High-voltage interleaved series LLC power topological structure

Abstract

The invention discloses a high-voltage interleaved series LLC power topological structure, which comprises an LLC conversion circuit assembly, two synchronous rectification circuits and an output load, and is characterized in that the LLC conversion circuit assembly is composed of a first LLC conversion circuit, a second LLC conversion circuit and a PI control circuit, the first LLC conversion circuit and the second LLC conversion circuit are connected in series, and the PI control circuit is provided with a voltage control loop and a current loop; according to the invention, the use cost of the device can be reduced, an LLC structure is adopted, input voltage-sharing control of soft switching and two paths of full-bridge LLC can be realized, an interleaving control mode is adopted, output ripples are reduced, the power density can be improved, the requirements of high voltage input and high power density are met, and the device is suitable for a high voltage input occasion.

Description

Technical Field

[0001] The invention relates to the technical field of DC / DC converter LLC power, in particular to a high-voltage staggered series LLC power topology structure. Background Art

[0002] With the development of power electronics technology, high voltage and high current power supply systems have been widely used in airborne equipment in order to obtain higher conversion efficiency and power density. In order to meet the functions and performance of the converter with high voltage input and high current output in the airborne power supply system, the traditional topology structure is either difficult to meet the input high voltage and high current output occasions, or difficult to achieve high power density. Summary of the invention

[0003] The object of the present invention is to provide a high-voltage staggered series LLC power topology structure to solve the problem that the traditional topology structure proposed in the above background technology is difficult to meet the requirements of high-voltage input and high-current output.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a high-voltage staggered series LLC power topology structure, including an LLC conversion circuit component, two synchronous rectification circuits and an output load, wherein the LLC conversion circuit component is composed of a first LLC conversion circuit and a second LLC conversion circuit connected in series, and a PI control circuit, wherein the output end of the first LLC conversion circuit is connected to one synchronous rectification circuit, the output end of the second LLC conversion circuit is connected to another synchronous rectification circuit, and the input end of the LLC conversion circuit component is connected to the power supply end through a full-bridge tube component, and a voltage-equalizing capacitor component and a voltage-equalizing resistor component are provided between the full-bridge tube component and the power supply end; the PI control circuit has two parts, a voltage control loop and a current loop, wherein the voltage control loop is used to collect the output voltage to generate a voltage control signal, and the current loop is used to collect the output current to generate a current control signal, and the output ends of the current loop and the voltage control loop are connected to a voltage-controlled oscillator.

[0005] Furthermore, the full-bridge tube assembly includes four groups of full-bridge tubes S1-S4 connected to the first LLC conversion circuit, and four groups of full-bridge tubes S5-S8 connected to the second LLC conversion circuit. The full-bridge tube assembly is used to receive the output frequency control signal of the voltage-controlled oscillator.

[0006] Furthermore, the synchronous rectification circuit includes four groups of rectifier tubes Q1-Q4, wherein the rectifier tubes Q1 and Q2 are connected to the first LLC conversion circuit, and the rectifier tubes Q3 and Q4 are connected to the second LLC conversion circuit.

[0007] Furthermore, the voltage-equalizing capacitor assembly is composed of a capacitor C1 and a capacitor C2, wherein the capacitor C1 and the capacitor C2 are connected in series, and the capacitor C1 is connected to the first LLC conversion circuit, and the capacitor C2 is connected to the second LLC conversion circuit.

[0008] Furthermore, the voltage-equalizing resistor component includes a resistor R1 and a resistor R2 connected to the first LLC conversion circuit, and a resistor R3 and a resistor R4 connected to the second LLC conversion circuit.

[0009] The beneficial effects of the present invention are as follows: the present invention can reduce the voltage stress of the input switch tube, reduce the use cost of the device, enable it to adapt to high-voltage input occasions, and adopt an LLC structure to achieve soft switching and input voltage equalization control of two full-bridge LLCs, thereby reducing the switching loss of the full-bridge tube or the rectifier tube and improving the conversion efficiency of the converter; at the same time, an interleaved control method is adopted to reduce the output ripple while improving the power density, meeting the requirements of high voltage input and high power density. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the staggered series LLC power topology structure of the present invention.

[0011] In the figure: 1 first LLC conversion circuit, 2 second LLC conversion circuit, 3 output load. DETAILED DESCRIPTION

[0012] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0013] See also Figure 1 , which provides a technical solution for the present invention, a high-voltage staggered series LLC power topology structure, including an LLC conversion circuit component, two synchronous rectification circuits and an output load 3, the LLC conversion circuit component is composed of a first LLC conversion circuit 1 and a second LLC conversion circuit 2 connected in series, and a PI control circuit, the output end of the first LLC conversion circuit 1 is connected to one synchronous rectification circuit, the output end of the second LLC conversion circuit 2 is connected to another synchronous rectification circuit, and the input end of the LLC conversion circuit component is connected to the power supply end through a full-bridge tube component, the power supply end is marked with Vdc, and the power supply end inputs 540V high voltage; a voltage-equalizing capacitor component and a voltage-equalizing resistor component are provided between the full-bridge tube component and the power supply end.

[0014] In this embodiment, the synchronous rectification circuit includes four groups of rectifier tubes Q1-Q4, and the four groups of rectifier tubes Q1-Q4 constitute one synchronous rectification circuit. The rectifier tube Q1 and the rectifier tube Q2 are connected to the first LLC conversion circuit 1, and the rectifier tube Q3 and the rectifier tube Q4 are connected to the second LLC conversion circuit 2, and the rectifier tube Q3 and the rectifier tube Q4 constitute another synchronous rectification circuit.

[0015] It should be noted that the voltage-equalizing capacitor component is composed of a capacitor C1 and a capacitor C2, which are connected in series, and the capacitor C1 is connected to the first LLC conversion circuit 1, and the capacitor C2 is connected to the second LLC conversion circuit 2; the voltage-equalizing resistor component includes a resistor R1 and a resistor R2 connected to the first LLC conversion circuit 1, and a resistor R3 and a resistor R4 connected to the second LLC conversion circuit 2.

[0016] In this embodiment, the PI control circuit mentioned has two parts: a voltage control loop and a current loop. The voltage control loop is used to collect the output voltage to generate a voltage control signal, and the current loop is used to collect the output current to generate a current control signal. The output ends of the current loop and the voltage control loop are connected to a voltage-controlled oscillator.

[0017] In this embodiment, the full-bridge tube assembly mentioned includes four groups of full-bridge tubes S1-S4 connected to the first LLC conversion circuit 1, and four groups of full-bridge tubes S5-S8 connected to the second LLC conversion circuit 2. The full-bridge tube assembly is used to receive the output frequency control signal of the voltage-controlled oscillator.

[0018] The staggered series LLC power topology structure suitable for 540V power supply input has a 540V high voltage connected to the power supply end, and adopts a first LLC conversion circuit 1 and a second LLC conversion circuit 2 connected in series. Then, the input voltage of each LLC is 270V, and the voltage stress borne by each tube is 270V / 2; the PI control circuit mentioned realizes the control of the output voltage of the LLC conversion circuit, so that the output voltage is stabilized at about 29V; the voltage control loop obtains the corresponding voltage control signal by collecting the output voltage, comparing it with the reference voltage, and then performing PI control; and the current control loop obtains the corresponding current control signal by collecting the output current, comparing it with the reference current, and then performing PI control. Then, by comparing the voltage control signal and the current control signal, and taking the smallest control signal to enter the voltage-controlled oscillator to output the frequency control signal, the corresponding drive signal is generated to drive the full-bridge tubes S1, S2, S3, S4, S5, S6, S7, S8 and the rectifier tubes Q1, Q2, Q3, Q4 to operate, so as to realize the control of the LLC conversion circuit; the voltage-controlled oscillator adopts VCO marking; among them, the control signal sent by the PI control circuit generates a drive signal to drive the conduction and shutdown of the rectifier tubes Q1, Q2, Q3, Q4 to realize the conversion of the LLC conversion circuit; among them, the PI control circuit mainly outputs the corresponding control signal after conditioning and controlling the collected voltage and current signals.

[0019] It is worth noting that the current loop only works when the output current is relatively large. This is because when the output current Io is small, the output voltage Vo is relatively large, and the voltage control signal after adjustment by the current loop and the voltage control loop is relatively small. At this time, only the voltage control loop works; conversely, when the output current Io is large, the current loop works.

[0020] In summary: the staggered series LLC power topology structure suitable for 540V power supply input can achieve a high voltage input of 540V~700V and a stable output of 29V. The converter efficiency using the staggered series LLC power topology structure can reach more than 96%.

[0021] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0022] The above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be understood that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. In the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", "connection", "fixation" and the like should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection, or integrated; it can be a mechanical connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two components or the interaction relationship between two components; among them, there are many ways of detachable installation, for example, it can be through the way of plug-in and snap-fit, for example, through the way of bolt connection, etc.

[0023] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high voltage staggered series LLC power topology structure, characterized by: It includes an LLC conversion circuit component, two synchronous rectification circuits and an output load. The LLC conversion circuit component is composed of a first LLC conversion circuit and a second LLC conversion circuit connected in series, and a PI control circuit. The output end of the first LLC conversion circuit is connected to one synchronous rectification circuit, the output end of the second LLC conversion circuit is connected to another synchronous rectification circuit, and the input end of the LLC conversion circuit component is connected to the power supply end through a full-bridge tube component. A voltage-equalizing capacitor component and a voltage-equalizing resistor component are provided between the full-bridge tube component and the power supply end. The PI control circuit has two parts, a voltage control loop and a current loop. The voltage control loop is used to collect the output voltage to generate a voltage control signal, and the current loop is used to collect the output current to generate a current control signal. The output ends of the current loop and the voltage control loop are connected to a voltage-controlled oscillator.

2. A high voltage staggered series LLC power topology structure according to claim 1, characterized in that: The full-bridge tube assembly includes four groups of full-bridge tubes S1-S4 connected to the first LLC conversion circuit and four groups of full-bridge tubes S5-S8 connected to the second LLC conversion circuit. The full-bridge tube assembly is used to receive the output frequency control signal of the voltage-controlled oscillator.

3. A high voltage staggered series LLC power topology structure according to claim 1, characterized in that: The synchronous rectification circuit comprises four groups of rectifier tubes Q1-Q4, wherein the rectifier tubes Q1 and Q2 are connected to the first LLC conversion circuit, and the rectifier tubes Q3 and Q4 are connected to the second LLC conversion circuit.

4. A high voltage staggered series LLC power topology structure according to claim 1, characterized in that: The voltage-equalizing capacitor assembly is composed of a capacitor C1 and a capacitor C2. The capacitor C1 and the capacitor C2 are connected in series, and the capacitor C1 is connected to the first LLC conversion circuit, and the capacitor C2 is connected to the second LLC conversion circuit.

5. The high-voltage staggered series LLC power topology structure according to claim 1, characterized in that: The voltage-equalizing resistor assembly includes a resistor R1 and a resistor R2 connected to the first LLC conversion circuit, and a resistor R3 and a resistor R4 connected to the second LLC conversion circuit.

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