus voltage to follow the expected bus voltage;

[0048] Step S6: Control the actual speed of the engine 4 to follow the expected speed.

[0049] The energy conversion driving method for a hybrid vehicle provided by an embodiment of the present invention can be used in the power reduction condition or the failure condition of the power battery of the hybrid vehicle. If the power battery has situations such as overheating, overcooling, too low SOC, hardware failure, etc., according to the control strategy of the battery, its output power can be restricted. For example, the maximum output power is derated, and this condition is the power reduction condition. In some other scenarios, if the power battery has an irreparable fault or other reasons, based on safety considerations, it can be disconnected from the vehicle's electronic control system, which is equivalent to the power battery being disconnected, and this is the failure condition.

[0050] The energy conversion driving method of the hybrid vehicle provided by the embodiment of the present invention mainly includes the planned control of the bus voltage, the planned control of the torque of the generator 2, and the planned control of the speed of the engine 4. With such a configuration, the power matching between the power output and the power generation output of the whole vehicle is ensured, and the engine 4, the generator 2, and the motor 3 are jointly controlled to drive the whole vehicle when the power battery is in a power reduction condition or a failure condition. When the power battery fails, the motor 3 can still participate in driving the whole vehicle, especially ensuring the driving reliability of the range extender vehicle type. When the power battery is in a power reduction condition, the energy conversion driving method of the hybrid vehicle provided by the present invention can at least partially replace (or can also completely replace) the power output of the power battery, realize the voltage stabilization function, ensure the normal driving of the whole vehicle while protecting the power battery, and reduce or prevent the occurrence of adverse conditions that affect the battery life, such as overheating and catching fire of the power battery, lithium precipitation at low temperature, and over-discharge.

[0051] The following specifically describes each step of the energy conversion driving method of the hybrid vehicle provided by the embodiment of the present invention.

[0052] Step S1 is to set the desired bus voltage and the desired speed of the engine 4. It can be understood that to achieve the planned control of the bus voltage and the planned control of the speed of the engine 4, a desired target value, target interval, or target trajectory needs to be set first. Here, the setting of the desired bus voltage is relatively simple. Because after the hardware conditions of the hybrid vehicle (such as the specification model of the motor 3 or the rated voltage of the power battery, etc.) are determined, the parameters such as the rated voltage of the motor 3 are also determined. At this time, the desired bus voltage can be directly set according to the rated voltage of the power battery, for example, 380V. Of course, the desired bus voltage can also be adjusted to a certain extent according to the current vehicle condition or the temperature of the bus capacitor 5, etc.

[0053] For the desired speed of the engine 4, on the one hand, it is also set based on the hardware conditions of the hybrid vehicle (such as the specification model of the engine 4), and on the other hand, it is preferably adjusted according to the current vehicle condition. For example, the maximum speed of a certain model of the engine 4 is 6000 revolutions per minute, then the desired speed of the engine 4 cannot exceed its maximum speed, and it is preferably set in a relatively high-efficiency speed range. On the other hand, the maximum torque and maximum power that the engine 4 can output at different speeds are different. The current vehicle condition includes, for example, the current vehicle speed, load, etc. If the vehicle is in a low-speed and light-load condition, the desired speed of the engine 4 can be set relatively low. Conversely, if the vehicle is in a high-speed and heavy-load condition, the desired speed of the engine 4 can be appropriately increased. The desired speed can also be adjusted according to the feedforward desired negative torque in the subsequent step S2. For specific understanding, reference can be made to the following description. The specific setting of the desired speed of the engine 4 can be understood with reference to the prior art.

[0054] Step S2 is the step of obtaining the feedforward expected negative torque of the generator 2. In the energy conversion and drive method of the hybrid vehicle in this embodiment, the torque matching and control of the generator 2 are important control points for achieving power matching. The generator 2 requires a certain amount of power to maintain the bus voltage and drive the motor 3, and this power demand is converted into negative torque, which is satisfied by the torque output of the engine 4.

[0055] Optionally, the power demand is obtained based on the throttle request (driver's action) or the predicted trajectory of the ADS (Advanced Driving Assistance System). Based on the power demand, the output power pwr of the motor 3 within a future time period t (e.g., several seconds) can be calculated and predicted. mtr (t) = torq mtr (t) * n mtr (t) + pwr loss1 ; where torq mtr is the output torque of the motor 3, n mtr is the output speed of the motor 3, and pwr loss1 is the power loss of the driveline.

[0056] After obtaining the output power pwr of the motor 3 mtr , the feedforward expected negative torque of the generator 2 can be obtained according to the output power pwr of the motor 3 mtr . In a demonstration example, the power generation power pwr of the generator 2 can be obtained first based on the output power pwr of the motor 3 mtr ; considering the losses in energy conversion and transmission, the power generation power pwr of the generator 2 Gene can be calculated by the following formula: Gene pwr

[0057] (t) = pwr Gene (t) + pwr mtr + pwr lossMtr + pwr lossCap

[0058] where pwr lossMtr is the power loss of the motor inverter 31 and the motor 3, and pwr lossCap is the power loss of the bus capacitor 5. The specific values of pwr lossMtr and pwr lossCap can be estimated and selected in combination with the actual hardware conditions of the current vehicle, and will not be elaborated here.

[0059] Furthermore, obtain the current speed of the engine 4. Please refer to Figure 1, For a hybrid vehicle based on the prior art, the output end of the engine 4 is connected to the generator 2, and a flywheel 6 is often provided. The rotational speeds of the engine 4, the generator 2, and the flywheel 6 can be considered to be the same value. Therefore, the step of obtaining the current rotational speed of the engine 4 can be achieved, for example, by collecting the rotational speed of the flywheel 6. That is, the current rotational speed of the engine 4 is n FlyW .

[0060] Then, the feedforward desired negative torque torq of the generator 2 can be determined based on the following formula GeneFF :[[]]

[0061] torq GeneFF (t) = pwr Gene (t) / n FlyW

[0062] The inventor further studied and found that for the planned control of the torque of the generator 2, due to the lack of the peak shaving and valley filling effect of the power battery in some application scenarios (such as power battery failure), if only the feedforward desired negative torque torq GeneFF is used as the desired input negative torque, the following defects may exist:

[0063] 1. Unable to compensate for model errors and parameter drifts: Feedforward control relies on an accurate system model. In practice, the mismatch of model parameters (such as parameters like pwr lossMtr and pwr lossCap etc.) will lead to feedforward calculation errors, causing the generated power pwr Gene to deviate from the expected value, and at the same time, in the absence of power battery adjustment, it will cause the bus voltage to shift. For example, in an example, if pwr lossMtr and pwr lossCap in step S2 are underestimated, the feedforward desired negative torque torq GeneFF will be too small. If only feedforward control is used for the torque following of the generator 2, it will result in insufficient output power of the generator 2, causing the bus voltage to be too low and the motor 3 unable to achieve the expected output power.

[0064] 2. Unable to suppress external disturbances: The load change of the motor 3 and the output power fluctuation of the engine 4 will both form external disturbances, and feedforward control alone may not be able to correct these sudden disturbances in real time.

[0065] 3. Dynamic response lag: It can be understood that the feedforward signal is obtained based on the predicted power demand in the future time period t. The window of this time period t (such as 5 seconds) cannot cover short-term dynamics (such as load mutations at the 0.1-second level). Similarly, due to the lack of power battery adjustment, it is easy to cause the bus voltage to shift.

[0066] 4. Inability to handle non - linear factors: The characteristic curves of components such as generator 2, motor 3, engine 4, motor inverter 31, bus capacitor 5, and the powertrain may not be completely linear, and feed - forward control may not be able to cope with this non - linear deviation.

[0067] Based on this, the inventors have found through research that in addition to using the feed - forward desired negative torque torq GeneFF as the desired input negative torque, it is also necessary to incorporate the feedback based on the actual situation of the bus system into the desired input negative torque of generator 2. That is, simultaneously input the feed - forward desired negative torque torq GeneFF and the feedback desired negative torque from the bus system to control the torque following of generator 2.

[0068] Step S3 is the step for obtaining the feedback desired negative torque. Please refer to Figure 3 and Figure 4 , the bus system can be described by the following formula:

[0069]

[0070] where, u dc is the actual bus voltage, which can be obtained by real - time sampling; pwr GeneReal is the actual power generation of generator 2, pwr mtrReal is the actual output power of motor 3, and C is the capacitance value of bus capacitor 5. The above formula expresses the relationship between the dynamic change of bus voltage and power balance. Based on the above formula, it can be understood how the bus voltage changes according to the power difference between generator 2 and motor 3 and the capacitance value of bus capacitor 5. When the actual power generation of generator 2 is greater than the actual output power of motor 3, the excess power is stored in bus capacitor 5, resulting in an increase in the actual bus voltage u dc ; conversely, when the power consumed by motor 3 exceeds the power provided by generator 2, bus capacitor 5 releases energy, resulting in a decrease in the bus voltage u dc .

[0071] Controller 1 can estimate the bus current i Mtr at the motor end and the bus current i Gene at the power generation end in real - time, so as to obtain the current difference Δi = i Mtr at the motor end minus the bus current i Gene at the power generation end, that is, Δi = i Mtr -i Gene .

[0072] By real - time collecting the actual bus voltage u dc , comparing and taking the difference with the desired bus voltage u dcDes set in step S1, the voltage difference Δu = u dcDes -u dc can be obtained.

[0073] Furthermore, according to the actual bus voltage u dc , the voltage difference Δu, the current difference Δi, and the capacitance value C of the bus capacitor 5, the feedback expected negative torque torq can be output GeneFB :

[0074] torq GeneFB =(f(Δu, Δi, u dc , C)*u dc ) / n FlyW

[0075] Step S4 describes the simultaneous input of the feedforward expected negative torque torq GeneFF and the feedback expected negative torque torq from the bus system GeneFB to control the torque following of the generator 2. The expected input negative torque torq of the generator 2 GeneDes is described based on the following formula:

[0076] torq GeneDes =torq GeneFF +torq GeneFB

[0077] Step S5 is the planning control for the bus voltage. Preferably, the actual bus voltage u dc following the expected bus voltage u dcDes is configured as a closed-loop control. Please refer to Figure 4 . After obtaining the voltage difference Δu between the expected bus voltage u dcDes and the actual bus voltage u dc , the torque of the generator 2 is controlled to follow the expected input negative torque torq GeneDes , thereby realizing the reverse adjustment of the actual bus voltage u dc , so that the actual bus voltage u dc follows near the expected bus voltage u dcDes , and the voltage difference Δu is less than a certain threshold (for example, within ±5% of the expected bus voltage u dcDes ), realizing the closed-loop control of the bus voltage.

[0078] Step S6 is the planning control for the rotational speed. Please refer to Figure 5 . Preferably, the actual rotational speed n of the engine 4 FlyW following the expected rotational speed n FlyWDes is configured as a closed-loop control. In an exemplary embodiment, the actual output torque of the engine 4 is configured to follow the feedforward expected negative torque torq of the generator 2 obtained in the previous step S2 GeneFF .

[0079] For the generator 2, it is required to achieve power balance (feedforward) and bus voltage stability (feedback) simultaneously, and its feedback expects a negative torque GeneFB It is mainly used to dynamically compensate the real-time deviation of the bus voltage and to achieve closed-loop control of the bus voltage. For the engine 4, the control of its speed is actually decoupled from the bus voltage control. The feedforward expected negative torque of the generator 2 GeneFF directly reflects the power demand of the generator 2. Based on the feedforward expected negative torque GeneFF , after requesting the same value of feedforward expected positive torque from the engine 4, it has been able to cover the main power balance demand of the system. Therefore, the actual output torque of the engine 4 is configured to follow the feedforward expected negative torque GeneFF . In practice, this feedforward quantity can be achieved, for example, by controlling the fuel injection quantity of the engine 4. Based on this, the follow-up adjustment of the actual speed n FlyW is also realized, so that the actual speed n FlyW follows near the expected speed n FlyWDes , and the speed difference between the two is less than a certain threshold (for example, within the range of ±50 rpm), realizing closed-loop control of the speed of the engine 4.

[0080] In some embodiments, the expected speed n FlyWDes of the engine 4 is also configured to be set to select one from multiple GeneFF gears according to the feedforward expected negative torque of the generator 2. There is a certain relationship between the speed and the torque of the engine 4, but it is not one-to-one. Specifically, at a certain speed, the maximum torque that the engine 4 can output is determined, and its actual output torque is not greater than this maximum torque. In fact, according to the control of parameters such as fuel, intake air, ignition, etc., and the response to the load, the actual output torque of the engine 4 is adjustable at a certain speed. Here, for the expected speed n FlyWDes of the engine 4, several gears are set, and the setting principle is that when the engine 4 is set at the speed of a certain gear, its maximum output torque can cover the feedforward expected negative torque of the generator 2 GeneFF . In this way, in some scenarios with lower loads (such as low speed, uniform speed, light load, flat road driving), the engine 4 does not have to operate at its rated speed and can operate at the expected speed n FlyWDes of a lower gear, which is beneficial to reducing fuel consumption and improving NVH performance.

[0081] The above embodiments exemplarily illustrate the situation where when the power battery is in a failure condition, all the power supply of the motor 3 comes from the engine 4 and the generator 2. It is easy to understand that if the power battery is in a power reduction condition and it can still output a certain amount of electric energy, at this time, the feedforward expected negative torque of the generator 2 can be reduced in step S2, and other steps can continue to refer to the description above.

[0082] Based on the energy conversion driving method of the hybrid vehicle as described above, an embodiment of the present invention further provides a controller for a hybrid vehicle. The controller is configured to control the operation of the engine 4, the generator 2, and the motor 3 according to the energy conversion driving method of the hybrid vehicle as described above, so as to enable the electric energy generated by the engine 4 driving the generator 2 to supply the motor 3, and enable the motor 3 to drive the whole vehicle to travel.

[0083] It can be understood that the execution carrier of the above energy conversion driving method of the hybrid vehicle can be software, such as a program, or can be a physical hardware, such as a readable storage medium storing a program. The above controller includes these software, programs, or readable storage media, so as to be used to execute the energy conversion driving method of the hybrid vehicle as described above. The above controller can be set independently or integrated in the ECU of the hybrid vehicle, and this embodiment is not limited thereto.

[0084] In summary, in the energy conversion driving method of the hybrid vehicle and the controller of the hybrid vehicle provided by the present invention, the energy conversion driving method of the hybrid vehicle includes: setting a desired bus voltage and a desired engine speed according to the hardware conditions of the hybrid vehicle; calculating and predicting the output power of the motor in a future time period according to the power demand, and obtaining a feedforward desired negative torque of the generator according to the output power of the motor; outputting a feedback desired negative torque according to the actual bus voltage, the voltage difference between the desired bus voltage and the actual bus voltage, the current difference between the motor-side bus current and the generator-side bus current, and the capacitance value of the bus capacitor; using the sum of the feedforward desired negative torque and the feedback desired negative torque as the desired input negative torque of the generator, and controlling the actual torque of the generator to follow the desired input negative torque; controlling the actual bus voltage to follow the desired bus voltage based on the desired bus voltage; controlling the actual speed of the engine to follow the desired speed. With such a configuration, through the planned control of the bus voltage, the planned control of the torque of the generator, and the planned control of the speed of the engine, the power matching between the power output and the power generation output of the whole vehicle is ensured, and the joint control of the engine, the generator, and the motor to drive the whole vehicle to travel is realized in the case of the power battery being in a power reduction working condition or a failure working condition. When the power battery fails, the motor can still participate in driving the whole vehicle, especially ensuring the driving reliability of the range-extended electric vehicle model. When the power battery is in a power reduction working condition, the energy conversion driving method of the hybrid vehicle provided by the present invention can at least partially replace the power output of the power battery, realize the voltage stabilization function, ensure the normal driving of the whole vehicle while protecting the power battery, and reduce or prevent the occurrence of adverse conditions that affect the battery life, such as overheating and catching fire of the power battery, lithium precipitation at low temperature, and over-discharge.

[0085] It should be noted that the above-mentioned several embodiments can be combined with each other. The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention according to the above disclosure belong to the protection scope of the present invention.

Claims

1. An energy conversion driving method for a hybrid vehicle, characterized in that: include: Setting a desired bus voltage and a desired engine speed according to hardware conditions of the hybrid vehicle; Calculate and predict the output power of the motor in a future time period according to the power demand, and obtain the feedforward expected negative torque of the generator according to the output power of the motor; Output feedback expected negative torque according to the actual bus voltage, the voltage difference between the expected bus voltage and the actual bus voltage, the current difference between the motor-end bus current and the generator-end bus current, and the capacitance of the bus capacitor; Taking the sum of the feedforward expected negative torque and the feedback expected negative torque as the expected input negative torque of the generator, and controlling the actual torque of the generator to follow the expected input negative torque; Based on the desired bus voltage, controlling the actual bus voltage to follow the desired bus voltage; The actual speed of the engine is controlled to follow the desired speed.

2. The energy conversion driving method for a hybrid vehicle according to claim 1, characterized in that: The actual output torque of the engine is configured to follow the feed-forward desired negative torque of the generator.

3. The energy conversion driving method for a hybrid vehicle according to claim 1, characterized in that: The step of obtaining the feedforward expected negative torque of the generator according to the output power of the motor comprises: The power generation power pwr of the generator is obtained according to the output power of the motor Gene ; Get the current speed n of the engine FlyW ; The feedforward expects negative torsion torq GeneFF (t) = pwr Gene (t) / n FlyW .

4. The energy conversion driving method for a hybrid vehicle according to claim 3, characterized in that: The desired speed of the engine is also configured to be set in one of the plurality of gears according to the feedforward desired negative torque of the generator.

5. The energy conversion driving method for a hybrid vehicle according to claim 1, characterized in that: The feedback expects negative torsional torq GeneFB =(f(Δu, Δi, u dc , C)*u dc ) / n FlyW ; Wherein, Δu is the voltage difference between the desired bus voltage and the actual bus voltage, Δi is the current difference between the motor-end bus current and the generator-end bus current, and u dc is the actual bus voltage, C is the capacitance of the bus capacitor, n FlyW is the current speed of the engine.

6. The energy conversion driving method for a hybrid vehicle according to claim 1, characterized in that: The motor-end bus current and the generator-end bus current are estimated based on a controller.

7. The energy conversion driving method for a hybrid vehicle according to claim 1, characterized in that: The energy conversion driving method of the hybrid vehicle is used in a power reduction condition or a failure condition of the power battery of the hybrid vehicle.

8. The energy conversion driving method for a hybrid vehicle according to claim 1, characterized in that: The power demand is obtained based on the throttle request or the predicted trajectory of the ADS; The output power pwr of the motor in the future time period t mtr (t) = torq mtr (t)*n mtr (t)+pwr loss1 ; Among them, torq mtr is the output torque of the motor, n mtr is the output speed of the motor, pwr loss1 It is the power loss of the transmission system.

9. The energy conversion driving method for a hybrid vehicle according to claim 1, characterized in that: The actual bus voltage follows the desired bus voltage and the actual engine speed follows the desired engine speed, both of which are configured as closed-loop control.

10. A controller for a hybrid vehicle, characterized in that: The controller is configured to control the operation of the engine, the generator and the motor according to the energy conversion driving method for a hybrid vehicle according to any one of claims 1 to 9, so that the engine drives the electric energy generated by the generator to supply the motor, so that the motor drives the entire vehicle to travel.

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