Hybrid boost control system, method, and vehicle

Abstract

The application discloses a kind of hybrid power boost control system, method and vehicle, including engine, control system, battery management system, power battery, generator system and drive motor system;Control system is connected with engine, battery management system, power battery, generator system and drive motor system respectively;Generator system is connected with drive motor system;Power battery is connected with generator system through main relay;When needing to boost, control main relay is disconnected, and bus voltage closed-loop control is carried out by generator, and voltage target value is set as the working voltage of electric drive optimum;When needing to output larger power or energy recovery, the voltage target value of generator is adjusted to power battery voltage, and when generator output voltage is consistent with power battery voltage, control main relay is closed, and generator and power battery supply power to drive motor simultaneously.The application simplifies the boost process and reduces the cost.

Description

Technical Field

[0001] This invention belongs to the field of hybrid vehicle technology, specifically relating to a hybrid power boost control system, method, and vehicle. Background Technology

[0002] In hybrid electric vehicles (HEVs), in series mode, the drive motor uses the electrical energy output from the generator. When the generator's capacity is insufficient, it is supplemented by the battery. The DC bus voltage is determined by the battery's state of matter. Common HEVs use permanent magnet synchronous motors (PMSMs). When operating at higher speeds, if the DC bus voltage is too low, the efficiency of both the drive motor and the generator will decrease. However, the bus voltage is determined by the battery and is uncontrollable. To increase the voltage, a DC boost converter is usually added between the battery and the motor. This converter contains two high-power inductors and high-power switching transistors, resulting in high costs. For example, the hybrid vehicle disclosed in patent document CN104802788B uses a high-power boost converter to convert the battery voltage to a suitable voltage for the drive motor and generator. This patent uses a complex boost converter, which is also costly.

[0003] Therefore, it is necessary to develop a new hybrid power boost control system, method, and vehicle. Summary of the Invention

[0004] The purpose of this invention is to provide a hybrid power boost control system, method, and vehicle that can simplify the boost process and reduce costs.

[0005] In a first aspect, the hybrid power boost control system of the present invention includes an engine, a control system, a battery management system, a power battery, a generator system, and a drive motor system.

[0006] The control system is connected to the engine, battery management system, power battery, generator system and drive motor system respectively;

[0007] The generator system is connected to the drive motor system;

[0008] The power battery is connected to the generator system via a main relay;

[0009] The hybrid boost control system is configured as follows:

[0010] When a voltage boost is required, the main control relay is disconnected, and the generator performs closed-loop control of the bus voltage, with the target voltage value set to the optimal operating voltage of the electric drive.

[0011] When a larger power output or energy recovery is required, the generator's target voltage is lowered to the power battery voltage. When the generator's output voltage matches the power battery voltage, the main relay is closed, and the generator and power battery simultaneously supply power to the drive motor.

[0012] Optionally, it also includes a diode D1 connected in series between the main relay and the generator system, and a step-down switch connected in parallel with the diode D1.

[0013] When the drive motor outputs a high power, the engine cannot immediately increase its output power. The drive motor will pull down the controller voltage. Once the voltage drops to the battery voltage, the diode will clamp the controller voltage to the battery voltage, providing energy in parallel. However, when the power demand decreases, the generator can raise the voltage to the optimal voltage, restoring optimal efficiency.

[0014] Optionally, it also includes an inductor L and a diode D2, wherein the inductor L is connected in series between the main relay and the diode D1;

[0015] One end of diode D2 is connected to the connection point of inductor L and diode D1;

[0016] The other end of diode D2 is connected to the connection point of the power battery and generator system. This invention allows the step-down switch and related circuits to form a step-down loop during energy recovery, enabling the high voltage from the drive unit to actively charge the power battery.

[0017] Secondly, the hybrid power boost control method of the present invention employs the hybrid power boost control system as described in the present invention, and the method includes the following steps:

[0018] Step 1: After the vehicle starts, the main control relay closes, the system enters parallel operation mode, and the drive motor is powered by both the engine and the power battery.

[0019] Step 2: Determine whether the system meets the conditions for entering the series working mode. If the system meets the conditions for entering the series working mode, proceed to Step 3; otherwise, the system remains in the parallel working mode.

[0020] Step 3: The engine enters speed control mode; the generator enters voltage closed-loop mode, with the voltage target being the battery voltage; the main relay is disconnected; the voltage target of the generator voltage closed loop is the optimal voltage for the electric drive; the engine speed is set to the optimal engine operating speed.

[0021] Step 4: Determine if the accelerator pedal is depressed. If the accelerator pedal is depressed, and the generator power is insufficient, the generator will actively reduce the closed-loop target voltage or the drive motor will passively pull down the bus voltage. When the voltage drops to the battery voltage, it will enter parallel mode and proceed to step 2. If the accelerator pedal is not depressed, the drive motor will enter energy recovery mode. The generator will reduce the closed-loop target voltage to the battery bus voltage. When the voltage drops to the battery voltage, it will enter parallel mode and proceed to step 2.

[0022] Thirdly, the hybrid power boost control method of the present invention employs the hybrid power boost control system as described in the present invention, and the method includes the following steps:

[0023] Step 1: After the vehicle is started, the main control relay and the step-down switch are closed, and the system enters the parallel working mode, where the drive motor is powered by both the engine and the power battery.

[0024] Step 2: Determine whether the system meets the conditions for entering the series working mode. If the system meets the conditions for entering the series working mode, proceed to Step 3; otherwise, the system remains in the parallel working mode.

[0025] Step 3: The engine enters speed control mode; the generator enters voltage closed-loop mode, with the voltage target being the battery voltage; the step-down switch is disconnected; the voltage target of the generator voltage closed loop is the optimal voltage for the electric drive; the engine speed is set to the optimal operating speed of the engine.

[0026] Step 4: Determine if the accelerator pedal is depressed. If the accelerator pedal is depressed, when the generator power is insufficient, the generator actively reduces the closed-loop target voltage or the drive motor passively pulls down the bus voltage. When the voltage drops to the battery voltage, it enters parallel mode and proceeds to step 2. If the accelerator pedal is not depressed, it will soon enter energy recovery mode. The generator reduces the closed-loop target voltage to the battery bus voltage. When the voltage drops to the battery voltage, it enters parallel mode and proceeds to step 2.

[0027] Fourthly, the hybrid power boost control method of the present invention employs the hybrid power boost control system as described in the present invention, and the method includes the following steps:

[0028] Step 1: After the vehicle is started, the main control relay and the step-down switch are closed, and the system enters the parallel working mode, where the drive motor is powered by both the engine and the power battery.

[0029] Step 2: Determine whether the system meets the conditions for entering the series working mode. If the system meets the conditions for entering the series working mode, proceed to Step 3; otherwise, the system remains in the parallel working mode.

[0030] Step 3: The engine enters speed control mode; the generator enters voltage closed-loop mode, with the voltage target being the battery voltage; the step-down switch is disconnected; the voltage target of the generator voltage closed loop is the optimal voltage for the electric drive; the engine speed is set to the optimal operating speed of the engine.

[0031] Step 4: Determine if the drive motor is in drive mode. If the drive motor is in drive mode, when the generator power is insufficient, the generator actively reduces the closed-loop target voltage or the drive motor passively pulls down the bus voltage. When the voltage drops to the battery voltage, it enters parallel mode and proceeds to step 2. If the drive motor is in energy recovery mode, the generator maintains the target speed, the step-down switch performs step-down control to ensure that the drive motor and step-down system are at the optimal system voltage, and proceeds to step 2.

[0032] Fifthly, the vehicle described in this invention employs a hybrid power boost control system as described in this invention.

[0033] The present invention has the following advantages:

[0034] (1) The present invention simplifies the hardware of the DC boost converter, requiring only one relay.

[0035] (2) By adding diodes and step-down switches, when the output power of the drive motor is large and the engine cannot immediately increase the output power, the drive motor will pull down the voltage at the controller terminal. When the voltage drops to the battery voltage, the diodes will clamp the controller voltage to the battery voltage and provide energy in parallel. When the demand power decreases, the generator can raise the voltage to the optimal voltage and restore the optimal efficiency.

[0036] (3) By adding clamping diodes, buck switches, inductors and freewheeling diodes, the present invention forms a series connection with better performance. During energy recovery, the buck switch and related circuits form a buck circuit, which can actively charge the battery with the high voltage of the drive.

[0037] In summary, this invention simplifies the boost process, achieves the same performance using a control algorithm and fewer components, and has the advantage of low cost. Attached Figure Description

[0038] Figure 1 This is the architecture diagram of Embodiment 1;

[0039] Figure 2 This is a flowchart of Embodiment 1;

[0040] Figure 3 This is the architecture diagram of Embodiment 2;

[0041] Figure 4 This is a flowchart of Embodiment 2;

[0042] Figure 5 This is the architecture diagram for Embodiment 3;

[0043] Figure 6 This is a flowchart of Example 3. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings.

[0045] Example 1

[0046] like Figure 1 As shown, a hybrid power boost control system includes an engine, a control system, a battery management system, a power battery, a generator system, and a drive motor system. The control system is connected to the engine, the battery management system, the power battery, the generator system, and the drive motor system. The generator system is connected to the drive motor system. The power battery is connected to the generator system via a main relay. The hybrid power boost control system is configured such that: when a boost is needed, the main relay is opened, and the generator performs closed-loop control of the bus voltage, with the target voltage value set to the optimal operating voltage for the electric drive; when a larger power output or energy recovery is needed, the generator's target voltage value is lowered to the power battery voltage; when the generator output voltage matches the power battery voltage, the main relay is closed, and the generator and the power battery simultaneously supply power to the drive motor.

[0047] In this embodiment, the working process of the hybrid power boost control system is as follows:

[0048] 1. After the vehicle starts, the main relay is closed by default. The drive motor can be powered by both the engine and the battery. The engine and the drive motor are connected in parallel. When the engine is working, the engine is in torque mode and the generator is in speed control mode, or the engine is in speed mode and the generator is in torque mode. The bus voltage is determined by the battery voltage.

[0049] 2. When the battery voltage is low (i.e., the battery voltage is less than the preset voltage), if the drive motor is working at high speed (i.e., the speed of the drive motor is greater than the preset speed), the control system recognizes that the efficiency of the drive motor is low at this time. If the efficiency can be improved by increasing the bus voltage, the system will switch to series mode.

[0050] 3. Upon entering series mode, the main relay is disconnected, and the engine enters speed control mode to maintain its speed. As the output load increases, the torque can be automatically increased. The generator enters voltage closed-loop mode; as the load increases, the voltage drops, and the generator can automatically increase its power output. The generator limits its power output based on its performance; when the output power is too high, the generator maintains maximum power output.

[0051] 4. In series mode, since energy can only be supplied to the drive motor in one direction by the generator, the drive motor cannot recover energy, and the maximum power generation must be greater than the maximum drive power, so high power output is not possible. When the control system detects the above conditions through the change of the throttle pedal, the control system controls the generator to reduce the generator voltage closed-loop target voltage. When the bus voltage is consistent with the battery voltage, the main relay is closed to enter parallel mode, after which high power output or energy recovery can be performed.

[0052] like Figure 2 As shown in this embodiment, a hybrid power boost control method employs the hybrid power boost control system described in this embodiment, and the method includes the following steps:

[0053] Step 1: After the vehicle starts, the main control relay closes, the system enters parallel operation mode, and the drive motor is powered by both the engine and the power battery.

[0054] Step 2: Determine whether the system has entered the series operating mode, specifically:

[0055] When the battery voltage is detected to be lower than the preset voltage, the drive motor speed is higher than the preset speed, and the efficiency can be improved by increasing the bus voltage, the system switches to series mode and proceeds to step 3; otherwise, the system remains in parallel operation mode.

[0056] Step 3: The engine enters speed control mode; the generator enters voltage closed-loop mode, with the voltage target being the battery voltage; the main relay is disconnected; the voltage target of the generator voltage closed loop is the optimal voltage for the electric drive; the engine speed is set to the optimal engine operating speed.

[0057] Step 4: Determine if the accelerator pedal is depressed. If the accelerator pedal is depressed, and the generator power is insufficient, the generator will actively reduce the closed-loop target voltage or the drive motor will passively pull down the bus voltage. When the voltage drops to the battery voltage, it will enter parallel mode and proceed to step 2. If the accelerator pedal is not depressed, the drive motor will enter energy recovery mode. The generator will reduce the closed-loop target voltage to the battery bus voltage. When the voltage drops to the battery voltage, it will enter parallel mode and proceed to step 2.

[0058] In this embodiment, a vehicle employs a hybrid power boost control system as described in this embodiment.

[0059] Example 2

[0060] like Figure 3As shown, a hybrid power boost control system further includes a diode D1 connected in series between the main relay and the generator system, and a buck switch connected in parallel with diode D1. When the drive motor output power is high, the engine cannot immediately increase its output power, and the drive motor will pull down the controller voltage. When the voltage drops to the battery voltage, the diode will clamp the controller voltage to the battery voltage, providing energy in parallel. However, when the power demand decreases, the generator can boost the voltage to the optimal voltage, restoring optimal efficiency. The rest is the same as in Embodiment 1.

[0061] In this embodiment, the working process of the hybrid power boost control system is as follows:

[0062] 1. After the vehicle starts, the main relay and step-down switch are closed by default. The drive motor can be powered by both the engine and the battery. The engine and the drive motor are connected in parallel. When the engine is working, the engine is in torque mode and the generator is in speed control mode, or the engine is in speed mode and the generator is in torque mode. The bus voltage is determined by the battery voltage.

[0063] 2. When the battery voltage is low, if the drive motor is operating at high speed, the control system will recognize that the drive motor efficiency is low at this time. If the efficiency can be improved by increasing the bus voltage, the system will switch to series mode.

[0064] 3. Entering series mode, the step-down switch is disconnected, and the engine enters speed control mode to maintain the speed. As the output load increases, the torque can be automatically increased. The generator enters voltage closed-loop mode; as the load increases, the voltage drops, and the generator can automatically increase its power output. The generator limits its power output according to its performance; when the output power is too high, the generator maintains maximum power output.

[0065] 4. In series mode, since energy can only be supplied to the drive motor in one direction by the generator, the drive motor cannot recover energy, and the maximum power generation must be greater than the maximum drive power, so high power output cannot be performed. When the control system recognizes the above conditions through the change of the accelerator pedal, the control system controls the generator to reduce the generator voltage closed-loop target voltage. When the bus voltage is consistent with the battery, the main relay is closed to enter parallel mode. After that, high power output or energy recovery can be performed and return to step 1.

[0066] When very aggressive driving conditions occur and the power of the drive motor increases significantly, causing a large voltage drop, the diodes can clamp the voltage back to the battery voltage, thus enhancing the drivability of the system.

[0067] like Figure 4 As shown in this embodiment, a hybrid power boost control method employs the hybrid power boost control system described in this embodiment, and the method includes the following steps:

[0068] Step 1: After the vehicle is started, the main control relay and the step-down switch are closed, and the system enters the parallel working mode, where the drive motor is powered by both the engine and the power battery.

[0069] Step 2: Determine whether the system has entered the series operating mode, specifically:

[0070] When the battery voltage is detected to be lower than the preset voltage, the drive motor speed is higher than the preset speed, and the efficiency can be improved by increasing the bus voltage, the system switches to series mode and proceeds to step 3; otherwise, the system remains in parallel operation mode.

[0071] Step 3: The engine enters speed control mode; the generator enters voltage closed-loop mode, with the voltage target being the battery voltage; the step-down switch is disconnected; the voltage target of the generator voltage closed loop is the optimal voltage for the electric drive; the engine speed is set to the optimal operating speed of the engine.

[0072] Step 4: Determine if the accelerator pedal is depressed. If the accelerator pedal is depressed, when the generator power is insufficient, the generator actively reduces the closed-loop target voltage or the drive motor passively pulls down the bus voltage. When the voltage drops to the battery voltage, it enters parallel mode and proceeds to step 2. If the accelerator pedal is not depressed, it will soon enter energy recovery mode. The generator reduces the closed-loop target voltage to the battery bus voltage. When the voltage drops to the battery voltage, it enters parallel mode and proceeds to step 2.

[0073] In this embodiment, a vehicle employs the steps of a hybrid power boost control system as described in this embodiment.

[0074] Example 3

[0075] like Figure 5 As shown, a hybrid power boost control system further includes an inductor L and a diode D2. The inductor L is connected in series between the main relay and the diode D1. One end of the diode D2 is connected to the connection point of the inductor L and the diode D1. The other end of the diode D2 is connected to the connection point of the power battery and the generator system. This invention allows the step-down switch and related circuits to form a step-down loop during energy recovery, enabling the high voltage from the drive unit to actively charge the power battery. The rest is the same as in Embodiment 2.

[0076] This system enables the vehicle to have better drivability and reduces the problem of frequent fluctuations in the generator's target voltage caused by frequent switching between drive and energy recovery during driving.

[0077] In this embodiment, the working process of the hybrid power boost control system is as follows:

[0078] 1. After the vehicle starts, the main relay and step-down switch are closed by default. The drive motor can be powered by both the engine and the battery. The engine and the drive motor are connected in parallel. When the engine is working, the engine is in torque mode and the generator is in speed control mode, or the engine is in speed mode and the generator is in torque mode. The bus voltage is determined by the battery voltage.

[0079] 2. When the battery voltage is low, if the drive motor is operating at high speed, the control system will recognize that the drive motor efficiency is low at this time. If the efficiency can be improved by increasing the bus voltage, the system will switch to series mode.

[0080] 3. Entering series mode, the step-down switch is disconnected, and the engine enters speed control mode to maintain the speed. As the output load increases, the torque can be automatically increased. The generator enters voltage closed-loop mode; as the load increases, the voltage drops, and the generator can automatically increase its power output. The generator limits its power output according to its performance; when the output power is too high, the generator maintains maximum power output.

[0081] 4. In series mode, during energy recovery, the bus voltage rises. The step-down switch, together with inductor L and diode D2, forms a buck circuit. The step-down switch operates in PWM mode, enabling the controller to charge the power battery from the DC side using a step-down method. In drive mode (i.e., when the torque of the drive motor in the drive motor system is greater than 0), when the drive power is greater than the generation power, the bus voltage will passively decrease. When the bus voltage matches the power battery voltage, the step-down switch closes to enter parallel mode, after which high-power output can be achieved.

[0082] like Figure 6 As shown in this embodiment, a hybrid power boost control method employs the hybrid power boost control system described in this embodiment, and the method includes the following steps:

[0083] Step 1: After the vehicle is started, the main control relay and the step-down switch are closed, and the system enters the parallel working mode, where the drive motor is powered by both the engine and the power battery.

[0084] Step 2: Determine whether the system has entered the series operating mode, specifically:

[0085] When the battery voltage is detected to be lower than the preset voltage, the drive motor speed is higher than the preset speed, and the efficiency can be improved by increasing the bus voltage, the system switches to series mode and proceeds to step 3; otherwise, the system remains in parallel operation mode.

[0086] Step 3: The engine enters speed control mode; the generator enters voltage closed-loop mode, with the voltage target being the battery voltage; the step-down switch is disconnected; the voltage target of the generator voltage closed loop is the optimal voltage for the electric drive; the engine speed is set to the optimal operating speed of the engine.

[0087] Step 4: Determine if the drive motor is in drive mode. If the drive motor is in drive mode, when the generator power is insufficient, the generator actively reduces the closed-loop target voltage or the drive motor passively pulls down the bus voltage. When the voltage drops to the battery voltage, it enters parallel mode and proceeds to step 2. If the drive motor is in energy recovery mode, the generator maintains the target speed, the step-down switch performs step-down control to ensure that the drive motor and step-down system are at the optimal system voltage, and proceeds to step 2.

[0088] In this embodiment, a vehicle employs the steps of a hybrid power boost control system as described in this embodiment.

[0089] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A hybrid power boost control system, characterized in that: This includes the engine, control system, battery management system, power battery, generator system, and drive motor system; The control system is connected to the engine, battery management system, power battery, generator system and drive motor system respectively; The generator system is connected to the drive motor system; The power battery is connected to the generator system via a main relay; The hybrid power boost control system is configured as follows: It also includes a diode D1 connected in series between the main relay and the generator system, and a step-down switch connected in parallel with the diode D1; When a voltage boost is required, the main control relay is disconnected, and the generator performs closed-loop control of the bus voltage, with the target voltage value set to the optimal operating voltage of the electric drive. When a larger power output or energy recovery is required, the generator's voltage target value is lowered to the power battery voltage. When the generator output voltage is consistent with the power battery voltage, the main relay is closed, and the generator and power battery simultaneously supply power to the drive motor. Furthermore, when the output power of the drive motor is large and the engine cannot immediately increase the output power, the drive motor pulls down the voltage at the controller terminal. When the voltage drops to the battery voltage, the diode D1 clamps the controller voltage to the battery voltage to provide energy in parallel. When the demand power decreases, the generator raises the voltage to the optimal voltage to restore the optimal efficiency. It also includes an inductor L and a diode D2, wherein the inductor L is connected in series between the main relay and the diode D1; One end of diode D2 is connected to the connection point of inductor L and diode D1; The other end of the diode D2 is connected to the connection point of the power battery and generator system.

2. A hybrid power boost control method, characterized in that: The method employing the hybrid power boost control system as described in claim 1 includes the following steps: Step 1: After the vehicle starts, the main control relay closes, the system enters parallel operation mode, and the drive motor is powered by both the engine and the power battery. Step 2: Determine whether the system meets the conditions for entering the series working mode. If the system meets the conditions for entering the series working mode, proceed to Step 3; otherwise, the system remains in the parallel working mode. Step 3: The engine enters speed control mode; the generator enters voltage closed-loop mode, with the voltage target being the battery voltage; the main relay is disconnected; the voltage target of the generator voltage closed loop is the optimal voltage for the electric drive; the engine speed is set to the optimal engine operating speed. Step 4: Determine if the accelerator pedal is depressed. If the accelerator pedal is depressed, and the generator power is insufficient, the generator will actively reduce the closed-loop target voltage or the drive motor will passively pull down the bus voltage. When the voltage drops to the battery voltage, it will enter parallel mode and proceed to step 2. If the accelerator pedal is not depressed, the drive motor will enter energy recovery mode. The generator will reduce the closed-loop target voltage to the battery bus voltage. When the voltage drops to the battery voltage, it will enter parallel mode and proceed to step 2.

3. The hybrid power boost control method according to claim 2, characterized in that: When the battery voltage is detected to be lower than the preset voltage, the drive motor speed is higher than the preset speed, and efficiency can be improved by increasing the bus voltage, the system switches to series mode.

4. A vehicle, characterized in that: The hybrid power boost control system as described in claim 1 is adopted.

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