High-power 28V direct-current power supply and control method thereof

Abstract

A high-power 28V direct-current power supply comprises an engine with a CAN communication speed regulation control function, a water-cooling permanent magnet alternating-current generator designed by combining the output power torque characteristic of the engine, and a power generation system controller used for stably outputting high-power direct-current voltage by adjusting the rotating speed of the engine. The power generation system controller comprises a rectification circuit, an output voltage feedback circuit, a digital-analog processing circuit, a PI operation circuit, a CAN communication circuit and a CPU circuit. The engine and the water-cooled permanent magnet alternating-current generator are coaxially connected; the U / V / W three-phase output of the water-cooled permanent magnet alternating-current generator is electrically connected with the input end of the rectifying circuit; the output voltage feedback circuit, the digital-analog processing circuit, the PI operation circuit and the CAN communication circuit are electrically connected with the CPU circuit through the PCB circuit. The CAN communication circuit is electrically connected with an engine ECU. The engine ECU receives the issued target rotating speed instruction and controls the rotating speed of the engine according to the target rotating speed instruction. The power generation system has the advantages of being compact in structure, small in size, light in weight, high in efficiency and the like.

Description

Technical Field

[0001] The present application relates to the field of direct current power supply technology, and in particular to a technology for stably outputting high-power direct current power supply by adjusting the engine speed, which is suitable for direct current power supply applications with high load change frequency and relatively large output power. Background Art

[0002] At present, most of the voltage regulation and stabilization technologies of diesel engine DC generator sets at home and abroad adopt the fixed speed working state. After the generator output voltage is rectified, the output DC power supply is controlled by the switching power supply or the BUG step-down circuit, and most of them are used for DC power output with small power demand. At present, the output DC power supply is controlled by the switching power supply or the BUG step-down circuit. The single power supply generally does not exceed 700W. In order to achieve a higher power output (greater than 1kW), it is necessary to use multiple power modules in parallel. If one or more power modules are damaged, it will bring an avalanche effect. This combination of power modules is expensive, and the reliability decreases with the increase of the combination. The power module management technology of the combined output is relatively required. With the centralized heat dissipation management system, the volume of the entire power supply will also become larger; the AC generator set driven by the fixed speed diesel engine can also output high-power DC power after rectification, but the AC motor is relatively large, and the heat dissipation problem of the rectifier block is very prominent. When the large current is suddenly loaded or unloaded, the surge voltage cannot be simulated, which brings huge undervoltage and overvoltage damage risks to the electrical equipment. Summary of the invention

[0003] The object of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a high-quality, high-power 28V DC power supply with stable voltage output.

[0004] The technical solution adopted by the present invention is: a high-power 28V DC power supply, including an engine with CAN communication speed control function, a water-cooled permanent magnet AC generator designed in combination with the engine output power torque characteristics, and a power generation system controller for stably outputting high-power DC voltage by adjusting the engine speed.

[0005] The power generation system controller includes a rectifier circuit, an output voltage feedback circuit, a digital-analog processing circuit, a PI operation circuit, a CAN communication circuit, and a CPU (ARM) circuit.

[0006] The engine and water-cooled permanent magnet AC generator are coaxially connected to realize energy conversion; the U / V / W three-phase output of the water-cooled permanent magnet AC generator is electrically connected to the input end of the rectifier circuit through a copper bus cable to realize AC-DC conversion; the output voltage feedback circuit, digital-to-analog processing circuit, PI operation circuit, and CAN communication circuit are electrically connected to the CPU (ARM) circuit through a PCB circuit to realize the issuance of the engine speed target value instruction; the CAN communication circuit is electrically connected to the engine ECU to transmit the target speed instruction; the engine ECU receives the issued target speed instruction and controls the engine speed accordingly.

[0007] After the engine is started, it drives the water-cooled permanent magnet AC generator to rotate and output, which is rectified by the rectifier circuit, and the output DC voltage is fed back by the output voltage feedback circuit; the power generation control CPU (ARM) circuit sends the feedback result of the output voltage feedback circuit to the PI operation circuit for processing to obtain the target value for controlling the engine speed, and then sends the target speed value instruction through the CAN communication circuit to control the engine speed.

[0008] The engine is mechanically connected to a water-cooled permanent magnet alternator.

[0009] The rectifier circuit adopts 5 MOS tube rectifier modules divided into two groups of three-phase rectifier outputs, and a single MOS tube can provide a maximum output current of 300A.

[0010] The mathematical model of the water-cooled permanent magnet alternator designed in combination with the engine output power torque characteristics is as follows:

[0011] Magnetic flux equation:

[0012]

[0013] Voltage equation:

[0014]

[0015] Electromagnetic torque equation:

[0016]

[0017] Mechanical equation of motion:

[0018]

[0019] Among them, T e is the electromagnetic torque; Ud is the working voltage; i d 、i q , L d , L q are the current and inductance of the d-axis and q-axis respectively; Ψ f is the permanent magnet flux; dis the d-axis flux of the stator winding; q is the q-axis flux of the stator winding; R s is the stator winding resistance; is the partial derivative of the d-axis current with respect to time; is the partial derivative of the q-axis current with respect to time; Ω e is the electrical angular velocity; p is the number of pole pairs; J is the moment of inertia; Ω is the mechanical angular velocity; B is the viscous friction coefficient of the system; T L is the load torque;

[0020] From formula (4), we can get

[0021]

[0022] In order to improve the anti-interference ability of the system, considering the influence of the viscous friction coefficient on the torque, a work damping B is introduced into the speed loop. a link, and define

[0023] i q =i′ q -S a Ω (6)

[0024] In the formula, B a is the active damping parameter; i′ q is the stator current component after considering viscous friction compensation;

[0025] Using the field oriented control strategy and assuming that the motor is started under no-load conditions, we can obtain from equations (3) and (5):

[0026]

[0027] but

[0028]

[0029] The closed-loop bandwidth α of the speed loop is expressed as

[0030]

[0031] Then there is

[0032]

[0033] Using PI regulator, the control relationship of the speed loop controller is:

[0034]

[0035] in K i =αK p .

[0036] The rated speed of the water-cooled permanent magnet alternator (2) is the speed corresponding to the maximum torque output of the engine.

[0037] The control model adopted by the power generation system controller satisfies the following formula:

[0038] u(t)=K p ×e(t)+K i ×∫e(t)dt

[0039] Where:

[0040] u(t) is the target voltage value;

[0041] e(t) is the difference between the actual voltage value fed back by the output voltage feedback circuit (4) and the target voltage value u(t);

[0042] K p is the proportionality coefficient; K i is the integration coefficient;

[0043] When the instantaneous increase in current is too large, the voltage will drop too large. When the voltage drops to the control threshold, the controller gives the engine a speed-up command; when the instantaneous decrease in current is too large, the voltage will rise too large. When the voltage rises to the control threshold, the controller gives the engine a speed-down command; the engine speed change is calculated by the difference between the target voltage and the actual voltage. After the engine speed reaches the target value, the actual voltage is compared with the target voltage again. If the actual voltage is inconsistent with the target voltage value, the engine speed that needs to be adjusted will continue to be calculated, and the engine speed control command will be given until the actual voltage is consistent with the target voltage value, and the voltage control process ends.

[0044] The present invention also provides a high-power 28V DC power supply control method, including a power generation system controller for stably outputting a high-power DC voltage by adjusting the engine speed; the power generation system controller includes a rectifier circuit, an output voltage feedback circuit, a digital-analog processing circuit, a PI operation circuit, a CAN communication circuit, and a CPU (ARM) circuit; after the engine is started, it drives the water-cooled permanent magnet AC generator to rotate and output, which is rectified by the rectifier circuit, and the output DC voltage is fed back by the output voltage feedback circuit; the power generation control CPU (ARM) circuit sends the feedback result of the output voltage feedback circuit to the PI operation circuit for processing, obtains the target value for controlling the engine speed, and then sends the target speed value instruction through the CAN communication circuit to control the engine speed.

[0045] Compared with the existing voltage-regulated and stabilized DC power supply technology at home and abroad, the present invention outputs a high-power 28-volt DC power supply through speed regulation and voltage stabilization. The design of the generator combines the maximum torque speed of the engine and the best fuel economy point characteristics, and can achieve high-power DC current output at a lower cost. In addition, the present invention realizes low-speed operation of the engine when low-power output is achieved, and high-speed operation of the engine when high-power output is achieved. It can achieve high-power DC power supply output with stable voltage within a larger speed range, while reducing the fuel consumption and noise of the diesel engine.

[0046] The method for outputting a high-power 28V DC power supply through the speed regulation and voltage stabilization technology provided by the present invention has the advantages of a more compact power generation system structure, a small power generation system volume, reduced weight, improved efficiency, and the like.

[0047] The present invention realizes low voltage and high current output at a relatively low cost, and realizes stable output of 28V power supply in a wide speed range when the load power changes frequently. When the load of the generator decreases, the engine does not need to provide a large torque to overcome the electromagnetic torque output by the generator. At this time, the engine speed can be reduced to achieve an economical operation state with low noise, low fuel consumption and low wear. The application of this technology can reduce the fuel consumption and noise of the diesel engine while providing high-quality power supply, extend the maintenance cycle of the engine, and fully reduce the operating cost of the power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a principle block diagram of the present invention.

[0049] Figure 2 This is a screenshot of the voltage waveform during the sudden addition and removal test according to the electrical characteristics requirements of the 28V power supply for military vehicles in accordance with GJB298-87 for this patented technology.

[0050] Figure 3 It is the target value of surge voltage control for the electrical characteristics of 28V power supply for military vehicles in GJB298-87.

[0051] Figure 4 Response diagram for calculating target value of PI for suppressing surge voltage. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without carrying out creative work are within the scope of protection of the present invention.

[0053] Technologies, methods, and apparatus known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, such technologies, methods, and apparatus should be considered part of the authorization specification.

[0054] The first aspect of the present invention provides a high-power 28V DC power supply, including an engine 1 with a CAN communication speed control function, a water-cooled permanent magnet AC generator 2 designed in combination with the output power torque characteristics of the engine 1, and a power generation system controller for stably outputting a high-power DC voltage by adjusting the speed of the engine 1.

[0055] The power generation system controller includes a rectifier circuit 3, an output voltage feedback circuit 4, a digital-analog processing circuit 5, a PI operation circuit 6, a CAN communication circuit 7, and a CPU (ARM) circuit 8; the engine 1 and the water-cooled permanent magnet AC generator 2 are coaxially connected to realize energy conversion; the U / V / W three-phase output of the water-cooled permanent magnet AC generator 2 is electrically connected to the input end of the rectifier circuit 3 through a copper bus cable to realize AC-DC conversion; the output voltage feedback circuit 4, the digital-analog processing circuit 5, the PI operation circuit 6, and the CAN communication circuit 7 are electrically connected to the CPU (ARM) circuit 8 through a PCB circuit to realize the issuance of the engine speed target value instruction; the CAN communication circuit 7 is electrically connected to the engine 1 ECU to transmit the target speed instruction; the engine 1 ECU receives the issued target speed instruction and controls the engine 1 speed accordingly.

[0056] The present invention is based on the precise speed control of an advanced engine with a precise high-pressure common rail electronic injection system function using CAN technology, thereby obtaining a high-quality, high-power, and stable voltage output 28V DC power supply. The method of outputting a high-power 28V DC power supply through speed regulation and voltage stabilization technology has the following technical principles: after the engine 1 with the CAN communication speed regulation control function is started, it drives the high-power water-cooled permanent magnet AC generator 2 designed in combination with the engine output power torque characteristics to rotate and output, and is rectified by the high-power water-cooled MOS tube rectifier circuit 3, and the output DC voltage is fed back by the output voltage feedback circuit 4. The power generation control CPU (ARM) circuit 8 performs PI operation circuit 6 processing according to the feedback result of the output voltage feedback circuit 4 and the torque curve of the engine, and quickly calculates the target value for controlling the engine speed, and then sends the target speed value command through the CAN communication circuit 7 to control the speed of the engine 1 with the CAN communication speed regulation control function, so as to achieve a fast and stable output of a high-power 28V DC power supply. In the application of this technology, there are 1 engine CAN speed signal, 1 engine CAN temperature signal, 2 4-20mA voltage sampling signals, 2 4-20mA current sampling signals, 5 MOS tube temperature sampling resistor signals, and 2 generator winding temperature sampling resistor signals. These signals are processed by the digital-analog processing circuit 5 to realize the conversion of analog signals to digital signals, and sent to the ARM circuit for operation through the corresponding circuit of the PCB board. The PI operation circuit 6 performs PI calculation on the real-time change trend of the 2 4-20mA voltage sampling signals and the 2 4-20mA current sampling signals, and continuously sends the engine control target speed in a cycle of 30ms; at the same time, other collected signals are calculated and processed. The digital-analog processing circuit 5 realizes voltage and current sampling processing, and at the same time realizes the collection, calculation, comparison with the protection domain value, and execution of protection actions of various protection parameter values.

[0057] The rectifier circuit 3 uses a high-power water-cooled MOS tube rectifier circuit. In this example, five MOS tube rectifier modules are divided into two groups of three-phase rectifier outputs. A single MOS tube can provide a maximum output current of 300A.

[0058] The mathematical model of the water-cooled permanent magnet alternator 2 designed in combination with the output power torque characteristics of the engine 1 is as follows:

[0059] Magnetic flux equation:

[0060]

[0061] Voltage equation:

[0062]

[0063] Electromagnetic torque equation:

[0064]

[0065] Mechanical equation of motion:

[0066]

[0067] Among them, T e is the electromagnetic torque; Ud is the working voltage; i d 、i q , L d , L q are the current and inductance of the d-axis and q-axis respectively; Ψ f is the permanent magnet flux; d is the d-axis flux of the stator winding; q is the q-axis flux of the stator winding; R s is the stator winding resistance; is the partial derivative of the d-axis current with respect to time; is the partial derivative of the q-axis current with respect to time; Ω e is the electrical angular velocity; p is the number of pole pairs; J is the moment of inertia; Ω is the mechanical angular velocity; B is the viscous friction coefficient of the system; T L is the load torque;

[0068] From formula (4), we can get

[0069]

[0070] In order to improve the anti-interference ability of the system, considering the influence of the viscous friction coefficient on the torque, a work damping B is introduced into the speed loop. a link, and define

[0071] i q =i′ q -B a Ω (6)

[0072] In the formula, B a is the active damping parameter; i′ q is the stator current component after considering viscous friction compensation;

[0073] Using the field oriented control strategy and assuming that the motor is started under no-load conditions, we can obtain from equations (3) and (5):

[0074]

[0075] but

[0076]

[0077] The closed-loop bandwidth α of the speed loop is expressed as

[0078]

[0079] Then there is

[0080]

[0081] Using PI regulator, the control relationship of the speed loop controller is:

[0082]

[0083] in K i =αK p .

[0084] The present invention combines the generator design with the maximum torque point speed of the engine and the optimal fuel economy point speed. For example, the maximum torque speed of the engine is 2300 rpm and the lowest fuel consumption speed is 2600 rpm. When designing the electromagnetic scheme of the generator, the rated speed of the permanent magnet generator should be designed at 2300 rpm. In order to make the output frequency of the generator within the medium frequency range, the number of rotor pole pairs can be about 8 to 10 pairs. For example, when the number of rotor pole pairs is designed to be 8 pairs, the operating frequency of the generator is: If a low fuel consumption design is required, the rated speed of the generator can be designed to be 2600rpm. At low power output, a speed of 1900 to 2200 rpm can stably maintain DC output. When the output power increases to the rated power output, the control system calculates the target engine speed value of about 2300 rpm through voltage and current feedback, and sends the ECU speed control command to the engine through CAN communication. When the generator outputs rated output for a long time, the temperature of the generator winding and rotor magnet increases, and the generator efficiency will be relatively reduced. At this time, through voltage feedback, the power generation control system calculates the corresponding target speed value for compensation. When the generator reaches thermal equilibrium, the speed will stabilize at about 2500 to 2600 rpm. When the power output changes, the control system will quickly calculate the target speed for speed regulation and output DC voltage stably. In this technical application, the design of a high-power water-cooled permanent magnet AC generator 2 is combined with the maximum torque point speed and the best fuel economy point speed of the engine 1 with CAN communication speed control function to find the best torque and power matching speed balance point on the engine torque curve. The maximum electromagnetic torque when the generator outputs is exactly what consumes the maximum output torque of the engine. When the generator load decreases, the engine does not need to provide a large torque to overcome the electromagnetic torque of the generator output. At this time, the engine speed can be reduced to achieve an economical operating state with low noise, low fuel consumption and low wear.

[0085] The electromagnetic scheme design of the matching generator needs to be closely integrated with the engine power torque characteristics. The voltage feedback closed-loop PI operation of the electromagnetic scheme of the high-power water-cooled permanent magnet AC generator 2 designed in combination with the engine output power torque characteristics and the engine 1 torque characteristic curve with CAN communication speed control function is adopted to calculate the engine target speed and achieve the strategy of controlling the output voltage. The control model satisfies the following formula:

[0086] u(t)=K p ×e(t)+K i ×∫e(t)dt

[0087] Where:

[0088] u(t) is the actual output voltage value, which refers to the control target voltage value in the power generation system;

[0089] e(t) is the system deviation value, which refers to the difference between the actual voltage and the target voltage in the power generation system;

[0090] K p is the proportionality coefficient; K i is the integration coefficient.

[0091] PI operation process: When the load power increases or suddenly doubles, the output current will increase instantaneously, and the rate of increase will be large, which will cause the voltage to drop faster. When the voltage of the output voltage feedback circuit 4 drops to the control threshold, the PI operation circuit 6 calculates and sends the calculated speed target value to the engine 1ECU with CAN communication speed control function, and transmits the target value increase instruction, with the maximum target speed limit of ≤3000rpm; when the load power suddenly decreases, the output current will also decrease instantaneously, and the rate of decrease will be fast, which will cause the voltage to rise faster. When the voltage of the output voltage feedback circuit 4 rises to the control threshold, the PI operation circuit 6 calculates and sends the calculated speed target value to the engine 1ECU with CAN communication speed control function, and transmits the target value deceleration instruction, with the minimum target speed limit of ≥1800rpm.

[0092] The target value of the engine speed is calculated by the voltage difference between the target voltage and the feedback of the output voltage feedback circuit 4, and a CAN command speed control instruction is issued to the engine 1 ECU with the CAN communication speed control function until the surge voltage caused by loading or unloading is basically consistent with the control target voltage value. In actual application, the calculation of the target speed of the engine 1 with the CAN communication speed control function is always carried out without interruption.

[0093] See also Figure 3 When the surge voltage recovers to above 25V during sudden loading, the recovery time is ≤500ms; when the surge voltage recovers to below 30V during sudden unloading, the recovery time is ≤100ms. Figure 4 In the figure, 28V / 2300rpm is the steady-state voltage and speed value when the rated voltage and rated power are output in this example.

[0094] The present invention also provides a high-power 28V DC power supply control method, including a power generation system controller for stably outputting a high-power DC voltage by adjusting the engine speed; the power generation system controller includes a rectifier circuit, an output voltage feedback circuit, a digital-analog processing circuit, a PI operation circuit, a CAN communication circuit, and a CPU (ARM) circuit; after the engine is started, it drives the water-cooled permanent magnet AC generator to rotate and output, which is rectified by the rectifier circuit, and the output DC voltage is fed back by the output voltage feedback circuit; the power generation control CPU (ARM) circuit sends the feedback result of the output voltage feedback circuit to the PI operation circuit for processing, obtains a target value for controlling the engine speed, and then sends a target speed value command through the CAN communication circuit to control the engine speed.

[0095] The above description is only an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-power 28V DC power supply, characterized in that: It includes an engine with CAN communication speed control function, a water-cooled permanent magnet AC generator designed in combination with the engine output power torque characteristics, and a power generation system controller for stably outputting high-power DC voltage by adjusting the engine speed.

2. A high-power 28V DC power supply according to claim 1, characterized in that: The power generation system controller includes a rectifier circuit, an output voltage feedback circuit, a digital-analog processing circuit, a PI operation circuit, a CAN communication circuit, and a CPU circuit.

3. A high-power 28V DC power supply according to claim 2, characterized in that: The engine and water-cooled permanent magnet AC generator are coaxially connected to realize energy conversion; the U / V / W three-phase output of the water-cooled permanent magnet AC generator is electrically connected to the input end of the rectifier circuit to realize AC-DC conversion; the output voltage feedback circuit, digital-to-analog processing circuit, PI operation circuit, and CAN communication circuit are electrically connected to the CPU circuit through the PCB circuit to realize the issuance of the engine speed target value instruction; the CAN communication circuit is electrically connected to the engine ECU to transmit the target speed instruction; the engine ECU receives the issued target speed instruction and controls the engine speed accordingly.

4. A high-power 28V DC power supply according to claim 3, characterized in that: After the engine is started, it drives the water-cooled permanent magnet AC generator to rotate and output, which is rectified by the rectifier circuit, and the output DC voltage is fed back by the output voltage feedback circuit; the CPU circuit sends the feedback result of the output voltage feedback circuit to the PI operation circuit for processing to obtain the target value for controlling the engine speed, and then sends the target speed value instruction through the CAN communication circuit to control the engine speed.

5. A high-power 28V DC power supply according to claim 1, characterized in that: The engine is mechanically connected to a water-cooled permanent magnet alternator.

6. A high-power 28V DC power supply according to claim 2, characterized in that: The rectifier circuit adopts 5 MOS tube rectifier modules divided into two groups of three-phase rectifier outputs, and a single MOS tube can provide a maximum output current of 300A.

7. A high-power 28V DC power supply according to claim 1, characterized in that: The mathematical model of the water-cooled permanent magnet alternator designed in combination with the engine output power torque characteristics is as follows: Magnetic flux equation: Voltage equation: Electromagnetic torque equation: Mechanical equation of motion: Among them, T e is the electromagnetic torque; Ud is the working voltage; i d 、i q , L d , L q are the current and inductance of the d-axis and q-axis respectively; Ψ f is the permanent magnet flux; d is the d-axis flux of the stator winding; q is the q-axis flux of the stator winding; R s is the stator winding resistance; is the partial derivative of the d-axis current with respect to time; is the partial derivative of the q-axis current with respect to time; Ω e is the electrical angular velocity; p is the number of pole pairs; J is the moment of inertia; Ω is the mechanical angular velocity; B is the viscous friction coefficient of the system; T L is the load torque; From formula (4), we can get In order to improve the anti-interference ability of the system, considering the influence of the viscous friction coefficient on the torque, a work damping B is introduced into the speed loop. a link, and define i q =i' q -B a Ω (6) In the formula, B a is the active damping parameter; i' q is the stator current component after considering viscous friction compensation; Using the field oriented control strategy and assuming that the motor is started under no-load conditions, we can obtain from equations (3) and (5): but The closed-loop bandwidth α of the speed loop is expressed as Then there is Using PI regulator, the control relationship of the speed loop controller is: in K i =αK p .

8. A high-power 28V DC power supply according to claim 7, characterized in that: The rated speed of the water-cooled permanent magnet AC generator is the speed corresponding to the maximum torque output of the engine.

9. A high-power 28V DC power supply according to claim 1, characterized in that: The control model adopted by the power generation system controller satisfies the following formula: u(t)=K p ×e(t)+K i ×∫e(t)dt Where: u(t0 is the target voltage value; e(t) is the difference between the actual voltage value fed back by the output voltage feedback circuit and the target voltage value u(t); K p is the proportionality coefficient; K i is the integration coefficient; When the instantaneous increase in current is too large, the voltage will drop too large. When the voltage drops to the control threshold, the controller gives the engine a speed-up command; when the instantaneous decrease in current is too large, the voltage will rise too large. When the voltage rises to the control threshold, the controller gives the engine a speed-down command; the engine speed change is calculated by the difference between the target voltage and the actual voltage. After the engine speed reaches the target value, the actual voltage is compared with the target voltage again. If the actual voltage is inconsistent with the target voltage value, the engine speed that needs to be adjusted will continue to be calculated, and the engine speed control command will be given until the actual voltage is consistent with the target voltage value, and the voltage control process ends.

10. A high-power 28V DC power supply control method, characterized in that: It includes a power generation system controller for stably outputting high-power DC voltage by adjusting the engine speed; the power generation system controller includes a rectifier circuit, an output voltage feedback circuit, a digital-analog processing circuit, a PI operation circuit, a CAN communication circuit, and a CPU circuit; after the engine is started, it drives the water-cooled permanent magnet AC generator to rotate and output, which is rectified by the rectifier circuit, and the output DC voltage is fed back by the output voltage feedback circuit; the power generation control CPU circuit sends the feedback result of the output voltage feedback circuit to the PI operation circuit for processing, obtains the target value for controlling the engine speed, and then sends the target speed value instruction through the CAN communication circuit to control the engine speed.

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