A double duty ratio control based quadratic high gain boost converter
Patent Information
- Application Number
- CN202611117193.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-27
- Publication Date
- 2026-09-22
AI Technical Summary
[0005]本发明旨在解决现有高增益Boost变换器普遍存在的技术问题：为实现高升压比，通常需要采用多级级联、复杂磁耦合或大量开关电容单元，导致电路器件数量多、成本高、体积大；同时，能量在多个储能元件间循环转移造成额外的通态损耗和开关损耗，限制了整机效率的进一步提升；此外，开关器件的电压应力往往随着增益升高而急剧增大，迫使选用更高耐压等级的功率器件，进一步推高了系统成本并影响可靠性
[0016]有益效果：本发明提出一种面向超高增益应用的Boost类直流升压变换器，兼顾低损耗与低成本，并通过三项核心设计实现性能提升：首先，利用电容共享/复用与能量传输路径重构，减少冗余储能元件与无效能量循环，从源头降低器件数量与损耗叠加，并提升增益与成本指标；其次，采用储能元件，在开关管断开时可以与电感次级依次串联，大幅提高输出增益的同时又能限制住开关管的电压应力（开关管（S1、S2）所承受的峰值电压应力被有效钳位，其理论值仅为输出电压的
，即
，远低于输出电压，减少MOSFET的选型成本；再次，三个开关管(S1、S2、S3)的同时导通占空比为d1，第三个开关管(S3)的单独导通占空比为d2，无需考虑死区时间，控制简单，mosfet驱动电路部分可减少成本。
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Figure CN122801773A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of power electronic DC-DC converter technology, specifically relating to a quadratic high-gain Boost converter based on dual duty cycle control. Background Technology
[0002] Against the backdrop of accelerated progress in "dual carbon" and energy structure upgrading, scenarios such as photovoltaics, energy storage, and electric vehicles place higher demands on DC-DC boost stages: extremely high boost ratios (typically exceeding 10 times) need to be achieved over a wide input voltage fluctuation range, while simultaneously maintaining efficiency above 95%, low cost, and long-term operational reliability. While existing boost converters and their high-gain extensions can increase output voltage through cascading, coupled inductors, or switched capacitors, they often introduce additional losses due to repeated energy exchange between capacitors / magnetic devices. Furthermore, the voltage stress of the switching transistors and input current ripple tend to increase significantly with increasing gain, thus limiting the overall optimization of efficiency, power density, and cost. Taking photovoltaic grid connection as an example, a single module typically outputs only 20–40V, but needs to be boosted to approximately 380V or even higher to connect to the DC bus or grid interface. If traditional multi-stage high-gain solutions are adopted, device stress, losses, and the scale of passive components can easily drive up system costs and reduce overall performance, making it difficult to meet the dual goals of "high efficiency + economy" for new energy equipment.
[0003] Therefore, how to effectively reduce the voltage stress of power devices, simplify the circuit structure, and streamline the control logic while achieving extremely high voltage gain remains a key technical problem that urgently needs to be solved in this field. Summary of the Invention
[0004] (a) Technical problems to be solved
[0005] This invention aims to address common technical problems in existing high-gain boost converters: achieving a high boost ratio typically requires multi-stage cascading, complex magnetic coupling, or a large number of switched capacitor units, resulting in a large number of circuit components, high cost, and large size. Simultaneously, energy circulation and transfer between multiple energy storage elements causes additional conduction and switching losses, limiting further improvements in overall efficiency. Furthermore, the voltage stress on switching devices often increases dramatically with increasing gain, forcing the use of power devices with higher voltage ratings, further increasing system cost and affecting reliability. Therefore, how to effectively reduce switching stress, decrease the number of components, simplify control, and improve efficiency while achieving extremely high voltage gain has become a prominent technical challenge in this field.
[0006] (II) Technical Solution
[0007] To solve the above technical problem, the present invention provides a quadratic high-gain boost converter based on dual duty cycle control. The converter adopts a novel circuit topology and working mode, and the core lies in that through specific connection and multiplexing of components, the voltage stress of the first switching tube and the second switching tube is only of the output voltage, the voltage stress of the third switching tube is only of the output voltage, which greatly reduces the loss at the moment of turn-on and turn-off of the switching tubes, and the output gain is times that of the conventional boost converter.
[0008] The basic circuit structure of the converter comprises: one DC voltage source, a first inductor, a second inductor, a third inductor, a first switching tube, a second switching tube, a third switching tube, a first to a fourth capacitor, and a first to a fourth diode. Wherein, the fourth capacitor serves as an output filter capacitor, and the voltage across the fourth capacitor is the output voltage of the converter .
[0009] The key connection characteristics of the circuit are as follows: the positive terminal of the DC voltage source is connected to one end of the first inductor and the drain of the second switching tube respectively; the other end of the first inductor is connected to one end of the third inductor, the drain of the first switching tube and one end of the first capacitor respectively. The negative terminal of the DC voltage source is connected to one end of the second inductor and the source of the first switching tube respectively; the other end of the second inductor is connected to the source of the second switching tube, the cathode of the first diode, one end of the third capacitor, one end of the fourth capacitor and the negative output terminal respectively. The other end of the third inductor is connected to the drain of the third switching tube, the anode of the second diode and one end of the second capacitor respectively; the other end of the first capacitor is connected to the source of the third switching tube and the anode of the first diode respectively. The cathode of the second diode is connected to the anode of the third diode and the other end of the third capacitor respectively; the cathode of the third diode is connected to the anode of the fourth diode and the other end of the second capacitor respectively. The cathode of the fourth diode is connected to the other end of the fourth capacitor and the positive output terminal respectively.
[0010] The core control feature of the present invention is that the first switching tube, the second switching tube and the third switching tube have the same duty cycle (0<d1<1), and the third switching tube has an independent duty cycle (0, 1-d1), so it is not necessary to set a dead time. This greatly simplifies the driving and control circuits.
[0011] Based on the above control, the circuit presents 3 working modes in one switching cycle:
[0012] 1. In the first operating mode, the first, second, and third switching transistors are all turned on, charging the first inductor through a circuit consisting of a DC voltage source, the first inductor, and the first switching transistor; charging the second inductor through a circuit consisting of a DC voltage source, the second inductor, and the second switching transistor; charging the third inductor through a circuit consisting of a first capacitor, the third inductor, and the third switching transistor; charging the third capacitor through a circuit consisting of a DC voltage source, the first inductor, the third inductor, the second diode, the third capacitor, and the second inductor; and charging the fourth capacitor through a circuit consisting of a DC voltage source, the first inductor, the third inductor, the second capacitor, the fourth diode, the fourth capacitor, and the second inductor, while simultaneously supplying power to the load; the first and third diodes are in a reverse off state.
[0013] 2. In the second operating mode, neither the first nor the second switching transistor is conducting, while the third switching transistor is conducting. Through the DC voltage source, the first inductor, the first capacitor, the first diode, and the second inductor form a circuit. The first and second inductors release energy and discharge, and their current decreases. The circuit formed by the first capacitor, the third inductor, and the third switching transistor continues to charge the third inductor. The second to fourth diodes (D2-D4) are all in the reverse turn-off state. The second and third capacitors have no circuits and no voltage or current changes. The fourth capacitor supplies power to the load alone.
[0014] 3. In the third operating mode, the first switch, the second switch, and the third switch are all off; the first capacitor (C1) is charged through a circuit consisting of a DC voltage source, the first inductor, the first capacitor, and the first diode; the third capacitor charges the second capacitor through a circuit consisting of the third capacitor, the third diode, the second capacitor, the third inductor, the first capacitor, and the first diode; the fourth capacitor supplies power to the load independently; and the fourth diode is in the reverse off state.
[0015] The steady-state voltage gain (output voltage) of the converter With input voltage The ratio (d) is determined by the duty cycle d of the switching transistor. 1， d2 is determined, and its theoretical expression is: Where d1 is the duty cycle of all three switches conducting simultaneously, and d2 is the duty cycle of the third switch conducting alone. By adjusting d... 1， d2 enables a stable and extremely high voltage boost ratio over a wide range. Furthermore, the voltage stress borne by the first and second switching transistors in this converter... for Voltage stress borne by the third switching transistor for .
[0016] Beneficial Effects: This invention proposes a Boost-type DC-DC converter for ultra-high gain applications, balancing low loss and low cost. Performance is improved through three core design features: First, by utilizing capacitor sharing / reuse and energy transfer path reconfiguration, redundant energy storage components and ineffective energy cycling are reduced, decreasing the number of components and the cumulative loss from the source, while improving gain and cost performance. Second, by employing energy storage components, which can be connected in series with the inductor secondary winding when the switching transistors are off, the output gain is significantly increased while limiting the voltage stress on the switching transistors (the peak voltage stress borne by the switching transistors (S1, S2) is effectively clamped, and its theoretical value is only the output voltage). of ,Right now The voltage is much lower than the output voltage, reducing the cost of MOSFET selection; furthermore, the simultaneous conduction duty cycle of the three switches (S1, S2, S3) is d1, and the individual conduction duty cycle of the third switch (S3) is d2, eliminating the need to consider dead time, simplifying control, and reducing the cost of the MOSFET drive circuit.
[0017] Compared to common high-gain boost topologies, this invention achieves the same or even higher boost capability while using a more streamlined device configuration to achieve lower switching stress and better efficiency. This converter is suitable for typical "low input voltage – high output voltage level" applications in green energy systems such as battery power, photovoltaic front-end boost, and fuel cells. It features a high boost ratio, low device stress, low switching losses, simple control, high conversion efficiency, and a more advantageous overall cost. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the low-loss, low-cost, ultra-high-gain boost converter described in this invention.
[0019] Figure 2 The equivalent circuit diagram of the low-loss, low-cost, ultra-high-gain boost converter of the present invention when the first switch (S1), the second switch (S2), and the third switch (S3) are all turned on;
[0020] Figure 3 The equivalent circuit diagram of the low-loss, low-cost, ultra-high-gain boost converter of the present invention when the first switch (S1) and the second switch (S2) are turned off and the third switch (S3) is turned on;
[0021] Figure 4 The equivalent circuit diagram of the low-loss, low-cost, ultra-high-gain boost converter of the present invention when the first switch (S1), the second switch (S2), and the third switch (S3) are all turned off;
[0022] Figure 5.1 , 5.25.3 represents the input voltage under ideal conditions, when the duty cycle d1=0.50, d2=0.27, and d1=0.50. Simulation waveform diagram of the converter described in this invention; wherein, Figure 5.1 The input voltage waveform is shown below. Figure 5.2 For output voltage ( Waveform diagram (580V) Figure 5.3 The drain-source voltage of the switching transistor ( Waveform diagram. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0024] Example 1
[0025] Combination Figure 1 As shown, this embodiment provides a quadratic high-gain Boost converter based on dual duty cycle control. The converter includes: a DC voltage source. The converter comprises: a first inductor L1, a second inductor L2, a third inductor L3, a first switching transistor S1, a second switching transistor S2, a third switching transistor S3, first to fourth capacitors C1-C4, and first to fourth diodes D1-D4. The fourth capacitor C4 serves as the output filter capacitor, and the voltage across it is the output voltage of the converter. The converter uses a total of 3 inductors, 3 switching transistors, 4 capacitors, and 4 diodes.
[0026] The specific connection relationship of the circuit is as follows: Figure 1 As shown:
[0027] The positive terminal of the DC voltage source Vin is connected to one end of the first inductor L1 and the drain of the second switch S2, respectively; the other end of the first inductor L1 is connected to one end of the third inductor L3, the drain of the first switch S1, and one end of the first capacitor C1, respectively.
[0028] The negative terminal of the DC voltage source Vin is connected to one end of the second inductor L2 and the source of the first switch S1, respectively; the other end of the second inductor L2 is connected to the source of the second switch S2, the cathode of the first diode D1, one end of the third capacitor C3, one end of the fourth capacitor C4, and the output negative terminal OUT−, respectively.
[0029] The other end of the third inductor L3 is connected to the drain of the third switch S3, the anode of the second diode D2, and one end of the second capacitor C2, respectively; the other end of the first capacitor C1 is connected to the source of the third switch S3 and the anode of the first diode D1, respectively.
[0030] The cathode of the second diode D2 is connected to the anode of the third diode D3 and the other end of the third capacitor C3, respectively; the cathode of the third diode D3 is connected to the anode of the fourth diode D4 and the other end of the second capacitor C2, respectively.
[0031] The cathode of the fourth diode D4 is connected to the other end of the fourth capacitor C4 and the positive output terminal OUT+.
[0032] Voltage gain of boost converter ;in, For output voltage, d1 is the input voltage, d2 is the duty cycle of the three switches S1, S2 and S3 conducting simultaneously, and d2 is the duty cycle of the third switch S3 conducting alone.
[0033] This circuit has three operating modes within one switching cycle, determined by the switching actions of transistors S1, S2, and S3. Their equivalent circuits are as follows: Figure 2 , Figure 3 and Figure 4 As shown:
[0034] Mode 1 (Switch-on mode): Combined with Figure 2 As shown, the first switch S1, the second switch S2, and the third switch S3 are all turned on. The first inductor L1 is charged through a circuit consisting of a DC voltage source Vin, the first inductor L1, and the first switch S1; the second inductor L2 is charged through a circuit consisting of a DC voltage source Vin, the second inductor L2, and the second switch S2; the third inductor L3 is charged through a circuit consisting of a first capacitor C1, the third inductor L3, and the third switch S3; the third capacitor C3 is charged through a circuit consisting of a DC voltage source Vin, the first inductor L1, the third inductor L3, the second diode D2, the third capacitor (C3), and the second inductor L2; the fourth capacitor C4 is charged through a circuit consisting of a DC voltage source Vin, the first inductor L1, the third inductor L3, the second capacitor C2, the fourth diode D4, the fourth capacitor C4, and the second inductor L2, while simultaneously supplying power to the load; the two diodes D1 and D3 are in a reverse-biased off state.
[0035] Mode 2 (Switching transistors S1 and S2 are off, switching transistor S3 is on): Combined with Figure 3As shown, neither the first switch S1 nor the second switch S2 is conducting, while the third switch S3 is conducting. A circuit is formed through the DC voltage source Vin, the first inductor L1, the first capacitor C1, the first diode D1, and the second inductor L2. The first inductor L1 and the second inductor L2 release energy and discharge, reducing their current. The circuit formed by the first capacitor C1, the third inductor L3, and the third switch S3 continues to charge the third inductor L3. All three diodes D2-D4 are in the reverse off state. The two capacitors C2-C3 have no circuit and show no voltage or current change. The fourth capacitor C4 supplies power to the load alone.
[0036] Mode 3 (Switch-off mode): Combined with Figure 4 As shown, the first switch S1, the second switch S2, and the third switch S3 are all off; the first capacitor C1 is charged through a circuit consisting of the DC voltage source Vin, the first inductor L1, the first capacitor C1, and the first diode D1; the third capacitor C3 charges the second capacitor C2 through a circuit consisting of the third capacitor C3, the third diode D3, the second capacitor C2, the third inductor L3, the first capacitor C1, and the first diode D1; the fourth capacitor C4 supplies power to the load alone; and the fourth diode D4 is in the reverse off state.
[0037] like Figure 5.1 and Figure 5.2 As shown, when the input voltage With a voltage of 20V, a duty cycle of d1=0.50, and d2=0.27, a stable output voltage of up to 580V can be obtained. This verifies its strong boost capability. Simultaneously, the voltage stress on its switching devices is effectively clamped. The peak voltage stress on switching transistors S1 and S2 is... Output voltage only of ,Right now The peak voltage stress of switches S1 and S2 is only around 40V, far lower than the output voltage. The voltage stress of the third switch S3... The theoretical value is: ,Right now Its value is also much lower than the 580V output voltage. The lower stress allows for the use of low-cost, low-on-resistance switching transistors, combined with a simplified component count (only 14 active and passive components: 3 inductors, 3 switching transistors, 4 capacitors, and 4 diodes), which contributes to both reduced system cost and improved conversion efficiency. Furthermore, the first switching transistor S1, the second switching transistor S2, and the third switching transistor S3 have the same duty cycle (0°C).
Claims
1. A quadratic high-gain Boost converter based on dual duty cycle control, characterized in that, include: A DC voltage source ( The circuit consists of: a first inductor (L1), a second inductor (L2), a third inductor (L3), a first switching transistor (S1), a second switching transistor (S2), a third switch (S3), first to fourth capacitors (C1-C4), and first to fourth diodes (D1-D4); among which, The DC voltage source (V) in The positive terminal of the first inductor (L1) is connected to one end of the first inductor (L1) and the drain of the second switch (S2); the other end of the first inductor (L1) is connected to one end of the third inductor (L3), the drain of the first switch (S1), and one end of the first capacitor (C1). The negative terminal of the DC voltage source (Vin) is connected to one end of the second inductor (L2) and the source of the first switching transistor (S1); the other end of the second inductor (L2) is connected to the source of the second switching transistor (S2), the cathode of the first diode (D1), one end of the third capacitor (C3), one end of the fourth capacitor (C4), and the output negative terminal (OUT−). The other end of the third inductor (L3) is connected to the drain of the third switch (S3), the anode of the second diode (D2), and one end of the second capacitor (C2); the other end of the first capacitor (C1) is connected to the source of the third switch (S3) and the anode of the first diode (D1). The cathode of the second diode (D2) is connected to the anode of the third diode (D3) and the other end of the third capacitor (C3); the cathode of the third diode (D3) is connected to the anode of the fourth diode (D4) and the other end of the second capacitor (C2). The cathode of the fourth diode (D4) is connected to the other end of the fourth capacitor (C4) and the positive output terminal (OUT+).
2. The quadratic high-gain Boost converter based on dual duty cycle control according to claim 1, characterized in that, The theoretical voltage gain G of the converter is expressed as follows: ,in, For output voltage, d1 is the input voltage, d2 is the duty cycle of the three switches (S1, S2, S3) conducting simultaneously, and d2 is the duty cycle of the third switch (S3) conducting alone.
3. The quadratic high-gain Boost converter based on dual duty cycle control according to claim 1 or 2, characterized in that, The control terminals of the first switch (S1), the second switch (S2), and the third switch (S3) receive a drive signal with a duty cycle of d1, and the control terminal of the third switch (S3) receives a drive signal with a duty cycle of d2; within one switching cycle, there are three operating modes: S1 on, S2 on, and S3 on; S1 off, S2 off, and S3 on; and S1 off, S2 off, and S3 off.
4. The quadratic high-gain Boost converter based on dual duty cycle control according to claim 3, characterized in that, In the first operating mode, the first switch (S1), the second switch (S2), and the third switch (S2) are all turned on. The first inductor (L1) is charged through a circuit consisting of the DC voltage source (Vin), the first inductor (L1), and the first switch (S1); the second inductor (L2) is charged through a circuit consisting of the DC voltage source (Vin), the second inductor (L2), and the second switch (S2); and the third inductor (L3) is charged through a circuit consisting of the first capacitor (C1), the third inductor (L3), and the third switch (S3). Charging; the third capacitor (C3) is charged through a circuit consisting of a DC voltage source (Vin), a first inductor (L1), a third inductor (L3), a second diode (D2), a third capacitor (C3), and a second inductor (L2); the fourth capacitor (C4) is charged through a circuit consisting of a DC voltage source (Vin), a first inductor (L1), a third inductor (L3), a second capacitor (C2), a fourth diode (D4), a fourth capacitor (C4), and a second inductor (L2) while simultaneously supplying power to the load; the two diodes (D1, D3) are in a reverse off state.
5. The quadratic high-gain Boost converter based on dual duty cycle control according to claim 3, characterized in that, In the second operating mode, neither the first switch (S1) nor the second switch (S2) is conducting, while the third switch (S3) is conducting. A circuit is formed through the DC voltage source (Vin), the first inductor (L1), the first capacitor (C1), the first diode (D1), and the second inductor (L2). The first inductor (L1) and the second inductor (L2) release energy and discharge, reducing the current. The circuit formed by the first capacitor (C1), the third inductor (L3), and the third switch (S3) continues to charge the third inductor (L3). All three diodes (D2-D4) are in the reverse turn-off state. There is no circuit between the two capacitors (C2-C3), and there is no change in voltage or current. The fourth capacitor (C4) supplies power to the load alone.
6. The quadratic high-gain Boost converter based on dual duty cycle control according to claim 3, characterized in that, In the third operating mode, the first switch (S1), the second switch (S2), and the third switch (S3) are all not turned on; the first capacitor (C1) is charged through a circuit consisting of a DC voltage source (Vin), the first inductor (L1), the first capacitor (C1), and the first diode (D1); in the circuit consisting of the third capacitor (C3), the third diode (D3), the second capacitor (C2), the third inductor (L3), the first capacitor (C1), and the first diode (D1), the third capacitor (C3) charges the second capacitor (C2); the fourth capacitor (C4) supplies power to the load alone; and the fourth diode (D4) is in the reverse off state.
7. The quadratic high-gain Boost converter based on dual duty cycle control according to claim 2, characterized in that, The adjustment range of the conduction duty cycle d1 is (0,1); the adjustment range of the conduction duty cycle d2 is (0,1-d1).
8. The quadratic high-gain Boost converter based on dual duty cycle control according to claim 1, characterized in that, Voltage stress on the first switch (S1) and the second switch (S2) for: ,in The output voltage is given by d1, where d1 is the simultaneous conduction duty cycle of the three switches (S1, S2, S3), d2 is the individual conduction duty cycle of the third switch (S3), and d2 is the voltage stress on the third switch (S3). for: .