DC / DC Converter and Its Output Voltage Control Method

Abstract

The present application provides a DC / DC converter and an output voltage control method thereof. The DC / DC converter includes an inverter circuit, a transformer, a first rectifier circuit, a second rectifier circuit, and a voltage management circuit. The transformer includes a first primary winding, a first secondary winding, and a second secondary winding. Two ends of the first primary winding are respectively connected to a first output end and a second output end of the inverter circuit. Two ends of the first secondary winding are connected to two input ends of the first rectifier circuit. Two ends of the second secondary winding are connected to two input ends of the second rectifier circuit. The voltage management circuit controls the first rectifier circuit's output end, the second rectifier circuit's output end, and the DC / DC converter's output end to be in a first connection relationship during a first sub-period within a first working period, and to be in a second connection relationship during a second sub-period within the first working period. By adopting the present application, the input voltage compatibility range of the DC / DC converter can be expanded, and the applicability is strong.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and particularly to a DC / DC converter and an output voltage control method thereof. Background Art

[0002] Isolated DC / DC converters with -48V input are widely used in the communication field for the power supply design of communication devices. For different communication devices and application scenarios, there are also different requirements for DC / DC converters. One typical application is to convert a wide-range DC input voltage with -48V as the typical value into a stable DC voltage output, where the output voltage includes multiple levels such as 5V, 12V, 54V, etc.

[0003] Currently, mainly the Figure 1 shown DC / DC converter is used for DC conversion of a wide-range input voltage. As Figure 1 shown, the DC / DC converter includes switching transistors Q1-Q8, a primary winding L1, a secondary winding L2, an iron core T, and rectifying diodes D1-D4. Among them, Q1-Q4 form a common Buck-Boost circuit, Q5-Q8 form a common open-loop LLC circuit, L1, L2, and T form a transformer, and D1-D4 form a rectifying circuit. Q5 and Q7 in the open-loop LLC circuit are respectively connected to different input sources. Among them, the drain of Q5 is connected to the positive output terminal of the Buck-Boost circuit, and the drain of Q7 is connected to the positive output terminal of the DC power supply. Based on the structure of this DC / DC converter, the output voltage V out =(V b +V in ) / (2N), where N is the turns ratio between the primary winding L1 and the secondary winding L2. Therefore, for different input voltages V in , this DC / DC converter can achieve a stable output of V b by adjusting the output voltage V out of the Buck-Boost circuit.

[0004] However, according to the formula for calculating V out above, the above DC / DC converter is only applicable to the case of V out ≥V in / (2N). When the required V out is very small, and at the same time V in is very large, voltage regulation cannot be achieved only by adjusting V b . Therefore, the above DC / DC converter has a small input voltage compatibility range and poor applicability. Summary of the Invention

[0005] The present application provides a DC / DC converter and an output voltage control method thereof. By changing the connection relationship among the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit, and the output terminal of the DC / DC converter, step-up and step-down conversion of the input voltage of the DC / DC converter can be achieved, so as to ensure that the voltage value stably output by the DC / DC converter is the target output voltage regardless of the value of the input voltage of the DC / DC converter, thereby expanding the input voltage compatibility range of the DC / DC converter and having strong applicability.

[0006] In a first aspect, the present application provides a DC / DC converter. The DC / DC converter includes an inverter circuit, a transformer, a first rectifier circuit, a second rectifier circuit, and a voltage management circuit. Among them, the input terminal of the inverter circuit serves as the input terminal of the DC / DC converter and is used to connect to a DC power supply; the transformer includes a first primary winding, a first secondary winding, and a second secondary winding. One end of the first primary winding is connected to the first output terminal of the inverter circuit, and the other end of the first primary winding is connected to the second output terminal of the inverter circuit. The two ends of the first secondary winding are connected to the two input terminals of the first rectifier circuit, and the two ends of the second secondary winding are connected to the two input terminals of the second rectifier circuit; the voltage management circuit controls the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit, and the output terminal of the DC / DC converter to be in a first connection relationship during a first sub-period within the first working cycle, and controls the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit, and the output terminal of the DC / DC converter to be in a second connection relationship during a second sub-period within the first working cycle. Thus, by changing the connection relationship among the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit, and the output terminal of the DC / DC converter, step-up and step-down conversion of the input voltage of the DC / DC converter can be achieved, so as to ensure that the voltage value stably output by the DC / DC converter is the target output voltage regardless of the value of the input voltage of the DC / DC converter, thereby expanding the input voltage compatibility range of the DC / DC converter and having strong applicability.

[0007] In combination with the first aspect, in a first possible implementation manner, the DC / DC converter further includes a controller. The controller sends a first control signal and a second control signal to the voltage management circuit. The voltage management circuit controls the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit, and the output terminal of the DC / DC converter to be in a first connection relationship during the first sub-period according to the first control signal, and controls the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit, and the output terminal of the DC / DC converter to be in a second connection relationship during the second sub-period according to the second control signal. Here, the controller can be located inside the voltage management circuit or inside the DC / DC converter and independent of the voltage management circuit, with high flexibility.

[0008] In combination with the first aspect, in the second possible implementation manner, the first connection relationship and the second connection relationship are any two of the following connection relationships:

[0009] The branch where the output end of the first rectifier circuit and the output end of the second rectifier circuit are located are connected in series and then connected to the output end of the DC / DC converter; or

[0010] The branch where the output end of the second rectifier circuit is located is connected to the output end of the DC / DC converter; or

[0011] The output end of the first rectifier circuit is connected to the output end of the DC / DC converter, and the first end of the branch where the output end of the second rectifier circuit is located is connected to the first output end of the DC / DC converter; and

[0012] The branch where the output end of the second rectifier circuit is located and the output end of the first rectifier circuit are connected in parallel to the output end of the DC / DC converter. It can be understood that after the DC / DC converter works, by realizing any combination of at least two of the above four connection relationships within the first working cycle, stable output of different voltages can be achieved, with high flexibility and strong applicability.

[0013] In combination with the first aspect, in the third possible implementation manner, when the input voltage of the DC / DC converter is less than the preset voltage, the voltage management circuit controls the output end of the first rectifier circuit, the output end of the second rectifier circuit, and the output end of the DC / DC converter to be in the first connection relationship within the first sub-cycle and in the second connection relationship within the second sub-cycle, where the first connection relationship is that the branch where the output end of the first rectifier circuit and the output end of the second rectifier circuit are located are connected in series and then connected to the output end of the DC / DC converter; the second connection relationship is that the branch where the output end of the second rectifier circuit is located is connected to the output end of the DC / DC converter. It can be understood that when the input voltage of the DC / DC converter is less than the preset voltage, the above method can be used to ensure the stable output of the target output voltage of the DC / DC converter, with strong adaptability.

[0014] In combination with the first aspect, in the fourth possible implementation manner, when the input voltage of the DC / DC converter is less than the preset voltage, the output voltage V out of the DC / DC converter = V1*D1 + V2, where V1 is the output voltage of the first rectifier circuit, V2 is the output voltage of the second rectifier circuit, and D1 is the ratio between the first sub-cycle and the first working cycle. Furthermore, by adjusting D1, the DC / DC converter can stably output the target output voltage required, with simple operation and strong applicability.

[0015] In combination with the first aspect, in the fifth possible implementation manner, when the input voltage of the DC / DC converter is greater than or equal to a preset voltage, the voltage management circuit controls the output end of the first rectifier circuit, the output end of the second rectifier circuit, and the output end of the DC / DC converter to be in a first connection relationship in the first sub-cycle and in a second connection relationship in the second sub-cycle. Among them, the first connection relationship is that the output end of the first rectifier circuit is connected to the output end of the DC / DC converter, and the first end of the branch where the output end of the second rectifier circuit is located is connected to the first output end of the DC / DC converter; the second connection relationship is that the branch where the output end of the second rectifier circuit is located is connected in parallel with the output end of the first rectifier circuit to the output end of the DC / DC converter. It can be understood that when the input voltage of the DC / DC converter is greater than or equal to the preset voltage, the stable output of the target output voltage of the DC / DC converter can be ensured through the above method, and the adaptability is strong.

[0016] In combination with the first aspect, in the sixth possible implementation manner, when the input voltage of the DC / DC converter is greater than or equal to the preset voltage, the output voltage V of the DC / DC converter out = V2 / (1 - D1), where V2 is the output voltage of the second rectifier circuit, and D1 is the ratio between the first sub-cycle and the first working cycle. Furthermore, the target output voltage required to be output by the DC / DC converter can be stably output by adjusting D1, and the operation is simple and the applicability is strong.

[0017] In combination with the first aspect, in the seventh possible implementation manner, the voltage management circuit includes a first inductor, a first switch tube, a second switch tube, and a third switch tube. Among them, the first end of the third switch tube is connected to the first output end of the first rectifier circuit and the second output end of the DC / DC converter, the second end of the third switch tube is connected to the first output end of the second rectifier circuit through the first inductor, the second end of the third switch tube is connected to the first end of the second switch tube, the second end of the second switch tube is connected to the second output end of the first rectifier circuit and the first end of the first switch tube, and the second end of the first switch tube is connected to the second output end of the second rectifier circuit and the first output end of the DC / DC converter. Compared with the Buck-Boost circuit with 4 switch tubes of the ordinary partial power transmission topology, the number of switch tubes required in the voltage management circuit is less. Moreover, not only can the input voltage be normally stepped up and down, but also the connection relationship between the output end of the first rectifier circuit, the output end of the second rectifier circuit, and the output end of the DC / DC converter can be changed. The circuit cost is low and the functionality is strong.

[0018] In combination with the first aspect, in the eighth possible implementation manner, when the DC / DC converter includes a first primary winding, the output voltage V1 of the first rectifier circuit = V in / N11, the output voltage V2 of the second rectifier circuit = Vin / N12, where V in is the input voltage of the DC / DC converter, N11 is the turns ratio between the first primary winding and the first secondary winding, and N12 is the turns ratio between the first primary winding and the second secondary winding.

[0019] Combined with the first aspect, in the ninth possible implementation manner, the transformer further includes a second primary winding. One end of the second primary winding is connected to the second output end of the inverter circuit, and the other end of the second primary winding is connected to the third output end of the inverter circuit. Furthermore, by controlling the connection relationship between the first primary winding and the second primary winding, the input voltage compatibility range of the DC / DC converter can be further expanded, and the applicability is stronger.

[0020] Combined with the first aspect, in the tenth possible implementation manner, the inverter circuit controls the first primary winding and the second primary winding to be connected in parallel to both ends of the DC power supply, or controls the first primary winding and the second primary winding to be connected in series and then connected to both ends of the DC power supply. Furthermore, by controlling the parallel or series connection of the first primary winding and the second primary winding, the input voltage of the DC / DC converter can be increased or decreased, thereby further expanding the input voltage compatibility range of the DC / DC converter, and the applicability is stronger.

[0021] Combined with the first aspect, in the eleventh possible implementation manner, when the DC / DC converter includes a controller, the controller sends a third control signal to the inverter circuit, and the inverter circuit makes the first primary winding and the second primary winding connected in parallel to both ends of the DC power supply according to the received third control signal, or controls the inverter circuit to make the first primary winding and the second primary winding connected in series and then connected to both ends of the DC power supply.

[0022] Combined with the first aspect, in the twelfth possible implementation manner, when the input voltage of the DC / DC converter is less than the preset voltage, the controller sends a third control signal to the inverter circuit, and the third control signal is used to control the inverter circuit to make the first primary winding and the second primary winding connected in parallel to both ends of the DC power supply.

[0023] Combined with the first aspect, in the thirteenth possible implementation manner, when the first primary winding and the second primary winding are connected in parallel to the DC power supply, the output voltage V1 of the first rectifier circuit = V in / N1, the output voltage V2 of the second rectifier circuit = V in / N2, V inis the input voltage of the DC / DC converter, N1 is the turns ratio between the first primary winding and the first secondary winding, and N2 is the turns ratio between the second primary winding and the second secondary winding. When designing the DC / DC converter, the turns of each winding in the first primary winding, the first secondary winding, the second primary winding, and the second secondary winding can be changed to meet different actual output voltage requirements, with strong applicability.

[0024] Combined with the first aspect, in the fourteenth possible implementation manner, when the input voltage of the DC / DC converter is greater than or equal to a preset voltage, the controller sends a third control signal to the inverter circuit, and the third control signal is used to control the inverter circuit to connect the two ends of the DC power supply after the first primary winding and the second primary winding are connected in series.

[0025] Combined with the first aspect, in the fifteenth possible implementation manner, when the first primary winding and the second primary winding are connected in series to the DC power supply, the output voltage V1 of the first rectifier circuit = V in1 / N1, the output voltage V2 of the second rectifier circuit = V in2 / N2, V in1 and V in2 are both determined by the input voltage of the DC / DC converter, N1 is the turns ratio between the first primary winding and the first secondary winding, and N2 is the turns ratio between the second primary winding and the second secondary winding. When designing the DC / DC converter, the turns of each winding in the first primary winding, the first secondary winding, the second primary winding, and the second secondary winding can be changed to meet different actual output voltage requirements, with strong applicability.

[0026] Combined with the first aspect, in the sixteenth possible implementation manner, the DC / DC converter further includes a first resonant circuit and a second resonant circuit. The first output end of the inverter circuit is connected to one end of the first primary winding through the first resonant circuit, and the third output end of the inverter circuit is connected to the other end of the second primary winding through the second resonant circuit. The resonant parameters of the first resonant circuit are the same as those of the second resonant circuit. Furthermore, the switching loss of the switching tube in the DC / DC converter can be reduced when the switching tube is in zero-voltage switching or zero-current switching, with strong applicability.

[0027] Second aspect, the present application provides a method for controlling the output voltage of a DC / DC converter. The DC / DC converter includes an inverter circuit, a transformer, a first rectifier circuit, and a second rectifier circuit. Among them, the input end of the inverter circuit serves as the input end of the DC / DC converter and is used to connect to a DC power supply. The transformer includes a first primary winding, a first secondary winding, and a second secondary winding. One end of the first primary winding is connected to the first output end of the inverter circuit, and the other end of the first primary winding is connected to the second output end of the inverter circuit. The two ends of the first secondary winding are connected to the two input ends of the first rectifier circuit, and the two ends of the second secondary winding are connected to the two input ends of the second rectifier circuit. The method includes: controlling the output end of the first rectifier circuit, the output end of the second rectifier circuit, and the output end of the DC / DC converter to be in a first connection relationship during a first sub-period within a first working cycle, and controlling the output end of the first rectifier circuit, the output end of the second rectifier circuit, and the output end of the DC / DC converter to be in a second connection relationship during a second sub-period within the first working cycle.

[0028] In combination with the second aspect, in a first possible implementation manner, according to a first control signal, during the first sub-period, control the output end of the first rectifier circuit, the output end of the second rectifier circuit, and the output end of the DC / DC converter to be in a first connection relationship; according to a second control signal, during the second sub-period, control the output end of the first rectifier circuit, the output end of the second rectifier circuit, and the output end of the DC / DC converter to be in a second connection relationship.

[0029] In combination with the second aspect, in a second possible implementation manner, the first connection relationship and the second connection relationship are any two of the following connection relationships:

[0030] The branches where the output end of the first rectifier circuit and the output end of the second rectifier circuit are located are connected in series and then connected to the output end of the DC / DC converter; or

[0031] The branch where the output end of the second rectifier circuit is located is connected to the output end of the DC / DC converter; or

[0032] The output end of the first rectifier circuit is connected to the output end of the DC / DC converter, and the first end of the branch where the output end of the second rectifier circuit is located is connected to the first output end of the DC / DC converter; and

[0033] The branch where the output end of the second rectifier circuit is located is connected in parallel with the output end of the first rectifier circuit to the output end of the DC / DC converter.

[0034] In combination with the second aspect, in a third possible implementation manner, when the input voltage of the DC / DC converter is less than a preset voltage, the output end of the first rectifier circuit, the output end of the second rectifier circuit, and the output end of the DC / DC converter are in a first connection relationship in a first sub-cycle and in a second connection relationship in a second sub-cycle, where the first connection relationship is that the branches where the output end of the first rectifier circuit and the output end of the second rectifier circuit are located are connected in series and then connected to the output end of the DC / DC converter; the second connection relationship is that the branch where the output end of the second rectifier circuit is located is connected to the output end of the DC / DC converter.

[0035] In combination with the second aspect, in a fourth possible implementation manner, the output voltage V of the DC / DC converter out = V1*D1 + V2, where V1 is the output voltage of the first rectifier circuit, V2 is the output voltage of the second rectifier circuit, and D1 is the ratio between the first sub-cycle and the first working cycle.

[0036] In combination with the second aspect, in a fifth possible implementation manner, when the input voltage of the DC / DC converter is greater than or equal to the preset voltage, the output end of the first rectifier circuit, the output end of the second rectifier circuit, and the output end of the DC / DC converter are in a first connection relationship in a first sub-cycle and in a second connection relationship in a second sub-cycle, where the first connection relationship is that the output end of the first rectifier circuit is connected to the output end of the DC / DC converter, and the first end of the branch where the output end of the second rectifier circuit is located is connected to the first output end of the DC / DC converter; the second connection relationship is that the branch where the output end of the second rectifier circuit is located is connected in parallel with the output end of the first rectifier circuit to the output end of the DC / DC converter.

[0037] In combination with the second aspect, in a sixth possible implementation manner, the output voltage V of the DC / DC converter out = V2 / (1 - D1), where V2 is the output voltage of the second rectifier circuit, and D1 is the ratio between the first sub-cycle and the first working cycle.

[0038] In combination with the second aspect, in a seventh possible implementation manner, when the transformer includes a first primary winding, the output voltage V1 of the first rectifier circuit = V in / N11, and the output voltage V2 of the second rectifier circuit = V in / N12, where V in is the input voltage of the DC / DC converter, N11 is the turns ratio between the first primary winding and the first secondary winding, and N12 is the turns ratio between the first primary winding and the second secondary winding.

[0039] In combination with the second aspect, in the eighth possible implementation manner, the transformer further includes a second primary winding. One end of the second primary winding is connected to the second output terminal of the inverter circuit, and the other end of the second primary winding is connected to the third output terminal of the inverter circuit.

[0040] In combination with the second aspect, in the ninth possible implementation manner, control the inverter circuit to connect the first primary winding and the second primary winding in parallel to both ends of the DC power supply, or control the inverter circuit to connect the first primary winding and the second primary winding in series and then connect to both ends of the DC power supply.

[0041] In combination with the second aspect, in the tenth possible implementation manner, when the input voltage of the DC / DC converter is less than the preset voltage, control the inverter circuit to connect the first primary winding and the second primary winding in parallel to both ends of the DC power supply.

[0042] In combination with the second aspect, in the eleventh possible implementation manner, when the first primary winding and the second primary winding are connected in parallel to both ends of the DC power supply, the output voltage V1 of the first rectifier circuit = V in / N1, and the output voltage V2 of the second rectifier circuit = V in / N2, where V in is the input voltage of the DC / DC converter, N1 is the turns ratio between the first primary winding and the first secondary winding, and N2 is the turns ratio between the second primary winding and the second secondary winding.

[0043] In combination with the second aspect, in the twelfth possible implementation manner, when the input voltage of the DC / DC converter is greater than or equal to the preset voltage, control the inverter circuit to connect the first primary winding and the second primary winding in series and then connect to both ends of the DC power supply.

[0044] In combination with the second aspect, in the thirteenth possible implementation manner, when the first primary winding and the second primary winding are connected in series and then connected to both ends of the DC power supply, the output voltage V1 of the first rectifier circuit = V in1 / N1, and the output voltage V2 of the second rectifier circuit = V in2 / N2, where V in1 and V in2 are both determined by the input voltage of the DC / DC converter, N1 is the turns ratio between the first primary winding and the first secondary winding, and N2 is the turns ratio between the second primary winding and the second secondary winding.

[0045] In combination with the second aspect, in the fourteenth possible implementation manner, the DC / DC converter further includes a first resonance circuit and a second resonance circuit. The first output terminal of the inverter circuit is connected to one end of the first primary winding through the first resonance circuit, and the third output terminal of the inverter circuit is connected to the other end of the second primary winding through the second resonance circuit. The resonance parameters of the first resonance circuit are the same as those of the second resonance circuit.

[0046] It should be understood that the implementations and beneficial effects of the above multiple aspects of the present application can be referred to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a schematic structural diagram of a DC / DC converter provided by the prior art;

[0048] Figure 2 is a schematic diagram of an application scenario of the DC / DC converter provided by the present application;

[0049] Figure 3 is a schematic structural diagram of a DC / DC converter provided by the present application;

[0050] Figure 4 is another schematic structural diagram of a DC / DC converter provided by the present application;

[0051] Figure 5 is yet another schematic structural diagram of a DC / DC converter provided by the present application;

[0052] Figure 6 is a schematic flowchart of a method for controlling the output voltage of the DC / DC converter provided by the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] The DC / DC converter provided by the present application can be applied to different application scenarios. For example, power supply application scenarios of electronic devices (electronic devices include smart phones, tablet computers, desktop computers, smart speakers, etc.), new energy power supply scenarios (such as photovoltaic power supply scenarios, wind power supply scenarios, etc.). The following will take the power supply scenario of electronic devices as an example for illustration, and will not be repeated hereinafter.

[0054] See Figure 2 , Figure 2 is a schematic diagram of an application scenario of the DC / DC converter provided by the present application. In the power supply scenario of electronic devices, such as Figure 2As shown in the figure, the input end of the DC / DC converter is connected to the output end of the inverter, and the output end is connected to the electronic device. When power supply to the electronic device is required, the inverter can first invert the AC voltage (such as 220V) provided by the power grid into a first DC voltage and output it to the input end of the DC / DC converter. The DC / DC converter performs DC conversion on the first DC voltage at the input end to obtain a second DC voltage, and outputs the second DC voltage to the electronic device, thereby realizing power supply to the electronic device. The DC / DC converter provided in this application can change the connection relationship between the output end of the first rectification circuit, the output end of the second rectification circuit, and the output end of the DC / DC converter, thereby realizing step-up and step-down of the input voltage of the DC / DC converter, and further expanding the input voltage compatibility range of the DC / DC converter, with strong applicability.

[0055] The above is only an example of the application scenario of the DC / DC converter provided in this application, rather than an exhaustive list. This application does not limit the application scenario.

[0056] The following combines Figures 3 to 5 to give an example and explanation of the working principle of the DC / DC converter provided in this application.

[0057] Refer to Figure 3 , Figure 3 which is a schematic structural diagram of the DC / DC converter provided in this application. As Figure 3 shown, the DC / DC converter 1 includes an inverter circuit 11, a transformer 12, a first rectification circuit 13, a second rectification circuit 14, and a voltage management circuit 15. Among them, the input end of the inverter circuit 11 serves as the input end of the DC / DC converter 1 and is used to connect to a DC power supply. The transformer 12 includes a first primary winding 121, a first secondary winding 122, and a second secondary winding 123. The same-name end of the first primary winding 121 (i.e., the winding end with a marked point in the first primary winding 121) is connected to the first output end out111 of the inverter circuit 11, and the different-name end of the first primary winding 121 (i.e., the winding end without a marked point in the first primary winding 121) is connected to the second output end out112 of the inverter circuit 11; both ends of the first secondary winding 122 are connected to the two input ends of the first rectification circuit 13, and both ends of the second secondary winding 123 are connected to the two input ends of the second rectification circuit 14. The voltage management circuit 15 is connected to the output end of the first rectification circuit 13, the output end of the second rectification circuit 14, and the output end of the DC / DC converter 1.

[0058] In an alternative embodiment, the voltage management circuit 15 controls the output terminals of the first rectifier circuit 13, the output terminals of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 to be in a first connection relationship during a first sub-period within the first operating cycle, and controls the output terminals of the first rectifier circuit 13, the output terminals of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 to be in a second connection relationship during a second sub-period within the first operating cycle.

[0059] Specifically, when the controller is external to the voltage management circuit 15, the controller sends a first control signal and a second control signal to the voltage management circuit 15. The voltage management circuit 15 controls the output terminals of the first rectifier circuit 13, the output terminals of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 to be in a first connection relationship during the first sub-period according to the received first control signal, and controls the output terminals of the first rectifier circuit 13, the output terminals of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 to be in a second connection relationship during the second sub-period according to the received second control signal. It should be noted that when the controller is external to the voltage management circuit 15, the controller can be either a controller within the DC / DC converter 1 or a controller in other devices except the DC / DC converter 1, and the present application does not limit this.

[0060] Optionally, when the controller is within the voltage management circuit 15, the voltage management circuit 15 controls the output terminals of the first rectifier circuit 13, the output terminals of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 to be in a first connection relationship during a first sub-period within the first operating cycle, and controls the output terminals of the first rectifier circuit 13, the output terminals of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 to be in a second connection relationship during a second sub-period within the first operating cycle.

[0061] It can be understood that the voltage management circuit 15 can control the output terminals of the first rectifier circuit 13, the output terminals of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 to be in a first connection relationship and a second connection relationship within the first operating cycle, so as to realize step-up and step-down of the input voltage V of the DC / DC converter 1 by changing the connection relationship between the output terminals of the first rectifier circuit 13, the output terminals of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1. in Thereby ensuring that regardless of the value of V in the voltage value stably output by the DC / DC converter 1 can be the target output voltage, and further expanding the input voltage compatibility range of the DC / DC converter 1, with strong applicability.

[0062] Exemplarily, refer to Figure 4 , Figure 4It is another structural schematic diagram of the DC / DC converter provided by this application. As Figure 4 shown, the inverter circuit 11 includes switching transistors Q1-Q4, and these switching transistors are metal-oxide-semiconductor field-effect transistors MOSFETs. Among them, Q1 and Q2 are connected in series to form the first phase leg, and Q3 and Q4 are connected in series to form the second phase leg. The first end of the first phase leg (i.e., the drain of Q1) and the first end of the second phase leg (i.e., the drain of Q3) are connected to form the positive input terminal of the inverter circuit 11, that is, the positive input terminal of the DC / DC converter 1; the second end of the first phase leg (i.e., the source of Q2) and the second end of the second phase leg (i.e., the source of Q4) are connected to form the negative input terminal of the inverter circuit 11, that is, the negative input terminal of the DC / DC converter 1. The connection point of Q1 and Q2 forms the first output terminal out111 of the inverter circuit 11, and the connection point of Q3 and Q4 forms the second output terminal out112 of the inverter circuit 11. The transformer 12 further includes a first iron core 124, and the first primary winding 121, the first secondary winding 122, and the second secondary winding 123 are all coupled to the first iron core 124. The voltage management circuit 15 includes a first inductor L1, a first switching transistor Q5, a second switching transistor Q6, and a third switching transistor Q7. Among them, the first end of Q7 (i.e., the drain of Q7) is connected to the first output terminal of the first rectifier circuit 13 (i.e., the positive output terminal of the first rectifier circuit 13) and the second output terminal of the DC / DC converter 1 (i.e., the positive output terminal of the DC / DC converter 1), the second end of Q7 (i.e., the source of Q7) is connected to the first output terminal of the second rectifier circuit 14 (i.e., the positive output terminal of the second rectifier circuit 14) through L1, the second end of Q7 is connected to the first end of Q6 (i.e., the drain of Q6), the second end of Q6 (i.e., the source of Q6) is connected to the second output terminal of the first rectifier circuit 13 (i.e., the negative output terminal of the first rectifier circuit 13) and the first end of Q5 (i.e., the drain of Q5), and the second end of Q5 (i.e., the source of Q5) is connected to the second output terminal of the second rectifier circuit 14 (i.e., the negative output terminal of the second rectifier circuit 14) and the first output terminal of the DC / DC converter 1 (the negative output terminal of the DC / DC converter 1).

[0063] Optionally, the DC / DC converter 1 further includes a first resonant circuit 16. The first resonant circuit 16 includes an inductor Lr1 and a capacitor Cr1. The first output terminal out111 of the inverter circuit 11 is connected to the same-named terminal of the first primary winding 121 through the inductor Lr1 and the capacitor Cr1 in sequence. The first resonant circuit 16 is configured to convert the sinusoidal alternating current output by the inverter circuit 11 into a sinusoidal alternating current with a zero crossing point. The first resonant circuit 16 can reduce the switching loss of the switching tubes in the DC / DC converter 1. Among them, zero-voltage switching means that the switching is performed when the voltage across the switching tube in the DC / DC converter is 0, which can avoid the generation of switching loss. Zero-current switching means that the switching is performed when the current flowing through the switching tube in the DC / DC converter is 0, which can avoid the generation of switching loss.

[0064] Optionally, the DC / DC converter 1 further includes capacitors C1 and C2. The two ends of C1 are connected to the two output terminals of the first rectifier circuit 13, and are used for filtering and stabilizing the DC voltage output by the first rectifier circuit 13. The two ends of C2 are connected to the two output terminals of the second rectifier circuit 14, and are used for filtering and stabilizing the DC voltage output by the second rectifier circuit 14. Figure 4 The switching tubes in can also be IGBTs, triodes, etc.

[0065] The following takes the controller being located inside the voltage management circuit 15 as an example for illustration.

[0066] In an optional embodiment, after the DC / DC converter 1 starts to work, the controller in the voltage management circuit 15 controls the working states of Q5-Q7, so that the output terminal of the first rectifier circuit 13, the output terminal of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 are in a first connection relationship in the first sub-period within the first working cycle, and are in a second connection relationship in the second sub-period within the first working cycle.

[0067] Among them, the first connection relationship and the second connection relationship can be any two of the following connection relationships:

[0068] The branches where the output terminal of the first rectifier circuit 13 and the output terminal of the second rectifier circuit 14 are located are connected in series and then connected to the output terminal of the DC / DC converter 1; or

[0069] The branch where the output terminal of the second rectifier circuit 14 is located is connected to the output terminal of the DC / DC converter 1; or

[0070] The output terminal of the first rectifier circuit 13 is connected to the output terminal of the DC / DC converter 1, and the first end of the branch where the output terminal of the second rectifier circuit 14 is located is connected to the first output terminal of the DC / DC converter 1; and

[0071] The branch where the output terminal of the second rectifier circuit 14 is located is connected in parallel with the output terminal of the first rectifier circuit 13 to the output terminal of the DC / DC converter 1.

[0072] Specifically, after the DC / DC converter 1 starts to operate, the controller in the voltage management circuit 15 controls Q1 and Q4 to conduct in the third sub-period of the second working cycle and controls Q2 and Q3 to conduct in the fourth sub-period of the second working cycle by sending PWM waves to Q1 - Q4. Here, both the third sub-period and the fourth sub-period are half of the second working cycle. Thus, the direct current at the input terminal of the DC / DC converter 1 can be converted into sinusoidal alternating current through the inverter circuit 11, and then the sinusoidal alternating current output by the inverter circuit 11 can be transformed into a sinusoidal alternating current with zero crossing through the first resonant circuit 16. The transformer 12 transforms the alternating current output by the first resonant circuit 16 and outputs it to the output terminals of the first rectifier circuit 13 and the second rectifier circuit 14. The first rectifier circuit 13 rectifies the alternating current output by the first secondary winding 122 to obtain the output voltage of the first rectifier circuit 13, that is, the direct current voltage V1 = V in / N11; the second rectifier circuit 14 rectifies the alternating current output by the second secondary winding 123 to obtain the output voltage of the second rectifier circuit 14, that is, the direct current voltage V2 = V in / N12, where V in is the input voltage of the DC / DC converter 1, N11 is the turns ratio between the first primary winding 121 and the first secondary winding 122, and N12 is the turns ratio between the first primary winding 121 and the second secondary winding 123. The second working cycle here can be the same as or different from the first working cycle, and this application does not limit this.

[0073] Meanwhile, after the DC / DC converter 1 starts to operate, the controller in the voltage management circuit 15 acquires the input voltage V in of the DC / DC converter 1 and controls the connection relationship among the output terminal of the first rectifier circuit 13, the output terminal of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 according to V in

[0074] In an optional embodiment, when the input voltage V inWhen the voltage is less than the preset voltage, the controller controls Q5 to turn off and Q6 to turn on in the first sub-cycle. Here, the preset voltage is the product of the target output voltage and N11. Since Q6 and Q7 conduct complementarily, when Q6 conducts, Q7 is off. Therefore, in the first sub-cycle, the current flows from the positive output terminal of the second rectifier circuit 14 through L1, Q6, and C1 to the positive output terminal of the DC / DC converter 1. Then, it can be obtained that in the first sub-cycle, the branch where the output terminal of the first rectifier circuit 13 and the output terminal of the second rectifier circuit 14 are located (i.e., the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) is connected in series with the two output terminals of the DC / DC converter 1. At the same time, it can be obtained that in the first sub-cycle, the current change amount ΔI1 of L1 = (V1 + V2 - V out ) * D1 * T / L, where L is the inductance of L1, and D1 is the ratio of the first sub-cycle to the first working cycle T, that is, the duty cycle when Q6 conducts; and in the second sub-cycle, control Q5 to turn off and Q7 to turn on. Since Q6 and Q7 conduct complementarily, when Q7 conducts, Q6 is off. Therefore, in the second sub-cycle, the current flows from the positive output terminal of the second rectifier circuit 14 through L1 and Q7 to the positive output terminal of the DC / DC converter 1. Then, it can be obtained that in the second sub-cycle, the branch where the output terminal of the second rectifier circuit 14 is located (i.e., the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) is connected to the two output terminals of the DC / DC converter 1. At the same time, it can be obtained that in the second sub-cycle, the current change amount ΔI2 of L1 = (V out - V2) * (1 - D1) * T / L. Among them, the sum of the first sub-cycle and the second sub-cycle can be the first working cycle or a part of the first working cycle.

[0075] Since when the inductor is in a stable state, the current change amount during the inductor energy storage process is equal to the current change amount during the inductor energy release process. Therefore, when the sum of the first sub-cycle and the second sub-cycle is the first working cycle, it can be obtained that ΔI1 = ΔI2, and thus the output terminal voltage V of the DC / DC converter 1 can be obtained out = V1 * D1 + V2. Furthermore, the target output voltage that needs to be output stably by the DC / DC converter 1 can be obtained by adjusting the duty cycle D1 when Q6 conducts. It should be noted that when the sum of the first sub-cycle, the second sub-cycle, and the fifth sub-cycle is the first working cycle, and Q5 - Q7 are all off in the fifth sub-cycle, the output terminal voltage V of the DC / DC converter 1 can still be obtained out = V1 * D1 + V2. Furthermore, the target output voltage that needs to be output stably by the DC / DC converter 1 can still be obtained by adjusting the duty cycle D1 when Q6 conducts.

[0076] It can be understood that at the input voltage V of the DC / DC converter 1 inWhen the voltage is less than the preset voltage, the voltage V is subjected to voltage conversion and rectification through the transformer 12, the first rectification circuit 13, and the second rectification circuit 14 in When the output voltages of the first rectification circuit 13 and the second rectification circuit 14 obtained after voltage conversion and rectification do not reach the target output voltage, the operating states of the switching tubes in the voltage management circuit 15 can be controlled to make the voltage management circuit 15 step down the output voltage of the first rectification circuit 13, so as to ensure that the sum of the output voltage of the first rectification circuit 13 after stepping down and the output voltage of the second rectification circuit 14 is the target output voltage, that is, to ensure that the voltage at the output end of the DC / DC converter 1 is the target output voltage.

[0077] In another alternative embodiment, when the input voltage V of the DC / DC converter 1 in is greater than or equal to the preset voltage, the controller controls Q5 to conduct and Q6 to conduct in the first sub-cycle, where the preset voltage is the product of the target output voltage and N1. Since Q6 and Q7 conduct complementarily and Q7 is off when Q6 conducts, in the first sub-cycle, the current flows from the positive output terminal of the second rectification circuit 14 through L1, Q6, and Q5 to the negative output terminal of the second rectification circuit 14 in sequence. Then, it can be obtained that in the first sub-cycle, the two output terminals of the first rectification circuit 13 are connected to the two output terminals of the DC / DC converter 1, and the first end of the branch where the output terminal of the second rectification circuit 14 is located (that is, the branch formed by the series connection of the output terminal of the second rectification circuit 14 and L1) (that is, the end where L1 is connected to the drain of Q6) is connected to the first output terminal of the DC / DC converter 1 (that is, the negative output terminal of the DC / DC converter 1). At the same time, it can be obtained that in the first sub-cycle, the current change amount ΔI1 on L1 = V2*D1*T / L, where L is the inductance of L1 and D1 is the ratio of the first sub-cycle to the first working cycle T, that is, the duty cycle when Q6 conducts; and in the second sub-cycle, Q5 is controlled to conduct and Q7 is controlled to conduct. Since Q6 and Q7 conduct complementarily and Q6 is off when Q7 conducts, in the second sub-cycle, the current flows from the positive output terminal of the second rectification circuit 14 through L1 and Q7 to the positive output terminal of the DC / DC converter 1. Then, it can be obtained that in the second sub-cycle, the branch where the output terminal of the second rectification circuit 14 is located (that is, the branch formed by the series connection of the output terminal of the second rectification circuit 14 and L1) is connected in parallel with the output terminal of the first rectification circuit 13 to the two output terminals of the DC / DC converter 1. At the same time, it can be obtained that in the second sub-cycle, the current change amount ΔI2 on L1 = (V out - V2)*(1 - D1)*T / L. Among them, the sum of the first sub-cycle and the second sub-cycle can be the first working cycle or a part of the first working cycle.

[0078] Since the current change during the inductor energy storage process is equal to the current change during the inductor energy release process when the inductor is in a stable state, when the sum of the first sub-cycle and the second sub-cycle is the first working cycle, ΔI1=ΔI2 can be obtained, and thus the output voltage V of the DC / DC converter 1 can be obtained. out =V2 / (1-D1), and then the DC / DC converter 1 can stably output the target output voltage by adjusting the duty cycle D1 of Q6. It should be noted that when the sum of the first sub-period, the second sub-period and the fifth sub-period is the first working cycle, and when Q5-Q7 are all turned off in the fifth sub-period, the output voltage V of the DC / DC converter 1 can still be obtained. out =V2 / (1-D1), and thus the DC / DC converter 1 can still stably output the target output voltage by adjusting the duty cycle D1 of Q6.

[0079] It can be understood that the voltage V at the input of the DC / DC converter 1 is in When the voltage is greater than or equal to the preset voltage, the voltage V in When the output voltage of the first rectifier circuit 13 after voltage conversion and rectification does not reach the target output voltage and the output voltage of the second rectifier circuit 14 exceeds the target output voltage, the voltage management circuit 15 can be used to boost the output voltage of the second rectifier circuit 14 by controlling the working state of each switch tube in the voltage management circuit 15, and then discharge C1 through the electric energy stored on L1 to ensure that the output voltage of the first rectifier circuit 13 is increased to the target output voltage, that is, to ensure that the output terminal voltage of the DC / DC converter 1 is the target output voltage.

[0080] The following description will be made by taking an example where the controller is located outside the voltage management circuit 15 .

[0081] In an optional embodiment, the controller sends a first control signal and a second control signal to the voltage management circuit 15. Based on the received first control signal, the voltage management circuit 15 controls the output end of the first rectifier circuit 13 and the output end of the second rectifier circuit 14 to be in a first connection relationship with the output end of the DC / DC converter 1 in a first sub-period, and based on the received second control signal, controls the output end of the first rectifier circuit 13 and the output end of the second rectifier circuit 14 to be in a second connection relationship with the output end of the DC / DC converter 1 in a second sub-period.

[0082] The first connection relationship and the second connection relationship may be any two of the following connection relationships:

[0083] The output terminal of the first rectifier circuit 13 and the branch where the output terminal of the second rectifier circuit 14 is located are connected in series and then connected to the output terminal of the DC / DC converter 1; or

[0084] The branch where the output terminal of the second rectifier circuit 14 is located is connected to the output terminal of the DC / DC converter 1; or

[0085] The output terminal of the first rectifier circuit 13 is connected to the output terminal of the DC / DC converter 1, and the first end of the branch where the output terminal of the second rectifier circuit 14 is located is connected to the first output terminal of the DC / DC converter 1; and

[0086] The branch where the output terminal of the second rectifier circuit 14 is located is connected in parallel with the output terminal of the first rectifier circuit 13 to the output terminal of the DC / DC converter 1.

[0087] Specifically, after the DC / DC converter 1 starts to work, the controller controls Q1 and Q4 to conduct in the third sub-cycle within the second working cycle and controls Q2 and Q3 to conduct in the fourth sub-cycle within the second working cycle by sending PWM waves to Q1 - Q4. Here, both the third sub-cycle and the fourth sub-cycle are half of the second working cycle. Thus, the direct current at the input terminal of the DC / DC converter 1 can be converted into sinusoidal alternating current through the inverter circuit 11. The transformer 12 performs voltage transformation on the alternating current output by the inverter circuit 11 and outputs it to the output terminals of the first rectifier circuit 13 and the second rectifier circuit 14. The first rectifier circuit 13 rectifies the alternating current output by the first secondary winding 122 to obtain the output voltage of the first rectifier circuit 13, that is, the direct current voltage V1 = V in / N11; the second rectifier circuit 14 rectifies the alternating current output by the second secondary winding 123 to obtain the output voltage of the second rectifier circuit 14, that is, the direct current voltage V2 = V in / N12, where V in is the input voltage of the DC / DC converter 1, N11 is the turns ratio between the first primary winding 121 and the first secondary winding 122, and N12 is the turns ratio between the first primary winding 121 and the second secondary winding 123. The second working cycle here can be the same as or different from the first working cycle, and this application does not limit this.

[0088] Meanwhile, after the DC / DC converter 1 starts to work, the controller obtains the input voltage V in of the DC / DC converter 1 and sends a control signal to the voltage management circuit 15 according to V in so that the voltage management circuit 15 controls the connection relationship among the output terminal of the first rectifier circuit 13, the output terminal of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 according to the received control signal.

[0089] In an optional embodiment, when the input voltage V of the DC / DC converter 1 in is less than a preset voltage, the controller sends a first control signal and a second control signal to the voltage management circuit 15. Wherein, the preset voltage is the product of the target output voltage and N1. Q5 and Q6 in the voltage management circuit 15 are in the off state and on state respectively in the first sub-period according to the received first control signal. Since Q6 and Q7 conduct complementarily, when Q6 conducts, Q7 is off. Therefore, in the first sub-period, the current flows from the positive output terminal of the second rectifier circuit 14 through L1, Q6 and C1 to the positive output terminal of the DC / DC converter 1. Then it can be obtained that in the first sub-period, the branch where the output terminal of the first rectifier circuit 13 and the output terminal of the second rectifier circuit 14 are located (that is, the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) is connected in series with the two output terminals of the DC / DC converter 1. At the same time, it can be obtained that in the first sub-period, the current change amount ΔI1 of L1 = (V1 + V2 - V out ) * D1 * T / L, where L is the inductance of L1, and D1 is the ratio of the first sub-period to the first working period T, that is, the duty cycle when Q6 conducts; Q5 and Q7 in the voltage management circuit 15 are in the off state and on state respectively in the second sub-period according to the received second control signal. Since Q6 and Q7 conduct complementarily, when Q7 conducts, Q6 is off. Therefore, in the second sub-period, the current flows from the positive output terminal of the second rectifier circuit 14 through L1 and Q7 to the positive output terminal of the DC / DC converter 1. Then it can be obtained that in the second sub-period, the branch where the output terminal of the second rectifier circuit 14 is located (that is, the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) is connected to the two output terminals of the DC / DC converter 1. At the same time, it can be obtained that in the second sub-period, the current change amount ΔI2 of L1 = (V out - V2) * (1 - D1) * T / L. Wherein, the sum of the first sub-period and the second sub-period can be the first working period, or a part of the first working period.

[0090] Since when the inductor is in a stable state, the current change amount during the inductor energy storage process is equal to the current change amount during the inductor energy release process. Therefore, when the sum of the first sub-period and the second sub-period is the first working period, it can be obtained that ΔI1 = ΔI2. Thus, the output voltage V of the DC / DC converter 1 out = V1 * D1 + V2. Furthermore, the target output voltage that needs to be output stably by the DC / DC converter 1 can be obtained by adjusting the duty cycle D1 when Q6 conducts. It should be noted that when the sum of the first sub-period, the second sub-period and the fifth sub-period is the first working period, and Q5 - Q7 are all off in the fifth sub-period, the output voltage V of the DC / DC converter 1 can still be obtained out=V1*D1+V2, and thus the DC / DC converter 1 can still stably output the target output voltage by adjusting the duty cycle D1 of Q6.

[0091] It can be understood that the voltage V at the input of the DC / DC converter 1 is in When the voltage is less than the preset voltage, the voltage V in When the output voltage of the first rectifier circuit 13 and the output voltage of the second rectifier circuit 14 obtained after voltage conversion and rectification do not reach the target output voltage, the voltage management circuit 15 can control the working state of each switch tube in the voltage management circuit 15 to cause the voltage management circuit 15 to step down the output voltage of the first rectifier circuit 13 to ensure that the sum of the output voltage of the first rectifier circuit 13 and the output voltage of the second rectifier circuit 14 after stepping down is the target output voltage, that is, to ensure that the output terminal voltage of the DC / DC converter 1 is the target output voltage.

[0092] In another alternative embodiment, the voltage V at the input terminal of the DC / DC converter 1 is inWhen it is greater than or equal to a preset voltage, the controller sends a first control signal and a second control signal to the voltage management circuit 15, where the preset voltage is the product of the target output voltage and N1. Q5 and Q6 in the voltage management circuit 15 are in the on state during the first sub-cycle according to the received first control signal. Since Q6 and Q7 are complementary and conduct, when Q6 conducts, Q7 is off. Therefore, during the first sub-cycle, the current flows from the positive output terminal of the second rectifier circuit 14 through L1, Q6, and Q5 to the negative output terminal of the second rectifier circuit 14. Then it can be obtained that during the first sub-cycle, the two output terminals of the first rectifier circuit 13 are connected to the two output terminals of the DC / DC converter 1, and the first end of the branch where the output terminal of the second rectifier circuit 14 is located (that is, the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) (that is, the end where L1 is connected to the drain of Q6) is connected to the first output terminal of the DC / DC converter 1 (that is, the negative output terminal of the DC / DC converter 1). At the same time, it can be obtained that during the first sub-cycle, the current change amount ΔI1 on L1 = V2 * D1 * T / L, where L is the inductance of L1, and D1 is the ratio of the first sub-cycle to the first working cycle T, that is, the duty cycle when Q6 conducts; Q5 and Q7 in the voltage management circuit 15 are in the on state during the second sub-cycle according to the received second control signal. Since Q6 and Q7 are complementary and conduct, when Q7 conducts, Q6 is off. Therefore, during the second sub-cycle, the current flows from the positive output terminal of the second rectifier circuit 14 through L1 and Q7 to the positive output terminal of the DC / DC converter 1. Then it can be obtained that during the second sub-cycle, the branch where the output terminal of the second rectifier circuit 14 is located (that is, the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) is connected in parallel with the output terminal of the first rectifier circuit 13 to the two output terminals of the DC / DC converter 1. At the same time, it can be obtained that during the second sub-cycle, the current change amount ΔI2 on L1 = (V out - V2) * (1 - D1) * T / L. Among them, the sum of the first sub-cycle and the second sub-cycle can be the first working cycle or a part of the first working cycle.

[0093] Since when the inductor is in a stable state, the current change amount during the inductor energy storage process is equal to the current change amount during the inductor energy release process. Therefore, when the sum of the first sub-cycle and the second sub-cycle is the first working cycle, it can be obtained that ΔI1 = ΔI2, and thus the output terminal voltage V of the DC / DC converter 1 can be obtained out = V2 / (1 - D1). Furthermore, the target output voltage that needs to be output stably by the DC / DC converter 1 can be obtained by adjusting the duty cycle D1 when Q6 conducts. It should be noted that when the sum of the first sub-cycle, the second sub-cycle, and the fifth sub-cycle is the first working cycle, and Q5 - Q7 are all off during the fifth sub-cycle, the output terminal voltage V of the DC / DC converter 1 can still be obtainedout = V2 / (1 - D1), and thus the target output voltage required for stable output of the DC / DC converter 1 can still be achieved by adjusting the duty cycle D1 of Q6 conduction.

[0094] It can be understood that when the input voltage V of the DC / DC converter 1 in is greater than or equal to the preset voltage, after voltage conversion and rectification by the transformer 12, the first rectification circuit 13, and the second rectification circuit 14 for V in if the output voltage of the first rectification circuit 13 does not reach the target output voltage and the output voltage of the second rectification circuit 14 exceeds the target output voltage after voltage conversion and rectification, the working states of the switching tubes in the voltage management circuit 15 can be controlled to boost the output voltage of the second rectification circuit 14 by the voltage management circuit 15, and then the electric energy stored in L1 is used to discharge C1 to ensure that the output voltage of the first rectification circuit 13 rises to the target output voltage, that is, to ensure that the output voltage of the DC / DC converter 1 is the target output voltage.

[0095] In this embodiment, the buck-boost of the input voltage V of the DC / DC converter 1 can be achieved by presetting N11 and N12, and then according to the magnitude relationship between V in and the preset voltage, the connection relationship between the output terminal of the first rectification circuit 13, the output terminal of the second rectification circuit 14, and the output terminal of the DC / DC converter 1 is changed by the voltage management circuit 15 to further buck-boost V in so as to ensure that no matter what value V in takes, the voltage value stably output by the DC / DC converter 1 can be the target output voltage, thereby expanding the input voltage compatibility range of the DC / DC converter 1 and having strong applicability. in

[0096] Exemplarily, please refer to Figure 5 , Figure 5 which is another structural schematic diagram of the DC / DC converter provided by the present application. As shown in Figure 5 ​As shown, the inverter circuit 11 includes switching transistors Q1 - Q4, Q8, and Q9, which are metal - oxide - semiconductor field - effect transistors (MOSFETs). Among them, Q1 and Q2 are connected in series to form the first phase leg, Q3 and Q4 are connected in series to form the second phase leg, and Q8 and Q9 are connected in series to form the third phase leg. The first ends of the first phase leg (i.e., the drain of Q1), the second phase leg (i.e., the drain of Q3), and the third phase leg (i.e., the drain of Q8) are connected to form the positive input terminal of the inverter circuit 11, which is also the positive input terminal of the DC / DC converter 1. The second ends of the first phase leg (i.e., the source of Q2), the second phase leg (i.e., the source of Q4), and the third phase leg (i.e., the source of Q9) are connected to form the negative input terminal of the inverter circuit 11, which is also the negative input terminal of the DC / DC converter 1. The connection between Q1 and Q2 forms the first output terminal out111 of the inverter circuit 11, the connection between Q3 and Q4 forms the second output terminal out112 of the inverter circuit 11, and the connection between Q8 and Q9 forms the third output terminal out113 of the inverter circuit 11. The transformer 12 further includes a first iron core 124, a second primary winding 125, and a second iron core 126. The first primary winding 121 and the first secondary winding 122 are coupled to the first iron core 124, and the second primary winding 125 and the second secondary winding 123 are coupled to the second iron core 126. The voltage management circuit 15 includes a first inductor L1, a first switching transistor Q5, a second switching transistor Q6, and a third switching transistor Q7. Among them, the first end of Q7 (i.e., the drain of Q7) is connected to the first output terminal of the first rectifier circuit 13 (i.e., the positive output terminal of the first rectifier circuit 13) and the second output terminal of the DC / DC converter 1 (i.e., the positive output terminal of the DC / DC converter 1). The second end of Q7 (i.e., the source of Q7) is connected to the first output terminal of the second rectifier circuit 14 (i.e., the positive output terminal of the second rectifier circuit 14) through L1. The second end of Q7 is connected to the first end of Q6 (i.e., the drain of Q6). The second end of Q6 (i.e., the source of Q6) is connected to the second output terminal of the first rectifier circuit 13 (i.e., the negative output terminal of the first rectifier circuit 13) and the first end of Q5 (i.e., the drain of Q5). The second end of Q5 (i.e., the source of Q5) is connected to the second output terminal of the second rectifier circuit 14 (i.e., the negative output terminal of the second rectifier circuit 14) and the first output terminal of the DC / DC converter 1 (the negative output terminal of the DC / DC converter 1).

[0097] Optionally, the DC / DC converter 1 further includes a first resonant circuit 16 and a second resonant circuit 17. The first resonant circuit 16 includes an inductor Lr1 and a capacitor Cr1. The first output terminal out111 of the inverter circuit 11 is sequentially connected to the same-named terminal of the first primary winding 121 through Lr1 and Cr1. The first resonant circuit 16 is configured to convert the sinusoidal alternating current output by the inverter circuit 11 into a sinusoidal alternating current with a zero crossing point. The second resonant circuit 17 includes an inductor Lr2 and a capacitor Cr2. The third output terminal out113 of the inverter circuit 11 is sequentially connected to the different-named terminal of the second primary winding 125 through Lr2 and Cr2. The second resonant circuit 17 is configured to convert the sinusoidal alternating current output by the inverter circuit 11 into a sinusoidal alternating current with a zero crossing point. Wherein, the resonant parameters of the first resonant circuit 16 are the same as those of the second resonant circuit 17, that is, Lr1 = Lr2 and Cr1 = Cr2. Both the first resonant circuit 16 and the second resonant circuit 17 can reduce the switching tube loss when the switching tubes in the DC / DC converter 1 are in zero-voltage switching or zero-current switching.

[0098] Optionally, the DC / DC converter 1 further includes capacitors C1 and C2. Two ends of C1 are connected to two output terminals of the first rectifier circuit 13, and are configured to filter and regulate the DC voltage output by the first rectifier circuit 13. Two ends of C2 are connected to two output terminals of the second rectifier circuit 14, and are configured to filter and regulate the DC voltage output by the second rectifier circuit 14. Figure 5 Each switching tube in can also be an IGBT, a triode, etc.

[0099] The following takes the controller being located inside the voltage management circuit 15 as an example for illustration.

[0100] In an optional implementation manner, after the DC / DC converter 1 starts to work, the controller in the voltage management circuit 15 controls the working states of Q5-Q7, so that the output terminal of the first rectifier circuit 13, the output terminal of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 are in a first connection relationship in a first sub-period within a first working period, and are in a second connection relationship in a second sub-period within the first working period.

[0101] Wherein, the first connection relationship and the second connection relationship can be any two of the following connection relationships:

[0102] The branches where the output terminal of the first rectifier circuit 13 and the output terminal of the second rectifier circuit 14 are located are connected in series and then connected to the output terminal of the DC / DC converter 1; or

[0103] The branch where the output terminal of the second rectifier circuit 14 is located is connected to the output terminal of the DC / DC converter 1; or

[0104] The output terminal of the first rectifier circuit 13 is connected to the output terminal of the DC / DC converter 1, and the first end of the branch where the output terminal of the second rectifier circuit 14 is located is connected to the first output terminal of the DC / DC converter 1; and

[0105] The branch where the output terminal of the second rectifier circuit 14 is located is connected in parallel with the output terminal of the first rectifier circuit 13 to the output terminal of the DC / DC converter 1.

[0106] Specifically, after the DC / DC converter 1 starts to work, the controller in the voltage management circuit 15 obtains the input voltage V of the DC / DC converter 1 in , and according to V in controls the working states of the switching tubes in the inverter circuit 11, and the connection relationship among the output terminal of the first rectifier circuit 13, the output terminal of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1.

[0107] In an alternative embodiment, when the input voltage V of the DC / DC converter 1 in is less than the preset voltage, the controller in the voltage management circuit 15 controls Q1, Q4, and Q8 to conduct in the third sub-period of the second working period and controls Q2, Q3, and Q9 to conduct in the fourth sub-period of the second working period by sending PWM waves to Q1-Q4, Q8, and Q9. Here, the preset voltage is the product of the target output voltage and N1, where N1 is the turns ratio between the first primary winding 121 and the first secondary winding 122. Both the third sub-period and the fourth sub-period are half of the second working period, and the second working period is the same as the working period of the first resonant circuit 16. Here, the second working period and the first working period may be the same or different, and the present application does not limit this. Since in the third sub-period, after the current flows into the positive input terminal of the DC / DC converter 1, part of the current sequentially passes through Q1, Lr1, Cr1, the first primary winding 121, and Q4 and flows to the negative input terminal of the DC / DC converter 1, and the other part of the current sequentially passes through Q8, Lr2, Cr2, the second primary winding 125, and Q4 and flows to the negative input terminal of the DC / DC converter 1; in the fourth sub-period, after the current flows into the positive input terminal of the DC / DC converter 1, part of the current sequentially passes through Q3, the first primary winding 121, Cr1, Lr1, and Q2 and flows to the negative input terminal of the DC / DC converter 1, and the other part of the current sequentially passes through Q3, the second primary winding 125, Cr2, Lr2, and Q9 and flows to the negative input terminal of the DC / DC converter 1. Therefore, it can be obtained that the first primary winding 121 and the second primary winding 125 are connected in parallel to the two voltage input terminals of the DC / DC converter 1 within the second working period.

[0108] Since both the third sub - cycle and the fourth sub - cycle are half of the second working cycle, the direct current at the input end of the DC / DC converter 1 can be converted into sinusoidal alternating current by the inverter circuit 11. Then, through the first resonant circuit 16 and the second resonant circuit 17, the sinusoidal alternating current output by the inverter circuit 11 is converted into a zero - crossing sinusoidal alternating current and output to the first primary winding 121 and the second primary winding 125. The alternating current flowing through the first primary winding 121 generates an alternating magnetic flux. Through the magnetic conduction of the first iron core 124, an alternating current is induced in the first secondary winding 122, and the induced alternating current is output to the output end of the first rectifier circuit 13; the alternating current flowing through the second primary winding 125 generates an alternating magnetic flux. Through the magnetic conduction of the second iron core 126, an alternating current is induced in the second secondary winding 123, and the induced alternating current is output to the output end of the second rectifier circuit 14. The first rectifier circuit 13 rectifies the alternating current output by the first secondary winding 122 to obtain the output voltage of the first rectifier circuit 13, that is, the DC voltage V1 = V in / N1; the second rectifier circuit 14 rectifies the alternating current output by the second secondary winding 123 to obtain the output voltage of the second rectifier circuit 14, that is, the DC voltage V2 = V in / N2, where V in is the input - end voltage of the DC / DC converter 1, N1 is the turns ratio between the first primary winding 121 and the first secondary winding 122, and N2 is the turns ratio between the second primary winding 125 and the second secondary winding 123.

[0109] At the same time, when the input - end voltage V in of the DC / DC converter 1 is less than the preset voltage, the controller in the voltage management circuit 15 controls Q5 to turn off and Q6 to turn on in the first sub - cycle. Since Q6 and Q7 conduct complementarily and Q7 turns off when Q6 turns on, in the first sub - cycle, the current flows from the positive output end of the second rectifier circuit 14 through L1, Q6, and C1 to the positive output end of the DC / DC converter 1 in sequence. Then, it can be obtained that in the first sub - cycle, the branch where the output ends of the first rectifier circuit 13 and the second rectifier circuit 14 are located (that is, the branch formed by the series connection of the output end of the second rectifier circuit 14 and L1) is connected in series with the two output ends of the DC / DC converter 1. At the same time, it can be obtained that in the first sub - cycle, the current change amount ΔI1 on L1 = (V1 + V2 - V out)*D1*T / L, where L is the inductance of L1, D1 is the ratio between the first sub - period and the first working period T, that is, the duty cycle when Q6 conducts; and in the second sub - period, control Q5 to turn off and Q7 to conduct. Since Q6 and Q7 conduct complementarily, when Q7 conducts, Q6 is off. Therefore, in the second sub - period, the current flows from the positive output terminal of the second rectifier circuit 14 through L1 and Q7 to the positive output terminal of the DC / DC converter 1. Then, it can be obtained that in the second sub - period, the branch where the output terminal of the second rectifier circuit 14 is located (that is, the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) is connected to the two output terminals of the DC / DC converter 1. At the same time, it can be obtained that in the second sub - period, the current change amount ΔI2 of L1=(V out -V2)*(1 - D1)*T / L. Among them, the sum of the first sub - period and the second sub - period can be the first working period or a part of the first working period.

[0110] Since when the inductor is in a stable state, the current change amount during the inductor energy storage process is equal to the current change amount during the inductor energy release process. Therefore, when the sum of the first sub - period and the second sub - period is the first working period, it can be obtained that ΔI1 = ΔI2, and thus the output terminal voltage V of the DC / DC converter 1 can be obtained out =V1*D1 + V2. Furthermore, the target output voltage that needs to be output can be stably output by adjusting the duty cycle D1 when Q6 conducts. It should be noted that when the sum of the first sub - period, the second sub - period and the fifth sub - period is the first working period, and Q5 - Q7 are all turned off in the fifth sub - period, the output terminal voltage V of the DC / DC converter 1 can still be obtained out =V1*D1 + V2. Furthermore, the target output voltage that needs to be output can still be stably output by adjusting the duty cycle D1 when Q6 conducts.

[0111] It can be understood that when the input terminal voltage V of the DC / DC converter 1 in is less than the preset voltage, the first primary winding 121 and the second primary winding 125 are controlled to be connected in parallel to the two voltage input terminals of the DC / DC converter 1 through the inverter circuit 11, and the working states of the switching tubes in the voltage management circuit 15 are controlled to step - down the output voltage of the first rectifier circuit 14 by the voltage management circuit 15, so as to ensure that the sum of the output voltage of the stepped - down first rectifier circuit 13 and the output voltage of the second rectifier circuit 14 is the target output voltage, that is, to ensure that the output terminal voltage of the DC / DC converter 1 is the target output voltage.

[0112] In another alternative embodiment, when the input terminal voltage V of the DC / DC converter 1 inWhen the voltage is greater than or equal to a preset voltage, the controller in the voltage management circuit 15 controls Q3 and Q4 to turn off and controls Q1 and Q9 to conduct in the third sub-cycle within the second working cycle and Q2 and Q8 to conduct in the fourth sub-cycle within the second working cycle by sending PWM waves to Q1-Q4, Q8, and Q9. Here, the preset voltage is the product of the target output voltage and N1, where N1 is the turns ratio between the first primary winding 121 and the first secondary winding 122. Both the third sub-cycle and the fourth sub-cycle are half of the second working cycle, and the second working cycle is the same as the working cycle of the first resonant circuit 16. The second working cycle and the first working cycle here can be the same or different, and this application does not limit this. Since in the third cycle, after the current flows into the positive input terminal of the DC / DC converter 1, it successively passes through Q1, Lr1, Cr1, the first primary winding 121, the second primary winding 125, Cr2, Lr2, and Q9 and flows to the negative input terminal of the DC / DC converter 1; in the fourth sub-cycle, after the current flows into the positive input terminal of the DC / DC converter 1, it successively passes through Q8, Lr2, Cr2, the second primary winding 125, the first primary winding 121, Cr1, Lr1, and Q2 and flows to the negative input terminal of the DC / DC converter 1. Therefore, it can be obtained that the first primary winding 121 and the second primary winding 125 are connected in series and then connected to the two voltage input terminals of the DC / DC converter 1 within the second working cycle.

[0113] Since both the third sub-cycle and the fourth sub-cycle are half of the second working cycle, the direct current at the input terminal of the DC / DC converter 1 can be converted into sinusoidal alternating current through the inverter circuit 11, and then the sinusoidal alternating current output by the inverter circuit 11 can be converted into a zero-crossing sinusoidal alternating current through the first resonant circuit 16 and the second resonant circuit 17 and output to the first primary winding 121 and the second primary winding 125. The alternating current flowing through the first primary winding 121 generates an alternating magnetic flux. Through the magnetic conduction of the first iron core 124, an alternating current is induced in the first secondary winding 122, and the induced alternating current is output to the output terminal of the first rectifier circuit 13; the alternating current flowing through the second primary winding 125 generates an alternating magnetic flux. Through the magnetic conduction of the second iron core 126, an alternating current is induced in the second secondary winding 123, and the induced alternating current is output to the output terminal of the second rectifier circuit 14. The first rectifier circuit 13 rectifies the alternating current output by the first secondary winding 122 to obtain the output voltage of the first rectifier circuit 13, that is, the DC voltage V1 = V in1 / N1; the second rectifier circuit 14 rectifies the alternating current output by the second secondary winding 123 to obtain the output voltage of the second rectifier circuit 14, that is, the DC voltage V2 = V in2 / N2, where, V in1 = V in *Z1 / (Z1 + Z2), Vin2 = V in * Z2 / (Z1 + Z2), where Z1 is the AC impedance after the first primary winding 121 is connected in parallel with C1, and Z2 is the AC impedance after the second primary winding 125 is connected in parallel with C2, and V in is the input voltage of the DC / DC converter 1.

[0114] Meanwhile, when the input voltage V of the DC / DC converter 1 in is greater than or equal to the preset voltage, the controller in the voltage management circuit 15 controls Q5 to conduct and Q6 to conduct in the first sub-cycle. Since Q6 and Q7 conduct complementarily, when Q6 conducts, Q7 is off. Therefore, in the first sub-cycle, the current flows from the positive output terminal of the second rectifier circuit 14 through L1, Q6, and Q5 to the negative output terminal of the second rectifier circuit 14. Then, it can be obtained that in the first sub-cycle, the two output terminals of the first rectifier circuit 13 are connected to the two output terminals of the DC / DC converter 1, and the first end of the branch where the output terminal of the second rectifier circuit 14 is located (i.e., the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) (i.e., the end where L1 is connected to the drain of Q6) is connected to the first output terminal of the DC / DC converter 1 (i.e., the negative output terminal of the DC / DC converter 1). At the same time, it can be obtained that in the first sub-cycle, the current change amount ΔI1 on L1 = V2 * D1 * T / L, where L is the inductance of L1, and D1 is the ratio between the first sub-cycle and the first working cycle T, that is, the duty cycle when Q6 conducts; and in the second sub-cycle, Q5 is controlled to conduct and Q7 is controlled to conduct. Since Q6 and Q7 conduct complementarily, when Q7 conducts, Q6 is off. Therefore, in the second sub-cycle, the current flows from the positive output terminal of the second rectifier circuit 14 through L1 and Q7 to the positive output terminal of the DC / DC converter 1. Then, it can be obtained that in the second sub-cycle, the branch where the output terminal of the second rectifier circuit 14 is located (i.e., the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) is connected in parallel with the output terminals of the first rectifier circuit 13 to the two output terminals of the DC / DC converter 1. At the same time, it can be obtained that in the second sub-cycle, the current change amount ΔI2 on L1 = (V out - V2) * (1 - D1) * T / L. Among them, the sum of the first sub-cycle and the second sub-cycle can be the first working cycle or a part of the first working cycle.

[0115] Since when the inductor is in a stable state, the current change amount during the inductor energy storage process is equal to the current change amount during the inductor energy release process. Therefore, when the sum of the first sub-cycle and the second sub-cycle is the first working cycle, it can be obtained that ΔI1 = ΔI2, and thus the output voltage V of the DC / DC converter 1 can be obtained out= V2 / (1 - D1). Further, the target output voltage required to be output stably by the DC / DC converter 1 can be achieved by adjusting the duty cycle D1 of Q6 conduction. It should be noted that when the sum of the first sub-cycle, the second sub-cycle, and the fifth sub-cycle is the first working cycle, and Q5 - Q7 are all turned off in the fifth sub-cycle, the output voltage V at the output terminal of the DC / DC converter 1 can still be obtained. out = V2 / (1 - D1). Further, the target output voltage required to be output stably by the DC / DC converter 1 can still be achieved by adjusting the duty cycle D1 of Q6 conduction.

[0116] It can be understood that when the input voltage V at the input terminal of the DC / DC converter 1 in is greater than or equal to the preset voltage, by controlling the series connection of the first primary winding 121 and the second primary winding 125 to the two voltage input terminals of the DC / DC converter
, and controlling the operating states of the switching tubes in the voltage management circuit 15 to boost the output voltage of the second rectification circuit 14 by the voltage management circuit 15, and then discharging the electrical energy stored in L1 to C1 to ensure that the output voltage of the first rectification circuit 13 rises to the target output voltage, that is, ensuring that the output voltage at the output terminal of the DC / DC converter 1 is the target output voltage.

[0117] The following will be described by taking the controller being located outside the voltage management circuit 15 as an example.

[0118] In an alternative embodiment, the controller sends a first control signal and a second control signal to the voltage management circuit 15. According to the received first control signal, the voltage management circuit 15 controls the output terminal of the first rectification circuit 13, the output terminal of the second rectification circuit 14, and the output terminal of the DC / DC converter 1 to be in a first connection relationship in the first sub-cycle, and according to the received second control signal, controls the output terminal of the first rectification circuit 13, the output terminal of the second rectification circuit 14, and the output terminal of the DC / DC converter 1 to be in a second connection relationship in the second sub-cycle.

[0119] Among them, the first connection relationship and the second connection relationship can be any two of the following connection relationships:

[0120] The branch where the output terminal of the first rectification circuit 13 and the output terminal of the second rectification circuit 14 are located are connected in series and then connected to the output terminal of the DC / DC converter 1; or

[0121] The branch where the output terminal of the second rectification circuit 14 is located is connected to the output terminal of the DC / DC converter 1; or

[0122] The output terminal of the first rectification circuit 13 is connected to the output terminal of the DC / DC converter 1, and the first end of the branch where the output terminal of the second rectification circuit 14 is located is connected to the first output terminal of the DC / DC converter 1; and

[0123] The branch where the output terminal of the second rectifier circuit 14 is located is connected in parallel with the output terminal of the first rectifier circuit 13 to the output terminal of the DC / DC converter 1.

[0124] Specifically, after the DC / DC converter 1 starts to work, the controller obtains the input voltage V of the DC / DC converter 1 in , and based on V in sends control signals to the inverter circuit 11 and the voltage management circuit 15, so that the inverter circuit 11 controls the working states of the respective switching tubes in the inverter circuit 11 according to the received control signals, and the voltage management circuit 15 controls the connection relationship among the output terminal of the first rectifier circuit 13, the output terminal of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 according to the received control signals.

[0125] In an alternative embodiment, when the input voltage V of the DC / DC converter 1 in is less than a preset voltage, the controller sends a third control signal to the inverter circuit 11, where the preset voltage is the product of the target output voltage and N1, and N1 is the turns ratio between the first primary winding 121 and the first secondary winding 122. Q1-Q4, Q8, and Q9 in the inverter circuit 11 are in the conducting state during the third sub-period in the second working period and Q2, Q3, and Q9 are in the conducting state during the fourth sub-period in the second working period according to the received third control signal, where both the third sub-period and the fourth sub-period are half of the second working period, and the second working period is the same as the working period of the first resonant circuit 16. Here, the second working period and the first working period may be the same or different, and the present application does not limit this. Since in the third sub-period, after the current flows into the positive input terminal of the DC / DC converter 1, a part of the current successively passes through Q1, Lr1, Cr1, the first primary winding 121, and Q4 and flows to the negative input terminal of the DC / DC converter 1, and another part of the current successively passes through Q8, Lr2, Cr2, the second primary winding 125, and Q4 and flows to the negative input terminal of the DC / DC converter 1; in the fourth sub-period, after the current flows into the positive input terminal of the DC / DC converter 1, a part of the current successively passes through Q3, the first primary winding 121, Cr1, Lr1, and Q2 and flows to the negative input terminal of the DC / DC converter 1, and another part of the current successively passes through Q3, the second primary winding 125, Cr2, Lr2, and Q9 and flows to the negative input terminal of the DC / DC converter 1. Therefore, it can be obtained that the first primary winding 121 and the second primary winding 125 are connected in parallel to the two voltage input terminals of the DC / DC converter 1 during the second working period.

[0126] Since both the third sub-cycle and the fourth sub-cycle are half of the second working cycle, the direct current at the input end of the DC / DC converter 1 can be converted into sinusoidal alternating current by the inverter circuit 11. Then, the sinusoidal alternating current output by the inverter circuit 11 is converted into a zero-crossing sinusoidal alternating current through the first resonant circuit 16 and the second resonant circuit 17 and output to the first primary winding 121 and the second primary winding 125. The alternating current flowing through the first primary winding 121 generates an alternating magnetic flux. Through the magnetic conduction of the first iron core 124, an alternating current is induced in the first secondary winding 122, and the induced alternating current is output to the output end of the first rectifier circuit 13. The alternating current flowing through the second primary winding 125 generates an alternating magnetic flux. Through the magnetic conduction of the second iron core 126, an alternating current is induced in the second secondary winding 123, and the induced alternating current is output to the output end of the second rectifier circuit 14. The first rectifier circuit 13 rectifies the alternating current output by the first secondary winding 122 to obtain the output voltage of the first rectifier circuit 13, that is, the DC voltage V1 = V in / N1; the second rectifier circuit 14 rectifies the alternating current output by the second secondary winding 123 to obtain the output voltage of the second rectifier circuit 14, that is, the DC voltage V2 = V in / N2, where V in is the input voltage of the DC / DC converter 1, N1 is the turns ratio between the first primary winding 121 and the first secondary winding 122, and N2 is the turns ratio between the second primary winding 125 and the second secondary winding 123.

[0127] At the same time, when the input voltage V in of the DC / DC converter 1 is less than the preset voltage, the controller sends a first control signal and a second control signal to the voltage management circuit 15. Q5 and Q6 in the voltage management circuit 15 are in the off state and on state respectively in the first sub-cycle according to the received first control signal. Since Q6 and Q7 are complementary-conducting, when Q6 is conducting, Q7 is off. Therefore, in the first sub-cycle, the current flows from the positive output end of the second rectifier circuit 14 through L1, Q6 and C1 to the positive output end of the DC / DC converter 1 in sequence. Then, it can be obtained that in the first sub-cycle, the branch where the output end of the first rectifier circuit 13 and the output end of the second rectifier circuit 14 are located (that is, the branch formed by the series connection of the output end of the second rectifier circuit 14 and L1) is connected in series with the two output ends of the DC / DC converter 1. At the same time, it can be obtained that in the first sub-cycle, the current change amount ΔI1 of L1 = (V1 + V2 - V out)*D1*T / L, where L is the inductance of L1, and D1 is the ratio between the first sub-period and the first working period T, that is, the duty cycle of Q6 conduction; Q5 and Q7 in the voltage management circuit 15 are in the off state and on state respectively in the second sub-period according to the received second control signal. Since Q6 and Q7 conduct complementarily, when Q7 conducts, Q6 is off. Therefore, in the second sub-period, the current flows from the positive output terminal of the second rectifier circuit 14 through L1 and Q7 to the positive output terminal of the DC / DC converter 1. Then, it can be obtained that the branch where the output terminal of the second rectifier circuit 14 is located (that is, the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) is connected to the two output terminals of the DC / DC converter 1 in the second sub-period. At the same time, it can be obtained that in the second sub-period, the current change amount ΔI2 of L1 = (V out -V2)*(1 - D1)*T / L. Among them, the sum of the first sub-period and the second sub-period can be the first working period or a part of the first working period.

[0128] Since when the inductor is in a stable state, the current change amount during the inductor energy storage process is equal to the current change amount during the inductor energy release process, when the sum of the first sub-period and the second sub-period is the first working period, ΔI1 = ΔI2 can be obtained. Thus, the output terminal voltage V of the DC / DC converter 1 can be obtained out = V1*D1 + V2. Furthermore, the target output voltage that needs to be output can be stably output by adjusting the duty cycle D1 of Q6 conduction. It should be noted that when the sum of the first sub-period, the second sub-period and the fifth sub-period is the first working period, and Q5 - Q7 are all off in the fifth sub-period, the output terminal voltage V of the DC / DC converter 1 can still be obtained out = V1*D1 + V2. Furthermore, the target output voltage that needs to be output can still be stably output by adjusting the duty cycle D1 of Q6 conduction.

[0129] It can be understood that when the input terminal voltage V of the DC / DC converter 1 in is less than the preset voltage, the first primary winding 121 and the second primary winding 125 are controlled to be connected in parallel to the two voltage input terminals of the DC / DC converter 1 by controlling the inverter circuit 11, and the working states of the switching tubes in the voltage management circuit 15 are controlled to step down the output voltage of the first rectifier circuit 14 by the voltage management circuit 15, so as to ensure that the sum of the output voltage of the stepped-down first rectifier circuit 13 and the output voltage of the second rectifier circuit 14 is the target output voltage, that is, to ensure that the output terminal voltage of the DC / DC converter 1 is the target output voltage.

[0130] In another alternative embodiment, when the input terminal voltage V of the DC / DC converter 1 inWhen it is greater than or equal to the preset voltage, the controller sends a third control signal to the inverter circuit 11. Here, the preset voltage is the product of the target output voltage and N1, where N1 is the turns ratio between the first primary winding 121 and the first secondary winding 122. According to the received third control signal, Q1 - Q4, Q8, and Q9 in the inverter circuit 11 are such that Q3 and Q4 are in the off state, Q1 and Q9 are in the on state during the third sub - cycle within the second working cycle, and Q2 and Q8 are in the on state during the fourth sub - cycle within the second working cycle. Here, both the third sub - cycle and the fourth sub - cycle are half of the second working cycle, and the second working cycle is the same as the working cycle of the first resonant circuit 16. Here, the second working cycle and the first working cycle can be the same or different, and this application does not limit this. Since in the third cycle, after the current flows into the positive input terminal of the DC / DC converter 1, it successively passes through Q1, Lr1, Cr1, the first primary winding 121, the second primary winding 125, Cr2, Lr2, and Q9 and flows to the negative input terminal of the DC / DC converter 1; in the fourth sub - cycle, after the current flows into the positive input terminal of the DC / DC converter 1, it successively passes through Q8, Lr2, Cr2, the second primary winding 125, the first primary winding 121, Cr1, Lr1, and Q2 and flows to the negative input terminal of the DC / DC converter 1. Therefore, it can be obtained that the first primary winding 121 and the second primary winding 125 are connected in series and then connected to the two voltage input terminals of the DC / DC converter 1 within the second working cycle.

[0131] Since both the third sub - cycle and the fourth sub - cycle are half of the second working cycle, the direct current at the input terminal of the DC / DC converter 1 can be converted into sinusoidal alternating current through the inverter circuit 11. Then, through the first resonant circuit 16 and the second resonant circuit 17, the sinusoidal alternating current output by the inverter circuit 11 is transformed into a sinusoidal alternating current with zero crossing and output to the first primary winding 121 and the second primary winding 125. The alternating current flowing through the first primary winding 121 generates an alternating magnetic flux. Through the magnetic conduction of the first iron core 124, an alternating current is induced in the first secondary winding 122, and the induced alternating current is output to the output terminal of the first rectifier circuit 13; the alternating current flowing through the second primary winding 125 generates an alternating magnetic flux. Through the magnetic conduction of the second iron core 126, an alternating current is induced in the second secondary winding 123, and the induced alternating current is output to the output terminal of the second rectifier circuit 14. The first rectifier circuit 13 rectifies the alternating current output by the first secondary winding 122 to obtain the output voltage of the first rectifier circuit 13, that is, the DC voltage V1 = V in1 / N1; the second rectifier circuit 14 rectifies the alternating current output by the second secondary winding 123 to obtain the output voltage of the second rectifier circuit 14, that is, the DC voltage V2 = V in2 / N2, where V in1 = V in*Z1 / (Z1 + Z2), V in2 = V in *Z2 / (Z1 + Z2), where Z1 is the AC impedance after the first primary winding 121 is connected in parallel with C1, and Z2 is the AC impedance after the second primary winding 125 is connected in parallel with C2, and V in is the input voltage of the DC / DC converter 1.

[0132] Meanwhile, when the input voltage V in of the DC / DC converter 1 is greater than or equal to the preset voltage, the controller sends a first control signal and a second control signal to the voltage management circuit 15. Q5 and Q6 in the voltage management circuit 15 are both in the conducting state in the first sub-cycle according to the received first control signal. Since Q6 and Q7 are complementary-conducting, when Q6 is conducting, Q7 is off. Therefore, in the first sub-cycle, the current flows from the positive output terminal of the second rectifier circuit 14 through L1, Q6, and Q5 to the negative output terminal of the second rectifier circuit 14. Then, it can be obtained that in the first sub-cycle, the two output terminals of the first rectifier circuit 13 are connected to the two output terminals of the DC / DC converter 1, and the first end of the branch where the output terminal of the second rectifier circuit 14 is located (i.e., the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) (i.e., the end where L1 is connected to the drain of Q6) is connected to the first output terminal of the DC / DC converter 1 (i.e., the negative output terminal of the DC / DC converter 1). At the same time, it can be obtained that in the first sub-cycle, the current change amount ΔI1 on L1 = V2 * D1 * T / L, where L is the inductance of L1, and D1 is the ratio between the first sub-cycle and the first working cycle T, that is, the duty cycle when Q6 is conducting; Q5 and Q7 in the voltage management circuit 15 are both in the conducting state in the second sub-cycle according to the received second control signal. Since Q6 and Q7 are complementary-conducting, when Q7 is conducting, Q6 is off. Therefore, in the second sub-cycle, the current flows from the positive output terminal of the second rectifier circuit 14 through L1 and Q7 to the positive output terminal of the DC / DC converter 1. Then, it can be obtained that in the second sub-cycle, the branch where the output terminal of the second rectifier circuit 14 is located (i.e., the branch formed by the series connection of the output terminal of the second rectifier circuit 14 and L1) is connected in parallel with the output terminal of the first rectifier circuit 13 to the two output terminals of the DC / DC converter 1. At the same time, it can be obtained that in the second sub-cycle, the current change amount ΔI2 on L1 = (V out - V2) * (1 - D1) * T / L. Among them, the sum of the first sub-cycle and the second sub-cycle can be the first working cycle or a part of the first working cycle.

[0133] When the inductor is in a stable state, the current change amount during the inductor energy storage process is equal to the current change amount during the inductor energy release process. Therefore, when the sum of the first sub-cycle and the second sub-cycle is the first working cycle, ΔI1 = ΔI2 can be obtained, and thus the output voltage V of the DC / DC converter 1 can be obtained. out = V2 / (1 - D1). Furthermore, the target output voltage required to be output stably by the DC / DC converter 1 can be obtained by adjusting the duty cycle D1 of Q6 conduction. It should be noted that when the sum of the first sub-cycle, the second sub-cycle, and the fifth sub-cycle is the first working cycle, and Q5 - Q7 are all turned off during the fifth sub-cycle, the output voltage V of the DC / DC converter 1 can still be obtained. out = V2 / (1 - D1). Furthermore, the target output voltage required to be output stably by the DC / DC converter 1 can still be obtained by adjusting the duty cycle D1 of Q6 conduction.

[0134] It can be understood that when the input voltage V of the DC / DC converter 1 in is greater than or equal to the preset voltage, by controlling the series connection of the first primary winding 121 and the second primary winding 125 to the two voltage input ends of the DC / DC converter 1, and controlling the working states of the switching tubes in the voltage management circuit 15 to boost the output voltage of the second rectifying circuit 14 by the voltage management circuit 15, and then discharging the electric energy stored in L1 to C1 to ensure that the output voltage of the first rectifying circuit 13 is increased to the target output voltage, that is, ensuring that the output voltage of the DC / DC converter 1 is the target output voltage.

[0135] In this embodiment, according to the magnitude relationship between the input voltage V of the DC / DC converter 1 in and the preset voltage, the connection relationship between the first primary winding 121, the second primary winding 125 and the two voltage input ends of the DC / DC converter 1 can be controlled by the inverter circuit 11, and the connection relationship between the output end of the first rectifying circuit 13, the output end of the second rectifying circuit 14 and the output end of the DC / DC converter 1 can be changed by the voltage management circuit 15 to realize the step-up and step-down of V in , so as to ensure that no matter what value V in takes, the voltage value stably output by the DC / DC converter 1 can be the target output voltage, which can further expand the input voltage compatibility range of the DC / DC converter 1 and has stronger applicability. In addition, the DC / DC converter 1 maintains the characteristic that the isolation transformer and the voltage stabilizing topology are separated in part of the power, and at the same time, under the boundary gain, such as the conditions of high-voltage input and low-voltage output or low-voltage input and high-voltage output, the power processed by the voltage stabilizing topology is less, so that the efficiency curve is relatively flat in the full gain range and has strong applicability.

[0136] See Figure 6 ,Figure 6 It is a schematic flowchart of the output voltage control method of the DC / DC converter provided by this application. The output voltage control method of the DC / DC converter provided by this application is applicable to the voltage management circuit 15 or the controller in the cascaded converter shown above Figures 3 to 5 The method includes the steps:

[0137] S101, in the first sub-cycle of the first working cycle, control the output ends of the first rectifier circuit, the output ends of the second rectifier circuit and the output end of the DC / DC converter to be in a first connection relationship.

[0138] Among them, the first connection relationship and the second connection relationship can be any two of the following connection relationships:

[0139] The branches where the output ends of the first rectifier circuit 13 and the output ends of the second rectifier circuit 14 are connected in series and then connected to the output end of the DC / DC converter 1; or

[0140] The branch where the output end of the second rectifier circuit 14 is located is connected to the output end of the DC / DC converter 1; or

[0141] The output end of the first rectifier circuit 13 is connected to the output end of the DC / DC converter 1, and the first end of the branch where the output end of the second rectifier circuit 14 is located is connected to the first output end of the DC / DC converter 1; and

[0142] The branch where the output end of the second rectifier circuit 14 is located is connected in parallel with the output end of the first rectifier circuit 13 to the output end of the DC / DC converter 1.

[0143] In an alternative embodiment, when the controller is inside the voltage management circuit 15, when the input voltage V of the DC / DC converter 1 in is less than the preset voltage, by controlling the working states of Q5-Q7, the output ends of the first rectifier circuit 13, the output ends of the second rectifier circuit 14 and the output end of the DC / DC converter 1 are in the first connection relationship in the first sub-cycle of the first working cycle, where the first connection relationship is that the output ends of the first rectifier circuit 13 and the second rectifier circuit 14 are connected in series and then connected to the two output ends of the DC / DC converter 1.

[0144] In another alternative embodiment, when the controller is inside the voltage management circuit 15, when the input voltage V of the DC / DC converter 1 inWhen it is greater than or equal to a preset voltage, by controlling the working states of Q5 - Q7, the output terminal of the first rectification circuit 13, the output terminal of the second rectification circuit 14, and the output terminal of the DC / DC converter 1 are in a first connection relationship during the first sub - period of the first working cycle. Among them, the first connection relationship is that the output terminal of the first rectification circuit 13 is connected to the output terminal of the DC / DC converter 1, and the first end of the branch where the output terminal of the second rectification circuit 14 is located is connected to the first output terminal of the DC / DC converter 1.

[0145] In another alternative embodiment, when the controller is located outside the voltage management circuit 15, when the input voltage V of the DC / DC converter 1 in is less than the preset voltage, a first control signal is sent to the voltage management circuit 15. The voltage management circuit 15 makes the output terminal of the first rectification circuit 13, the output terminal of the second rectification circuit 14, and the output terminal of the DC / DC converter 1 be in a first connection relationship during the first sub - period of the first working cycle according to the received first control signal. Among them, the first connection relationship is that the output terminal of the first rectification circuit 13 and the branch where the output terminal of the second rectification circuit 14 is located are connected in series and then connected to the two output terminals of the DC / DC converter 1.

[0146] In yet another alternative embodiment, when the controller is located outside the voltage management circuit 15, when the input voltage V of the DC / DC converter 1 in is greater than or equal to the preset voltage, a first control signal is sent to the voltage management circuit 15. The voltage management circuit 15 makes the output terminal of the first rectification circuit 13, the output terminal of the second rectification circuit 14, and the output terminal of the DC / DC converter 1 be in a first connection relationship during the first sub - period of the first working cycle according to the received first control signal. Among them, the first connection relationship is that the output terminal of the first rectification circuit 13 is connected to the output terminal of the DC / DC converter 1, and the first end of the branch where the output terminal of the second rectification circuit 14 is located is connected to the first output terminal of the DC / DC converter 1.

[0147] S102, control the output terminal of the first rectification circuit, the output terminal of the second rectification circuit, and the output terminal of the DC / DC converter to be in a second connection relationship during the second sub - period of the first working cycle.

[0148] In an alternative embodiment, when the controller is located inside the voltage management circuit 15, when the input voltage V of the DC / DC converter 1 inWhen the voltage is less than the preset voltage, by controlling the operating states of Q5 - Q7, the output terminal of the first rectifier circuit 13, the output terminal of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 are in a second connection relationship during the second sub - cycle of the first working cycle, where the second connection relationship is that the branch where the output terminal of the second rectifier circuit 14 is located is connected to the two output terminals of the DC / DC converter 1.

[0149] In another alternative embodiment, when the controller is inside the voltage management circuit 15, when the input voltage V of the DC / DC converter 1 in is greater than or equal to the preset voltage, by controlling the operating states of Q5 - Q7, the output terminal of the first rectifier circuit 13, the output terminal of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 are in a second connection relationship during the second sub - cycle of the first working cycle, where the second connection relationship is that the branch where the output terminal of the second rectifier circuit 14 is located is in parallel with the output terminal of the first rectifier circuit 13 and connected to the two output terminals of the DC / DC converter 1.

[0150] In another alternative embodiment, when the controller is outside the voltage management circuit 15, when the input voltage V of the DC / DC converter 1 in is less than the preset voltage, a second control signal is sent to the voltage management circuit 15. The voltage management circuit 15 makes the output terminal of the first rectifier circuit 13, the output terminal of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 be in a second connection relationship during the second sub - cycle of the first working cycle according to the received second control signal, where the first connection relationship is that the branch where the output terminal of the second rectifier circuit 14 is located is connected to the two output terminals of the DC / DC converter 1.

[0151] In yet another alternative embodiment, when the controller is outside the voltage management circuit 15, when the input voltage V of the DC / DC converter 1 in is greater than or equal to the preset voltage, a second control signal is sent to the voltage management circuit 15. The voltage management circuit 15 makes the output terminal of the first rectifier circuit 13, the output terminal of the second rectifier circuit 14, and the output terminal of the DC / DC converter 1 be in a second connection relationship during the second sub - cycle of the first working cycle according to the received second control signal, where the first connection relationship is that the branch where the output terminal of the second rectifier circuit 14 is located is in parallel with the output terminal of the first rectifier circuit 13 and connected to the two output terminals of the DC / DC converter 1.

[0152] In specific implementation, for more operations performed by the voltage management circuit and the controller in the output voltage control method of the DC / DC converter provided in this application, reference can be made to Figures 3 to 5The implementation manners performed by the voltage management circuit 15 and the controller in the DC / DC converter 1 shown and its working principle will not be described herein again.

[0153] In this application, by changing the connection relationship among the output terminal of the first rectification circuit 13, the output terminal of the second rectification circuit 14, and the output terminal of the DC / DC converter 1, the input voltage V of the DC / DC converter 1 in can be stepped up or down, so as to ensure that no matter what value V in takes, the voltage value stably output by the DC / DC converter 1 can be the target output voltage, thereby expanding the input voltage compatibility range of the DC / DC converter 1 and having strong applicability.

[0154] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed in this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.

Claims

1. A DC / DC converter, characterized in that, The DC / DC converter includes an inverter circuit, a transformer, a first rectifier circuit, a second rectifier circuit, and a voltage management circuit, where: The input end of the inverter circuit serves as the input end of the DC / DC converter and is used to connect to a DC power supply; The transformer includes a first primary winding, a first secondary winding, and a second secondary winding. One end of the first primary winding is connected to the first output end of the inverter circuit, and the other end of the first primary winding is connected to the second output end of the inverter circuit. The two ends of the first secondary winding are connected to the two input ends of the first rectifier circuit, and the two ends of the second secondary winding are connected to the two input ends of the second rectifier circuit; The voltage management circuit is used to control the first rectifier circuit output end, the second rectifier circuit output end, and the DC / DC converter output end to be in a first connection relationship during a first sub-cycle within a first working cycle, and to control the first rectifier circuit output end, the second rectifier circuit output end, and the DC / DC converter output end to be in a second connection relationship during a second sub-cycle within the first working cycle; where the first connection relationship is that the branches where the output ends of the first rectifier circuit and the second rectifier circuit are located are connected in series and then connected to the output end of the DC / DC converter, and the second connection relationship is that the branch where the output end of the second rectifier circuit is located is connected to the output end of the DC / DC converter; or, the first connection relationship is that the output end of the first rectifier circuit is connected to the output end of the DC / DC converter, and the first end of the branch where the output end of the second rectifier circuit is located is connected to the first output end of the DC / DC converter, and the second connection relationship is that the branch where the output end of the second rectifier circuit is located is connected in parallel with the output end of the first rectifier circuit to the output end of the DC / DC converter; Wherein, the voltage management circuit includes a first inductor, a first switching tube, a second switching tube, and a third switching tube. The first end of the third switching tube is connected to the first output end of the first rectifier circuit and the second output end of the DC / DC converter. The second end of the third switching tube is connected to the first output end of the second rectifier circuit through the first inductor. The second end of the third switching tube is connected to the first end of the second switching tube. The second end of the second switching tube is connected to the second output end of the first rectifier circuit and the first end of the first switching tube. The second end of the first switching tube is connected to the second output end of the second rectifier circuit and the first output end of the DC / DC converter; the branch where the output end of the second rectifier circuit is located is the branch formed by connecting the first output end of the second rectifier circuit in series with the first inductor, and the first end of the branch where the output end of the second rectifier circuit is located is the end of the first inductor connected to the second switching tube and the third switching tube.

2. The DC / DC converter according to claim 1, characterized in that, The DC / DC converter further includes a controller; The controller is used to send a first control signal and a second control signal to the voltage management circuit; The voltage management circuit is configured to, according to the first control signal, control the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit, and the output terminal of the DC / DC converter to be in the first connection relationship during the first sub-cycle, and, according to the second control signal, control the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit, and the output terminal of the DC / DC converter to be in the second connection relationship during the second sub-cycle.

3. The DC / DC converter according to claim 2, wherein, The first connection relationship is that the branches where the output terminal of the first rectifier circuit and the output terminal of the second rectifier circuit are located are connected in series and then connected to the output terminal of the DC / DC converter; the second connection relationship is that the branch where the output terminal of the second rectifier circuit is located is connected to the output terminal of the DC / DC converter; The voltage management circuit is configured to, when the input voltage of the DC / DC converter is less than a preset voltage, control the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit, and the output terminal of the DC / DC converter to be in the first connection relationship during the first sub-cycle and in the second connection relationship during the second sub-cycle.

4. The DC / DC converter according to claim 3, characterized in that, The output voltage V of the DC / DC converter out = V1*D1 + V2, where V1 is the output voltage of the first rectifier circuit, V2 is the output voltage of the second rectifier circuit, and D1 is the ratio between the first sub-period and the first working period.

5. The DC / DC converter according to claim 2, characterized in that, The first connection relationship is that the output terminal of the first rectifier circuit is connected to the output terminal of the DC / DC converter, and the first end of the branch where the output terminal of the second rectifier circuit is located is connected to the first output terminal of the DC / DC converter; the second connection relationship is that the branch where the output terminal of the second rectifier circuit is located is connected in parallel with the output terminal of the first rectifier circuit to the output terminal of the DC / DC converter; The voltage management circuit is configured to, when the input voltage of the DC / DC converter is greater than or equal to the preset voltage, control the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit, and the output terminal of the DC / DC converter to be in the first connection relationship during the first sub-cycle and in the second connection relationship during the second sub-cycle.

6. The DC / DC converter according to claim 5, characterized in that, The output voltage V of the DC / DC converter out = V2 / (1 - D1), where V2 is the output voltage of the second rectifier circuit, and D1 is the ratio between the first sub-period and the first working period.

7. The DC / DC converter according to any one of claims 1-6, characterized in that The output voltage V1 of the first rectifier circuit is V1 = V in / N11, and the output voltage V2 of the second rectifier circuit is V2 = V in / N12, where the V in is the input voltage of the DC / DC converter, N11 is the turn ratio between the first primary winding and the first secondary winding, and N12 is the turn ratio between the first primary winding and the second secondary winding.

8. The DC / DC converter according to any one of claims 1-6, characterized in that, The transformer further includes a second primary winding, one end of the second primary winding is connected to the second output terminal of the inverter circuit, and the other end of the second primary winding is connected to the third output terminal of the inverter circuit.

9. The DC / DC converter according to claim 8, characterized in that, The inverter circuit is configured to control the first primary winding and the second primary winding to be connected in parallel to both ends of the DC power supply, or control the first primary winding and the second primary winding to be connected in series and then connected to both ends of the DC power supply.

10. The DC / DC converter according to claim 9, characterized in that, When the DC / DC converter includes a controller, the controller is configured to send a third control signal to the inverter circuit, and the third control signal is used to control the inverter circuit to connect the first primary winding and the second primary winding in parallel to both ends of the DC power supply, or control the inverter circuit to connect the first primary winding and the second primary winding in series and then connect to both ends of the DC power supply.

11. The DC / DC converter according to claim 10, characterized in that, The controller is configured to send the third control signal to the inverter circuit when the input voltage of the DC / DC converter is less than a preset voltage, and the third control signal is used to control the inverter circuit to parallel the first primary winding and the second primary winding to both ends of the DC power supply.

12. The DC / DC converter according to any one of claims 9-11, wherein When the first primary winding and the second primary winding are connected in parallel to the DC power supply, the output voltage V1 of the first rectifier circuit is V1 = V in / N1, and the output voltage V2 of the second rectifier circuit is V2 = V in / N2, where V in is the input voltage of the DC / DC converter, N1 is the turns ratio between the first primary winding and the first secondary winding, and N2 is the turns ratio between the second primary winding and the second secondary winding.

13. The DC / DC converter according to claim 10, characterized in that, The controller is configured to send the third control signal to the inverter circuit when the input voltage of the DC / DC converter is greater than or equal to the preset voltage, and the third control signal is used to control the inverter circuit to connect the first primary winding and the second primary winding in series and then connect them to both ends of the DC power supply.

14. The DC / DC converter according to claim 9, 10 or 13, characterized in that, When the first primary winding and the second primary winding are connected in series and then connected to the DC power supply, the output voltage V1 of the first rectification circuit is V in1 / N1, and the output voltage V2 of the second rectification circuit is V in2 / N2, where the V in1 and the V in2 are both determined by the input voltage of the DC / DC converter, N1 is the turn ratio between the first primary winding and the first secondary winding, and N2 is the turn ratio between the second primary winding and the second secondary winding.

15. The DC / DC converter according to any one of claims 8-14, characterized in that, The DC / DC converter further includes a first resonant circuit and a second resonant circuit. A first output end of the inverter circuit is connected to one end of the first primary winding through the first resonant circuit, and a third output end of the inverter circuit is connected to the other end of the second primary winding through the second resonant circuit. The resonant parameters of the first resonant circuit are the same as those of the second resonant circuit.

16. A method for controlling the output voltage of a DC / DC converter, characterized in that, The DC / DC converter includes an inverter circuit, a transformer, a first rectifier circuit, a second rectifier circuit, and a voltage management circuit. Among them, the input end of the inverter circuit serves as the input end of the DC / DC converter and is used to connect to a DC power supply; the transformer includes a first primary winding, a first secondary winding, and a second secondary winding. One end of the first primary winding is connected to a first output end of the inverter circuit, and the other end of the first primary winding is connected to a second output end of the inverter circuit. Two ends of the first secondary winding are connected to two input ends of the first rectifier circuit, and two ends of the second secondary winding are connected to two input ends of the second rectifier circuit; the voltage management circuit includes a first inductor, a first switch tube, a second switch tube, and a third switch tube. A first end of the third switch tube is connected to a first output end of the first rectifier circuit and a second output end of the DC / DC converter. A second end of the third switch tube is connected to a first output end of the second rectifier circuit through the first inductor, and the second end of the third switch tube is connected to a first end of the second switch tube. A second end of the second switch tube is connected to a second output end of the first rectifier circuit and a first end of the first switch tube. A second end of the first switch tube is connected to a second output end of the second rectifier circuit and a first output end of the DC / DC converter; The method includes: In the first sub-cycle of the first working cycle, control the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit and the output terminal of the DC / DC converter to be in a first connection relationship, and in the second sub-cycle of the first working cycle, control the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit and the output terminal of the DC / DC converter to be in a second connection relationship; wherein, the first connection relationship is that the branches where the output terminal of the first rectifier circuit and the output terminal of the second rectifier circuit are located are connected in series and then connected to the output terminal of the DC / DC converter, and the second connection relationship is that the branch where the output terminal of the second rectifier circuit is located is connected to the output terminal of the DC / DC converter; or, the first connection relationship is that the output terminal of the first rectifier circuit is connected to the output terminal of the DC / DC converter, and the first end of the branch where the output terminal of the second rectifier circuit is located is connected to the first output terminal of the DC / DC converter, and the second connection relationship is that the branch where the output terminal of the second rectifier circuit is located and the output terminal of the first rectifier circuit are connected in parallel to the output terminal of the DC / DC converter; wherein, the branch where the output terminal of the second rectifier circuit is located is the branch formed by connecting the first output terminal of the second rectifier circuit in series with the first inductor, and the first end of the branch where the output terminal of the second rectifier circuit is located is the end where the first inductor is connected to the second switching tube and the third switching tube.

17. The method according to claim 16, wherein The control that in the first sub-cycle of the first working cycle, the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit and the output terminal of the DC / DC converter are in a first connection relationship includes: According to the first control signal, in the first sub-cycle, control the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit and the output terminal of the DC / DC converter to be in the first connection relationship; The control that in the second sub-cycle of the first working cycle, the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit and the output terminal of the DC / DC converter are in a second connection relationship includes: According to the second control signal, in the second sub-cycle, control the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit and the output terminal of the DC / DC converter to be in the second connection relationship.

18. The method according to claim 17, wherein The first connection relationship is that the branches where the output terminal of the first rectifier circuit and the output terminal of the second rectifier circuit are located are connected in series and then connected to the output terminal of the DC / DC converter; the second connection relationship is that the branch where the output terminal of the second rectifier circuit is located is connected to the output terminal of the DC / DC converter; The control that in the first sub-cycle of the first working cycle, the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit and the output terminal of the DC / DC converter are in a first connection relationship, and in the second sub-cycle of the first working cycle, the output terminal of the first rectifier circuit, the output terminal of the second rectifier circuit and the output terminal of the DC / DC converter are in a second connection relationship includes: When the input voltage of the DC / DC converter is less than the preset voltage, control the output end of the first rectifier circuit, the output end of the second rectifier circuit, and the output end of the DC / DC converter to be in the first connection relationship in the first sub-cycle and in the second connection relationship in the second sub-cycle.

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