DCDC voltage conversion device

Abstract

The utility model discloses a DCDC voltage conversion device, and relates to the technical field of power supplies, the DCDC voltage conversion device comprises an undervoltage / overvoltage protection circuit, a low-voltage conversion circuit and a dead time control circuit, the low-voltage conversion circuit comprises an inverter circuit, a transformer, a rectification circuit and a pi-type filter circuit, the under-voltage / over-voltage protection circuit judges whether the magnitude of the high-voltage direct current meets a preset condition or not; if yes, triggering a protection circuit; if not, inputting the high-voltage direct current into the inverter circuit; the inverter circuit converts high-voltage direct current into alternating current, the transformer reduces voltage of the alternating current to obtain low-voltage alternating current, the rectifying circuit rectifies the low-voltage alternating current into low-voltage direct current, and the pi-type filter circuit suppresses circuit ripples in the low-voltage direct current to obtain low-voltage output signals. And the dead time control circuit is used for adjusting the dead time of the power devices in the working state in the inverter circuit and the rectifying circuit. According to the invention, the stability and safety of the DCDC conversion device are improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of power supply, in particular to a DCDC voltage conversion device. BACKGROUND

[0002] At present, the DCDC voltage conversion device is faced with the problem of low conversion efficiency, and low efficiency is usually accompanied by high heat loss, thereby causing system overheating, power waste and even affecting the long-term stability of the equipment. In addition, many conventional DCDC conversion devices also face the problems of stability and safety. In the scene of rapid load change, the traditional DCDC converter is often difficult to achieve rapid and smooth response, and load mutation can cause large output voltage fluctuation, affecting the stability of the system, and one of the more important influencing factors is the opening time of the synchronous rectifier tube. In addition, for the traditional DCDC conversion device, single overcurrent or overtemperature protection can only solve some basic faults, and the protection mechanism responds slowly, which is easy to cause equipment damage or unstable operation. Therefore, it is necessary to set a reliable protection mechanism to alarm and take measures in time when a fault occurs, so as to protect the safety of equipment and personnel.

[0003] Therefore, it is necessary to provide a DCDC voltage conversion device to solve the above problems. CONTENT OF THE INVENTION

[0004] The application aims to provide a DCDC voltage conversion device, which improves the stability and safety of the DCDC conversion device.

[0005] To achieve the above-mentioned purpose, the application provides the following solutions.

[0006] The application provides a DCDC voltage conversion device, which comprises an under-voltage / over-voltage protection circuit, a low-voltage conversion circuit and a dead time control circuit, wherein the low-voltage conversion circuit comprises an inverter circuit, a transformer, a rectifier circuit and a pi-type filter circuit.

[0007] The under-voltage / over-voltage protection circuit, the inverter circuit, the transformer, the rectifier circuit and the pi-type filter circuit are connected in sequence, the under-voltage / over-voltage protection circuit is connected with a high-voltage direct-current power supply, and the dead time control circuit is connected with power devices in the inverter circuit and the rectifier circuit respectively.

[0008] The under-voltage / over-voltage protection circuit is configured to detect the size of high-voltage direct current output by a high-voltage direct current power supply, determine whether the size of the high-voltage direct current meets a corresponding preset condition, trigger a corresponding protection circuit if yes, and input the high-voltage direct current to the inverter circuit if no.

[0009] The inverter circuit is configured to convert the input high-voltage direct current into alternating current.

[0010] The transformer is configured to step down the conversion of the alternating current to obtain low-voltage alternating current.

[0011] The rectifier circuit is configured to rectify the low-voltage alternating current into low-voltage direct current.

[0012] The π-type filter circuit is configured to suppress circuit ripple in the low-voltage direct current to obtain a low-voltage output signal.

[0013] The dead-time control circuit is configured to adjust the dead time of power devices in the inverter circuit and the rectifier circuit that are in an operating state.

[0014] Optionally, the under-voltage / over-voltage protection circuit comprises a bias circuit, a voltage protection circuit, a resistance voltage dividing circuit, and a comparator circuit, and the comparator circuit comprises a first comparator circuit and a second comparator circuit.

[0015] The first end of the bias circuit is connected to an input current, the second end of the bias circuit is connected to one end of the voltage protection circuit, the third end of the bias circuit is connected to the first end of the resistance voltage dividing circuit, the second end of the resistance voltage dividing circuit is connected to the first comparator circuit, and the third end of the resistance voltage dividing circuit is connected to the second comparator circuit.

[0016] Optionally, the inverter circuit is a high-frequency single-phase inverter bridge.

[0017] Optionally, the high-frequency single-phase inverter bridge comprises a first power tube, a second power tube, a third power tube, and a fourth power tube.

[0018] The collector of the first power tube is connected to the under-voltage / over-voltage protection circuit and the collector of the third power tube, the emitter of the first power tube is connected to the collector of the second power tube and the first end of the transformer, the emitter of the second power tube is connected to the under-voltage / over-voltage protection circuit and the emitter of the fourth power tube, and the emitter of the third power tube is connected to the collector of the fourth power tube and the second end of the transformer.

[0019] Optionally, the rectifier circuit is a high-frequency rectifier bridge.

[0020] Optionally, the high-frequency rectifier bridge comprises a first diode, a second diode, a third diode and a fourth diode.

[0021] The first end of the first diode is connected with the third end of the transformer, the second end of the first diode is connected with the first end of the third diode, the first end of the second diode is connected with the third end of the transformer, the second end of the second diode is connected with the first end of the fourth diode, the first end of the third diode is further connected with the π-type filter circuit, the second end of the third diode is connected with the fourth end of the transformer, and the second end of the fourth diode is connected with the second end of the second diode and the π-type filter circuit respectively.

[0022] Optionally, the π-type filter circuit comprises a water-cooled filter inductor, a first capacitor, a second capacitor and a first resistor.

[0023] The first capacitor, the second capacitor and the first resistor are connected in parallel, the first end of the water-cooled filter inductor is connected with the first end of the third diode, the second end of the water-cooled filter inductor is connected with the first end of the first capacitor, the first end of the second capacitor and the first end of the first resistor respectively, and the second end of the fourth diode is connected with the second end of the first capacitor, the second end of the second capacitor and the second end of the first resistor respectively.

[0024] Optionally, the dead-time control circuit comprises an NOR gate, an NAND gate and a first inverter chain and a second inverter chain.

[0025] The first end of the NOR gate is connected with the first end of the NAND gate, the second end of the NOR gate is connected with the first end of the second inverter chain, the third end of the NOR gate is connected with the first end of the first inverter chain, the second end of the NAND gate is connected with the second end of the first inverter chain, the third end of the NAND gate is connected with the second end of the second inverter chain, the second end of the first inverter chain is connected with the first power tube, the second power tube, the third power tube or the fourth power tube, and the first end of the second inverter chain is connected with the first end of the first inverter chain and the first power tube, the second power tube, the third power tube or the fourth power tube.

[0026] Optionally, the first inverter chain comprises a first inverter, a second inverter and a third inverter, and the second inverter chain comprises a fourth inverter, a fifth inverter and a sixth inverter.

[0027] The first end of the first inverter is the first end of the first inverter chain, the second end of the third inverter is the second end of the first inverter chain, the first end of the first inverter is connected with the second end of the NOR gate, and the second end of the third inverter is connected with the second end of the NAND gate.

[0028] The first end of the fourth inverter is the second end of the second inverter chain, the second end of the sixth inverter is the first end of the second inverter chain, the first end of the fourth inverter is connected with the third end of the NAND gate, and the second end of the sixth inverter is connected with the second end of the NOR gate.

[0029] Optionally, the transformer is a water-cooled high-frequency transformer.

[0030] According to the specific embodiments provided in the application, the application has the following technical effects:

[0031] The application discloses a DCDC voltage conversion device, which comprises an under-voltage / over-voltage protection circuit, a low-voltage conversion circuit and a dead time control circuit, wherein the low-voltage conversion circuit comprises an inverter circuit, a transformer, a rectifier circuit and a pi-type filter circuit. Firstly, the application sets up a multiple protection mechanism by setting up the under-voltage / over-voltage protection circuit, thereby improving the stability of the circuit; secondly, the application suppresses the ripple of the low-voltage output signal by setting up the low-voltage conversion circuit, thereby improving the stability of the circuit; finally, the application sets up the dead time control circuit, accurately controls the opening time of the synchronous rectifier tube, reduces the loss and output waveform distortion, and further improves the stability and safety. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0033] Figure 1 The figure is a functional module schematic diagram of the DCDC voltage conversion device in an embodiment of the application.

[0034] Figure 2 The figure is a principle schematic diagram of the under-voltage / over-voltage protection circuit provided in an embodiment of the application.

[0035] Figure 3 The figure is a low-voltage conversion circuit schematic diagram provided in an embodiment of the application.

[0036] Figure 4 The figure is a low-voltage conversion circuit principle diagram provided in an embodiment of the application.

[0037] Figure 5 The figure is a dead time control circuit schematic diagram provided in an embodiment of the application.

[0038] Reference signs:

[0039] The under-voltage / over-voltage protection circuit 1, the low-voltage conversion circuit 2, the inverter circuit 21, the transformer 22, the rectifier circuit 23, the π-type filter circuit 24, and the dead-time control circuit 3. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0041] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0042] In one exemplary embodiment, as shown in Figure 1 a DCDC voltage conversion device is provided, comprising: an under-voltage / over-voltage protection circuit 1, a low-voltage conversion circuit 2, and a dead-time control circuit 3, the low-voltage conversion circuit comprising: an inverter circuit 21, a transformer 22, a rectifier circuit 23, and a π-type filter circuit 24.

[0043] The under-voltage / over-voltage protection circuit 1, the inverter circuit 21, the transformer 22, the rectifier circuit 23, and the π-type filter circuit 24 are connected in sequence, the under-voltage / over-voltage protection circuit 1 is connected with a high-voltage DC power supply, and the dead-time control circuit 3 is connected with power devices in the inverter circuit 21 and the rectifier circuit 23, respectively.

[0044] The under-voltage / over-voltage protection circuit 1 is configured to detect the size of high-voltage DC power output by the high-voltage DC power supply, determine whether the size of the high-voltage DC power meets a corresponding preset condition, trigger a corresponding protection circuit if yes, and input the high-voltage DC power to the inverter circuit 21 if no. The protection circuit comprises an over-voltage protection circuit or an under-voltage lockout circuit, the preset condition is that the high-voltage DC power is less than a first preset threshold or the high-voltage DC power is greater than a second preset threshold, and the second preset threshold is greater than the first preset threshold.

[0045] The inverter circuit 21 is configured to convert the input high-voltage DC power into alternating current.

[0046] The transformer 22 is configured to step down the conversion of the alternating current to obtain low-voltage alternating current.

[0047] The rectifier circuit 23 is configured to rectify the low-voltage alternating current into low-voltage direct current.

[0048] The pi-type filter circuit 24 is used for suppressing circuit ripple in low-voltage direct current to obtain a low-voltage output signal.

[0049] The dead-time control circuit 3 is used for adjusting the dead time of power devices in working state in the inverter circuit 21 and the rectifier circuit 23.

[0050] Specifically, high-voltage direct current is input to the low-voltage conversion circuit 2 after being stabilized by the under-voltage / over-voltage protection circuit 1. The inverter circuit 21 converts the input high-voltage direct current into alternating current, which is input to the rectifier circuit 23 through the transformer 22. The rectifier circuit 23 rectifies the alternating current input through the transformer 22 into low-voltage direct current, which is stabilized after being suppressed by the circuit ripple by the pi-type filter circuit 24, so as to obtain a stable low-voltage output signal. The dead-time control circuit 3 can adjust the dead time of power devices (MOS tube or diode) in the inverter circuit 21 and the rectifier circuit 23, so as to reduce the dead-time loss.

[0051] The pi-type filter adopted in the present application is mainly used for suppressing or attenuating signals in a specific frequency range. The RC-type pi-type filter adopted in the present application has the following basic working principle: for low-frequency signals, the inductive element has a high impedance, resulting in that the low-frequency signals are isolated by the inductive element, while the capacitive element has a low impedance to the low-frequency signals, so that the low-frequency signals bypass the entire filter through the capacitive element; for high-frequency signals, the inductive element has a low impedance to the high-frequency signals, so that the high-frequency signals can pass through the inductive element, while the capacitive element has a high impedance to the high-frequency signals, so as to prevent the high-frequency signals from continuing to pass. The pi-type filter has the advantages of simple structure, low cost, effective filtering characteristics, good impedance matching effect, high stability and the like in actual application scenarios.

[0052] As an optional implementation manner, as shown in Figure 2 The under-voltage / over-voltage protection circuit 1 includes a bias circuit, a voltage protection circuit, a resistance voltage dividing circuit and a comparator circuit. The comparator circuit includes a first comparator circuit (such as the comparator A circuit in Figure 2 ) and a second comparator circuit (such as the comparator B circuit in Figure 2 ).

[0053] The first end of the bias circuit is connected to an input current, the second end of the bias circuit is connected to one end of the voltage protection circuit, the third end of the bias circuit is connected to the first end of the resistance voltage dividing circuit, the second end of the resistance voltage dividing circuit is connected to the first comparator circuit, and the third end of the resistance voltage dividing circuit is connected to the second comparator circuit.

[0054] Specifically, the chip of the DCDC voltage conversion device has a great influence on the stability of the chip when the chip is working normally. If the input voltage is too low, the working state of the sub-modules in the chip is uncertain, and even some modules do not work. If the input voltage is too high, the electronic components in the sub-modules in the chip will be damaged when the voltage exceeds the withstand voltage of the electronic components, so that the circuit cannot work normally. Therefore, the reliability and stability of the power supply play a crucial role in the normal work of the chip. Based on this, the under-voltage / over-voltage protection circuit 1 is designed, that is, the under-voltage / over-voltage protection circuit 1 is used to suppress the fluctuation of the input voltage and prevent the chip from being damaged due to the fluctuation of the input voltage. The principle diagram of the under-voltage / over-voltage protection circuit 1 is shown in Figure 2 e where I e is the input current; M1, M2, and M3 are MOS tubes; R1, R2, and R3 are voltage dividing resistors; V1 is a reference high voltage, and V2 is a reference low voltage.

[0055] The working principle of the over-voltage / under-voltage protection circuit is as follows: (1) Bias circuit: the bias current is provided by the current reference circuit and is mirrored to other branches through the current mirror structure to provide bias current and bias voltage for the comparator circuit. (2) Resistance voltage dividing circuit: when the circuit is powered on, the resistance voltage dividing circuit divides the voltage and compares it with the reference voltage in the over-voltage / under-voltage protection circuit, and outputs to the control chip. In order to reduce the power consumption of the entire circuit, a large resistance value resistor needs to flow through a small current on the resistance voltage dividing circuit, but a large resistance value resistor will occupy a large area on the layout. Therefore, in the circuit design, the problem of power consumption and area needs to be considered.

[0056] As an optional implementation, the inverter circuit 21 is a high-frequency single-phase inverter bridge.

[0057] As an optional implementation, as shown in Figure 3 , the high-frequency single-phase inverter bridge includes a first power tube Q1, a second power tube Q2, a third power tube Q3, and a fourth power tube Q4.

[0058] The collector of the first power tube is connected with the under-voltage / over-voltage protection circuit 1 and the collector of the third power tube respectively, the emitter of the first power tube is connected with the collector of the second power tube and the first end of the transformer 22L1 respectively, the emitter of the second power tube is connected with the under-voltage / over-voltage protection circuit 1 and the emitter of the fourth power tube respectively, and the emitter of the third power tube is connected with the collector of the fourth power tube and the second end of the transformer 22L1 respectively.

[0059] As an optional embodiment, the rectifier circuit 23 is a high-frequency rectifier bridge.

[0060] As an optional embodiment, as shown in Figure 3 the high-frequency rectifier bridge comprises a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4.

[0061] The first end of the first diode is connected with the third end of the transformer 22, the second end of the first diode is connected with the first end of the third diode, the first end of the second diode is connected with the third end of the transformer 22, the second end of the second diode is connected with the first end of the fourth diode, the first end of the third diode is also connected with the π-type filter circuit 24, the second end of the third diode is connected with the fourth end of the transformer 22, and the second end of the fourth diode is connected with the second end of the second diode and the π-type filter circuit 24 respectively.

[0062] As an optional embodiment, the π-type filter circuit 24 comprises a water-cooled filter inductor Lz, a first capacitor C1, a second capacitor C2 and a first resistor Rz.

[0063] The first capacitor, the second capacitor and the first resistor are connected in parallel, the first end of the water-cooled filter inductor is connected with the first end of the third diode, the second end of the water-cooled filter inductor is connected with the first end of the first capacitor, the first end of the second capacitor and the first end of the first resistor respectively, and the second end of the fourth diode is connected with the second end of the first capacitor, the second end of the second capacitor and the second end of the first resistor respectively.

[0064] Specifically, for the DCDC voltage conversion device, since the low-voltage output is usually formed through AC rectification, voltage stabilization and other links, some AC components are inevitably brought in the DC, thereby causing a certain ripple in the DC stability, the existence of the ripple will affect the quality of the low-voltage current output, increase the additional loss, reduce the power efficiency, and also affect the normal work of the circuit and other devices, so the ripple of the low-voltage output part must be suppressed as much as possible to reduce its negative impact, therefore, the low-voltage conversion circuit 2 ripple rate optimization design is adopted in the application, the target is to make the low-voltage output end voltage ripple rate not greater than 3%, and the device maximum ripple state is designed, that is, when the 50% duty cycle is the state conversion condition, through optimization calculation, the capacitor, inductor and other devices of the stable voltage are reasonably selected, and the ripple is suppressed to an acceptable range. The schematic diagram of the low-voltage conversion circuit 2 is shown in Figure 3 , and the circuit principle diagram is shown in Figure 4 , wherein S1-S4 jointly constitute a high-frequency single-phase inverter bridge, L 1A , L 1B , L 2A , L 2B and Rm, Lm constitute a water-cooled high-frequency transformer 22, K1-K4 jointly constitute a high-frequency rectifier bridge, Lz is a water-cooled filter inductor, and C1, C2 and Rz constitute a π-type filter circuit 24 to realize circuit ripple suppression. The high-voltage DC is converted into AC through the alternate on-off of the switching tubes S1, S4 and S2, S3.

[0065] As an optional implementation manner, as shown in Figure 5 , the dead time control circuit 3 comprises an NOR gate, an NAND gate, a first inverter chain and a second inverter chain.

[0066] The first end of the NOR gate is connected with the first end of the NAND gate, the second end of the NOR gate is connected with the first end of the second inverter chain, the third end of the NOR gate is connected with the first end of the first inverter chain, the second end of the NAND gate is connected with the second end of the first inverter chain, the third end of the NAND gate is connected with the second end of the second inverter chain, the second end of the first inverter chain is connected with the first power tube, the second power tube, the third power tube or the fourth power tube, and the first end of the second inverter chain is connected with the first power tube, the second power tube, the third power tube or the fourth power tube.

[0067] As an optional implementation manner, the first inverter chain comprises a first inverter, a second inverter and a third inverter, and the second inverter chain comprises a fourth inverter, a fifth inverter and a sixth inverter.

[0068] The first end of the first inverter is the first end of the first inverter chain, the second end of the third inverter is the second end of the first inverter chain, the first end of the first inverter is connected with the second end of the NOR gate, and the second end of the third inverter is connected with the second end of the NAND gate.

[0069] The first end of the fourth inverter is the second end of the second inverter chain, the second end of the sixth inverter is the first end of the second inverter chain, the first end of the fourth inverter is connected with the third end of the NAND gate, and the second end of the sixth inverter is connected with the second end of the NOR gate.

[0070] Specifically, the dead time control is an important means to prevent MOSFET or IGBT shoot-through in power converters, which ensures that the upper and lower bridge arms will not be turned on at the same time due to switching delay. The setting of the dead time needs to balance the system reliability and the output waveform quality, which is usually in the order of microseconds. Dynamic adjustment of the dead time can reduce the conduction time of the body diode, suppress the ringing phenomenon, and improve the efficiency. In practical applications, appropriate dead time should be set according to the characteristics of power elements to ensure safety and optimize performance. The dead time control circuit 3 reduces the loss of the power switch driving circuit by adjusting the size of the dead time. If the dead time is set too long, although the power switch driving circuit works more stably and has less power consumption, the efficiency of the power switch will decrease, resulting in output waveform distortion; if the dead time is set too short, the conduction time of the upper and lower bridge arms overlaps, which is easy to cause loss.

[0071] Therefore, the application adopts staggered delay dead time control as the synchronous rectification dead time control method. The staggered delay dead time is realized by an inverter chain to control the dead time. The optimal dead time is when the voltage of the switching node (i.e. the point where the inductor is connected to the power tube) drops to zero, the synchronous rectifier (i.e. the first diode D1, the second diode D2, the third diode D3 or the fourth diode D4) is turned on, and the power tube (i.e. the first power tube Q1, the second power tube Q2, the third power tube Q3 or the fourth power tube Q4) is completely turned off without dead time loss. This is because the synchronous rectifier is turned on after the end of the dead time, which can be turned on when the voltage of the switching node drops to zero. At this time, since the power switch has been completely turned off, the current of the switching node no longer flows, so the synchronous rectifier will not produce cross-conduction loss when it is turned on, and will not conflict with the power switch.

[0072] The schematic diagram of the dead time control circuit 3 is shown in Figure 5 . The dead time control circuit 3 mainly realizes the dead time through staggered delay and the delay characteristics of the gate circuit, and the working principle is as follows: assuming that the states of M P and M N are M P is turned on, and M NWhen the PWM signal changes from low to high, since point P is initially low, after passing through the NAND gate and inverter chain, point N's potential remains low. N The tube remains closed, but the signal fed back from point N, after passing through a NOR gate in the previous branch, outputs a low level, while the output at point P is high. P When the rectifier diode is turned off, the potential at point P is transmitted to the next branch through the feedback loop. At this time, the inputs of the NAND gates in the next branch are all high. After passing through the inverter chain, the voltage at point N is high, and the rectifier diode is turned on. The change in the voltage state at point N occurs after the change at point P, and the delay time is approximately the sum of the propagation delays of the three inverters and the NAND gates. Similarly, when the PWM signal changes from high to low, the delay time is approximately the sum of the propagation delays of the three inverters and the NOR gates.

[0073] Furthermore, the electrical interfaces of the DC-DC voltage conversion device of this application mainly include a high-voltage interface and a low-voltage interface. The high-voltage interface mainly includes a DC high-voltage input interface, and the low-voltage interface includes a low-voltage output interface, a low-voltage power supply, and a CAN communication interface. All electrical cables are high-temperature shielded cables. The DC-DC voltage conversion device of this application has a power distribution interface, and all output ports can be controlled to switch on and off via a bus. It also has a CAN communication interface and the ability to supply power to the vehicle's low-voltage system using a high-voltage power battery.

[0074] A problem with traditional DC-DC voltage converters is their low level of intelligence, lacking flexible debugging and remote control functions. When problems occur, technicians are required to debug on-site, a process that relies on manual operation and makes real-time monitoring of the equipment's operating status impossible. This application, however, provides remote debugging, status monitoring, and parameter setting functions by supporting communication interfaces such as UART / I2C / SPI, greatly enhancing the system's controllability and intelligence, and facilitating remote maintenance and adjustment. Furthermore, some traditional DC-DC converters are designed primarily for specific applications, such as supporting only fixed input and output voltage ranges, lacking flexibility and versatility. This application, through multiple control modes (PWM, PFM) and adjustable operating parameters, adapts to a wider range of application scenarios, allowing for flexible adjustment according to actual needs, providing better adaptability and functional expandability.

[0075] The DC-DC voltage converter in this application also includes software programming, which uses digital control methods to precisely regulate the voltage and current of the converter and provides protection functions to ensure stable and reliable operation of the system under various operating conditions. The main functions included in the software program are as follows:

[0076] 1) Main control function: Using PID control algorithm, calculate adjustment output according to the difference between set value and feedback signal, adjust PWM duty cycle in real time, ensure output voltage stable at set value.

[0077] 2) Feedback sampling function: Collect output voltage, current and temperature signals through ADC (Analog-to-Digital Converter), monitor system status in real time, provide data support for control algorithm.

[0078] 3) PWM modulation function: According to the duty cycle output by control algorithm, generate corresponding PWM signal, used to drive power switch (such as MOSFET), adjust energy transmission.

[0079] 4) Protection mechanism function: Monitor input signal, when detecting overvoltage, overcurrent, short circuit or overtemperature, etc. Abnormal conditions, trigger protection action immediately, such as turning off output or alarm.

[0080] 5) Communication interface function: Through UART / I2C / SPI interface, realize data interaction with external controller, display or monitoring system, support remote debugging, parameter setting and status monitoring.

[0081] The specific steps of the flow of the software program design part of the DCDC voltage conversion device of the application are as follows:

[0082] 1) System initialization: After system power on, initialize each hardware module (such as ADC, PWM, communication interface, etc.), and set related parameters, such as PID Kp, Ki, Kd value, protection threshold, etc.

[0083] 2) Main loop starts: The core part of the program, repeatedly execute control and protection logic to realize real-time adjustment and monitoring.

[0084] 3) Feedback sampling module: Sample voltage, current, temperature, read ADC data, provide for PID controller, digital filter processing can reduce sampling noise, improve control precision.

[0085] 4) Control algorithm execution (PID): Calculate error according to current feedback value and set value, generate duty cycle, adjust output through PID algorithm, maintain set voltage.

[0086] 5) PWM duty cycle update: Update the duty cycle set value output by PID control to PWM module, used to control MOSFET switching.

[0087] 6) Protection mechanism check: According to the set protection condition, monitor system status (test overvoltage, overcurrent, short circuit, etc.), return to main loop when in normal state; When an abnormality occurs, trigger protection circuit (turn off output, etc.), avoid damaging equipment.

[0088] 7) Communication and data interaction module: communicate with external control devices or monitoring systems, transmit system status and receive control instructions, realize remote management.

[0089] 8) End of main loop, return.

[0090] The beneficial effects of the present application are:

[0091] 1) The DCDC voltage conversion device of the present application has high-efficiency electrical design and optimized performance. An isolation design is adopted to adapt to high-low voltage conversion and signal control requirements, while the electrical element layout is optimized to ensure system insulation characteristics and electromagnetic interference suppression capability. The low-voltage circuit is designed with a ripple rate optimization (target ripple rate ≤ 3%), combined with water-cooled high-frequency transformer 22, π-type filter circuit 24, etc., to ensure the stability and high quality of the output voltage. High-performance MOSFET and synchronous rectification technology are used, combined with multiple control methods (PWM, PFM), to achieve conversion efficiency of more than 90% and low heat loss.

[0092] 2) The DCDC voltage conversion device of the present application has comprehensive protection and safety mechanisms. The DCDC voltage conversion device of the present application is equipped with total positive and total negative insulation real-time state monitoring function, which triggers alarm and processing measures when the system insulation decreases, ensuring the safety of equipment and personnel. The under-voltage / over-voltage protection circuit 1 realizes the suppression of input voltage fluctuation through bias circuit, resistance voltage dividing circuit and comparator circuit, and balances power consumption and area in the design. The dead time control uses staggered delay technology to accurately control the opening time of the synchronous rectification tube, reducing loss and output waveform distortion, further improving stability and safety.

[0093] 3) The DCDC voltage conversion device of the present application has the characteristics of intelligent software control and high degree of functional integration. The device realizes accurate regulation of voltage and current through digital control, and the core functions include PID control, real-time feedback sampling, PWM signal modulation and various protection mechanisms (overvoltage, overcurrent, short circuit, overtemperature, etc.). It supports UART / I2C / SPI communication interfaces, provides remote debugging, state monitoring and parameter setting functions, and enhances the intelligence and controllability of the system. The software design process is rigorous, including hardware initialization, real-time regulation main loop and protection mechanism check, to ensure stable and reliable operation of the system under various working conditions.

[0094] The technical features of the above embodiments can be combined in any way. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the present disclosure.

[0095] The principles and implementations of the present application are described in the specific examples in this article, and the above examples are only used to help understand the device and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation and application range will be changed. Therefore, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A DCDC voltage conversion device, characterized by, The DCDC voltage conversion device comprises an under-voltage / over-voltage protection circuit, a low-voltage conversion circuit and a dead time control circuit, wherein the low-voltage conversion circuit comprises an inverter circuit, a transformer, a rectifier circuit and a pi filter circuit; The under-voltage / over-voltage protection circuit, the inverter circuit, the transformer, the rectifier circuit and the pi filter circuit are sequentially connected, the under-voltage / over-voltage protection circuit is connected with a high-voltage direct-current power supply, and the dead time control circuit is connected with power devices in the inverter circuit and the rectifier circuit respectively; The under-voltage / over-voltage protection circuit is used for detecting the size of high-voltage direct-current electricity output by the high-voltage direct-current power supply, judging whether the size of the high-voltage direct-current electricity meets a corresponding preset condition, triggering a corresponding protection circuit if yes, and inputting the high-voltage direct-current electricity into the inverter circuit if no; the protection circuit comprises an over-voltage protection circuit or an under-voltage locking circuit, the preset condition is that the high-voltage direct-current electricity is less than a first preset threshold or the high-voltage direct-current electricity is greater than a second preset threshold, and the second preset threshold is greater than the first preset threshold; The inverter circuit is used for converting the input high-voltage direct-current electricity into alternating current electricity; The transformer is used for reducing the voltage of the alternating current electricity conversion to obtain low-voltage alternating current electricity; The rectifier circuit is used for rectifying the low-voltage alternating current electricity into low-voltage direct-current electricity; The pi filter circuit is used for suppressing circuit ripple in the low-voltage direct-current electricity to obtain a low-voltage output signal; The dead time control circuit is used for adjusting the dead time of power devices in the inverter circuit and the rectifier circuit in a working state.

2. The DCDC voltage conversion device according to claim 1, characterized in that, The under-voltage / over-voltage protection circuit comprises a bias circuit, a voltage protection circuit, a resistance voltage dividing circuit and a comparator circuit, and the comparator circuit comprises a first comparator circuit and a second comparator circuit; The first end of the bias circuit is connected with an input current, the second end of the bias circuit is connected with one end of the voltage protection circuit, the third end of the bias circuit is connected with the first end of the resistance voltage dividing circuit, the second end of the resistance voltage dividing circuit is connected with the first comparator circuit, and the third end of the resistance voltage dividing circuit is connected with the second comparator circuit.

3. The DCDC voltage conversion device according to claim 2, characterized in that, The inverter circuit is a high-frequency single-phase inverter bridge.

4. The DCDC voltage conversion device according to claim 3, characterized in that, The high-frequency single-phase inverter bridge comprises a first power tube, a second power tube, a third power tube and a fourth power tube; The collector of the first power tube is connected with the collector of the third power tube and the under-voltage / over-voltage protection circuit, the emitter of the first power tube is connected with the collector of the second power tube and the first end of the transformer, the emitter of the second power tube is connected with the emitter of the fourth power tube and the under-voltage / over-voltage protection circuit, and the emitter of the third power tube is connected with the collector of the fourth power tube and the second end of the transformer.

5. The DCDC voltage conversion device according to claim 4, characterized in that, The rectifier circuit is a high-frequency rectifier bridge.

6. The DCDC voltage conversion device according to claim 5, characterized in that, The high-frequency rectifier bridge comprises a first diode, a second diode, a third diode and a fourth diode. The first end of the first diode is connected with the third end of the transformer, the second end of the first diode is connected with the first end of the third diode, the first end of the second diode is connected with the third end of the transformer, the second end of the second diode is connected with the first end of the fourth diode, the first end of the third diode is also connected with the π-type filter circuit, the second end of the third diode is connected with the fourth end of the transformer, and the second end of the fourth diode is connected with the second end of the second diode and the π-type filter circuit respectively.

7. The DCDC voltage conversion device according to claim 6, characterized in that, The π-type filter circuit comprises a water-cooled filter inductor, a first capacitor, a second capacitor and a first resistor. The first capacitor, the second capacitor and the first resistor are connected in parallel, the first end of the water-cooled filter inductor is connected with the first end of the third diode, the second end of the water-cooled filter inductor is connected with the first end of the first capacitor, the first end of the second capacitor and the first end of the first resistor respectively, and the second end of the fourth diode is connected with the second end of the first capacitor, the second end of the second capacitor and the second end of the first resistor respectively.

8. The DCDC voltage conversion device according to claim 7, characterized in that, The dead time control circuit comprises an NOR gate, an NAND gate, a first inverter chain and a second inverter chain. The first end of the NOR gate is connected with the first end of the NAND gate, the second end of the NOR gate is connected with the first end of the second inverter chain, the third end of the NOR gate is connected with the first end of the first inverter chain, the second end of the NAND gate is connected with the second end of the first inverter chain, the third end of the NAND gate is connected with the second end of the second inverter chain, the second end of the first inverter chain is connected with the first power tube, the second power tube, the third power tube or the fourth power tube, and the first end of the second inverter chain is connected with the first power tube, the second power tube, the third power tube or the fourth power tube.

9. The DCDC voltage conversion device according to claim 8, characterized in that, The first inverter chain comprises a first inverter, a second inverter and a third inverter, and the second inverter chain comprises a fourth inverter, a fifth inverter and a sixth inverter. The first end of the first inverter is the first end of the first inverter chain, the second end of the third inverter is the second end of the first inverter chain, the first end of the first inverter is connected with the second end of the NOR gate, and the second end of the third inverter is connected with the second end of the NAND gate. The first end of the fourth inverter is the second end of the second inverter chain, the second end of the sixth inverter is the first end of the second inverter chain, the first end of the fourth inverter is connected with the third end of the NAND gate, and the second end of the sixth inverter is connected with the second end of the NOR gate.

10. The DCDC voltage conversion device according to claim 1, characterized in that, The transformer is a water-cooled high-frequency transformer.

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