A voltage regulator based on a two-stage DC-DC circuit

Abstract

The present application provides a voltage regulation device based on a two-stage DC-DC circuit, comprising: a voltage acquisition module, a current acquisition module, a controller, a first-stage DC-DC converter, a second-stage DC-DC converter, a first drive circuit, and a second drive circuit; the controller is used to receive the voltage value and current value collected by the voltage acquisition module and the current acquisition module, and send control instructions to the first-stage DC-DC converter and the second-stage DC-DC converter through the first drive circuit and the second drive circuit to adjust the voltage respectively; the controller adjusts the first-stage DC-DC converter by selecting a suitable first-stage DC-DC modulation duty cycle according to the calculated ideal modulation ratio; the controller adjusts the second-stage DC-DC converter by a sliding mode control algorithm. The advantages of the present application are: significantly improving conversion efficiency, reducing power loss and heat generation, maintaining high stability and reliability, and being suitable for aerospace applications.

Description

Technical Field

[0001] The present application belongs to the technical field of voltage regulation, and specifically relates to a voltage regulation device based on a two-stage DC-DC circuit. Background Art

[0002] In applications such as space exploration, satellite communications, and space science research, power systems must meet the requirements of high efficiency, reliability, and precise voltage control. The challenges of power technology in these applications mainly include:

[0003] 1. Efficiency: Space missions are usually subject to energy constraints, and it is necessary to increase power conversion efficiency as much as possible to reduce power loss and reduce heat dissipation requirements, thereby improving the system's endurance.

[0004] 2. Precise voltage control: Many space exploration equipment and scientific instruments such as electrostatic analyzers require a stable high-voltage power supply to ensure data accuracy and measurement precision, which places high demands on the precise control of power output.

[0005] 3. Reliability and environmental resistance: Space equipment needs to operate for a long time in harsh environments such as extreme temperature, radiation and vacuum, which places strict requirements on the reliability and environmental resistance of the power supply system.

[0006] 4. Most of the current voltage control algorithms are PID control algorithms. PID control is the most common algorithm in voltage regulation. It has a simple principle and is easy to implement. It is easy to understand and implement, suitable for linear systems, and can also be adjusted by adjusting parameters. K p , K i , K d Realize the elimination of steady-state error and the adjustment of response speed.

[0007] In the context of these requirements, existing technologies mainly rely on linear regulators (such as LM117, etc.) to reduce the input high voltage to the required low voltage output by adjusting the series power transistors to work in the amplification region. Its advantages are simple design, low ripple, good transient response, and suitable for low current and low noise applications. However, this solution is inefficient. When the difference between the input voltage and the output voltage is large, the power loss increases significantly. The heat dissipation requirements are high in high current applications, and it is not suitable for high-efficiency applications in aerospace environments. Specifically, it includes:

[0008] 1. Low efficiency and large energy waste;

[0009] Traditional linear regulators, such as the LM117, reduce the input voltage to the desired output voltage by adjusting the operating state of the transistor. Since its working principle is linear regulation, the efficiency is affected by the difference between the input voltage and the output voltage. Especially in the case of high input voltage and low output voltage, the efficiency drops sharply. For example, when the input is 24V and the output is 12V, the efficiency of the LM117 is only 50%. This low efficiency will cause a lot of energy to be dissipated in the form of heat, increasing the difficulty of thermal management of the system, and also reducing the overall energy efficiency of the system, which is especially unacceptable in aerospace applications.

[0010] For single-stage DC-DC converters, although the efficiency is usually high, when the load fluctuates greatly or the input voltage changes, the control algorithm may not be able to respond in time, resulting in fluctuations in the output voltage and a decrease in efficiency.

[0011] 2. Poor adjustment accuracy and stability;

[0012] Traditional linear regulators regulate current through feedback to maintain output voltage, but their accuracy and stability are low, especially in scenarios with high precision requirements (such as space exploration and scientific experimental equipment). For example, the LM117, the voltage regulation accuracy it provides is limited by its design and the accuracy of the external resistors. In applications with high precision requirements, traditional regulators may not be able to achieve low enough ripple or accurate enough voltage output. In high-precision applications such as aerospace, this lack of accuracy may lead to deviations in measurement and experimental results.

[0013] Although single-stage DC-DC converters are highly efficient, they still have problems with accuracy and ripple control, and cannot meet the strict requirements of aerospace systems for output voltage accuracy and stability. Although single-stage DC-DC has advantages in conversion efficiency, it usually uses a simple feedback mechanism to adjust the output voltage, which may not meet strict accuracy requirements. Especially when the load changes, the single-stage DC-DC may not be able to adjust quickly, and the response speed of the duty cycle adjustment may lag, resulting in increased voltage fluctuations and ripples.

[0014] 3. Unable to flexibly respond to different load conditions;

[0015] Traditional linear regulators and single-stage DC-DC converters usually respond slowly to load changes. Especially in aerospace equipment, load changes may be rapid and frequent, which requires the power supply system to respond quickly to load changes to ensure voltage stability. In traditional technologies, the power supply system may cause instantaneous voltage fluctuations due to untimely response, affecting the normal operation of aerospace equipment.

[0016] 4. Poor adaptability to the environment;

[0017] Linear regulators generate a lot of heat at high power output, requiring complex heat dissipation design. Under extreme environmental conditions, such as high temperature and radiation, the thermal management capabilities of traditional regulators may be insufficient, affecting their stability and reliability in space missions.

[0018] The PID algorithm has poor adaptability to nonlinear systems. The PID parameters are closely related to the dynamic characteristics of the system. When the system exhibits strong nonlinearity, the performance degrades; it is not very adaptable to external disturbances such as input voltage fluctuations and load changes; and large overshoot and delay may occur in fast response scenarios.

[0019] For single-stage DC-DC converters, although the DC-DC converter has high efficiency, the durability, radiation resistance and thermal management of components under extreme environmental conditions are still key issues in its design.

[0020] Traditional linear regulators and some single-stage DC-DC converters perform poorly in environments with extreme temperatures, radiation, and long-term stable operation, especially in aerospace or space exploration missions, where equipment needs to be able to withstand harsh conditions such as high temperature, radiation, and vacuum. Traditional solutions have large power losses and high heat, and often cannot meet the stability and reliability requirements of aerospace equipment. Summary of the invention

[0021] The purpose of this application is to overcome the defects of the prior art, such as large power loss, high heat, and stability and reliability that cannot meet the requirements of aerospace equipment.

[0022] In order to achieve the above-mentioned purpose, the present application proposes a voltage regulation device based on a two-stage DC-DC circuit, comprising: a voltage acquisition module, a current acquisition module, a controller, a first-stage DC-DC converter, a second-stage DC-DC converter, a first drive circuit and a second drive circuit; wherein,

[0023] The voltage acquisition module is used to collect the output voltage value and the target voltage signal output from the outside in real time;

[0024] The current acquisition module is used to acquire the output current value in real time;

[0025] The controller is used to receive the voltage value and the current value collected by the voltage collection module and the current collection module, and send control instructions to the first-stage DC-DC converter and the second-stage DC-DC converter to adjust the voltage through the first drive circuit and the second drive circuit respectively;

[0026] The first-stage DC-DC converter is used to perform a first-stage regulation on the output voltage;

[0027] The second-stage DC-DC converter is used to perform a second-stage adjustment on the voltage based on the adjustment by the first-stage DC-DC converter;

[0028] The first driving circuit is used to drive the power switch tube of the first-stage DC-DC converter according to the duty cycle signal output by the controller;

[0029] The second driving circuit is used to drive the power switch tube of the second-stage DC-DC converter according to the duty cycle signal output by the controller;

[0030] The controller regulates the first-stage DC-DC converter by selecting a suitable first-stage DC-DC modulation duty cycle according to the calculated ideal modulation ratio;

[0031] The controller regulates the second-stage DC-DC converter using a sliding mode control algorithm.

[0032] As an improvement of the above device, the method for adjusting the first-stage DC-DC converter by the controller includes:

[0033] The duty cycle adjustment gear of the first-stage DC-DC converter is divided into n gears;

[0034] Calculate the first stage duty cycle = output voltage ÷ (input voltage × second stage DC-DC converter duty cycle setting value);

[0035] The smallest gear among the n gears that is greater than the first-stage duty cycle is selected as the adjustment gear for the duty cycle of the first-stage DC-DC converter.

[0036] As an improvement of the above device, the n is 5;

[0037] The five duty cycle adjustment gears of the first-stage DC-DC converter are 90%, 70%, 50%, 30% and 10% respectively.

[0038] As an improvement to the above device, the duty cycle setting value of the second-stage DC-DC converter is 90%.

[0039] As an improvement of the above device, the method for adjusting the second-stage DC-DC converter by the controller includes:

[0040] Calculation of sliding surface by error and disturbance estimation :

[0041]

[0042] in, Represents the voltage error, represents the target voltage, Represents the sampled output voltage; Represents the design parameters of the sliding surface, which is used to adjust the dynamic response of the system; It represents the disturbance estimation term, which compensates for the influence of external disturbance on the system; t Indicates time;

[0043] Design of synovial film control law :

[0044]

[0045] in, represents the switching gain of the sliding mode controller, which is used to suppress disturbances; represents the sliding mode switching function; represents the disturbance estimation term; represents the system parameters, which are used to normalize the control input; represents the rate of change of the disturbance estimate;

[0046] Calculate the feedforward term And add it to the PI controller to get the voltage regulation of the D axis ,Will Output to PWM:

[0047]

[0048] in, Indicates the input reference signal of the D axis; Indicates the system switching frequency; Indicates the inductance value; represents the D-axis current, i.e., the steady-state component; and Indicates the PI controller parameters of the D axis; Indicates the current error of the D-axis.

[0049] As an improvement of the above device, the voltage acquisition module adopts MCP6022.

[0050] As an improvement of the above device, the controller adopts an STM32 single-chip microcomputer.

[0051] As an improvement of the above device, the first driving circuit and the second driving circuit adopt a half-bridge driver IR2104.

[0052] Compared with the prior art, the advantages of this application are:

[0053] 1. High efficiency: By replacing the traditional linear regulator (such as LM117) with a two-stage DC-DC converter, the conversion efficiency is significantly improved, and power loss and heat generation are reduced.

[0054] 2. Precise voltage control: This solution is specially designed to provide high-precision voltage output to ensure voltage stability and accuracy under complex environmental conditions, and is particularly suitable for aerospace applications.

[0055] 3. Adapt to harsh environments: The power system can adapt to the challenges of extreme environments such as spacecraft, such as high radiation, temperature fluctuations, vacuum, etc., and maintain high stability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 The figure shows the architecture of a voltage regulator device based on a two-stage DC-DC circuit;

[0057] Figure 2 Shown is a working principle diagram of a DC-DC converter;

[0058] Figure 3 Shown is the working principle diagram of the voltage sampling module;

[0059] Figure 4 Shown is a working principle diagram of the first driving circuit and the second driving circuit;

[0060] Figure 5 Shown is the working principle diagram of the current sampling module;

[0061] Figure 6 The figure shows the flow chart of the controller adjusting the two-stage DC-DC voltage;

[0062] Figure 7 Shown is a schematic diagram of a controller adjusting two-stage DC-DC voltage. DETAILED DESCRIPTION

[0063] The technical solution of the present application is described in detail below with reference to the accompanying drawings.

[0064] For high-voltage power supplies of space exploration payloads or other aerospace equipment, the output voltage needs to be accurately controlled. In the design of the output closed loop, the current of the sampled output small signal needs to be amplified, so as to convert the control signal into a power signal, and then adjust the voltage at the output end.

[0065] The prior art uses a linear regulator such as the LM117 chip. As a high-voltage adjustable three-terminal regulator, the chip guarantees an output current of 1.5A. It can raise the voltage of the input signal and convert it as a signal end, playing a role of current amplification, thereby amplifying the power and making the output signal have a greater load capacity.

[0066] The linear regulator reduces the input voltage to the target output voltage by adjusting the internal power element (usually a series transistor). It cannot achieve a "switching" state during operation, but always maintains a linear region, which causes power loss to be related to the input and output voltage difference. Its power loss can be expressed as: ,in is the input voltage, is the output voltage, is the output current. It can be seen that when the input voltage and output voltage When the difference is large, the loss will increase, especially when the output current In larger cases, the loss is more significant.

[0067] This voltage drop loss means that part of the input power of the linear regulator is not effectively transmitted to the output when converting the voltage, but is wasted inside the regulator. The series transistor in the regulator consumes this power and dissipates it in the form of heat. Therefore, in the case of high current, in order to dissipate heat and prevent the chip from failing due to excessive temperature, additional heat sinks or fans are usually required to dissipate heat, which further increases the complexity of the system.

[0068] The voltage regulating device based on the two-stage DC-DC circuit provided in the present application adopts a DC-DC circuit to replace the original linear regulator LM117 chip. In the process of converting the control signal into a power signal, a DC-DC circuit is used for conversion, and the input control signal size is converted into a PWM duty cycle change. The step-up and step-down conditions in the DC-DC circuit are adjusted by the change of the PWM duty cycle. Unlike linear regulators, DC-DC converters (such as step-down switching regulators) convert voltage to a target value through high-speed switches and energy storage elements (inductors and capacitors), which can achieve an efficiency of more than 90%. Because it does not dissipate energy directly through voltage drop, but maintains high efficiency through energy conversion, which makes DC-DC converters more suitable for occasions with large currents and large voltage differences.

[0069] The voltage regulation device based on the two-stage DC-DC circuit provided in the present application utilizes a two-stage DC-DC converter to replace a traditional linear regulator (such as LM117), providing a high-efficiency, high-precision high-voltage power supply in aerospace applications, and solving the shortcomings of the current background technology in terms of efficiency, regulation accuracy, and reliability of applicable environments.

[0070] The voltage regulation device based on the two-stage DC-DC circuit provided in the present application involves replacing the traditional linear regulator (such as LM117) with a two-stage DC-DC converter, and is used in aerospace equipment or other power supply systems with high precision and high efficiency requirements. In the implementation process, the DC-DC converter stabilizes the input voltage to the required output voltage through a two-stage step-down conversion method, thereby providing an efficient, stable and accurate power supply.

[0071] The voltage regulating device based on the two-stage DC-DC circuit provided in the present application includes:

[0072] The voltage sampling module is used to collect the output voltage value and the target voltage signal output from the outside in real time, and send it to the controller through the ADC for sliding mode control calculation. This module converts the output voltage signal into a small voltage signal that can be collected by the controller. The voltage sampling module of this application adopts MCP6022, and its schematic diagram is as follows Figure 3 shown.

[0073] The current acquisition module is used to collect the inductor current and protect the additional feedback of the sliding surface design. The schematic diagram of the current acquisition module is as follows: Figure 5 shown.

[0074] The controller is used to run the sliding mode control algorithm, generate a PWM signal, and adjust the conduction time of the power switch tube in the two-stage DC-DC. The controller calculates the error, sliding mode surface and control quantity according to the sliding mode control algorithm, and generates a corresponding PWM signal. The controller of this application adopts an STM32 microcontroller.

[0075] like Figure 6 and Figure 7 As shown, the STM32 microcontroller collects the output voltage value through the ADC sampling system and compares it with the target voltage value. When it is not equal to the target value, it will start to adjust the output voltage. The sliding mode control algorithm is used for the regulation process of the second-stage DC-DC converter, and its principle is as follows:

[0076] 1. Sliding surface design

[0077]

[0078] in, is the voltage error; is the target voltage; is the output voltage (obtained by sampling); is the design parameter of the sliding surface, which is used to adjust the dynamic response of the system; It is the disturbance estimation term, which compensates the influence of external disturbance on the system.

[0079] 2. Sliding mode control law design

[0080] In order to ensure the stable motion of the system on the sliding surface, the sliding mode control law is designed as follows:

[0081]

[0082] in, s Indicates synovial surface; represents the switching gain of the sliding mode controller, which is used to suppress disturbances; represents the sliding mode switching function; represents the disturbance estimation term; represents the system parameters, which are used to normalize the control input; represents the rate of change of the disturbance estimate.

[0083] Introducing the Lyapunov function , by taking the derivative of the Lyapunov function, it is verified that the system can reach the sliding surface within a finite time and eventually converge to the equilibrium point:

[0084]

[0085] This proves that the system is globally stable.

[0086] 3. Feedforward compensation design (decoupling control)

[0087] In order to improve the dynamic performance of the system, PI control based on the feedforward decoupling idea is used to adjust the current inner loop:

[0088]

[0089] in, and Respectively represent the feedforward items of the D-axis and Q-axis, which are used to compensate for the dynamic coupling relationship, represents the system switching frequency, Indicates the inductance value, represents the D-axis current, i.e. the steady-state component, represents the Q-axis current, i.e. the dynamic component; , , and They represent the PI controller parameters of the D-axis and Q-axis respectively; and Represent the current errors of the D-axis and Q-axis respectively; and Represent the input reference signals of the D-axis and Q-axis respectively; and Respectively represent the voltage regulation of the D axis and Q axis, which is the voltage reference input to the PWM modulator and ultimately determines the output voltage duty cycle. Through decoupling terms and PI control, and The current components of the D-axis and Q-axis can be adjusted independently to achieve active and reactive power control of the system.

[0090] The PI control formula is: , the three parts here are proportional control, integral control and differential control. It represents the error obtained. The first term multiplies the error by a constant. For example, the voltage error on the D axis is 2. Set it to 100, the first item is 200 as a whole. Subtracting this part is equivalent to subtracting 200 from the PWM value. The same is true for the next two items. There is no need to add differential control here, and use proportional-integral to adjust the current error.

[0091] The DQ coordinate system to which the D-axis and Q-axis belong is a mathematical change. The D-axis component corresponds to the active component in the system (i.e., the component in phase with the reference voltage); the Q-axis component corresponds to the reactive component in the system (i.e., the component orthogonal to the reference voltage). , represents the error of D-axis current, which is used to adjust active power or output voltage; , represents the error of Q-axis current, which is used to adjust reactive power or decouple dynamic components. These two errors are independent of each other and can be adjusted by PI controllers respectively.

[0092] In actual systems, due to the coupling characteristics of the DQ axis, the D-axis and Q-axis currents affect each other, making it difficult to separate the control. Therefore, it is necessary to design a feedforward decoupling term (such as and ) to compensate for this dynamic coupling relationship, thereby achieving independent control of the two currents.

[0093] The specific process of the sliding mode control algorithm includes:

[0094] (1) System initialization: Configure the STM32 PWM output, ADC sampling voltage and current. Initialize system parameters (inductance L , voltage setting value , PI controller parameters, sliding surface parameters k wait).

[0095] (2) Calculate real-time error: Sample output voltage and output current ; Calculate voltage error ; Calculate current error and .

[0096] (3) Sliding surface calculation: The sliding surface is calculated by error and disturbance estimation:

[0097]

[0098] (4) Implementation of sliding mode control law: According to the sliding surface s, the control input is calculated in real time:

[0099]

[0100] (5) Feedforward compensation and PI control (inner loop): Calculate the feedforward term And added to the PI controller:

[0101]

[0102] The calculated Output to PWM.

[0103] feedforward term The calculation method is: The second-level system switching frequency Use 10k; inductance value L Use 1mL; measure the output current , and the current error is obtained by subtracting the target current ;Will Decompose into D-axis components and Q-axis component In the sliding mode control or double closed-loop control structure, the voltage outer loop calculates the reference current As input to the current inner loop. Rapidly adjust the dynamic component is the total error minus the steady-state component , which can be further used for feedforward compensation or sliding mode control in response to dynamic load disturbances.

[0104] The first-stage DC-DC converter roughly adjusts the output voltage, and the second-stage DC-DC converter fine-tunes the output voltage. The first-stage DC-DC converter divides the output voltage into five levels: 90%, 70%, 50%, 30% and 10%. Select the appropriate first-stage DC-DC modulation duty cycle based on the calculated ideal modulation ratio. The selection method is: calculate the duty cycle of the first stage based on the duty cycle of the second-stage DC-DC converter as 90%. For example, if you need to convert 24v input to 12v, according to the formula: 24 (First level duty cycle) (90%) = 12v; the first level is 55%, and 70% is selected for upward compatibility. After the first-level DC-DC converter is selected, the duty cycle of the second-level DC-DC is automatically adjusted according to the sliding mode control method. In other embodiments, the output voltage of the first-level DC-DC converter can also be divided into n, 3<=n<=9 levels, and the specific number of levels can be determined according to the adjustment accuracy.

[0105] The first drive circuit and the second drive circuit are used to drive the power switch tube of the DC-DC conversion circuit according to the duty cycle signal output by the controller. The two drive circuits amplify the PWM signal output by the STM32 to a 12V PWM signal that is more capable of controlling the switch tube. The drive circuit of the present application adopts the half-bridge driver IR2104, and its schematic diagram is shown in FIG. Figure 4 shown.

[0106] The two-stage DC-DC converter as the main circuit includes a first-stage DC-DC converter and a second-stage DC-DC converter, and is a core circuit for realizing the conversion of input voltage into target output voltage, including a power switch tube, a filter and a drive circuit.

[0107] like Figure 2 As shown, the working principle of the DC-DC converter is as follows:

[0108] When the synchronous rectification bidirectional DC-DC converter is in Buck mode, the switch tubes Q1 and Q2 are both in the switching state and in a complementary state. In one cycle, when Q1 is turned on and Q2 is turned off, the inductor stores energy, and the power supply V1 supplies power to the load through the inductor, and the load voltage is V2; when Q1 is turned off and Q2 is turned on, the load current continues to flow through Q2. Assume that the duty cycle of the switch tube Q1 is D, and the inductor L It is large enough to ensure that the circuit works in continuous mode, and the step-down ratio of the converter is AV: AV=D.

[0109] The function of the first-stage DC-DC converter is to reduce the output voltage that is higher than the output voltage to a relatively intermediate voltage, which plays a role in rough voltage regulation. The function of the second-stage DC-DC converter is to reduce the output voltage of the first-stage DC-DC converter to the final required precise output voltage. In this stage, the sliding mode control method is used to control the voltage to ensure the stability of the output voltage and the bottom ripple.

[0110] The modules of this device realize data interaction through analog signals (sampling voltage and current) and digital signals (PWM control signals).

[0111] like Figure 1 As shown, the working process of the voltage regulating device based on the two-stage DC-DC circuit includes: first, the voltage sampling module samples the output signal, the controller samples the output signal, and the PWM duty cycle required to be adjusted is obtained through software processing, and the two-stage PWM signals are respectively input into the two-stage DC-DC converter through the first drive circuit and the second drive circuit, thereby adjusting the DC-DC circuit.

[0112] The input voltage usually comes from the battery or other power system of the aerospace equipment. After filtering and adjusting, the input voltage is first transmitted to the first-stage DC-DC converter, whose main task is to reduce the higher input voltage (such as 24V) to a lower intermediate voltage. The first-stage DC-DC converter adopts switch mode control, which has high conversion efficiency and effectively reduces power loss. The first-stage DC-DC converter uses suitable switch tubes (such as MOSFET) and inductor components to operate in high-frequency switching mode. By adjusting the on-time (duty cycle) of the switch tube, the current change of the inductor is controlled to achieve the conversion from input voltage to intermediate voltage. The key to this stage is to achieve high efficiency and minimize electromagnetic interference (EMI) and voltage ripple. The intermediate voltage after the first-stage DC-DC converter steps down enters the second-stage DC-DC converter, which is used to accurately control the output voltage to ensure its stability and high precision. At this stage, a high-precision feedback loop control is used to detect the difference between the output voltage and the set value, and the working state of the switch tube is adjusted through PWM (pulse width modulation) to ensure that the output voltage accurately meets the requirements. The design requirements of the second-stage DC-DC converter include low ripple output, high regulation accuracy, and fast response under load changes to keep the output voltage stable. The feedback control loop plays a vital role in the whole process. The voltage sampling module in the feedback circuit monitors the output voltage in real time and ensures the constant output voltage by dynamically adjusting the input signal. When the load changes, the feedback circuit can respond quickly and adjust the operating parameters of the two-stage DC-DC converter to keep the voltage stable. Although the overall efficiency of the two-stage DC-DC converter is high, effective heat dissipation design is still required. Each DC-DC converter component (especially the switch tube and inductor) will generate a certain amount of heat during operation, so a reasonable heat dissipation design is required to ensure the stable operation of the components. The heat dissipation design includes cooling methods such as heat sinks to ensure that the entire power system will not be damaged due to overheating when operating efficiently.

[0113] The design process of the voltage regulator based on the two-stage DC-DC circuit includes: first, the overall design of the system needs to be carried out, the input voltage, output voltage and load requirements are clarified, and the appropriate DC-DC converter topology (such as Buck-Boost structure, or two-stage Buck structure) is selected. Then, the schematic diagram is designed and the appropriate power stage components (such as MOSFET, inductor, feedback circuit, etc.) are selected. According to the design requirements, appropriate components are selected, including efficient switch tubes (MOSFET), low ESR capacitors, high-quality inductors, feedback control chips, etc. For the precision voltage regulation stage, high-precision voltage reference and control circuits need to be selected. Before the circuit is built, circuit simulation is performed to verify the feasibility of the design, adjust the circuit parameters, and optimize the efficiency, ripple, response time, etc. The simulation process should optimize the key parameters of the converter such as switching frequency, duty cycle, feedback loop, etc. to ensure the performance of the power supply system. After the circuit design and optimization are completed, the PCB (printed circuit board) is designed and produced. Reasonable layout and wiring are crucial to the stability and efficiency of the power supply system. Especially in high-frequency switching power supplies, strict electromagnetic compatibility (EMC) design is required to reduce noise interference. After assembly, preliminary system debugging is carried out to test the accuracy, stability, ripple, efficiency and other parameters of the output voltage. Through actual testing, various performance indicators are verified, and the working parameters of the power module are adjusted to ensure that it can work stably under different load and input voltage conditions. The system is subjected to load testing, temperature testing and long-term operation testing to ensure that the power system can continue to work stably under extreme conditions and meet the strict requirements of aerospace and other fields. At the same time, through test data analysis, the design is optimized to reduce power loss and further improve system efficiency.

[0114] The voltage regulator based on the two-stage DC-DC circuit provided in this application is a circuit for improving efficiency, pursuing low loss and high efficiency of the entire DC-DC circuit. The method for improving efficiency is reflected in the following aspects:

[0115] 1. Use synchronous rectification method and use SiC switch tube to replace traditional Si MOSFET to reduce the conduction loss of the switch tube.

[0116] 2. Use soft switching technology to reduce the impact of the Miller platform, use zero voltage switching, and reduce switching losses.

[0117] 3. Reasonable layout and routing to avoid the influence of parasitic parameters. Keep the high-frequency switching node as close as possible to the switch tube and filter capacitor to reduce the loss caused by parasitic inductance and capacitance.

[0118] 4. The sliding film control algorithm is used to control the second-level voltage. Compared with the traditional PID control algorithm, it can increase the robustness of the output voltage and speed up the response speed of the system, so that the output ripple is controlled at 0.5%. It increases the accuracy and stability of the system, especially for dealing with extreme temperatures and strong disturbances, making it more suitable for aerospace environments.

[0119] The voltage regulation device based on the two-stage DC-DC circuit provided in the present application adopts a two-stage DC-DC circuit. Since there are many limitations for a one-stage DC-DC circuit to achieve an output voltage adjustable from 0V, a two-stage circuit is adopted to increase the circuit adjustment range.

[0120] The key technical points of the voltage regulation device based on the two-stage DC-DC circuit provided by the present application are:

[0121] 1. The adjustable output voltage range starts from 0V;

[0122] The device can achieve continuous adjustable output voltage starting from 0V. Through precise control and adjustment, the system can provide a flexible output voltage range to adapt to different load requirements and meet the voltage regulation needs of high-precision occasions such as aerospace.

[0123] 2. Two-stage DC-DC modulation fine control;

[0124] The device uses a two-stage DC-DC converter, where:

[0125] The first stage DC-DC converter is responsible for coarse adjustment of the output voltage, providing a rough voltage adjustment range. The output voltage of the first stage is adjusted by adjusting the duty cycle, which is divided into five gears: 90%, 70%, 50%, 30% and 10%. According to the calculated ideal modulation ratio, select the appropriate duty cycle for coarse adjustment.

[0126] The second stage DC-DC converter is fine-tuned based on the voltage converted in the first stage. Its duty cycle is automatically adjusted by the sliding mode control method, ensuring higher output voltage accuracy, stability, and fast response to load changes.

[0127] The prior art uses LM117 as a linear regulator, whose output voltage is set by an internal reference voltage (1.25V) and an adjustment resistor, and usually can only provide a fixed output voltage adjustment. Specifically, the difference between the output voltage and the input voltage of the LM117 must meet certain conditions, and its adjustment range and control method are limited, and the output voltage is mainly set by changing the feedback resistor.

[0128] In addition, although single-stage DC-DC converters (such as Buck, Boost or Buck-Boost) can provide high-efficiency voltage conversion, they are insufficient in high-precision voltage control. Especially when precise high voltage output is required (such as high-voltage equipment in space missions), the accuracy and output stability of single-stage converters are often difficult to meet strict requirements. This accuracy problem usually manifests itself as voltage ripple, output voltage offset and other problems, which is an unacceptable defect for precision instruments and payload equipment in aerospace, because precise voltage control is the prerequisite for efficient measurement and accurate data acquisition.

[0129] This application adopts a two-stage DC-DC converter architecture. Compared with LM117, DC-DC converters, especially switch-mode DC-DC converters, provide higher flexibility and control capabilities. The first-stage buck converter reduces the input voltage to an appropriate intermediate voltage. The first-stage voltage conversion range is small, which helps to improve efficiency. The second-stage boost converter further accurately adjusts the output voltage to ensure accurate high-voltage output. Through a multi-stage structure, higher-precision voltage regulation can be achieved. The first-stage conversion and the second-stage high-precision output regulation enable the system to maintain a stable, high-precision output voltage over a wide load and wide input voltage range. Especially for aerospace applications that require extremely high voltage accuracy, this design can meet the needs of precision instruments for stable output.

[0130] 3. High-efficiency power conversion;

[0131] Through the optimized two-stage DC-DC architecture, the device significantly improves the power conversion efficiency. Under the condition of 24V input, 12V output and 1A load, the system conversion efficiency can reach 90.6%. Compared with the traditional linear regulator solution, it significantly reduces power loss, reduces heat generation, and improves the energy efficiency of the overall system, which is suitable for applications such as aerospace and deep space exploration that require high efficiency.

[0132] Traditional linear regulators (such as LM117) linearly reduce the input voltage to the required output voltage by adjusting the working state of the power transistor. Under high voltage and high current conditions (such as the high voltage power supply requirements in spacecraft), traditional linear regulators will cause a lot of energy waste, especially in space missions, due to energy constraints, low efficiency will directly affect the mission endurance and overall system thermal management.

[0133] This application adopts a two-stage DC-DC converter solution, using a high-efficiency conversion method of a switch mode to replace a linear regulator. In this device, the first-stage DC-DC converter uses a buck converter to reduce the input high voltage to a lower intermediate voltage, and the second-stage DC-DC converter uses a boost converter to accurately adjust the intermediate voltage to the required voltage (high voltage or low voltage). This can solve the problem that it is difficult for a first-stage DC-DC converter to adjust the output voltage from 0 volts, while also being able to output high voltage, achieve wide-range regulation, and effectively avoid energy waste caused by excessive voltage differences.

[0134] Compared with linear regulators, the efficiency of two-stage DC-DC converters is greatly improved. When the one-stage DC-DC converter outputs 1A input voltage of 24V and the output voltage is 12V, the test system efficiency is 95.6%, and the two-stage DC-DC converter efficiency is 90.1%. When a linear regulator (such as LM117) is used under the same circumstances, the efficiency is less than 50%. Therefore, the improved design can achieve an increase of more than 40% in efficiency, which can greatly solve the heat loss of aerospace power, especially when outputting low voltage and high current.

[0135] 4. Low voltage ripple;

[0136] Sliding mode control dynamically adjusts the approach and stability of the output voltage by constructing a sliding surface. Sliding mode control is used to quickly respond to changes in voltage ripple, limit the system deviation near the sliding surface, and prevent ripple amplification caused by load or input voltage disturbances. A smooth approach law (such as a saturation function) is used instead of a traditional sign function to avoid the deterioration of output ripple caused by high-frequency jitter. The dynamic performance of sliding mode control is better than that of the PID algorithm, and it responds faster to ripple disturbances. The dual closed-loop design overcomes the problem of PID's strong dependence on parameter adjustment and improves robustness in nonlinear and dynamic scenarios.

[0137] The two-stage DC-DC converter uses high-reliability components (such as high-temperature durable MOSFET, low-radiation inductor, etc.) and is designed with an optimized thermal management structure. It can maintain stable operation under extreme temperature, radiation and long-term working conditions, which makes it particularly suitable for missions such as aerospace, satellite and deep space exploration.

[0138] 5. Design simplification and cost optimization;

[0139] Simplified design: Compared with single-stage DC-DC or traditional linear regulators, the two-stage DC-DC design can reduce complex thermal management design while ensuring high efficiency. Since the power conversion efficiency of each stage of the two-stage DC-DC converter is high, the total power loss of the system can be greatly reduced. Although the initial cost of the two-stage DC-DC converter may be slightly higher, the energy-saving effect and system stability in long-term operation greatly reduce the cost of maintenance and thermal management. In space missions, it can reduce energy consumption and improve equipment reliability, which in turn leads to overall cost optimization.

[0140] The voltage regulator based on the two-stage DC-DC circuit provided in this application is suitable for the following products:

[0141] Spacecraft power supply system: ① Space exploration payload power supply: Provides stable high-voltage power supply for space probes (such as planetary probes, astronomical telescopes, space laboratories, etc.). For these devices, high precision, stability and efficiency of power supply are crucial, especially in long-term space missions. ② Satellite power management system: Provides high-voltage power supply with precise voltage for different subsystems of satellites to ensure the stable operation of various satellite systems (such as communications, control, scientific instruments, etc.). ③ Space mission control equipment: Provides stable and accurate high-voltage power supply for control systems, navigation equipment, instruments, etc. in space missions to ensure long-term stable operation of equipment.

[0142] High-voltage precision power supply module: ① Space instrument power supply: Provide high-precision, high-voltage power supply for various space instruments (such as scientific detection equipment, imaging systems, sensors, etc.) to ensure the stable operation of the instruments in complex environments. ② Space experiment equipment power supply: Provide efficient and stable high-voltage power supply for equipment conducting space experiments to ensure the accuracy of experimental data and the long-term stability of the equipment.

[0143] High-voltage power supply system (ground or laboratory application): ① Power supply for scientific research and experimental equipment: High-precision high-voltage power supply system can be used in high-energy physics experiments, medical equipment, precision industrial equipment and other occasions to provide precise voltage regulation. ② Power supply system for special environments: such as power supply system for equipment working in extreme temperature and high radiation environment.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application is described in detail with reference to the embodiments, a person skilled in the art should understand that any modification or equivalent replacement of the technical solution of the present application does not depart from the spirit and scope of the technical solution of the present application and should be included in the scope of the claims of the present application.

Claims

1. A voltage regulator based on a two-stage DC-DC circuit, characterized in that: include: A voltage acquisition module, a current acquisition module, a controller, a first-stage DC-DC converter, a second-stage DC-DC converter, a first drive circuit and a second drive circuit; wherein, The voltage acquisition module is used to collect the output voltage value and the target voltage signal output from the outside in real time; The current acquisition module is used to acquire the output current value in real time; The controller is used to receive the voltage value and the current value collected by the voltage collection module and the current collection module, and send control instructions to the first-stage DC-DC converter and the second-stage DC-DC converter to adjust the voltage through the first drive circuit and the second drive circuit respectively; The first-stage DC-DC converter is used to perform a first-stage regulation on the output voltage; The second-stage DC-DC converter is used to perform a second-stage adjustment on the voltage based on the adjustment by the first-stage DC-DC converter; The first driving circuit is used to drive the power switch tube of the first-stage DC-DC converter according to the duty cycle signal output by the controller; The second driving circuit is used to drive the power switch tube of the second-stage DC-DC converter according to the duty cycle signal output by the controller; The controller regulates the first-stage DC-DC converter by selecting a suitable first-stage DC-DC modulation duty cycle according to the calculated ideal modulation ratio; The controller regulates the second-stage DC-DC converter using a sliding mode control algorithm; The controller regulates the second-stage DC-DC converter by: Calculation of sliding surface by error and disturbance estimation : ； in, Represents the voltage error, represents the target voltage, Represents the sampled output voltage; Represents the design parameters of the sliding surface, which is used to adjust the dynamic response of the system; It represents the disturbance estimation term, which compensates for the influence of external disturbance on the system; t Indicates time; Design of synovial film control law : ； in, represents the switching gain of the sliding mode controller, which is used to suppress disturbances; represents the sliding mode switching function; represents the disturbance estimation term; represents the system parameters, which are used to normalize the control input; represents the rate of change of the disturbance estimate; Calculate the feedforward term And add it to the PI controller to get the voltage regulation of the D axis ,Will Output to PWM: ； in, Indicates the input reference signal of the D axis; Indicates the system switching frequency; Indicates the inductance value; represents the D-axis current, i.e., the steady-state component; and Indicates the PI controller parameters of the D axis; Indicates the current error of the D-axis.

2. The voltage regulating device based on the two-stage DC-DC circuit according to claim 1, characterized in that: The controller regulates the first-stage DC-DC converter by: The duty cycle adjustment gear of the first-stage DC-DC converter is divided into n gears; Calculate the first stage duty cycle = output voltage ÷ (input voltage × second stage DC-DC converter duty cycle setting value); The smallest gear among the n gears that is greater than the first-stage duty cycle is selected as the adjustment gear for the duty cycle of the first-stage DC-DC converter.

3. The voltage regulating device based on the two-stage DC-DC circuit according to claim 2, characterized in that: The n is 5; The five duty cycle adjustment gears of the first-stage DC-DC converter are 90%, 70%, 50%, 30% and 10% respectively.

4. The voltage regulating device based on the two-stage DC-DC circuit according to claim 2, characterized in that: The duty cycle setting value of the second-stage DC-DC converter is 90%.

5. The voltage regulating device based on the two-stage DC-DC circuit according to claim 1, characterized in that: The voltage acquisition module adopts MCP6022.

6. The voltage regulating device based on the two-stage DC-DC circuit according to claim 1, characterized in that: The controller adopts STM32 single chip microcomputer.

7. The voltage regulating device based on the two-stage DC-DC circuit according to claim 1, characterized in that: The first driving circuit and the second driving circuit adopt a half-bridge driver IR2104.

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