Rectifier-diode-free single-inductor boost energy recovery circuit and control method thereof
By using a single-inductor boost energy recovery circuit without rectifier diodes and a simple closed-loop control method, the loss problem caused by rectifier diodes in bridgeless Boost PFC converters is solved, achieving efficient conversion of low-voltage energy and circuit simplification.
Patent Information
- Application Number
- CN202511240683.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-02
- Publication Date
- 2025-11-18
AI Technical Summary
Existing bridgeless Boost PFC converters still require the use of rectifier diodes, which leads to conduction losses and conduction voltage drop, reducing system efficiency, especially in low-voltage energy recovery scenarios where they cannot effectively convert voltage.
A single-inductor boost energy recovery circuit without rectifier diodes is adopted. It operates in boost mode during the positive half-cycle of AC input and in buck-boost mode during the negative half-cycle. Closed-loop control is achieved by combining simple single-voltage loop feedback or different control drive signals, thus eliminating the need for input rectifier diodes.
It reduces energy loss, simplifies circuit structure, improves converter efficiency, and achieves efficient conversion of low-voltage energy.
Smart Images
Figure CN120979157A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of power conversion circuit technology, and particularly relates to a single-inductor boost energy recovery circuit without rectifier diodes and its control method. Background Technology
[0002] Traditional boost power factor correction (PFC) converters are widely used to achieve AC-DC conversion, improving the power factor (PF) and reducing the total harmonic distortion (THDi) of the input current. A traditional boost PFC converter consists of a diode rectifier bridge and a boost converter unit, such as... Figure 1 As shown. Over the past decade, various bridgeless boost PFC converters have been extensively studied because they eliminate the need for input rectifier diodes. By eliminating the input diode rectifier bridge, these bridgeless boost PFC converters exhibit lower conduction losses. However, most bridgeless boost PFC converters in research are based on two boost converter units, and these converters typically require two input rectifier diodes. That is, one conducting diode is still used to achieve AC-DC conversion, and this conducting diode still affects the overall efficiency of the converter.
[0003] Furthermore, in applications of energy harvesting systems based on weak ambient energy, the harvested AC input voltage is typically low, such as 0.4–3V. The forward voltage drop in the rectifier diodes affects the harvested AC input power. Therefore, research on bridge-less AC-DC converters is of great significance.
[0004] Most existing bridgeless Boost PFC converters still require two rectifier diodes to achieve AC-DC power conversion. Rectifier diodes always have conduction losses and voltage drops, reducing the overall system efficiency. This is especially problematic for low-voltage input energy recovery scenarios, where the recovered voltage cannot be effectively converted to DC for use by subsequent charging circuits.
[0005] To address this issue, this invention proposes a diode-free single-inductor boost energy recovery circuit and its control method. Through a novel circuit topology, it can achieve operation in boost mode during the positive half of the AC input cycle and buck-boost mode during the negative half of the AC input cycle. This completely eliminates the input rectifier diode, avoiding voltage and power losses caused by diode forward voltage drop. Summary of the Invention
[0006] The present application aims to provide a single-inductor boost energy recovery circuit without rectifier diode and a control method thereof to solve the problems of the prior art, i.e., the existing bridgeless Boost PFC converter needs to use two rectifier diodes to achieve AC-DC power conversion, has conduction loss and conduction voltage drop, reduces the overall efficiency of the system, and cannot be used for low-voltage energy recovery.
[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:
[0008] In a first aspect, the present application provides a single-inductor boost energy recovery circuit without rectifier diode, which includes a switch S1, a switch S2, an inductor L, a diode D1, a diode D2, and an output capacitor C o .
[0009] One end of the AC input side is connected to the drain of the switch S1, the positive electrode of the output capacitor C o , and one end of the load R L ; the source of the switch S1 is connected to one end of the inductor L and the cathode of the diode D1; the negative electrode of the output capacitor C o is connected to the anode of the diode D1, the other end of the load R L , and the anode of the diode D2; the other end of the AC input side is connected to the drain of the switch S2, and the source of the switch S2 is connected to the other end of the inductor L and the cathode of the diode D2.
[0010] Preferably, the positive half-cycle of the circuit works in a boost mode, and the negative half-cycle works in a boost-buck mode.
[0011] Preferably, the working mode of the circuit in the positive half-cycle of the AC input is as follows:
[0012] Working mode 1: the switch S1 and the switch S2 are in the on state, and the diode D1 and the diode D2 are in the off state; the input end charges the inductor L through the switch S1 and the switch S2; in this stage, the inductor current i L increases linearly, and the output capacitor C o supplies energy to the load;
[0013] Working mode 2: the switch S1 is off, the switch S2 and the diode D1 are on, and the diode D2 is off; the input end and the energy stored in the inductor L are transmitted to the output capacitor C o and the load R L through the diode D1 and the switch S2; the inductor current i L decreases linearly;
[0014] Working mode 3: the switch S1 and the switch S2 are off, and the diode D1 and the diode D2 are off; in this working mode, the inductor current iL linearly decreases to zero, at which time the inductor current i L = 0, the output capacitor C o supplies energy to the subsequent circuit.
[0015] Preferably, the circuit in the working mode of the negative half of the AC input cycle is as follows:
[0016] Working mode 4: the switch S1 and the switch S2 are in the on state, the diode D1 and the diode D2 are in the off state, the input end passes through the switch S2 and the switch S1 to charge the inductor L; in this stage, the inductor current i L linearly increases, the output capacitor C o supplies energy to the load;
[0017] Working mode 5: the switch S2 is off, the switch S1 and the diode D2 are on, and the diode D1 is in the off state; the energy stored in the inductor L passes through the diode D2 and the body diode of the switch S1 to the output capacitor C o and the load R L transfers, and the inductor current i L linearly decreases;
[0018] Working mode 6: the switch S1 and the switch S2 are off, and the diode D1 and the diode D2 are off; this working mode starts when the inductor current i L linearly decreases to zero, at which time the inductor current i L = 0, and the output capacitor C o supplies energy to the subsequent circuit.
[0019] The present application proposes, in a second aspect, a control method of a single-inductor boost energy recovery circuit without rectifier diodes, wherein the switch S1 and the switch S2 are related to the input AC cycle, and different control driving signals are used to realize closed-loop control.
[0020] Preferably, the output reference voltage V o,ref and the output voltage sampling V o are summed and PI-regulated to generate an error feedback signal, the error feedback signal and a triangular wave are compared in a comparator 1 to generate an output signal of the comparator 1; at the same time, the output voltage sampling V o and the input voltage sampling V in are compared in a comparator 2 to generate an output signal of the comparator 2.
[0021] The output signals of the two comparators are generated into driving signals through a logic circuit to realize closed-loop control.
[0022] Further, the output signals of the two comparators are generated into driving signals through a logic circuit, which is as follows:
[0023] The output signals of comparator 1 and comparator 2 are ANDed together to generate the drive signal Gs1 for switch S1; the output signal of comparator 2 is ANDed together with the output signal of comparator 1 and then ANDed together to generate the drive signal Gs2 for switch S2.
[0024] In its third aspect, this invention proposes a control method for a single-inductor boost energy recovery circuit without a rectifier diode, wherein the switching transistors S1 and S2 use the same control drive signal to achieve closed-loop control.
[0025] Preferably, the output voltage is sampled by V. o With output reference voltage V o,ref An error feedback signal is generated by summation and PI adjustment. The error feedback signal and the triangular wave are compared by a comparator to generate the comparator's output signal, which serves as the drive signal for switches S1 and S2.
[0026] Compared with the prior art, the beneficial effects of the present invention are:
[0027] (1) The single-inductor boost energy recovery circuit without rectifier diode in this invention reduces energy loss and simplifies circuit structure by completely eliminating the diode rectifier bridge.
[0028] (2) The control method of the single-inductor boost energy recovery circuit without rectifier diode in this invention can achieve closed-loop control by using a simple single voltage loop feedback, and the two switching transistors can achieve closed-loop control by using the same driving signal.
[0029] (3) The control method of the single-inductor boost energy recovery circuit without rectifier diode in this invention can use a single voltage loop and the feedback of the input AC signal to achieve closed-loop control, further reducing the conduction loss of the switching transistor and improving the converter efficiency. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the topology of a traditional Boost power factor correction converter in the background technology.
[0031] Figure 2 This is a schematic diagram of the topology of the single-inductor boost energy recovery circuit without rectifier diodes in this invention;
[0032] Figure 3 This is a schematic diagram of the equivalent circuit of the single-inductor boost energy recovery circuit without rectifier diodes in the present invention during the positive half-cycle of the AC input. Figure 3 (a) represents working mode 1. Figure 3 (b) represents working mode 2. Figure 3 (c) is working mode 3);
[0033] Figure 4 Fig. 4 is a schematic diagram of an equivalent circuit of a working mode of the single-inductor boost energy recovery circuit without rectifier diode in the application in a negative half cycle of an AC input; Figure 4 (a) is working mode 4, Figure 4 (b) is working mode 5, Figure 4 (c) is working mode 6);
[0034] Figure 5 Fig. 5 is a schematic diagram of a control method 1 of the single-inductor boost energy recovery circuit without rectifier diode in the application;
[0035] Figure 6 Fig. 6 is a schematic diagram of a control method 2 of the single-inductor boost energy recovery circuit without rectifier diode in the application;
[0036] Figure 7 Fig. 7 is a theoretical waveform diagram of key devices of the single-inductor boost energy recovery circuit without rectifier diode in the application;
[0037] Figure 8 Fig. 8 is a simulation waveform diagram of key devices of the single-inductor boost energy recovery circuit without rectifier diode in the application. DETAILED DESCRIPTION
[0038] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the application.
[0039] Embodiment 1:
[0040] The single-inductor boost energy recovery circuit without rectifier diode is composed of a switch tube S1, a switch tube S2, an inductor L, a diode D1, a diode D2, and an output capacitor C o . Figure 2 The topological structure schematic diagram of the single-inductor boost energy recovery circuit without rectifier diode in the application is given.
[0041] Specifically, one end of an AC input side is connected with a drain of the switch tube S1, a positive electrode of the output capacitor C o , and one end of a load R L . A source of the switch tube S1 is connected with one end of the inductor L and a cathode of the diode D1. An anode of the diode D1 is connected with a negative electrode of the output capacitor C o , the other end of the load R L , and an anode of the diode D2. The other end of the AC input side is connected with a drain of the switch tube S2. A source of the switch tube S2 is connected with the other end of the inductor L and a cathode of the diode D2.
[0042] The positive half cycle of the AC input of the circuit of the present application is shown in the working mode chart of the boost mode as Figure 3 Figure 3 (a) is the working mode 1 equivalent circuit of the no rectifier diode single inductor boost energy recovery circuit in the positive half cycle of the AC input; Figure 3 (b) is the working mode 2 equivalent circuit of the no rectifier diode single inductor boost energy recovery circuit in the positive half cycle of the AC input; Figure 3 (c) is the working mode 3 equivalent circuit of the no rectifier diode single inductor boost energy recovery circuit in the positive half cycle of the AC input.
[0043] The negative half cycle of the AC input of the circuit of the present application is shown in the working mode chart of the boost-buck mode as Figure 4 Figure 4 (a) is the working mode 4 equivalent circuit of the no rectifier diode single inductor boost energy recovery circuit in the negative half cycle of the AC input; Figure 4 (b) is the working mode 5 equivalent circuit of the no rectifier diode single inductor boost energy recovery circuit in the negative half cycle of the AC input; Figure 4 (c) is the working mode 6 equivalent circuit of the no rectifier diode single inductor boost energy recovery circuit in the negative half cycle of the AC input.
[0044] Working mode 1: In this stage, the switch S1 and the switch S2 are in the on state, the diode D1 and the diode D2 are in the off state, the input end charges the inductor L through the switch S1 and the switch S2. In this stage, the inductor current i L increases linearly. The output capacitor C o supplies energy to the load.
[0045] Working mode 2: The switch S1 is off, the switch S2 and the diode D1 are on, the diode D2 is off, the input end and the energy stored in the inductor L transfer to the output capacitor C o and the load R L through the diode D1 and the switch S2; the inductor current i L decreases linearly.
[0046] Working mode 3: The switch S1 and the switch S2 remain off, the diode D1 and the diode D2 are in the off state. This working mode starts when the inductor current i L decreases linearly to zero, at this time, the inductor current i L = 0, the output capacitor C o supplies energy to the load.
[0047] Working mode 4: In this stage, switch S1 and switch S2 are in the on state, diode D1 and diode D2 are in the off state, the input end passes through switch S2 and switch S1 to charge the inductor L. In this stage, the inductor current i L increases linearly. The output capacitor C o supplies energy to the load.
[0048] Working mode 5: switch S2 is off, switch S1 and diode D2 are on, and diode D1 is in the off state. The energy stored in the inductor L passes through diode D2 and the body diode of switch S1 to charge the output capacitor C o and the load R L , and the inductor current i L decreases linearly.
[0049] Working mode 6: switch S1 and switch S2 remain off, and diode D1 and diode D2 are in the off state. This working mode starts when the inductor current i L decreases linearly to zero, at which time the inductor current i L = 0, and the output capacitor C o supplies energy to the subsequent circuit.
[0050] Figure 5 Control method 1 for the single-inductor boost energy recovery circuit without rectifier diode. The same control driving signal is used for both switches. Control method 1 uses a simple single-voltage closed-loop control to achieve the control of the double switches. The same control driving signal is used for switch S1 and switch S2, avoiding complex control.
[0051] Specifically, the output voltage sampling V o is compared with the output reference voltage V o,ref , and the error feedback signal is generated through summation and PI regulation. The error feedback signal and the triangular wave are compared in the comparator, and the output signal of the comparator is generated as the driving signal of switch S1 and switch S2.
[0052] Figure 6 Control method 2 for the single-inductor boost energy recovery circuit without rectifier diode. The two switches are related to the input AC period and are realized by different control driving signals. The specific control is as follows. First, the output reference voltage V o,ref is compared with the output voltage sampling V o , and the error feedback signal is generated through summation and PI regulation. This signal and the triangular wave are compared in comparator 1. At the same time, the output voltage sampling V o is compared with the input voltage sampling V in in comparator 2. The outputs of the two comparators are finally generated through a logic circuit to generate the driving signal, realizing the closed-loop control of the converter.
[0053] Specifically, the output signal of the comparator 1 and the output signal of the comparator 2 pass through an AND gate to generate the driving signal Gs1 of the switch S1; and the output signal of the comparator 2 passes through a NOT gate and then is combined with the output signal of the comparator 1 passing through an AND gate to generate the driving signal Gs2 of the switch S2.
[0054] Compared with the control method one, the switch S1 and the switch S2 are kept in the conducting state in the working mode 1 and the working mode 4 of the circuit respectively, so that the current flows through the switch instead of the parasitic body diode in the switch, and the voltage loss is further reduced.
[0055] Figure 7 The key device theoretical waveform diagram of the single-inductor boost energy recovery circuit without rectifier diode. It should be noted that, for the key device theoretical waveform, the key device theoretical waveform diagrams of the two control methods are the same. The main difference between the two control methods is the difference in the conduction duty ratio and the off duty ratio, and the specific conditions are as follows:
[0056] Since the switch S1 and the switch S2 in the control method one adopt the same control driving signal, the conduction duty ratio d 1on = d 2on , T s is a switching period. In the control method two, the switch S1 and the switch S2 adopt different control driving signals, and the conduction duty ratio d 1on of the switch S1 and the conduction duty ratio d 2on of the switch S2 exist certain differences. As shown in Figure 7 , the key devices of the conversion unit mainly work in half of the power frequency period and do not interfere with each other.
[0057] Experimental verification:
[0058] To verify the operation feasibility of the circuit under low-voltage alternating-current input, the control scheme shown in Figure 6 is adopted to simulate and verify the circuit in the PSIM simulation software. The specific parameters are as follows: the peak value of the alternating-current input voltage is 2V, the effective value is 1.41Vac, the frequency is 100Hz, the inductance L is 4uH, the capacitance C is 1980uF, the switching frequency of the PFC converter (the circuit of the application) is 50kHz, P is 3 and I is 0.005 in the PI parameter, and the output voltage of the converter is set to 4.8V. In addition, in order to ensure the continuity of the input current, an input capacitance C f is added to the input side and is set to C f =0.1uF.
[0059] Figure 8 The key device waveform simulation diagram of the single-inductor boost energy recovery circuit without rectifier diode. As shown in Figure 8It can be seen that in the case of AC input 1.41Vac (i.e. AC input voltage peak value 2V), frequency 100Hz, the circuit of the application realizes 4.8V output. Moreover, by controlling the switch tube S1 and switch tube S2 to turn on and turn off in the positive and negative half cycle of input voltage v in , the bridgeless operation of the AC-DC circuit of the application is realized. In addition, the circuit works in each half of the power frequency cycle, which is consistent with the theoretical key device waveform shown in Figure 7 , verifying the working principle of the bridgeless converter, and also showing that the converter can realize closed-loop stable operation through the system closed-loop control scheme shown in Figure 6 .
[0060] According to the above theoretical analysis and simulation results, it can be seen that the single voltage energy recovery circuit without input diode proposed in the application can realize 4.8V output voltage through simple single voltage closed-loop control under 1.4Vac AC input voltage, improve voltage and have rectification effect. Moreover, the two switch tubes can use various control methods to achieve the same control effect, and the circuit control scheme is simple and reliable.
[0061] The above is only used to help understand the method of the application and its core essence, but the protection scope of the application is not limited thereto. For those skilled in the art, according to the technical scheme and inventive concept of the application, equivalent replacement or change within the technical range disclosed by the application should be covered in the protection scope of the application. In summary, the content of the specification should not be understood as a limitation of the application.
Claims
1. A single-inductor boost energy recovery circuit without rectifier diode, characterized by, The circuit topology comprises a switch S1, a switch S2, an inductor L, a diode D1, a diode D2, an output capacitor C o ; One end of the AC input side is connected to the drain of the switching transistor S1, the positive electrode of the output capacitor C o , and one end of the load R L ; the source of the switching transistor S1 is connected to one end of the inductor L and the cathode of the diode D1; the negative electrode of the output capacitor C o is connected to the anode of the diode D1, the other end of the load R L , and the anode of the diode D2; the other end of the AC input side is connected to the drain of the switching transistor S2, and the source of the switching transistor S2 is connected to the other end of the inductor L and the cathode of the diode D2.
2. The no rectifying diode single-inductor boost energy recovery circuit according to claim 1, wherein, The positive half cycle of the AC input works in the boost mode and the negative half cycle works in the buck-boost mode.
3. The no rectifying diode single-inductor boost energy recovery circuit according to claim 1, wherein, The working mode of the circuit in the positive half cycle of the AC input is as follows: Working mode 1: the switch S1 and the switch S2 are in the on state, and the diode D1 and the diode D2 are in the off state; the input end charges the inductor L through the switch S1 and the switch S2; At this stage, the inductor current i L Linear rise, output capacitor C o Power supply for the load Operating mode 2: switch S1 is off, switch S2 and diode D1 are on, diode D2 is off; the input terminal is connected to the output capacitor C through diode D1 and switch S2 o and load R L Pass; inductor current i L Linear decline; Working mode 3: switch tube S1, switch tube S2 are off, diode D1, diode D2 are off; this working mode starts when the inductance current i L linearly drops to zero, at this time, the inductance current i L =0, the output capacitor C o is powered by the later stage circuit.
4. The no rectifying diode single-inductor boost energy recovery circuit according to claim 3, wherein, The working mode of the circuit in the negative half cycle of the AC input is as follows: Working mode 4: the switch S1 and the switch S2 are in the on state, and the diode D1 and the diode D2 are in the off state; the input end charges the inductor L through the switch S2 and the switch S1; At this stage, the inductor current i L Linear rise, output capacitor C o Power the load; Operating mode 5: switch S2 is off, switch S1 and diode D2 are on, diode D1 is off, the energy stored in the inductor L flows through diode D2 and the body diode of switch S1 to the output capacitor C o and the load R L is transferred, the inductor current i L linearly decreases; Operating mode 6: Switch S1, switch S2 off, diode D1, diode D2 off. This operating mode is entered when the inductance current i L drops linearly to zero, at which time the inductance current i L = 0, and the output capacitor C o supplies the energy for the following circuit.
5. The control method of the no-commutation diode single-inductor boost energy recovery circuit according to any one of claims 1 to 4, characterized by, The switch S1 and the switch S2 are related to the AC input cycle and adopt different control driving signals to realize the closed-loop control.
6. The control method of the no-commutation diode single-inductor boost energy recovery circuit according to claim 5, characterized by, The output reference voltage V o,ref The output voltage sample V o The error feedback signal is generated by summing and PI regulation, and the error feedback signal and the triangular wave are compared in the comparator 1 to generate the output signal of the comparator 1; meanwhile, the output voltage sample V o The input voltage sample V in are compared in the comparator 2 to generate the output signal of the comparator 2; The output signals of the two comparators generate driving signals through a logic circuit to realize the closed-loop control.
7. The control method of the no-commutation diode single-inductor boost energy recovery circuit according to claim 6, characterized by, The output signals of the two comparators generate driving signals through a logic circuit, and the specific process is as follows: The output signal of the comparator 1 and the output signal of the comparator 2 pass through an AND gate to generate the driving signal Gs1 of the switch S1; The output signal of the comparator 2 passes through a NOT gate and then passes through an AND gate with the output signal of the comparator 1 to generate the driving signal Gs2 of the switch S2.
8. The control method of the no-commutation-diode single-inductor boost energy recovery circuit according to claim 1 or 2, characterized by, The switch S1 and the switch S2 adopt the same control driving signal to realize the closed-loop control.
9. The control method of the no-commutation diode single-inductor boost energy recovery circuit according to claim 8, characterized by, The output voltage sample V o The output reference voltage V o,ref The error feedback signal is generated by summing and PI regulation, and the error feedback signal and the triangular wave are compared by a comparator to generate an output signal of the comparator as a driving signal of the switch tube S1 and the switch tube S2.