Voltage conversion circuit with wide voltage range and strategy switching method

Abstract

The embodiment of the invention provides a voltage conversion circuit with a wide voltage range and a strategy switching method, the method comprises a first-stage conversion module, a transformer and a second-stage conversion module, and the second-stage conversion module at least comprises a first switching unit and a second switching unit. According to the voltage switching strategy, the first switching unit and the second switching unit are controlled to be switched on and switched off, the input voltage is converted, a target voltage value is obtained, the first switching unit and the second switching unit in the second-stage conversion module are provided, the voltage switching strategy is formed according to the on-off of the first switching unit and the second switching unit, and the target voltage value is obtained. By adopting the voltage switching strategy, different input voltages are converted to generate a target voltage value, so that different batteries can be adapted, and stable operation and electric energy conversion under different voltage conditions can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, in particular to a voltage conversion circuit with a wide voltage range and a strategy switching method. BACKGROUND

[0002] With the large-scale use of high-voltage platforms, such as an 800V voltage platform, a direct current-direct current conversion circuit, i.e., a DC / DC converter, is needed to convert high-voltage power and charge a low-voltage battery. Considering modularity and low cost, the DC / DC converter needs to adapt to a wide input voltage range to be compatible with different voltage architectures. However, based on the traditional power topology design, the input voltage range is usually limited to a certain range, and relies on fixed turns ratio transformers or resonance parameters, resulting in insufficient voltage resistance of power devices, a sharp increase in switching loss, and a saturation risk of magnetic elements when the 800V high-voltage input is used, thereby failing to be compatible with different voltage platforms. Therefore, how to make the battery compatible with different voltage platforms is a problem that needs to be solved at present. SUMMARY

[0003] Some embodiments of the present application aim to provide a voltage conversion circuit with a wide voltage range and a strategy switching method. Through the technical solutions of the embodiments of the present application, a voltage conversion circuit with a wide voltage range is provided, which at least includes a first-stage conversion module, a transformer, and a second-stage conversion module, wherein the first-stage conversion module is connected to the second-stage conversion module through the transformer; the second-stage conversion module at least includes a first switching unit and a second switching unit, and the second-stage conversion module at least includes the first switching unit and the second switching unit. According to a voltage switching strategy, the conduction and the turn-off of the first switching unit and the second switching unit are controlled, the input voltage is converted, and a target voltage value is obtained. The voltage switching strategy is preset for different voltage values. The first switching unit and the second switching unit are controlled to realize full-wave rectification and full-bridge rectification switching. The embodiments of the present application form a voltage switching strategy by providing the first switching unit and the second switching unit in the second-stage conversion module and according to the on-off of the first switching unit and the second switching unit. The voltage switching strategy is used to convert different input voltages to generate a target voltage value. In this way, different batteries can be adapted, and stable operation and power conversion under different voltage conditions can be realized.

[0004] In a first aspect, some embodiments of the present application provide a voltage conversion circuit with a wide voltage range, which at least includes a first-stage conversion module, a transformer, and a second-stage conversion module, wherein the first-stage conversion module is connected to the second-stage conversion module through the transformer; The second-stage conversion module at least includes a first switching unit and a second switching unit, and the first switching unit and the second switching unit are controlled according to a voltage switching strategy to convert input voltages and obtain target voltage values.

[0005] Some embodiments of the present application provide the first switching unit and the second switching unit in the second-stage conversion module, and form a voltage switching strategy according to the on-off of the first switching unit and the second switching unit, and convert different input voltages to generate target voltage values, so that different batteries can be adapted and stable operation and power conversion under different voltage conditions can be realized.

[0006] Optionally, the first-stage conversion module is a rectifier circuit, and the first-stage conversion module at least includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, wherein the drain of the first switch tube and the drain of the second switch tube are connected and connected to a first end of an input of different voltage platforms, the source of the first switch tube is connected to the drain of the third switch tube, the source of the second switch tube is connected to the drain of the fourth switch tube, the source of the third switch tube and the source of the fourth switch tube are connected and connected to a second end of the input. Some embodiments of the present application provide a first-stage conversion module as a phase-shifted full-bridge for rectifying input voltages.

[0007] Optionally, the source of the first switch tube is connected to a first end of a primary side of a transformer, the source of the second switch tube is connected to a second end of the primary side of the transformer, and a secondary side of the transformer is connected to the second-stage conversion module. In some embodiments of the present application, the switch tubes in the first-stage conversion module are connected to the primary side and the secondary side of the transformer and the switch tubes in the second-stage conversion module.

[0008] Optionally, the second-stage conversion module at least includes a fifth switch tube, a sixth switch tube, a seventh switch tube, an eighth switch tube, a first switching unit and a second switching unit, wherein: a first end of the secondary side of the transformer is connected to the source of the fifth switch tube; a second end of the secondary side of the transformer is connected to the source of the first switching unit; and a third end of the secondary side of the transformer is connected to the drain of the eighth switch tube.

[0009] Some embodiments of the present application add the first switching unit and the second switching unit in the second-stage conversion module, and switch full-wave rectification and full-bridge rectification through the on-off of the first switching unit and the second switching unit, so as to switch high voltage and low voltage strategies. Optionally, the drain of the fifth switch tube is connected with the drain of the seventh switch tube and the drain of the second switching unit; The source of the fifth switch tube is connected with the drain of the sixth switch tube; The drain of the seventh switch tube is connected with the drain of the eighth switch tube; The source of the sixth switch tube is connected with the source of the eighth switch tube, and the output second end is connected; The drain of the first switching unit and the source of the second switching unit are connected with the output first end. Optionally, the first switching unit and the second switching unit are both switch tubes.

[0010] Some embodiments of the present application use full-bridge rectification in the low-voltage section to improve the gain (effectively improve the output capability of the low-voltage section), and use full-wave rectification in the high-voltage section to reduce the gain (effectively improve the output voltage ripple performance), thereby unifying the gain in the full voltage range and effectively improving the performance of the output voltage.

[0011] In a second aspect, some embodiments of the present application provide a strategy switching method applied to the wide-voltage-range voltage conversion circuit of the first aspect, and the method comprises: Obtaining an input voltage value; Converting the input voltage value according to a pre-set voltage switching strategy to obtain a target voltage value, wherein if the input voltage value is less than a preset value, the voltage switching strategy controls the transformer secondary side working mode to be a full-bridge rectification mode, and if the input voltage value is greater than or equal to the preset value, the voltage switching strategy controls the transformer secondary side working mode to be a full-wave rectification mode.

[0012] Some embodiments of the present application form a voltage switching strategy by providing the first switching unit and the second switching unit in the second-stage conversion module and according to the on-off of the first switching unit and the second switching unit, and convert different input voltages by using the voltage switching strategy to generate a target voltage value, so that different batteries can be adapted and stable operation and power conversion under different voltage conditions can be realized.

[0013] Optionally, in the case where the input voltage value is less than the preset value, the first switching unit is controlled to be always off and the second switching unit is controlled to be always on. Optionally, the transformer turns ratio is the ratio of the sum of the first number of turns and the second number of turns of the secondary side to the number of turns of the primary side, wherein the first number of turns is the number of turns between the secondary side first end and the secondary side second end, and the second number of turns is the number of turns between the secondary side second end and the secondary side third end.

[0014] In some embodiments of this application, when the input voltage is low (uHv ≤ 450V), the first switching unit is normally off and the second switching unit is normally on. The secondary side operates in full-bridge rectification mode, and the transformer turns ratio is (Ns+Ns):Np. The full-bridge rectification mode can double the DC gain.

[0015] Optionally, if the input voltage value is greater than or equal to a preset value, the first switching unit is controlled to be normally on and the second switching unit is controlled to be normally off.

[0016] Optionally, the transformer turns ratio is the ratio of the third number of turns on the secondary side to the number of turns on the primary side, wherein the third number of turns is the number between the second end and the third end of the secondary side.

[0017] In some embodiments of this application, when the input voltage is high (uHv > 450V), the first switching unit is normally on and the second switching unit is normally off. The secondary side operates in full-wave rectification mode, and the transformer turns ratio is Ns:Np. Compared with the low-voltage section, the transformer turns ratio is reduced by half. The full-wave rectification mode can improve the output voltage control accuracy of the high-voltage section.

[0018] Optionally, the method further includes: Obtain the target output voltage and target output current; Based on the preset voltage and preset current, determine a first difference corresponding to the target output voltage and a second difference corresponding to the target output current; The first difference and the second difference are compared, and the PWM of the wide voltage range voltage conversion circuit is adjusted according to the difference corresponding to the smaller value.

[0019] Some embodiments of this application employ a control method that uses a voltage loop and a current loop in competition, which can satisfy the buck voltage limiting and current limiting functions. The output voltage and output current are sampled, and the set voltage and set current are obtained as references. The smaller value of the two is taken as the output of the loop to control the duty cycle of the circuit. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of some embodiments of this application, the accompanying drawings used in some embodiments of this application will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A circuit diagram of a wide voltage range voltage conversion circuit provided in an embodiment of this application; Figure 2A schematic diagram of the low-voltage section operating modes provided in the embodiments of this application; Figure 3 A schematic diagram of the high-voltage section operating modes provided in the embodiments of this application; Figure 4 A schematic diagram of the continuous flow stage provided in an embodiment of this application; Figure 5 A schematic diagram illustrating the high-voltage / low-voltage switching strategy provided in an embodiment of this application; Figure 6 This is a schematic diagram of the dual-loop competition control process provided in an embodiment of this application. Detailed Implementation

[0022] The technical solutions of some embodiments of this application will now be described with reference to the accompanying drawings.

[0023] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] With the large-scale deployment of high-voltage platforms, such as 800V platforms, DC-DC converters are required to convert high-voltage electrical energy into power to charge low-voltage batteries. Considering modularity and low cost, these DC-DC converters need to be adaptable to a wide input voltage range to be compatible with different voltage architectures. However, current traditional power topology designs typically limit their input voltage range to a certain extent and rely on fixed turns ratio transformers or resonant parameters. This leads to insufficient voltage withstand capability, a surge in switching losses, and the risk of magnetic component saturation when using 800V high-voltage input, making them incompatible with different voltage platforms. Therefore, how to make batteries compatible with different voltage platforms is an urgent problem to be solved. In view of this, some embodiments of this application provide a wide voltage range voltage conversion circuit. The wide voltage range voltage conversion circuit includes at least: a first-stage conversion module, a transformer, and a second-stage conversion module. The first-stage conversion module is connected to the second-stage conversion module through the transformer. The second-stage conversion module includes at least a first switching unit and a second switching unit. The first and second switching units are controlled to turn on and off according to a voltage switching strategy to convert the input voltage and obtain a target voltage value. The voltage switching strategy is to control the first and second switching units under different preset voltage values ​​to achieve full-wave rectification and full-bridge rectification switching. The embodiments of this application provide a first and second switching unit in the second-stage conversion module, and form a voltage switching strategy according to the on and off of the first and second switching units. Using this voltage switching strategy, different input voltages are converted to generate a target voltage value. In this way, it can adapt to different batteries and achieve stable operation and energy conversion under different voltage conditions.

[0025] like Figure 1 As shown, embodiments of this application provide a voltage conversion circuit with a wide voltage range. The voltage conversion circuit includes at least: a first-stage conversion module, a transformer, and a second-stage conversion module. The first-stage conversion module is connected to the second-stage conversion module via the transformer. The second-stage conversion module includes at least a first switching unit Q9 and a second switching unit Q10. The first switching unit Q9 and the second switching unit Q10 are controlled to turn on and off according to a voltage switching strategy to convert the input voltage and obtain a target voltage value. The voltage switching strategy controls the first switching unit and the second switching unit under different preset voltage values ​​to achieve switching between full-wave rectification and full-bridge rectification.

[0026] Specifically, such as Figure 1As shown, the circuit also includes a control module, which is connected to the voltage conversion circuit. At uHV, a voltage platform with different voltage values ​​is connected, i.e., the input terminal. The control module obtains the input voltage at the input terminal and judges the input voltage. Based on the magnitude of the input voltage, it determines different voltage switching strategies.

[0027] After the input voltage is applied, the first-stage conversion module rectifies the input voltage to obtain the first-stage rectified voltage. The first-stage rectified voltage is then transmitted to the secondary side of the transformer through the transformer. Based on the voltage switching strategy obtained above, the corresponding switching transistor is controlled to turn on or off, thereby converting the voltage to obtain the target voltage value.

[0028] For example, if the control module determines that the input voltage is less than the preset value, it controls the first switch Q1 and the fourth switch Q4 in the first-stage conversion module to turn on, and controls the fifth switch, the eighth switch and the second switching unit in the second-stage conversion module to turn on, thereby obtaining the target voltage value and charging the battery according to the target voltage value; If the control module determines that the input voltage is greater than the preset value, it controls the first switch Q1 and the fourth switch Q4 in the first-stage conversion module to turn on, and controls the eighth switch and the first switching unit in the second-stage conversion module to turn on, thereby obtaining the target voltage value and charging the battery according to the target voltage value; After the battery is fully charged, it enters the freewheeling phase, such as... Figure 4 As shown, the control module cuts off the input voltage of the input platform and uses the output terminal as the power source to conduct through the eighth switch and the first switching unit for discharge.

[0029] Some embodiments of this application provide a first switching unit and a second switching unit in a second-stage conversion module, and form a voltage switching strategy based on the on / off state of the first switching unit and the second switching unit. Using this voltage switching strategy, different input voltages are converted to generate a target voltage value. In this way, different batteries can be adapted to achieve stable operation and energy conversion under different voltage conditions.

[0030] Another embodiment of this application further illustrates the wide voltage range voltage conversion circuit provided in the above embodiments.

[0031] This application provides a DC / DC converter topology and its switching strategy. Based on a hard-switching dual-mode DC / DC converter, a high-low voltage switching strategy is used to achieve stable operation and power conversion under different voltage conditions.

[0032] To accommodate the wide voltage output range of the battery and reduce input current ripple, a two-stage LLC converter is used. The input voltage is boosted by the front-stage Boost converter and then used as the input of the LLC resonant converter.

[0033] like Figure 1 As shown, this hard-switching dual-mode DC / DC converter topology has a phase-shifted full-bridge converter in the front stage and a rectifier circuit with two modes in the back stage.

[0034] For the control strategy of DC-DC converters, the buck chopper uses PWM control, and the loop employs a competitive control method between the voltage loop and the current loop, which can meet the buck voltage limiting and current limiting functions. The control block diagram is as follows: Figure 6 As shown. The output voltage and output current are sampled, and the set voltage and set current are obtained as references. The smaller value of the two is taken as the output of the loop to control the duty cycle of the buck.

[0035] Optionally, the first-stage conversion module is a rectifier circuit. The first-stage conversion module has at least a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4. The drain of the first switch Q1 and the drain of the second switch Q2 are connected and connected to the first input terminal of different voltage platforms. The source of the first switch Q1 is connected to the drain of the third switch Q3. The source of the second switch Q2 is connected to the drain of the fourth switch Q4. The sources of the third switch Q3 and the fourth switch Q4 are connected and connected to the second input terminal. Among them, the first input terminal and the second input terminal are input ports, which are the output voltage values ​​of different voltage platforms, such as 800V voltage platform or 400V voltage platform, etc.

[0036] Some embodiments of this application provide a first-stage conversion module as a phase-shifted full-bridge, used to rectify the input voltage.

[0037] Optionally, the source of the first switching transistor Q1 is connected to the first end of the primary side of the transformer, the source of the second switching transistor Q2 is connected to the second end of the primary side of the transformer, and the secondary side of the transformer is connected to the second-stage conversion module. In some embodiments of this application, the switching transistor in the first-stage conversion module is connected to the switching transistor in the second-stage conversion module via the primary and secondary sides of the transformer.

[0038] Optionally, the second-stage conversion module includes at least a fifth switch Q5, a sixth switch Q6, a seventh switch Q7, an eighth switch Q8, a first switching unit Q9, and a second switching unit Q10, wherein: The first terminal of the secondary side of the transformer is connected to the source of the fifth switching transistor Q5; the second terminal of the secondary side of the transformer is connected to the source of the first switching unit Q9; and the third terminal of the secondary side of the transformer is connected to the drain of the eighth switching transistor Q8.

[0039] In some embodiments of this application, a first switching unit and a second switching unit are added to the second-stage conversion module. By turning the first switching unit and the second switching unit on and off, the switching between full-wave rectification and full-bridge rectification is performed, thereby switching between high-voltage and low-voltage strategies. Optionally, the drain of the fifth switch Q5 is connected to the drain of the seventh switch Q7 and the drain of the second switching unit Q10. The source of the fifth switch Q5 is connected to the drain of the sixth switch Q6; The drain of the seventh switch Q7 is connected to the drain of the eighth switch Q8; The source of the sixth switch Q6 is connected to the source of the eighth switch Q8, and the second output terminal is also connected. The drain of the first switching unit Q9 and the source of the second switching unit Q10 are connected to the first output terminal. Optionally, both the first and second switching units are switching transistors.

[0040] The first and second output terminals represent the target voltage values, allowing different batteries to be charged.

[0041] In some embodiments of this application, full-bridge rectification is used in the low-voltage section to increase gain (effectively improving the output capability of the low-voltage section, etc.), while full-wave rectification is used in the high-voltage section to reduce gain (effectively improving the output voltage ripple performance, etc.). This unifies the gain across the entire voltage range, effectively improving the output voltage performance.

[0042] This application provides a DC / DC power topology and its switching strategy that adapts to a wide input voltage range, solving the compatibility problem between different voltage platforms of vehicle power supplies, enhancing the adaptability and flexibility of the module, improving the reusability of the DC / DC converter, and reducing development costs and development cycle.

[0043] It should be noted that each of the implementable methods in this embodiment can be implemented individually or in any combination without conflict. This application does not limit this.

[0044] Another embodiment of this application provides a strategy switching method applied to the aforementioned wide voltage range voltage conversion circuit, the method comprising: Obtain the input voltage value; According to the preset voltage switching strategy, the input voltage value is converted to obtain the target voltage value. The voltage switching strategy is as follows: if the input voltage value is less than the preset value, the secondary side of the control transformer is controlled to operate in full-bridge rectification mode; if the input voltage value is greater than or equal to the preset value, the secondary side of the control transformer is controlled to operate in full-wave rectification mode.

[0045] Some embodiments of this application provide a first switching unit and a second switching unit in a second-stage conversion module, and form a voltage switching strategy based on the on / off state of the first switching unit and the second switching unit. Using this voltage switching strategy, different input voltages are converted to generate a target voltage value. In this way, different batteries can be adapted to achieve stable operation and energy conversion under different voltage conditions.

[0046] Optionally, if the input voltage value is less than a preset value, the first switching unit is controlled to be normally off and the second switching unit is controlled to be normally on. Optionally, the transformer turns ratio is the ratio of the sum of the first number of turns Ns1 and the second number of turns Ns2 on the secondary side to the number of turns on the primary side, where the first number of turns is the number between the first end and the second end of the secondary side, and the second number of turns is the number between the second end and the third end of the secondary side.

[0047] like Figure 2 As shown, when the input voltage is low, i.e. less than the preset value (uHv ≤ 450V), the controller controls the first switch Q1 and the fourth switch Q4 in the first-stage conversion module to conduct, and controls the fifth switch, the eighth switch, and the second switching unit in the second-stage conversion module to conduct. That is, the first switching unit Q9 is normally off, the second switching unit Q10 is normally on, and the secondary side operates in full-bridge rectification mode. The transformer turns ratio is (Ns1+Ns2):Np. The full-bridge rectification mode can double the voltage gain.

[0048] If the input voltage is commutated, the control module will correspondingly control the second and third switching transistors to turn on.

[0049] The secondary side uses a full-bridge rectification method to convert the voltage transmitted from the primary side to obtain the target voltage value, which is then used to charge the battery. After charging is complete, the platform's input power is turned off, and it enters the freewheeling phase, such as... Figure 4 As shown, the output terminal is used as the power source, and the discharge is achieved by connecting the eighth switch and the first switching unit.

[0050] Optionally, when the input voltage value is greater than or equal to a preset value, the first switching unit is controlled to be normally on and the second switching unit is normally off.

[0051] Optionally, the transformer turns ratio is the ratio of the third number of turns on the secondary side to the number of turns on the primary side, where the third number of turns is the number between the second and third terminals of the secondary side.

[0052] Specifically, the control module judges the input voltage value, and when the input voltage value is high, that is, greater than or equal to a preset value (uHv > 450V), such as... Figure 3As shown, at this time, the first switching unit Q9 is normally on, the second switching unit Q10 is normally off, the secondary side operates in full-wave rectification mode, and the transformer turns ratio is Ns3:Np. Compared with the low-voltage section, the transformer turns ratio is reduced by half. The full-wave rectification mode can improve the output voltage control accuracy of the high-voltage section.

[0053] After charging is complete, the platform's input power is turned off, and it enters the freewheeling phase, such as... Figure 4 As shown, the output terminal is used as the power source, and the discharge is achieved by connecting the eighth switch and the first switching unit.

[0054] In some embodiments of this application, when the input voltage is high (uHv > 450V), the first switching unit is normally on and the second switching unit is normally off. The secondary side operates in full-wave rectification mode, and the transformer turns ratio is Ns:Np. Compared with the low-voltage section, the transformer turns ratio is reduced by half. The full-wave rectification mode can improve the output voltage control accuracy of the high-voltage section.

[0055] The first switching unit Q9 and the second switching unit Q10 provided in this embodiment are typical two-level bridge arms. Based on the two-level control method, the duty cycle D of the primary side bridge arm is used as the judgment object. By controlling the on and off of the secondary side switching transistor, the switching between full-wave rectification and full-bridge rectification is realized. The specific strategy is as follows: When the buck converter is operating in the low-voltage segment, if the duty cycle of the primary arm is <0.15, it indicates that the input voltage is too high. After 10ms, it switches to the high-voltage segment, where the duty cycle is twice that of the low-voltage segment, resulting in less back current and improved efficiency. When the buck converter is operating in the high-voltage section, if the duty cycle of the primary arm is >0.45, it indicates that the input voltage is off. After 10ms, it switches to low-voltage operation.

[0056] Optionally, the method further includes: Obtain the target output voltage and target output current; Based on the preset voltage and preset current, determine the first difference corresponding to the target output voltage and the second difference corresponding to the target output current; The first and second differences are compared, and the PWM of the voltage conversion circuit with a wide voltage range is adjusted according to the difference corresponding to the smaller value.

[0057] PWM (Pulse-width modulation) is an abbreviation for pulse width modulation. Pulse width modulation is a digital encoding method for analog signal levels. PWM reduces the average power transmitted by distributing the effective electrical signal into discrete forms. Therefore, according to the area equivalence rule, the desired waveform with the required amplitude and frequency can be obtained by changing the pulse's time width.

[0058] Duty cycle is the percentage of time a pulse is at a higher voltage during the entire pulse cycle; For example, such as Figure 5 As shown, within a period range (10ms), the time for acquiring the high level, i.e., the pulse width time, is 6ms. Then the low level time is 4ms. The total PWM duty cycle is 6 / (6+4)=60%, which is a pulse signal with a duty cycle of 60%.

[0059] Some embodiments of this application employ a control method that uses a voltage loop and a current loop in competition, which can satisfy the buck voltage limiting and current limiting functions. The output voltage and output current are sampled, and the set voltage and set current are obtained as references. The smaller value of the two is taken as the output of the loop to control the duty cycle of the circuit.

[0060] The above are merely embodiments of this application and are not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0061] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0062] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A voltage conversion circuit with a wide voltage range, characterized in that, The voltage conversion circuit includes at least: a first-stage conversion module, a transformer, and a second-stage conversion module, wherein the first-stage conversion module is connected to the second-stage conversion module through the transformer; The second-stage conversion module includes at least a first switching unit and a second switching unit. It controls the first switching unit and the second switching unit to turn on and off according to a voltage switching strategy to convert the input voltage and obtain the target voltage value. The voltage switching strategy is to control the first switching unit and the second switching unit under different preset voltage values ​​to realize the switching between full-wave rectification and full-bridge rectification.

2. The voltage conversion circuit with a wide voltage range according to claim 1, characterized in that, The first-stage conversion module is a rectifier circuit. The first-stage conversion module has at least a first switch, a second switch, a third switch, and a fourth switch. The drains of the first switch and the second switch are connected together and connected to the first input terminal of different voltage platforms. The source of the first switch is connected to the drain of the third switch. The source of the second switch is connected to the drain of the fourth switch. The sources of the third switch and the fourth switch are connected together and connected to the second input terminal.

3. The voltage conversion circuit with a wide voltage range according to claim 2, characterized in that, The source of the first switching transistor is connected to the first end of the primary side of the transformer, the source of the second switching transistor is connected to the second end of the primary side of the transformer, and the secondary side of the transformer is connected to the second-stage conversion module.

4. The voltage conversion circuit with a wide voltage range according to claim 3, characterized in that, The second-stage conversion module includes at least a fifth switch, a sixth switch, a seventh switch, an eighth switch, a first switching unit, and a second switching unit, wherein: The first end of the secondary side of the transformer is connected to the source of the fifth switching transistor; the second end of the secondary side of the transformer is connected to the source of the first switching unit; and the third end of the secondary side of the transformer is connected to the drain of the eighth switching transistor.

5. The voltage conversion circuit with a wide voltage range according to claim 4, characterized in that, The drain of the fifth switching transistor is connected to the drain of the seventh switching transistor and the drain of the second switching unit. The source of the fifth switch is connected to the drain of the sixth switch; The drain of the seventh switch is connected to the drain of the eighth switch. The source of the sixth switch is connected to the source of the eighth switch, and the second output terminal is also connected. The drain of the first switching unit and the source of the second switching unit are connected to the first output terminal.

6. The voltage conversion circuit with a wide voltage range according to claim 1, characterized in that, Both the first switching unit and the second switching unit are switching transistors.

7. A strategy switching method, characterized in that, The method, applied to a wide voltage range voltage conversion circuit as described in any one of claims 1-6, comprises: Obtain the input voltage value; According to a preset voltage switching strategy, the input voltage value is converted to obtain the target voltage value. The voltage switching strategy is as follows: if the input voltage value is less than the preset value, the secondary side of the transformer is controlled to operate in full-bridge rectification mode; if the input voltage value is greater than or equal to the preset value, the secondary side of the transformer is controlled to operate in full-wave rectification mode.

8. The strategy switching method according to claim 7, characterized in that, When the input voltage value is less than a preset value, the first switching unit is normally off and the second switching unit is normally on.

9. The strategy switching method according to claim 8, characterized in that, The transformer turns ratio is the ratio of the sum of the first and second turns on the secondary side to the number of turns on the primary side, wherein the first number of turns is the number between the first and second ends of the secondary side, and the second number of turns is the number between the second and third ends of the secondary side.

10. The strategy switching method according to claim 7, characterized in that, When the input voltage value is greater than or equal to a preset value, the first switching unit is controlled to be normally on and the second switching unit is controlled to be normally off.

11. The strategy switching method according to claim 10, characterized in that, The transformer turns ratio is the ratio of the third number of turns on the secondary side to the number of turns on the primary side, wherein the third number of turns is the number between the second end and the third end of the secondary side.

12. The strategy switching method according to claim 7, characterized in that, The method further includes: Obtain the target output voltage and target output current; Based on the preset voltage and preset current, determine a first difference corresponding to the target output voltage and a second difference corresponding to the target output current; The first difference and the second difference are compared, and the PWM of the wide voltage range voltage conversion circuit is adjusted according to the difference corresponding to the smaller value.

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