Hybrid power mode diesel engine range extender power generation control method

Abstract

The invention discloses a hybrid power mode diesel engine range extender power generation control method, relates to the field of new energy power systems, and solves the technical problems that an existing range extender system provided with a permanent magnet synchronous motor is limited by space, weight and cost, and economy is insufficient due to the fact that different battery voltage platforms are selected. The control method comprises the following steps: starting the engine according to the obtained discharge power and fault state of the high-voltage battery; setting a constant-voltage mode activation condition according to the constant-voltage mode instruction, the operation state of the engine and the grade fault of the RCU, and activating a constant-voltage mode when the constant-voltage mode activation condition meets a constant-voltage mode activation requirement; after the constant voltage mode is activated, the actual voltage of the range extender is obtained, and when the actual voltage of the range extender is lower than a first voltage threshold value, the bidirectional DCDC module is controlled to enter a discharging mode; the SOC value of the high-voltage battery is obtained, and when the SOC value is smaller than an SOC threshold value, the bidirectional DCDC module is controlled to enter a charging mode. The economical efficiency of the range extender of the diesel engine is improved.

Description

Technical Field

[0001] This invention relates to the field of new energy power systems, and more specifically, to a method for controlling the power generation of a hybrid diesel engine range extender. Background Technology

[0002] With the continuous development of new energy sources, the power systems of large locomotives and rolling stock in the marine and railway sectors are also constantly being optimized and upgraded. Previously, these locomotives mostly relied on DC generator sets to supplement electrical energy and extend their range. Compared to permanent magnet synchronous motors, DC generator sets have lower power density, lower efficiency, and higher noise. Therefore, range extender systems equipped with permanent magnet synchronous motors are increasingly widely used in locomotive equipment. However, the application of such equipment is limited by space, weight, and cost. For example, in marine power systems, insulation requirements and humid environments are taken into account; the battery only plays the role of an "energy buffer" and "power auxiliary device"; furthermore, the size and configuration of the power battery can be switched according to the application needs of different customers, thus requiring the selection of power batteries with different voltage platforms. When the selected battery voltage platform and the main drive voltage platform are inconsistent, it means that the range extender must output power in a constant voltage mode. During this process, when the main drive load is suddenly unloaded or disconnected, most current solutions on the market use bleed resistors to release excess energy, but this pure energy dissipation method is not economical. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a hybrid mode diesel engine range extender power generation control method to address the shortcomings of the existing technology, thereby solving the technical problem that the existing range extenders release too much energy during the constant pressure mode power output process, which is not conducive to economic efficiency.

[0004] The present invention discloses a hybrid mode diesel engine range extender power generation control method, which involves acquiring the discharge power and fault status of the high-voltage battery, and starting the engine according to the discharge power and fault status of the high-voltage battery.

[0005] The system acquires constant pressure mode commands, engine operating status, and RCU fault level. Based on these parameters, it sets constant pressure mode activation conditions and requirements. When the constant pressure mode activation conditions and requirements are met, the constant pressure mode is activated. When the constant voltage mode is activated, the actual voltage of the range extender is obtained. When the actual voltage of the range extender is lower than the preset first voltage threshold, the bidirectional DC-DC module is controlled to enter the discharge mode. The SOC value of the high-voltage battery is obtained. When the SOC value is less than the preset SOC threshold, the bidirectional DC-DC module is controlled to enter the charging mode.

[0006] As a further improvement, the method for starting the engine based on the discharge power of the high-voltage battery and the fault condition is as follows: When the high-voltage battery is in a fault state and the discharge power is less than the discharge power threshold, the RCU starts the engine through the low-voltage motor according to the preset start command; otherwise, the VCU first controls the bidirectional DC-DC module to enter the discharge mode, and the RCU starts the engine by controlling the motor.

[0007] Furthermore, the constant pressure mode activation conditions include whether the RCU receives a constant pressure mode command from the VCU, whether the RCU has a shutdown level or forced idle level fault, and whether the engine is in an idling state.

[0008] Furthermore, the constant pressure mode activation requirement is that the RCU receives the constant pressure mode command from the VCU, the RCU has no shutdown level or forced idle level faults, and the engine is in an idle state.

[0009] Furthermore, the method for calibrating the target speed based on the maximum allowable power generation is to obtain the motor efficiency and calibrate the target speed based on the maximum allowable power generation, engine external characteristic data, and motor efficiency.

[0010] Furthermore, when the constant pressure mode is activated, the engine warm-up status, engine external characteristic data, motor external characteristic data, and fault status are acquired. The maximum allowable power generation is calibrated based on the engine warm-up status, engine external characteristic data, motor external characteristic data, and fault status. The target speed is calibrated based on the maximum allowable power generation. The actual engine speed is controlled based on the target speed.

[0011] Furthermore, a target speed fluctuation range is set. When the actual engine speed is within the target speed fluctuation range, the RCU controls the GCU to enter constant pressure mode. At the same time, the RCU outputs a target voltage signal to the GCU and sends a maximum allowable power generation signal to the GCU.

[0012] Furthermore, the loading rate and unloading rate of the maximum allowable power generation are obtained, and loading rate thresholds and unloading rate thresholds are set. When the loading rate is greater than the loading rate threshold, the loading rate is equal to the loading rate threshold; when the unloading rate is greater than the unloading rate threshold, the unloading rate is equal to the unloading rate threshold.

[0013] Beneficial effects The advantages of this invention are: After activating the constant voltage mode, this invention acquires the actual voltage of the range extender. When the actual voltage of the range extender is lower than a preset first voltage threshold, it controls the bidirectional DC-DC module to enter the discharge mode. Through the outer voltage closed loop and the inner current closed loop, the output current shares the load with the range extender. It also acquires the SOC value of the high-voltage battery. When the SOC value is less than the preset SOC threshold, it controls the bidirectional DC-DC module to enter the charging mode. Through the outer voltage closed loop and the inner current closed loop, the input current completes the charging. Compared with the existing method of using a bleed resistor to bleed excessive energy, this invention solves the problem of constant voltage output power, improves the economy of the diesel engine range extender, improves energy utilization, and completes the power generation control for both power-assisted drive and simultaneous charging and driving. Attached Figure Description

[0014] Figure 1 This is a flowchart of the hybrid mode diesel engine range extender generator control method of the present invention; Figure 2 This is a modular schematic diagram of the hybrid mode diesel engine range extender generator control system of the present invention.

[0015] Among them: 1-Bidirectional DC-DC module, 2-VCU, 3-RCU, 4-GCU, 5-ECU, 6-Engine, 7-Motor, 8-High voltage battery, 9-High voltage accessory, 10-Distribution box, 11-Main drive system. Detailed Implementation

[0016] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0017] See Figures 1-2 The present invention provides a hybrid mode diesel engine range extender power generation control method, such as... Figure 1 As shown, the control method is as follows: Range extender start mode determination: Obtain the discharge power and fault status of the high-voltage battery 8, and start the engine 6 based on the discharge power and fault status of the high-voltage battery 8. The method for starting the engine 6 based on the discharge power and fault status of the high-voltage battery 8 is as follows: Set a discharge power threshold. When the fault status of the high-voltage battery 8 is fault and the discharge power is less than the discharge power threshold, RCU3 starts the engine 6 through the low-voltage motor according to the preset start command; otherwise, VCU2 first controls the bidirectional DC-DC module 1 to enter the discharge mode, and RCU3 starts the engine 6 by controlling the motor 7.

[0018] RCU constant pressure mode activation and deactivation determination: Obtain constant pressure mode command, engine 6 operating status and RCU3 level fault, set constant pressure mode activation conditions and constant pressure mode activation requirements according to constant pressure mode command, engine 6 operating status and RCU3 level fault, and activate constant pressure mode when the constant pressure mode activation conditions are met.

[0019] The constant pressure mode activation conditions are: whether RCU3 receives the constant pressure mode command from VCU2, whether RCU3 has a shutdown level or forced idle level fault, and whether engine 6 is in idle state. The constant pressure mode activation requirements are: RCU3 receives the constant pressure mode command from VCU2, RCU3 has no shutdown level or forced idle level fault, and engine 6 is in idle state.

[0020] When the constant pressure mode is activated, the engine warm-up status, engine external characteristic data, motor external characteristic data and fault status are acquired. The maximum allowable power generation is calibrated based on the engine warm-up status, engine external characteristic data, motor external characteristic data and fault status. The target speed is calibrated based on the maximum allowable power generation, and the actual engine speed is controlled based on the target speed.

[0021] Calculation of RCU maximum allowable power generation: The method for calibrating the target speed based on the maximum allowable power generation is to obtain the motor efficiency and calibrate the target speed based on the maximum allowable power generation, engine external characteristic data, and motor efficiency. In this embodiment, calibration can be performed based on pre-set engine warm-up curves, engine external characteristic curves, motor external characteristic curves, and torque curves after fault FID processing.

[0022] Calculation of target speed in RCU constant pressure mode: Based on the maximum allowable power generation, and then according to the engine external characteristic curve and motor efficiency pulse spectrum, select the speed corresponding to the optimal efficiency point for control; here, in order to prevent the power generated by the range extender system from exceeding the load and power battery absorption capacity after high voltage failure, the maximum available power used to calculate the target speed should be within the limit range of the vehicle load.

[0023] Constant pressure mode control: When constant pressure mode is activated, RCU3 sets the actual engine speed to the target speed. A target speed fluctuation range is set. When the actual engine speed falls within this range, RCU3 controls GCU4 to enter constant pressure mode. Simultaneously, RCU3 outputs a target voltage signal to GCU4 and sends a maximum allowable power generation signal to GCU4. The target speed fluctuation range is ±50 rpm.

[0024] At this point, for VCU2, this action represents the output capability of the range extender; for GCU4, this action represents the upper limit of the closed-loop control output power required during the closed-loop target voltage control process. Finally, RCU3 calculates and feeds back the actual generated power based on the actual voltage and current of the motor using the formula P=UI.

[0025] During this process, when the range extender system is in constant voltage generation mode, if the load on the drive system suddenly increases, the range extender system's ability to maintain the current voltage will inevitably be impacted. If this exceeds the current closed-loop voltage's capacity, the range extender system voltage will inevitably continue to drop. At this time, the DC-DC control system promptly activates the bidirectional DC-DC module 1 based on the detected voltage of the distribution box bus, allowing the high-voltage battery 8 to output energy and share the load, ensuring system voltage stability. When the SOC of the high-voltage battery 8 drops to a certain value, the bidirectional DC-DC module 1 switches to input mode, allowing the range extender to simultaneously charge the high-voltage battery 8 and drive the main drive system 11.

[0026] When the constant voltage mode is activated, the actual voltage of the range extender is acquired. When the actual voltage of the range extender is lower than the preset first voltage threshold, the bidirectional DC-DC module 1 enters the discharge mode, outputting current through the outer voltage closed loop and the inner current closed loop, sharing the load with the range extender. When VCU2 needs to start the range extender, firstly, VCU2 controls the bidirectional DC-DC module 1 to enter the discharge mode, allowing the battery to provide energy to the range extender motor bus. Then, RCU3 controls the motor 7 to output torque to drive the engine according to the start command of VCU2, completing the start of the engine 6.

[0027] The system obtains the SOC value of the high-voltage battery 8. When the SOC value is less than the preset SOC threshold, the bidirectional DC-DC module 1 enters charging mode. Charging is completed through an outer voltage closed loop, an inner current closed loop, and input current, allowing simultaneous charging and driving of the main drive. When the main drive load decreases and the required power decreases, the energy originally supplied to the load can be transferred to the battery by adjusting the current allowed to the battery in the bidirectional DC-DC module 1, improving energy utilization. After successful startup, if no further operation is required, the range extender remains at idle speed, and the bidirectional DC-DC module 1 operates in standby mode. If the range extender outputs power later, VCU2 sends a constant voltage mode command to RCU3 and calculates the upper limit of the power required by the load. RCU3 activates the constant voltage mode according to the constant voltage mode command from VCU2.

[0028] Obtain the loading rate and unloading rate of the maximum allowable power generation, set loading rate threshold and unloading rate threshold. When the loading rate is greater than the loading rate threshold, the loading rate is equal to the loading rate threshold; when the unloading rate is greater than the unloading rate threshold, the unloading rate is equal to the unloading rate threshold.

[0029] like Figure 2 As shown, the bidirectional DC-DC module 1 is connected to VCU2 and RCU3 respectively, and RCU3 is connected to ECU5 and GCU4 respectively. GCU4, ECU5, and RCU3 are connected via one communication channel; RCU3, VCU2 (vehicle controller), and the bidirectional DC-DC module 1 are connected via another communication channel, the CAN bus. RCU3, as the next-level subsystem of VCU2, obeys VCU commands and coordinates the control of ECU5 and GCU4 to complete startup and power generation. A capacitor is connected in parallel in the distribution box 10 to buffer voltage fluctuations in the generator system. The bidirectional DC-DC module detects the voltage at the terminals of the distribution box 10 and the high-voltage battery 8, and controls the energy flow in and out of the high-voltage battery 8 according to the energy demand of the VC2U.

[0030] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A method for controlling the power generation of a hybrid diesel engine range extender, characterized in that, The control method is to obtain the discharge power and fault status of the high-voltage battery (8), and start the engine (6) according to the discharge power and fault status of the high-voltage battery (8). Obtain the constant pressure mode command, the operating status of the engine (6) and the level fault of the RCU (3), set the constant pressure mode activation conditions according to the constant pressure mode command, the operating status of the engine (6) and the level fault of the RCU (3), set the constant pressure mode activation requirements, and activate the constant pressure mode when the constant pressure mode activation conditions meet the constant pressure mode activation requirements. When the constant voltage mode is activated, the actual voltage of the range extender is obtained. When the actual voltage of the range extender is lower than the preset first voltage threshold, the bidirectional DC-DC module (1) is controlled to enter the discharge mode. The SOC value of the high voltage battery (8) is obtained. When the SOC value is less than the preset SOC threshold, the bidirectional DC-DC module (1) is controlled to enter the charging mode.

2. The hybrid mode diesel engine range extender power generation control method according to claim 1, characterized in that, The method for starting the engine (6) based on the discharge power and fault condition of the high-voltage battery (8) is as follows: Set a discharge power threshold. When the fault state of the high voltage battery (8) is fault and the discharge power is less than the discharge power threshold, the RCU (3) starts the engine (6) through the low voltage motor according to the preset start command; otherwise, the VCU (2) first controls the bidirectional DC-DC module (1) to enter the discharge mode, and the RCU (3) starts the engine (6) by controlling the motor (7).

3. The hybrid mode diesel engine range extender power generation control method according to claim 1, characterized in that, The constant pressure mode activation conditions include whether the RCU (3) receives the constant pressure mode command from the VCU (2), whether the RCU (3) has a shutdown level and forced idle level fault, and whether the engine (6) is in an idle state.

4. The hybrid mode diesel engine range extender power generation control method according to claim 2, characterized in that, The constant pressure mode activation requirement is that the RCU (3) receives the constant pressure mode command from the VCU (2) and the RCU (3) has no shutdown level or forced idle level faults and the engine (6) is in idle state.

5. The hybrid mode diesel engine range extender power generation control method according to claim 1, characterized in that, When the constant pressure mode is activated, the engine warm-up status, engine external characteristic data, motor external characteristic data, and fault status are acquired. The maximum allowable power generation is calibrated based on the engine warm-up status, engine external characteristic data, motor external characteristic data, and fault status. The target speed is calibrated based on the maximum allowable power generation. The actual engine speed is controlled based on the target speed.

6. The hybrid mode diesel engine range extender power generation control method according to claim 5, characterized in that, The method for calibrating the target speed based on the maximum allowable power generation is to obtain the motor efficiency and calibrate the target speed based on the maximum allowable power generation, engine external characteristic data, and motor efficiency.

7. The hybrid mode diesel engine range extender power generation control method according to claim 5, characterized in that, Set the target speed fluctuation range. When the actual speed of the engine is within the target speed fluctuation range, the RCU (3) controls the GCU (4) to enter the constant pressure mode. At the same time, the RCU (3) outputs the target voltage signal to the GCU (4) and the RCU (3) sends the maximum allowable power generation signal to the GCU (4).

8. The hybrid mode diesel engine range extender power generation control method according to claim 5, characterized in that, Obtain the loading rate and unloading rate of the maximum allowable power generation, set loading rate threshold and unloading rate threshold, and when the loading rate is greater than the loading rate threshold, the loading rate is equal to the loading rate threshold; when the unloading rate is greater than the unloading rate threshold, the unloading rate is equal to the unloading rate threshold.

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