An integrated electric control system for a vehicle auxiliary power device

Abstract

The utility model relates to a kind of vehicle auxiliary power device comprehensive electronic control system, it is characterized by, including: electronic control unit, for executing the start, stop, power regulation and fault diagnosis protection logic of engine;Power conversion module, with the electronic control unit integration in same system, and with its communication connection;The utility model adopts full digital and intelligent design, with the characteristics of high integration, can significantly improve power density, reduce volume, to effectively improve the reliability and stability of equipment, meet the requirement of compactness and high performance of vehicle auxiliary power device.

Description

Technical Field

[0001] This utility model belongs to the field of vehicle auxiliary power control, specifically relating to an integrated electronic control system for vehicle auxiliary power devices. Background Technology

[0002] Auxiliary power units (APUs) provide backup power when the vehicle is stationary or when the main generator fails, and are widely used in special armored vehicles. Traditional fuel-powered APUs typically use a small internal combustion engine to drive a low-voltage output generator to produce direct current (DC). With the continuous development of new energy technologies, in pursuit of higher power density and operating efficiency, the new generation of auxiliary power units has upgraded the traditional low-voltage DC output generator to a high-voltage AC output generator, further optimizing the overall system performance and energy utilization efficiency.

[0003] Traditional auxiliary power units (APUs) have significant limitations in their system architecture. To meet basic control and safety requirements, an electronic control unit (ECU) is needed. Furthermore, to adapt the high-voltage AC output to the low-voltage 28V DC onboard equipment, rectifiers, DC-DC converters, and voltage regulators must be added at the rear. This not only occupies valuable vehicle space, but more importantly, these rear-end devices are independent of the APU itself, lacking information exchange and coordination. The system cannot dynamically adjust according to the vehicle's real-time status, resulting in slow response and a higher overall risk of failure. Utility Model Content

[0004] This utility model provides an integrated electronic control system for vehicle auxiliary power devices, and the technical problem it aims to solve is: To solve the above technical problems, this utility model provides an integrated electronic control system for vehicle auxiliary power devices, characterized in that it includes: The electronic control unit is used to execute the engine's starting, stopping, power regulation, and fault diagnosis and protection logic; The power conversion module is integrated into the same system as the electronic control unit and is communicatively connected to it; The power conversion module includes: A rectifier, whose input is used to connect to a high-voltage AC generator of an auxiliary power unit, converts high-voltage AC power into high-voltage DC power. A DC-DC converter, whose input is connected to the output of the rectifier, is used to convert and isolate high-voltage DC power into low-voltage DC power output required by the vehicle. The electronic control unit is configured to interact with the power conversion module via an internal communication bus and to coordinately control the engine and the power conversion module based on the vehicle load status and system operating parameters.

[0005] Furthermore, the DC-DC converter is an isolated converter with a half-bridge LLC resonant converter topology and synchronous rectification technology on its secondary side.

[0006] Furthermore, the half-bridge LLC resonant converter achieves zero-voltage turn-on of the switching transistor on the primary side and zero-current turn-off of the synchronous rectifier on the secondary side.

[0007] Furthermore, the internal communication bus between the electronic control unit and the power conversion module is a CAN bus.

[0008] Furthermore, the rectifier integrates a power factor correction circuit to improve the power factor of the input AC power and reduce current harmonic distortion.

[0009] Furthermore, the auxiliary power supply of the electronic control unit is directly taken from the vehicle's low-voltage battery, enabling the system to complete self-test and initialization before the main power circuit starts.

[0010] Furthermore, the system also includes a display operation module, which is communicatively connected to the electronic control unit and is used to provide system status display and receive start / stop operation commands from users.

[0011] Furthermore, the power switching devices in the DC-DC converter are silicon carbide MOSFETs.

[0012] Furthermore, the half-bridge LLC resonant converter includes a transformer T1, switching transistors Q1 and Q2 on the primary side of the transformer, a resonant capacitor, and a resonant inductor L1. The resonant inductor, the transformer magnetizing inductor, and the resonant capacitor are connected in series to form the core of the LLC resonant network. By controlling the two switching transistors Q1 and Q2 to conduct alternately, the DC input voltage Vin is converted into a square wave voltage with an amplitude of ±Vin / 2.

[0013] Furthermore, the square wave voltage is applied to the LLC resonant network, and the square wave voltage is converted into an approximately sinusoidal current by utilizing the resonant characteristics of the inductor and capacitor.

[0014] Beneficial effects: This utility model adopts a fully digital and intelligent design, and has the characteristics of high integration. It can significantly improve power density and reduce volume, thereby effectively improving the reliability and stability of the equipment and meeting the requirements of vehicle auxiliary power devices for compactness and high performance. Attached Figure Description

[0015] Figure 1 Composition of the vehicle auxiliary power unit integrated electronic control system Figure 2 Integrated electronic control system hardware principle block diagram Figure 3 Schematic diagram of a DC-DC converter. Detailed Implementation

[0016] To make the purpose, content and advantages of this utility model clearer, the specific embodiments of this utility model will be described in further detail below.

[0017] This utility model proposes a vehicle auxiliary power unit integrated electronic control system, which consists of an electronic control unit (ECU), a power conversion module, and a display and operation module. The power conversion module includes a rectifier and a DC-DC converter. The functions of each module are as follows: 1. Electronic Control Module (ECU): (1) Real-time data acquisition: Monitor engine speed, temperature, pressure and other parameters through sensors; (2) Automatically adjust the engine output power according to load demand to avoid overload or inefficient operation; (3) Fault diagnosis and handling: When overheating or downstream abnormality is detected, the shutdown protection is triggered; (4) System Communication: Receives operation commands from the display operation module, controls the engine's start and stop, and provides feedback on the system's operating status for display on the operation module. It communicates with the power conversion module via the CAN bus to dynamically adjust energy.

[0018] 2. Power conversion module rectifier: (1) Converting alternating current to direct current; (2) Power factor correction circuit (PFC) improves the power factor of AC power supply, reduces current harmonic distortion, and improves efficiency; (3) Filter out high-frequency noise and interference in the input power supply to ensure the stability and ripple of the input power supply; (4) Monitor AC input and DC output; the DC-DC converter will not work if there is an abnormality.

[0019] 3. Power conversion module DC-DC converter: (1) The transformer transfers the electrical energy of the input power supply to the output terminal through the magnetic coupling effect, thereby realizing the step-down conversion; (2) Filter out high-frequency noise and ripple at the output terminal; (3) Control is performed based on the feedback signal to adjust the on-time and interval of the switching transistor in order to maintain the stability of the output voltage; (4) Monitor the voltage, current and power device temperature of DC output.

[0020] 4. Display and Operation Module: User interaction, providing system operating status (engine speed, temperature, system output voltage, current, fault codes), operating system start and stop, and supporting remote start and stop.

[0021] The DC-DC converter topology employs a half-bridge LLC + synchronous rectification scheme, resulting in a wide-range input, highly reliable, and high-efficiency output-isolated converter. Compared to non-isolated DC-DC converters, the addition of a high-frequency transformer between the input and output provides electrical isolation, effectively preventing the risk of electric shock between high-voltage and low-voltage components in the circuit and protecting the input devices from potential electrical faults at the output. Furthermore, because the currents between the input and output are isolated, the isolated DC-DC converter can provide a stable output current, effectively filtering out current noise at the input and maintaining output stability.

[0022] As attached Figure 3 As shown, the symmetrical half-bridge LLC consists of transformer T1, primary-side switches Q1 and Q2, resonant capacitors Cr (divided into C1 and C2), and resonant inductor L1. The resonant inductor, transformer magnetizing inductance, and resonant capacitor are connected in series to form the core of the LLC resonant network. By controlling the alternating conduction of the two switches Q1 and Q2, the DC input voltage Vin is converted into a square wave voltage with an amplitude of ±Vin / 2. This square wave voltage is applied to the LLC resonant network, and utilizing the resonant characteristics of the inductor and capacitor, it is converted into an approximately sinusoidal current. This sinusoidal current is key to achieving soft-switching technologies such as zero-voltage turn-on (ZVS), thereby significantly reducing switching losses and improving converter efficiency. The LLC resonant circuit is divided into six stages according to different operating states: Phase 1: Q1 is off, Q2 is on. The energy output from the resonant inductor and resonant capacitor flows back to the negative terminal of the DC power supply through Q2. The current in the resonant inductor is negative. Phase 1 ends when Q2 is off. Second stage: Q1 turns off, Q2 turns off. During the dead time of the half-bridge circuit, the current in the resonant inductor is still negative. The resonant current discharges the output capacitor of Q1 and charges the output capacitor of Q2 until the voltage of the output capacitor of Q2 equals the input voltage (Vin). This creates the condition for zero-voltage turn-on of Q1 next time. When Q1 turns on, the second stage ends. Third stage: Q1 is on, Q2 is off. The current in the resonant inductor is still negative, and it flows back to the input terminal through the body diode of Q1. The third stage ends when the current in the resonant inductor is zero. Fourth stage: Q1 is turned on, Q2 is turned off. The resonant inductor current crosses zero and changes from negative to positive. Similar to the third stage, the resonant inductor current begins to flow from the positive terminal of the DC power supply through Q1 to the negative terminal. The fourth stage ends when Q1 is turned off. Fifth stage: Q1 turns off, Q2 turns off. During the dead time of the half-bridge circuit, the resonant inductor current charges the output capacitor of Q1 and discharges the output capacitor of Q2 until the voltage across the output capacitor of Q2 is zero, turning on the body diode of Q2 and creating conditions for Q2 to turn on at zero voltage. The fifth stage ends when Q2 turns on. Stage 6: Q1 is off, Q2 is on. Since the output capacitor of Q2 has been discharged to zero in Stage 5, Q2 is turned on with zero voltage. Repeating Stages 1 to 6, the LLC resonant circuit operates in zero-voltage switching (ZVS) mode.

[0023] In traditional LLC transformers, Schottky diodes are used for rectification on the secondary side of the transformer. Although diodes can achieve zero-current turn-off (ZCS), they have a fixed on-state voltage drop. At high current outputs, this voltage drop generates significant conduction losses, limiting further efficiency improvements.

[0024] The synchronous rectification circuit consists of switching transistors Q3 and Q4, using MOSFETs with extremely low on-resistance to replace diodes. The transformer secondary winding has a center tap. The current direction is determined by detecting the voltage Vds between the drain and source of the MOSFET. When Vds is negative, it is determined that current should be flowing through the MOSFETFE, and the MOSFET is quickly turned on, allowing current to flow through its channel instead of the body diode, thereby reducing voltage drop and losses. When a rise in Vds is detected, it means that the current is about to reverse or become zero, and the MOSFET is quickly turned off, thus achieving zero-current or near-zero-current turn-off (ZCS) and avoiding reverse conduction and voltage oscillation.

[0025] Synchronous rectifier switches have the ability to turn on and off quickly. They can minimize switching losses by utilizing their low conduction and cutoff losses, significantly reduce the losses of power switching devices, and lower the temperature and stress of the devices, thereby improving the energy conversion efficiency, reliability and lifespan of the system.

[0026] Key points of this utility model 1. Highly Integrated Design: The vehicle auxiliary power unit's integrated electronic control system adopts a highly integrated design, deeply integrating the electronic control unit, rectifier, DC-DC converter, and display and operation module. As the control core of the entire system, it can directly connect to and collaboratively manage the engine, generator, and cooling system, forming a complete and compact vehicle auxiliary power unit; 2. Fully Digital Control: The system is based on a fully digital architecture (digital control + digital communication), which can perform precise and rapid closed-loop regulation and status management of the engine, generator and power conversion unit, greatly improving the system's control accuracy, dynamic response speed and stability, and meeting the development requirements of vehicle intelligence and informatization. 3. High Efficiency: This system employs power factor correction (PFC), LLC resonant circuitry, and synchronous rectification techniques. This enables the DC-DC converter to achieve zero-voltage switching (ZVS) on the primary side and zero-current switching (ZCS) on the secondary side. ZVS and ZCS, as soft-switching technologies, allow the switching transistors to turn on when the voltage is zero and turn off when the current is zero, respectively, thus eliminating the losses caused by voltage and current overlap in traditional hard switching. Ultimately, this significantly reduces switching losses, improves overall efficiency, reduces electromagnetic interference (EMI), and enhances device reliability. 4. Comprehensive Protection Functions: The system possesses a comprehensive fault diagnosis and protection mechanism to ensure its safety and reliability under various abnormal operating conditions, including input over / under voltage protection, output overcurrent protection, and overtemperature protection. After the fault conditions are cleared, it can automatically attempt to resume operation, greatly improving the system's adaptability and reliability for continuous operation. 5. Use of new materials: The power MOSFET uses silicon carbide (SiC) devices. Compared with ordinary silicon, silicon carbide devices have lower conduction losses, higher operating frequencies, and higher temperature and voltage resistance, resulting in system-level benefits such as improved efficiency, reduced size, and extended lifespan. 6. Vehicle Adaptability Improvements: This integrated electronic control system has undergone specific adaptation improvements for the vehicle environment, which are reflected in the following aspects: Auxiliary power supply innovation: The traditional method of drawing power from the high-voltage side has been abandoned, and power is now drawn directly from the vehicle battery. This allows the system to complete self-checks and predictions before the main power circuit starts, greatly improving the system's startup reliability and safety. Standard communication integration: A built-in CAN bus communication interface allows for seamless integration with the vehicle's network. This enables data interaction and collaborative control with other vehicle control systems, meeting the functional requirements of intelligent connectivity.

[0027] This utility model presents a highly integrated, fully digital control solution for vehicle auxiliary power units. It integrates power source control and power conversion units, offering significant advantages such as small size, high power density, and high efficiency. The system features comprehensive protection functions and a user-friendly human-machine interface, fully meeting the various functional requirements of onboard auxiliary power units.

[0028] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A comprehensive electronic control system for a vehicle auxiliary power unit, characterized in that, include: The electronic control unit is used to execute the engine's starting, stopping, power regulation, and fault diagnosis and protection logic; The power conversion module is integrated into the same system as the electronic control unit and is communicatively connected to it; The power conversion module includes: A rectifier, whose input is used to connect to a high-voltage AC generator of an auxiliary power unit, converts high-voltage AC power into high-voltage DC power. A DC-DC converter, whose input is connected to the output of the rectifier, is used to convert and isolate high-voltage DC power into low-voltage DC power output required by the vehicle. The electronic control unit is configured to interact with the power conversion module via an internal communication bus and to coordinately control the engine and the power conversion module based on the vehicle load status and system operating parameters.

2. The system according to claim 1, characterized in that, The DC-DC converter is an isolated converter with a topology of a half-bridge LLC resonant converter and synchronous rectification technology is used on its secondary side.

3. The system according to claim 2, characterized in that, The half-bridge LLC resonant converter achieves zero-voltage turn-on of the switching transistor on the primary side and zero-current turn-off of the synchronous rectifier on the secondary side.

4. The system according to claim 1, characterized in that, The internal communication bus between the electronic control unit and the power conversion module is a CAN bus.

5. The system according to claim 1, characterized in that, The rectifier integrates a power factor correction circuit to improve the power factor of the input AC power and reduce current harmonic distortion.

6. The system according to claim 1, characterized in that, The auxiliary power supply of the electronic control unit is directly taken from the vehicle's low-voltage battery, enabling the system to complete self-test and initialization before the main power circuit starts.

7. The system according to claim 1, characterized in that, The system also includes a display operation module, which is communicatively connected to the electronic control unit and is used to provide system status display and receive start / stop operation commands from users.

8. The system according to claim 1, characterized in that, The power switching devices in the DC-DC converter are silicon carbide MOSFETs.

9. The system according to claim 2, characterized in that, The half-bridge LLC resonant converter includes a transformer T1, switching transistors Q1 and Q2 on the primary side of the transformer, a resonant capacitor, and a resonant inductor L1. The resonant inductor, the transformer magnetizing inductor, and the resonant capacitor are connected in series to form the core of the LLC resonant network. By controlling the two switching transistors Q1 and Q2 to conduct alternately, the DC input voltage Vin is converted into a square wave voltage with an amplitude of ±Vin / 2.

10. The system according to claim 9, characterized in that, The square wave voltage is applied to the LLC resonant network, and the square wave voltage is converted into an approximately sinusoidal current by utilizing the resonant characteristics of the inductor and capacitor.

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