Asymmetric half-bridge ac-dc single-stage converter and voltage division multi-output circuit thereof

Abstract

The application provides an asymmetric half-bridge AC-DC single-stage converter and a voltage division multi-output circuit thereof, relates to an isolated single-stage PFC technology in the field of power electronics / power supply conversion, realizes power factor correction, and stabilizes DC output. The converter comprises a rectifier bridge, an asymmetric half-bridge, a transformer, a rectifier circuit, an inductor La and a capacitor Cb, belongs to double-end conversion, and can transmit large power. The asymmetric half-bridge conversion can reduce the voltage stress of a switching tube, adopts asymmetric complementary PWM control, and realizes ZVS soft switching. Various rectifier topologies can reduce or eliminate the magnetic bias current of the transformer and reduce the volume of the transformer. The voltage division rectifier circuit and the multi-output rectifier circuit comprise diodes D1 and D2, capacitors Co1 and Co2, inductors Lo1, Lo2 or Lo, and utilize inductive coupling or taps to realize diode reverse voltage division balance and multi-voltage output. The topology of the application is simple, easy to control, low in cost and high in efficiency.

Description

Technical Field

[0001] This invention relates to an asymmetric half-bridge AC-DC single-stage converter and its voltage divider multi-output circuit, which is a switching power supply technology and belongs to the field of new energy power conversion and power electronics technology. Background Technology

[0002] Currently, the common technical solution for high-power, high-power-factor isolated AC-DC converters is a two-stage circuit topology. The first stage is a high-power-factor AC-DC non-isolated converter, generally using a boot converter topology; the second stage is a DC-DC isolated converter, mainly using phase-shifted full-bridge topology and LLC converter topology.

[0003] This two-stage circuit scheme has inherent shortcomings: (1) complex circuitry. (2) reduced overall efficiency. (3) reduced reliability. (4) higher cost. (5) larger size. These are all due to the two-stage power conversion. In addition, the high power factor AC-DC non-isolated converter in the first stage is not easy to implement soft switching.

[0004] The so-called "single-stage PFC (Power Factor Correction) converter" is an isolated AC-DC converter that can achieve a high power factor on the AC side and a stable DC output voltage with only one stage of power conversion.

[0005] For isolated single-stage PFC converters, flyback topologies are mostly used. Flyback converters are single-ended converters, and the power they can transmit cannot be too large, generally used for low-power conversion. Resonant bridge topologies can also be used for isolated single-stage PFC conversion, but they are only suitable for voltage source outputs with a narrow output voltage regulation range and a large reactive current component on the primary side. Phase-shift controlled full-bridge topologies can also be used for isolated single-stage PFC conversion, but they require four switches for active control on both the primary and secondary sides, resulting in more components and higher costs. Some so-called combined single-stage converters use a combination of boot-type and bridge topologies, resulting in complex circuitry and no significant advantages. There are also asymmetrical double-ended output single-stage topologies, but these place high voltage and current stress on the rectifier circuit, which is disadvantageous in high-power applications, especially in low-voltage, high-current scenarios.

[0006] In addition, existing isolated single-stage PFC converter topologies, when voltage division or multi-voltage output is required, generally involve tapping the secondary winding of the transformer or adding a secondary winding. In high-power applications, transformers are difficult to manufacture.

[0007] The above content is only used to help understand the technical solution of the present invention, and does not mean that the above are all prior art. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and propose an asymmetric half-bridge AC-DC single-stage converter and its voltage divider multi-output circuit. This converter is an isolated single-stage PFC circuit with a simplified rectifier-filter topology, reducing or eliminating transformer bias current. Inductive coupling or taps are used to achieve diode reverse voltage division balancing and multi-voltage output. This converter is a two-ended converter capable of transmitting high power; and the switching transistors can achieve ZVS soft switching, improving conversion efficiency. The converter employs asymmetric complementary PWM control to achieve power factor correction and stable DC output.

[0009] The technical solution of the present invention is as follows.

[0010] An asymmetric half-bridge AC-DC single-stage converter consists of a rectifier bridge, an asymmetric half-bridge, a transformer, a rectifier circuit, an inductor La, and a capacitor Cb. The rectifier bridge is a four-terminal network with a positive output terminal, a negative output terminal, and two AC input terminals.

[0011] The asymmetric half-bridge includes capacitors C1 and C2 and switching transistors Q1 and Q2. The first terminals of capacitors C1 and C2 are connected together as node Va, and the second terminal of capacitor C2 is connected to the drain of switching transistor Q2 as node Vd. The source of switching transistor Q2 is connected to the drain of switching transistor Q1 as node Vb, and the source of switching transistor Q1 is connected to the second terminal of capacitor C1 as node GND.

[0012] The transformer includes a primary winding Np and a secondary winding Ns. The primary winding Np has terminals P1 and P2, and the secondary winding Ns has terminals S1 and S2. Terminal S1 and terminal P1 are the same type of terminal, and terminal S2 and terminal P2 are the same type of terminal.

[0013] The rectifier circuit includes a diode D1, an inductor Lo, and a capacitor Co. The anode of diode D1 is connected to the first terminal of inductor Lo, forming node V1, and the cathode of diode D1 is connected to the positive terminal of capacitor Co, forming the positive terminal Vo. + The second terminal of inductor Lo is connected to the negative terminal of capacitor Co, serving as the negative terminal Vo. - .

[0014] The connection relationship of the asymmetric half-bridge AC-DC single-stage converter is: AC power supply u s The two ends are connected to the two AC input terminals of the rectifier bridge. The negative output terminal of the rectifier bridge is connected to node GND. The positive output terminal of the rectifier bridge (1) is connected to the first terminal of inductor La. The second terminal of inductor La is connected to node Va or node Vb of the asymmetric half-bridge. Nodes Va and Vb of the asymmetric half-bridge are respectively connected to terminals P2 and P1 of the primary winding Np of the transformer. Node V1 of the rectifier circuit is connected to terminal S1 of the secondary winding Ns. Terminal S2 of the secondary winding Ns is connected to the first terminal of capacitor Cb. The second terminal of capacitor Cb is connected to the positive terminal Vo. + Or the negative end Vo -Alternatively, capacitor Cb is connected in series between node V1 of the rectifier circuit and terminal S1 of the secondary winding Ns, and terminal S2 of the secondary winding Ns is connected to the positive terminal Vo. + Or the negative end Vo - .

[0015] When the second terminal of inductor La is connected to node Vb of the asymmetric half-bridge, the second terminal of capacitor C1 of the asymmetric half-bridge is connected to node GND or, instead, connected to the positive output terminal of the rectifier bridge. This improves control stability but increases input current ripple.

[0016] When the second terminal of capacitor Cb or the terminal S2 of the secondary winding Ns is connected to the negative terminal Vo - When capacitor Cb is in use, either retain it or remove it; when the second terminal of capacitor Cb or the terminal S2 of the secondary winding Ns is connected to the positive terminal Vo... + When capacitor Co is removed, the capacitor Co is retained or removed (if capacitor Co is removed, the converter is used for current source output); when capacitor Cb is removed and the second end of inductor La is connected to node Vb of the asymmetric half-bridge, inductor Lo is retained or removed.

[0017] The asymmetric half-bridge AC-DC single-stage converter described above can also employ an inverse dual connection relationship, that is: the anode and cathode of diode D1 in the rectifier circuit are interchanged, the positive and negative terminals of capacitor Co are interchanged, and the positive terminal Vo... + With the negative end Vo - The positions are interchanged; at the same time, the terminals S1 and S2 of the secondary winding Ns of the transformer are interchanged.

[0018] To achieve bidirectional AC-DC power flow or synchronous rectification, the rectifier bridge uses bidirectional thyristors or switching transistors, and the diode D1 in the rectifier circuit is replaced with the switching transistor Q3. The replacement rule is that the drain and source of the switching transistor correspond to the cathode and anode of the diode, respectively. Bidirectional power flow refers to the bidirectional flow of electrical energy between the AC side and the DC side.

[0019] To reduce the reverse voltage of diode D1, a voltage divider rectifier circuit is proposed to replace the rectifier circuit. To meet the requirements of multiple voltage outputs, a multi-output rectifier circuit is proposed to replace the rectifier circuit.

[0020] The voltage divider rectifier circuit includes: diodes D1 and D2, capacitors Co1 and Co2, and inductors Lo1 and Lo2; inductors Lo1 and Lo2 are coupled. The anode of diode D1 is connected to the first terminal of inductor Lo1 as node V1, and the cathode of diode D2 is connected to the second terminal of inductor Lo2 as node V2; the cathode of capacitor Co1 is connected to the anode of capacitor Co2 as node Vo2, and the anode of capacitor Co1 is the positive terminal Vo. + The negative terminal of the capacitor Co2 is used as the negative terminal Vo. -The second terminal of inductor Lo1 and the first terminal of inductor Lo2 are connected to node Vo2, and the cathode of diode D1 is connected to the positive terminal Vo. + The anode of diode D2 is connected to the negative terminal Vo. - Alternatively, the cathode of diode D1 and the anode of diode D2 are connected to node Vo2, and the first terminal of inductor Lo2 is connected to the positive terminal Vo. + The second terminal of inductor Lo1 is connected to the negative terminal Vo. - .

[0021] The connection relationship between the voltage divider rectifier circuit and the transformer: Terminal S1 of the transformer secondary winding Ns is connected to node 1 of the voltage divider rectifier circuit, and capacitor Cb is connected in series between node 2 and terminal S2; or, terminal S2 of the secondary winding Ns is connected to node 2 of the voltage divider rectifier circuit, and capacitor Cb is connected in series between node 1 and terminal S1. If the second terminal of inductor Lo1 and the first terminal of inductor Lo2 are connected to node Vo2, then capacitor Cb is retained or removed.

[0022] The multi-output rectifier circuit includes: diodes D1 and D2, capacitors Co1 and Co2, and inductor Lo; inductor Lo has a first terminal, a second terminal, and a tap terminal. The first terminal of inductor Lo is connected to the anode of diode D1 as node V1, the tap terminal of inductor Lo is connected to the anode of diode D2, and the second terminal of inductor Lo is connected to the negative terminal Vo of capacitor Co2. - The cathode of diode D2 is connected to the positive terminal of capacitor Co2 as node Vo2, and the cathode of diode D1 is connected to the positive terminal of capacitor Co1 as positive terminal Vo. + The negative terminal of capacitor Co1 is connected to node Vo2 or to the negative terminal Vo. - .

[0023] Connection relationship between the multi-output rectifier circuit and the transformer: Terminal S1 of the secondary winding Ns is connected to node V1 of the multi-output rectifier circuit or the tap of the inductor Lo; terminal S2 of the secondary winding Ns is connected to the first terminal of capacitor Cb; and the second terminal of capacitor Cb is connected to the positive terminal Vo of the multi-output rectifier circuit. + Or the negative end Vo - Alternatively, terminal S1 of the secondary winding Ns is connected to the first terminal of capacitor Cb, the second terminal of capacitor Cb is connected to node V1 or the tap of inductor Lo, and terminal S2 of the secondary winding Ns is connected to the positive terminal Vo. + Or the negative end Vo - .

[0024] When the second terminal of capacitor Cb or the terminal S2 of the secondary winding Ns is connected to the negative terminal Vo of the multi-output rectifier circuit - If so, then retain capacitor Cb, or remove capacitor Cb.

[0025] The multi-output rectifier circuit described above may employ a reverse dual connection relationship; that is, the anodes and cathodes of diodes D1 and D2 in the multi-output rectifier circuit are interchanged, and the positive and negative terminals of capacitors Co1 and Co2 are interchanged, with the positive terminal Vo... + With the negative end Vo - The positions are interchanged; at the same time, the terminals S1 and S2 of the secondary winding Ns of the transformer are interchanged.

[0026] When AC power u s When the voltage is low and the voltage withstand of the asymmetric half-bridge switch Q1 is high, the switch Q2 and capacitor C2 are removed to simplify the circuit and reduce costs.

[0027] The asymmetric half-bridge AC-DC single-stage converter and its voltage divider multi-output circuit, if the rectifier bridge is removed and a DC power supply is connected between the first end of the inductor La and the node GND of the asymmetric half-bridge, becomes a DC-DC converter.

[0028] For the aforementioned asymmetric half-bridge AC-DC single-stage converter and its voltage divider multi-output circuit, asymmetric complementary PWM control can be applied to the asymmetric half-bridge to achieve single-stage PFC conversion, resulting in high power factor and stable DC output. Specifically, two asymmetric and complementary PWM pulse signals with dead time drive the gates of the converter bridge's switching transistors Q1 and Q2, respectively, controlling their complementary on / off switching. The term "asymmetric and complementary" means that the duty cycles of the two PWM pulses are generally not equal, and their sum equals 1 when dead time is ignored.

[0029] The present invention has the following advantages compared with the prior art.

[0030] 1) This invention uses a single-stage AC-DC converter to achieve both power factor correction and stable DC output.

[0031] 2) This invention uses asymmetric half-bridge complementary PWM control, which can achieve zero-voltage soft switching (ZVS).

[0032] 3) The topology of this invention is an isolated double-ended converter, which can transmit high power.

[0033] 4) The topology of the present invention can reduce or eliminate the bias current of the transformer.

[0034] 5) This invention utilizes inductive coupling or taps to achieve diode reverse voltage division balancing or multi-voltage output.

[0035] 6) The present invention has a simplified topology, is easy to control, has high reliability, and is low-cost and high-efficiency. Attached Figure Description

[0036] Figure 1Schematic diagram of the first embodiment of an asymmetric half-bridge AC-DC single-stage converter.

[0037] Figure 2 Schematic diagram of the second embodiment of the asymmetric half-bridge AC-DC single-stage converter.

[0038] Figure 3 Schematic diagram of the third embodiment of the asymmetric half-bridge AC-DC single-stage converter.

[0039] Figure 4 The schematic diagram of the fourth embodiment of the asymmetric half-bridge AC-DC single-stage converter.

[0040] Figure 5 The schematic diagram of the fifth embodiment of the asymmetric half-bridge AC-DC single-stage converter.

[0041] Figure 6 The sixth embodiment of the asymmetric half-bridge AC-DC single-stage converter is shown in the schematic diagram.

[0042] Figure 7 Schematic diagram of Example 1 of the voltage divider rectifier circuit of an asymmetric half-bridge AC-DC single-stage converter.

[0043] Figure 8 Schematic diagram of Example 2 of the voltage divider rectifier circuit of the asymmetric half-bridge AC-DC single-stage converter.

[0044] Figure 9 Schematic diagram of Example 3 of the voltage divider rectifier circuit of the asymmetric half-bridge AC-DC single-stage converter.

[0045] Figure 10 Schematic diagram of an embodiment of a multi-output circuit for an asymmetric half-bridge AC-DC single-stage converter.

[0046] Figure 11 Schematic diagram of Example 2 of an asymmetric half-bridge AC-DC single-stage converter multi-output circuit.

[0047] Figure 12 Schematic diagram of Example 3 of an asymmetric half-bridge AC-DC single-stage converter with multiple outputs.

[0048] In the diagram, 1—rectifier bridge, 2—asymmetric half-bridge, 3—transformer, 4—rectifier circuit, 5—voltage divider rectifier circuit, 6—multi-output rectifier circuit; La—inductor, Cb—capacitor; Q1, Q2, Q3—switching transistors, D1, D2—diodes, C1, C2, Co, Co1, Co2—capacitors, Lo, Lo1, Lo2—inductors, Np—primary winding, Ns—secondary winding. s —Alternating current power supply.

[0049] In the diagram, P1 and P2 are the terminal symbols for the primary winding, and S1 and S2 are the terminal symbols for the secondary winding; V1, V2, Va, Vb, Vd, GND, and Vo2 are the node symbols; Vo + —Positive end, Vo - —Negative end. Detailed Implementation

[0050] The present invention will now be described and analyzed in detail with reference to the accompanying drawings and preferred embodiments. The described embodiments are only some, not all, of the embodiments of the present invention.

[0051] To reiterate, the serial numbers used in this patent application to designate devices or methods, such as "first," "second," etc., are solely for distinguishing the described objects and do not have any sequential or technical meaning. They should not be construed as indicating their relative importance or implicitly specifying the number of technical features. Unless otherwise specified, the term "connection" in this patent application includes both direct and indirect connections.

[0052] 1. Preferred embodiments of the present invention

[0053] like Figures 1-6 As shown, the asymmetric half-bridge AC-DC single-stage converter consists of a rectifier bridge (1), an asymmetric half-bridge (2), a transformer (3), a rectifier circuit (4), an inductor La, and a capacitor Cb.

[0054] Figure 1 The first embodiment of the asymmetric half-bridge AC-DC single-stage converter is shown, which consists of a rectifier bridge (1), an asymmetric half-bridge (2), a transformer (3), a rectifier circuit (4), an inductor La, and a capacitor Cb.

[0055] The rectifier bridge (1) uses, but is not limited to, diodes, thyristors or switching transistors. It is a four-terminal network with a positive output terminal, a negative output terminal and two AC input terminals.

[0056] The asymmetric half-bridge (2) includes capacitors C1 and C2 and switching transistors Q1 and Q2. The first ends of capacitors C1 and C2 are connected together as node Va, and the second end of capacitor C2 is connected to the drain of switching transistor Q2 as node Vd. The source of switching transistor Q2 is connected to the drain of switching transistor Q1 as node Vb, and the source of switching transistor Q1 is connected to the second end of capacitor C1 as node GND.

[0057] The transformer (3) includes a primary winding Np and a secondary winding Ns. The primary winding Np has terminals P1 and P2, and the secondary winding Ns has terminals S1 and S2. Terminal S1 and terminal P1 are the same type of terminal, and terminal S2 and terminal P2 are the same type of terminal.

[0058] The rectifier circuit (4) includes a diode D1, an inductor Lo, and a capacitor Co. The anode of diode D1 is connected to the first terminal of inductor Lo, serving as node V1, and the cathode of diode D1 is connected to the positive terminal of capacitor Co, serving as the positive terminal Vo. + The second terminal of inductor Lo is connected to the negative terminal of capacitor Co, serving as the negative terminal Vo-.

[0059] The connection relationship of the asymmetric half-bridge AC-DC single-stage converter is: AC power supply u s The two ends are connected to the two AC input terminals of the rectifier bridge (1). The negative output terminal of the rectifier bridge (1) is connected to node GND. The positive output terminal of the rectifier bridge (1) is connected to the first terminal of the inductor La. The second terminal of the inductor La is connected to node Va of the asymmetric half-bridge (2). Nodes Va and Vb of the asymmetric half-bridge (2) are connected to terminals P2 and P1 of the primary winding Np of the transformer (3), respectively. Node V1 of the rectifier circuit (4) is connected to terminal S1 of the secondary winding Ns. Terminal S2 of the secondary winding Ns is connected to the first terminal of the capacitor Cb. The second terminal of the capacitor Cb is connected to the negative terminal Vo-.

[0060] In the first embodiment, when the second terminal of inductor La is connected to node Va, its function is filtering, and the inductance is relatively small. When the second terminal of capacitor Cb is connected to the negative terminal Vo-, its function is only to block DC, and the average voltage of capacitor Cb is zero in steady state (therefore Cb can be removed). The current of capacitor Co is discontinuous, that is, the output current is discontinuous and the ripple is large (this can be improved when the two paths are interleaved in parallel). Transformer (3) has a bias magnetism (if the second terminal of inductor La is changed to be connected to node Vb, then there is no bias magnetism).

[0061] Figure 2 The image shows a second embodiment of an asymmetric half-bridge AC-DC single-stage converter. This second embodiment is similar to... Figure 1 Compared to the first embodiment shown, the difference is that the second end of the inductor La is connected to node Vb of the asymmetric half-bridge (2), and the second end of the capacitor Cb is connected to the positive terminal Vo. + The current through capacitor Co is continuous, meaning the output current is continuous and the ripple is small. Note: If the converter is required to function as a current source output, then capacitor Co should be removed.

[0062] In the second embodiment, two points need to be explained: First, the second end of inductor La is connected to node Vb. At this time, the function of inductor La is energy storage, and its inductance is relatively large (about 10 times that in the first embodiment). Second, the function of capacitor Cb is DC blocking and energy storage. In steady state, the average voltage of capacitor Cb is equal to that of capacitor Co (capacitor Cb must be retained). With these two points as necessary conditions, transformer (3) has no bias magnetism, that is, the positive and negative amplitudes of the excitation current are equal in each working cycle. Note: If the second end of inductor La is changed to connect to node Va of the asymmetric half-bridge (2), then transformer (3) will have bias magnetism.

[0063] Figure 3The image shows a third embodiment of an asymmetric half-bridge AC-DC single-stage converter. This third embodiment is... Figure 1 Based on the first embodiment shown, the rectifier bridge (1) uses a switching transistor, and the diode D1 in the rectifier circuit (4) is replaced with a switching transistor Q3. The drain and source of the switching transistor correspond to the cathode and anode of the original diode, respectively. The second end of the inductor La is connected to node Vb of the asymmetric half-bridge (2). The transformer (3) has a bias magnetism. The converter of the third embodiment is capable of bidirectional AC-DC power flow.

[0064] Figure 4 The image shows a fourth embodiment of an asymmetric half-bridge AC-DC single-stage converter. This fourth embodiment is... Figure 1 Based on the first embodiment shown, capacitor Cb is removed, simplifying the circuit while maintaining its basic characteristics. The bias magnetism of transformer (3) changes, varying with the relative changes in inductance Lo and transformer (3).

[0065] Figure 5 The image shows a fifth embodiment of an asymmetric half-bridge AC-DC single-stage converter. This fifth embodiment is... Figure 4 Based on the fourth embodiment shown, the inductor Lo is further removed, and the second end of the inductor La is changed to connect to node Vb of the asymmetric half-bridge (2). The transformer (3) has a biased magnetism and a larger volume. Although the inductor Lo is omitted, the function of the inductor La becomes energy storage, and its inductance is larger (approximately 10 times that when connected to node Va).

[0066] Figure 6 The image shows a sixth embodiment of an asymmetric half-bridge AC-DC single-stage converter. This sixth embodiment is... Figure 4 Based on the fourth embodiment shown, the switching transistor Q2 and capacitor C2 in the asymmetric half-bridge (2) are removed. When the switching transistor Q1 is turned off, its voltage spike is very high, requiring minimization of the leakage inductance of the transformer (3). This sixth embodiment is suitable for AC power supply u. s When the voltage is low and the voltage rating of the switching transistor Q1 is high, the circuit can be simplified and the cost reduced.

[0067] Figure 7 The following is an example 1 of the voltage divider rectifier circuit of the asymmetric half-bridge AC-DC single-stage converter, which consists of a rectifier bridge (1), an asymmetric half-bridge (2), a transformer (3), a voltage divider rectifier circuit (5), an inductor La, and a capacitor Cb.

[0068] The voltage divider rectifier circuit (5) includes: diodes D1 and D2, capacitors Co1 and Co2, and inductors Lo1 and Lo2; inductors Lo1 and Lo2 are coupled. The anode of diode D1 is connected to the first terminal of inductor Lo1 as node V1, and the cathode of diode D2 is connected to the second terminal of inductor Lo2 as node V2; the cathode of capacitor Co1 is connected to the anode of capacitor Co2 as node Vo2, and the anode of capacitor Co1 is the positive terminal Vo. + The negative terminal of the capacitor Co2 is used as the negative terminal Vo. - The second terminal of inductor Lo1 and the first terminal of inductor Lo2 are connected to node Vo2, and the cathode of diode D1 is connected to the positive terminal Vo. + The anode of diode D2 is connected to the negative terminal Vo. - .

[0069] This embodiment 1 is... Figure 1 Based on the first embodiment shown, the rectifier circuit (4) is replaced with a voltage divider rectifier circuit (5), and the capacitor Cb is connected in series between terminal S2 of the secondary winding Ns and node 2 of the voltage divider rectifier circuit (5). The circuit topology, connection relationship and working principle of other parts remain unchanged.

[0070] In Example 1, inductors Lo1 and Lo2 are directly connected, which facilitates fabrication. Diodes D1 and D2 share the total reverse voltage. Due to the coupling of inductors Lo1 and Lo2 and the clamping of capacitors Co1 and Co2, the voltage division can be dynamically balanced.

[0071] Figure 8 The diagram shows Example 2 of an asymmetric half-bridge AC-DC single-stage converter voltage divider rectifier circuit. This Example 2 is... Figure 2 Based on the second embodiment shown, the rectifier circuit (4) is replaced with a voltage divider rectifier circuit (5), and the capacitor Cb is connected in series between terminal S2 of the secondary winding Ns and node 2 of the voltage divider rectifier circuit (5). The topology, connection relationship and working principle of other parts of the circuit remain unchanged. The difference between the voltage divider rectifier circuit (5) in this embodiment 2 and that in embodiment 1 is that the cathode of diode D1 and the anode of diode D2 are connected to node Vo2, and the first end of inductor Lo2 is connected to the positive terminal Vo. + The second terminal of inductor Lo1 is connected to the negative terminal Vo. - .

[0072] In Example 2, diodes D1 and D2 are directly connected in series, which facilitates semiconductor integration. Based on the same principle as in Example 1, the reverse voltage division of diodes D1 and D2 can be dynamically balanced.

[0073] Figure 9 The diagram shows Example 3 of an asymmetric half-bridge AC-DC single-stage converter voltage divider rectifier circuit. This Example 3 is... Figure 7Based on Example 1 shown, capacitor Cb is removed. The circuit is relatively simplified, but the basic characteristics of the circuit remain unchanged. The bias magnetism of transformer (3) changes, depending on the relative changes in the inductance of inductors Lo1 and Lo2 and the inductance of transformer (3).

[0074] Figure 10 The diagram shows an embodiment of a multi-output circuit for an asymmetric half-bridge AC-DC single-stage converter, consisting of a rectifier bridge (1), an asymmetric half-bridge (2), a transformer (3), a multi-output rectifier circuit (6), an inductor La, and a capacitor Cb.

[0075] The multi-output rectifier circuit (6) includes: diodes D1 and D2, capacitors Co1 and Co2, and inductor Lo; inductor Lo has a first terminal, a second terminal, and a tap terminal. The first terminal of inductor Lo is connected to the anode of diode D1 as node V1, the tap terminal of inductor Lo is connected to the anode of diode D2, the second terminal of inductor Lo is connected to the cathode of capacitor Co2 as the negative terminal Vo-; the cathode of diode D2 is connected to the anode of capacitor Co2 as node Vo2, and the cathode of diode D1 is connected to the anode of capacitor Co1 as the positive terminal Vo. + The negative terminal of capacitor Co1 is connected to node Vo2.

[0076] This first embodiment is... Figure 1 Based on the first embodiment shown, the rectifier circuit (4) is replaced with a multi-output rectifier circuit (6). The circuit topology, connection relationship and working principle of other parts remain unchanged. The second end of the inductor La is connected to node Va, and its function is filtering. The function of the capacitor Cb is only to block DC. The transformer (3) has a bias magnetism.

[0077] By utilizing the tap of inductor Lo and adding diode D2 and capacitor Co2, a voltage divider output (i.e., the second output) Vo2 is generated. Compared with the voltage divider rectifier circuit (5), there is only one diode in each voltage output circuit, resulting in higher efficiency.

[0078] Figure 11 The image shows a second embodiment of an asymmetric half-bridge AC-DC single-stage converter with multiple outputs. This second embodiment is... Figure 2 Based on the second embodiment shown, the rectifier circuit (4) is replaced with a multi-output rectifier circuit (6). The circuit topology, connection relationship and working principle of other parts remain unchanged. The second end of the inductor La is connected to node Vb, and its function is to store energy. The function of the capacitor Cb is to block DC and store energy. The transformer (3) has no bias magnetism.

[0079] Figure 12 The diagram shows a third embodiment of an asymmetric half-bridge AC-DC single-stage converter with multiple outputs. This third embodiment is... Figure 10Based on the first embodiment shown, capacitor Cb is removed. The circuit is relatively simplified, but the basic characteristics of the circuit remain unchanged. The bias magnetism of transformer (3) changes, depending on the relative change between inductance Lo and the inductance of transformer (3).

[0080] 2. Working principle of the invention

[0081] For the aforementioned asymmetric half-bridge AC-DC single-stage converter and its voltage divider multi-output circuit, by applying asymmetric complementary PWM control to the asymmetric half-bridge (2), a single-stage AC-DC conversion can be completed, achieving a high power factor and stable DC output. That is, two asymmetric and complementary PWM pulse signals containing dead time drive the gates of the switching transistors Q1 and Q2 of the converter bridge respectively, so as to control the switching transistors Q1 and Q2 to perform complementary on-off switching. The so-called asymmetric and complementary means that the duty cycles of the two PWM pulses are generally not equal, and the sum of the two is equal to 1 when the dead time is ignored.

[0082] First, we analyze the working principle of the asymmetric half-bridge AC-DC single-stage converter, and then derive the electrical quantity relationship between its voltage divider rectifier circuit and multi-voltage output circuit.

[0083] 2.1 Asymmetric Half-Bridge AC-DC Single-Stage Converter

[0084] sinusoidal AC power supply u s After passing through the rectifier bridge (1), it is rectified into a sinusoidal half-wave pulsating DC voltage u. a The voltage u is applied to the first terminal of inductor La. a The expression is:

[0085]

[0086] In the formula, U s AC power supply u s The effective value of ω is u s angular frequency.

[0087] Set the voltage across capacitor C1 to V. a The voltage across capacitor C2 is V. c The voltage between node Vd and GND of the asymmetric half-bridge (2) is V. d Then we have:

[0088] V a =u a V d =V a +V c (E-2)

[0089] like Figure 1 As shown, if the second terminal of inductor La is connected to node Va, then the voltage u aAfter being filtered by inductor La, the current is applied to capacitor C1, V a =u a .like Figure 2 As shown, if the second terminal of inductor La is connected to node Vb, then the voltage u a After being connected to capacitor C1 via inductor La and primary winding Np, the volt-second balance relationship between inductor La and primary winding Np remains the same during the switching processes of transistors Q1 and Q2 (see equation (E-5) below), resulting in V. a =u a .

[0090] Let the voltage across capacitor Co (i.e., the DC output voltage) be V. o The voltage across capacitor Cb is V. e Note: The voltages set refer to the average voltage excluding high-frequency ripple.

[0091] Set the voltage of the secondary winding Ns to V. s And the direction from S1 to S2 is positive; the voltage of the primary winding Np is V. p And the direction from P1 to P2 is positive. Let the turns ratio of transformer (3) be n, and ignore the leakage inductance of transformer (3), then we have:

[0092] V s =n·V p (E-3)

[0093] 2.1.1 Relationship of charge when the second terminal of capacitor Cb is connected to the negative terminal Vo-

[0094] To simplify the analysis, we ignore the on-resistance and dead time of switching transistors Q1 and Q2, and the on-voltage drop and switching time of diodes D1 and D2.

[0095] like Figure 1 As shown, when switch Q2 is off and Q1 is on, terminal P1 of the primary winding Np of transformer (3) is connected to node GND, and the voltage u of capacitor C1 is... a When added to the primary winding Np, V p =u a The equivalent excitation current of transformer (3) increases; the voltage V induced in the secondary winding Ns increases. s =n·u a At this time, diode D1 of rectifier circuit (4) is cut off and there is no current output; capacitor Cb in series with secondary winding Ns applies voltage to inductor Lo, and inductor Lo stores energy and the current increases.

[0096] When switch Q1 is off and Q2 is on, terminal P1 of the primary winding Np of transformer (3) is connected to node Vd, and the voltage V of capacitor C2 is... cWhen added to the primary winding Np, V p =-V c The voltage V induced in the secondary winding Ns s =-n·V c At this time, diode D1 of rectifier circuit (4) is turned on, and inductor Lo provides freewheeling current to capacitor Co (i.e., DC output terminal) through diode D1. Inductor Lo releases energy and the current decreases. At the same time, capacitor Cb in series with secondary winding Ns also provides freewheeling current to capacitor Co through diode D1. The freewheeling current of secondary winding Ns comes from the release of equivalent excitation current. Note: The function of capacitor C2 is to buffer the equivalent excitation current of primary winding Np and clamp the flyback voltage.

[0097] When diode D1 of rectifier circuit (4) is turned on, the voltage across capacitor Co (i.e., the output voltage) is equal to:

[0098] V o =n·V c +V e (E-4)

[0099] If the duty cycle of switch Q1 is set to D, then the duty cycle of switch Q2 is (1-D). Based on the volt-second balance principle of switching, the voltage relationship of the primary winding Np is obtained as follows:

[0100] u a ·D=V c ·(1-D)(E-5)

[0101] The voltage applied to the inductor Lo of the rectifier circuit (4) satisfies the following relationship:

[0102] (n·u a -V e )·D=V o ·(1-D)(E-6)

[0103] By combining equations (E-6), (E-5), and (E-4), the following can be derived:

[0104]

[0105] As can be seen from equation (E-7), the DC output voltage V o The voltage can be adjusted and stabilized by regulating the duty cycle D; that is, the average value of the duty cycle D adjusts the average value of the output voltage, and the instantaneous change of D achieves power factor correction. The voltage V across capacitor Cb... e Since the average is zero, it can be removed.

[0106] The highest operating voltage of switching transistors Q1 and Q2 is the maximum voltage V between node Vd and GND of the asymmetric half-bridge (2). dMCombining equations (E-2) and (E-7), we obtain:

[0107]

[0108] The reverse voltage of diode D1 is denoted as V. R V R =V o +n·u a Its maximum value V RM for:

[0109]

[0110] According to equations (E-8) and (E-9), by adjusting the turns ratio n of transformer (3), the highest operating voltages of switching transistors Q1 and Q2 and diode D1 in the converter can be balanced.

[0111] Let the current in inductor Lo be I. L The current in diode D1 is I. D (This is the output current I) O The forward current of the secondary winding Ns of transformer (3) is I. S+ The negative current is I S- (Flowing out from terminal S2 is positive, and flowing in is negative). The charging / discharging current of capacitor Cb is equal to the positive / reverse current of the secondary winding Ns, respectively.

[0112] When switch Q2 is off and Q1 is on, diode D1 is off, and the current relationship is as follows:

[0113] I S+ ·D=I L ·D(E-10)

[0114] When switch Q1 is off and Q2 is on, diode D1 conducts, and the current relationship is as follows:

[0115] (I S- +I L )·(1-D)=I D ·(1-D)(E-11)

[0116] To maintain the charging and discharging balance of capacitor Cb, the following relationship must be satisfied:

[0117] I S+ ·D=I S- ·(1-D) (E-12)

[0118] By combining equations (E-10), (E-11), and (E-12), the following can be derived:

[0119]

[0120] The average value of the DC output current for:

[0121]

[0122] Set the charging / discharging current of capacitor Co to I. Co+ and I Co- When a constant DC load is connected to the rectifier output, the ripple current (i.e., charging / discharging current) of capacitor Co is:

[0123]

[0124] 2.1.2 Connect the second terminal of capacitor Cb to the positive terminal Vo. + Relationship of electricity at time

[0125] like Figure 2 As shown, when switch Q2 is off and Q1 is on, the voltage V applied to the primary winding Np is... p =u a The equivalent excitation current of transformer (3) increases; the voltage induced in the secondary winding Ns is V. s =n·u a At this time, diode D1 of rectifier circuit (4) is cut off, and capacitors Cb and Co in series with secondary winding Ns apply voltage to inductor Lo. Inductor Lo stores energy and the current increases. At the same time, capacitor Cb discharges.

[0126] When switching transistor Q1 is off and Q2 is on, the voltage V applied to the primary winding Np is... p =-V c The induced voltage on the secondary winding Ns is V. s =-n·V c At this time, diode D1 of rectifier circuit (4) is turned on, and inductor Lo provides freewheeling current to capacitor Co (i.e., the output terminal) through diode D1. Inductor Lo releases energy and the current decreases. At the same time, secondary winding Ns charges capacitor Cb through diode D1, and the equivalent excitation current of transformer (3) decreases.

[0127] When diode D1 of rectifier circuit (4) is turned on, the voltage across capacitor Cb is equal to:

[0128] V e =n·V c (E-16)

[0129] According to the volt-second balance principle of switching, the voltage applied to inductor Lo satisfies the following relationship:

[0130] (n·u a +V e -V o )·D=V o·(1-D)(E-17)

[0131] By combining equations (E-16), (E-17), and (E-5), the following can be derived:

[0132]

[0133] As can be seen from equation (E-18), the average voltages of capacitors Cb and Co are equal, therefore Cb is necessary. Combining equations (E-18) and (E-7), we can conclude that the voltage transfer function is the same for both connection methods of transformer (3) and rectifier circuit (4).

[0134] Analysis reveals (details omitted) that the maximum operating voltages of switching transistors Q1 and Q2, and diode D1, also conform to equations (E-8) and (E-9). The positive / negative currents of the secondary winding Ns and the current I of diode D1... D It also conforms to formula (E-13).

[0135] Set the charging / discharging current of capacitor Cb to I. Cb+ and I Cb- The ripple current (i.e., charging / discharging current) of capacitor Cb can be derived as follows:

[0136]

[0137] 2.2 Voltage divider rectifier circuit and multi-output rectifier circuit

[0138] Based on the working principle of the asymmetric half-bridge AC-DC single-stage converter, it can be seen from equations (E-8) and (E-9) that the highest operating voltages of the switching transistors Q1 and Q2 and the diode D1 are determined by the input voltage u. a Output voltage V o It is determined together with the transformer's turns ratio n.

[0139] Because switching transistors Q1 and Q2 are actively controllable semiconductor devices, while diode D1 is a passively uncontrollable semiconductor device, the operating voltage requirements of switching transistors Q1 and Q2 should be met first. When the output voltage is high, the maximum operating voltage V of switching transistors Q1 and Q2 should be met. dM After selecting the transformer turns ratio n according to the requirements, the highest operating voltage of diode D1 may exceed its maximum reverse voltage range. At this time, it is necessary to connect the diodes in series for voltage division. In order to balance the reverse voltage division of the series diodes, a voltage divider rectifier circuit (5) is proposed.

[0140] If inductors Lo1 and Lo2 are tightly coupled, then Lo1 and Lo2 can be considered as a transformer with an equivalent turns ratio n. L That is, it is equal to their turns ratio.

[0141]

[0142] In the formula, m1, m2 and L o1 L o2 These represent the number of turns and inductance of inductors Lo1 and Lo2, respectively.

[0143] like Figure 7 and Figure 8 As shown, when switch Q1 is off and Q2 is on, diodes D1 and D2 in the voltage divider rectifier circuit (5) are turned on. Inductors Lo1 and Lo2 then charge capacitors Co1 and Co2 through diodes D1 and D2, and the voltage V across capacitors Co1 and Co2 increases. Co1 V Co2 The ratio is:

[0144] V Co1 / V Co2 =n L (E-21)

[0145] When switch Q2 is off and Q1 is on, diodes D1 and D2 in the voltage divider rectifier circuit (5) are cut off, and the voltage V applied to inductors Lo1 and Lo2 by the secondary winding Ns in series with Cb is V. Lo1 V Lo2 The ratio is:

[0146] V Lo1 / V Lo2 =n L (E-22)

[0147] Therefore, the reverse voltage V of diodes D1 and D2 in the voltage divider rectifier circuit (5) R1 V R2 The relationship is:

[0148]

[0149] As can be seen from the formula, the turns ratio n of inductors Lo1 and Lo2 L The reverse voltage division ratio of diodes D1 and D2 was determined and was able to maintain dynamic balance.

[0150] To meet the requirements of multiple voltage outputs in the circuit, a multi-output rectifier circuit (6) is proposed. See below for reference. Figure 10 and Figure 11 Analyze its electrical quantity relationship and circuit characteristics.

[0151] An inductor Lo with a tap can be equivalent to an autotransformer. Let the total number of turns of inductor Lo be m, and the number of turns between the tap and the second terminal be m2. Set the positive terminal Vo of the multi-output rectifier circuit (6). + With the negative end Vo - The voltage between them is V O1The voltage between node Vo2 and the negative terminal Vo- is V. O2 .

[0152] When diodes D1 and D2 of the multi-output rectifier circuit (6) are turned on, inductor Lo charges capacitors Co1 and Co2 through diodes D1 and D2, and voltage V O1 With V O2 The ratio is:

[0153] V O2 / V O1 =m² / m (E-24)

[0154] Based on the aforementioned principle analysis, the maximum reverse voltage V of diodes D1 and D2 can be derived. RM1 and V RM2 :

[0155]

[0156] From equation (E-25), it can be seen that the reverse voltage of diodes D1 and D2 in the voltage divider rectifier circuit (5) is related to the output voltage V. O1 and V O2 It is directly proportional and cannot share the total reverse voltage. However, its advantage is that the output voltage V... O1 and V O2 Each circuit has only one diode, resulting in high efficiency.

[0157] Another circuit characteristic of the voltage divider rectifier circuit (5) is that the output voltage V O1 and V O2 It can carry both loads simultaneously and loads individually. This is determined by the self-coupling characteristics of the inductor's Lo tap.

[0158] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent topological transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct or indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An asymmetric half-bridge AC-DC single-stage converter, comprising a rectifier bridge (1), an asymmetric half-bridge (2), a transformer (3), a rectifier circuit (4), an inductor La, and a capacitor Cb; the rectifier bridge (1) is a four-terminal network with a positive output terminal, a negative output terminal, and two AC input terminals; characterized in that: The asymmetric half-bridge (2) includes capacitors C1 and C2 and switching transistors Q1 and Q2; the first ends of capacitors C1 and C2 are connected as node Va, the second end of capacitor C2 is connected to the drain of switching transistor Q2 as node Vd, the source of switching transistor Q2 is connected to the drain of switching transistor Q1 as node Vb, and the source of switching transistor Q1 is connected to the second end of capacitor C1 as node GND. The transformer (3) includes a primary winding Np and a secondary winding Ns. The primary winding Np has terminals P1 and P2, and the secondary winding Ns has terminals S1 and S2. Terminal S1 and terminal P1 are the same type of terminal, and terminal S2 and terminal P2 are the same type of terminal. The rectifier circuit (4) includes a diode D1, an inductor Lo, and a capacitor Co; the anode of diode D1 is connected to the first terminal of inductor Lo as node V1, and the cathode of diode D1 is connected to the positive terminal of capacitor Co as positive terminal Vo. + The second terminal of inductor Lo is connected to the negative terminal of capacitor Co, serving as the negative terminal Vo. - ; The connection relationships of the various parts of the asymmetric half-bridge AC-DC single-stage converter are as follows: AC power supply u s The two ends are connected to the two AC input terminals of the rectifier bridge (1). The negative output terminal of the rectifier bridge (1) is connected to node GND. The positive output terminal of the rectifier bridge (1) is connected to the first terminal of the inductor La. The second terminal of the inductor La is connected to node Va or node Vb of the asymmetric half-bridge (2). Nodes Va and Vb of the asymmetric half-bridge (2) are respectively connected to terminals P2 and P1 of the primary winding Np of the transformer (3). Node V1 of the rectifier circuit (4) is connected to terminal S1 of the secondary winding Ns. Terminal S2 of the secondary winding Ns is connected to the first terminal of the capacitor Cb. The second terminal of the capacitor Cb is connected to the positive terminal Vo. + Or the negative end Vo - Alternatively, capacitor Cb can be connected in series between node V1 of rectifier circuit (4) and terminal S1 of secondary winding Ns, with terminal S2 of secondary winding Ns connected to positive terminal Vo. + Or the negative end Vo - ; When the second end of the inductor La is connected to node Vb of the asymmetric half-bridge (2), the second end of the capacitor C1 of the asymmetric half-bridge (2) is connected to node GND or is changed to be connected to the positive output terminal of the rectifier bridge (1). When the second terminal of capacitor Cb or the terminal S2 of the secondary winding Ns is connected to the negative terminal Vo - When capacitor Cb is in use, either retain it or remove it; when the second terminal of capacitor Cb or the terminal S2 of the secondary winding Ns is connected to the positive terminal Vo... + When capacitor Cb is removed, capacitor Co is retained or removed; when capacitor Cb is removed and the second end of inductor La is connected to node Vb of the asymmetric half-bridge (2), inductor Lo is retained or removed.

2. The asymmetric half-bridge AC-DC single-stage converter according to claim 1, characterized in that: The rectifier circuit (4) and the transformer (3) are connected in a reverse dual relationship: the anode and cathode of diode D1 in the rectifier circuit (4) are interchanged, the positive and negative terminals of capacitor Co are interchanged, and the positive terminal Vo is... + With the negative end Vo - The positions are interchanged; at the same time, the terminals S1 and S2 of the secondary winding Ns of transformer (3) are interchanged.

3. The asymmetric half-bridge AC-DC single-stage converter according to claim 1, characterized in that: Replace the rectifier circuit (4) with a voltage divider rectifier circuit (5); The voltage divider rectifier circuit (5) includes: diodes D1 and D2, capacitors Co1 and Co2, and inductors Lo1 and Lo2; inductors Lo1 and Lo2 are coupled; the anode of diode D1 is connected to the first terminal of inductor Lo1 as node V1, and the cathode of diode D2 is connected to the second terminal of inductor Lo2 as node V2; the negative terminal of capacitor Co1 is connected to the positive terminal of capacitor Co2 as node Vo2, and the positive terminal of capacitor Co1 is the positive terminal Vo. + The negative terminal of the capacitor Co2 is used as the negative terminal Vo. - The second terminal of inductor Lo1 and the first terminal of inductor Lo2 are connected to node Vo2, and the cathode of diode D1 is connected to the positive terminal Vo. + The anode of diode D2 is connected to the negative terminal Vo. - Alternatively, the cathode of diode D1 and the anode of diode D2 are connected to node Vo2, and the first terminal of inductor Lo2 is connected to the positive terminal Vo. + The second terminal of inductor Lo1 is connected to the negative terminal Vo. - ; Connection relationship between voltage divider rectifier circuit (5) and transformer (3): Terminal S1 of secondary winding Ns of transformer (3) is connected to node 1 of voltage divider rectifier circuit (5), and capacitor Cb is connected in series between node 2 and terminal S2; or, terminal S2 of secondary winding Ns is connected to node 2 of voltage divider rectifier circuit (5), and capacitor Cb is connected in series between node 1 and terminal S1; if the second end of inductor Lo1 and the first end of inductor Lo2 are connected to node Vo2, then capacitor Cb is retained or removed.

4. The asymmetric half-bridge AC-DC single-stage converter according to claim 1, characterized in that: Replace the rectifier circuit (4) with a multi-output rectifier circuit (6); The multi-output rectifier circuit (6) includes: diodes D1 and D2, capacitors Co1 and Co2, and inductor Lo; inductor Lo has a first terminal, a second terminal, and a tap terminal; the first terminal of inductor Lo is connected to the anode of diode D1 as node V1, the tap terminal of inductor Lo is connected to the anode of diode D2, the second terminal of inductor Lo is connected to the negative terminal Vo- of capacitor Co2; the cathode of diode D2 is connected to the positive terminal of capacitor Co2 as node Vo2, and the cathode of diode D1 is connected to the positive terminal Vo- of capacitor Co1. + The negative terminal of capacitor Co1 is connected to node Vo2 or to the negative terminal Vo. - ; Connection relationship between the multi-output rectifier circuit (6) and the transformer (3): Terminal S1 of the secondary winding Ns is connected to node V1 of the multi-output rectifier circuit (6) or the tap of the inductor Lo; terminal S2 of the secondary winding Ns is connected to the first terminal of the capacitor Cb; and the second terminal of the capacitor Cb is connected to the positive terminal Vo of the multi-output rectifier circuit (6). + Or the negative end Vo - Alternatively, terminal S1 of the secondary winding Ns is connected to the first terminal of capacitor Cb, the second terminal of capacitor Cb is connected to node V1 or the tap of inductor Lo, and terminal S2 of the secondary winding Ns is connected to the positive terminal Vo. + Or the negative end Vo - ; When the second terminal of capacitor Cb or the terminal S2 of the secondary winding Ns is connected to the negative terminal Vo of the multi-output rectifier circuit (6) - If so, then either retain capacitor Cb or remove capacitor Cb.

5. The asymmetric half-bridge AC-DC single-stage converter according to claim 4, characterized in that: The multi-output rectifier circuit (6) and the transformer (3) are connected in a reverse dual relationship: the anodes and cathodes of diodes D1 and D2 in the multi-output rectifier circuit (6) are interchanged, the positive and negative terminals of capacitors Co1 and Co2 are interchanged, and the positive terminal Vo is... + With the negative end Vo - The positions are interchanged; at the same time, the terminals S1 and S2 of the secondary winding Ns of transformer (3) are interchanged.

6. The asymmetric half-bridge AC-DC single-stage converter according to any one of claims 1 and 2, characterized in that: The diode D1 in the rectifier circuit (4) is replaced with the switching transistor Q3. The replacement rule is that the connection positions of the drain and source of the switching transistor correspond to the connection positions of the cathode and anode of the diode, respectively. The rectifier bridge (1) uses a diode, thyristor, or switching transistor. The switching transistor is not limited to MOSFET or IGBT.

7. The asymmetric half-bridge AC-DC single-stage converter according to any one of claims 1 to 6, characterized in that: When the negative terminal Vo of the rectifier circuit (4) - When connected to the second terminal of capacitor Cb or terminal S2 of secondary winding Ns, or when the voltage divider rectifier circuit (5) is used instead of rectifier circuit (4), or when the multi-output rectifier circuit (6) is used instead of rectifier circuit (4), the switching transistor Q2 and capacitor C2 of the asymmetric half-bridge (2) are removed.

8. The asymmetric half-bridge AC-DC single-stage converter according to any one of claims 1 to 7, characterized in that: If the rectifier bridge (1) is removed and a DC power supply is connected between the first end of the inductor La and the node GND of the asymmetric half-bridge (2), it becomes a DC-DC converter.

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