CN100481692C - Power converter without ringing zero potential switching - Google Patents

Abstract

A ringing-free zero potential switching method and converter for power converter features that in the high-efficiency and high-density zero potential switching procedure of zero potential switching circuit on power converter, an oscillating L-C resonant circuit is generated on primary side of transformer to generate ringing phenomenon, which can short-circuit the current on inductor and clamp the voltage on capacitor to eliminate parasitic ringing effectively.

Description

Ringing-free zero-potential switching power converters

technical field

The invention relates to a zero-potential switching method without ringing applied to a power converter and a converter, especially to a method that can effectively reduce the magnetic loss and A ringing-free zero-potential switching method and a converter which reduce switching loss of the switch and reduce the withstand voltage of the secondary commutator.

Background technique

In recent years, in order to catch up with the trend of rapid miniaturization of electronic products, the technology of switching power converters has been developing towards high frequency, high efficiency and high density. Generally speaking, because the switching speed of the field effect power transistor (Power MOSFET, hereinafter referred to as the power switch tube) is much faster than that of the bipolar transistor (Bipolar Transistor), it is often widely used in the switching power converter in the industry as an upper However, the energy retained by the parasitic capacitance on this field effect power transistor (Power MOSFET) will be exhausted in the form of ohmic heat in its channel every time the transistor is turned on. The higher the switching frequency, the greater the loss. If this problem is not effectively solved, it will make it difficult for the switching power converter to continue to develop towards the design goal of high efficiency and high density.

Since 1988, three experts including C.P.Henze, H.C.Martin and D.W.Paraley from the United States published the concept of Zero Voltage Switching in IEEE publications. Circuits have been proposed one after another, effectively solving the problem of conduction loss in traditional field-effect power transistors (Power MOSFETs). Now, the more representative prior technologies are described as follows:

1. Forward Zero-Voltage Switching PowerConverter:

As shown in Figure 1, it is the circuit embodiment of the US No. 383,594 invention patent applied by Bruce Wilkinson in June 1989. The patent controls the circuit properly so that the transformer works in the positive and negative magnetic regions, so the same output power Next, it has the advantage that a smaller transformer can be selected. Due to the inspiration of this circuit design, Putrice R. Lethellier invented the first practical circuit with zero potential switching, as shown in Figure 2, which is the circuit structure diagram of the US Patent No. 4,975,821 approved in October 1990. The patent To achieve the purpose of zero-potential switching, the transformer adopts a loose cross-connection type, and an air gap (gap) is added to its magnetic core to obtain the necessary magnetizing inductance and leakage inductance, which can be connected in parallel with the switch SW1 The parasitic capacitance Cs above forms an L-C resonant circuit, which makes the switch SW1 obtain the condition of zero-potential switching due to the resonance of the L-C resonant circuit immediately after the switch SW2 is turned off. Similarly, when the switch SW1 is just turned off In an instant, due to the resonance of the L-C resonant circuit, the switch SW2 also obtains the condition of zero-potential switching. At this time, due to the air gap and leakage inductance added to the magnetic core of the transformer, a non-negligible magnetic loss is caused, making the switch SW2 While the circuit obtains the zero-potential switching condition, it also brings the disadvantages of abnormal heating and efficiency decline to the transformer.

As shown in Figures 3 and 4, it is the circuit embodiment of the US Patent No. 5,245,520 filed by Paul Imbertson in October 1991 and approved in September 1993. Figure 3 can be called "half-bridge asymmetric Forward converter (Half bridge asymmetrical buck converter)", Figure 4 can be called "full bridge asymmetrical forward converter (Full bridge symmetrical buck converter)", because the two circuits are externally equivalent to the transformer leakage inductance Auxiliary inductor La (auxiliary inductor), so when the zero-potential switching effect is achieved, the transformer does not have the problem of abnormal heating, but the auxiliary inductor La and the stray capacitance at both ends of the primary winding of the transformer produce a non-negligible Ringing (ringing) phenomenon, because the ringing current oscillates back and forth on the windings of the inductor and the transformer, it will produce an induction heating effect on the magnetic core, causing its efficiency to deteriorate accordingly. In addition, the parasitic oscillation In addition to increasing the EMI interference signal, it will also be reflected to the secondary winding of the transformer, so that the withstand voltage of the secondary rectification part needs to be increased by at least 1.5 times, which is the ringing on the bridge asymmetric forward converter of Imbertson resulting in many disadvantages. As shown in Figure 4, it is the ringing phenomenon produced by Imbertson's circuit on the primary winding and secondary winding of the transformer.

2. Flyback Zero-Voltage Switching PowerConverter:

As shown in Figures 6 and 7, it is the circuit embodiment of the U.S. Patent No. 5,057,986 approved in October 1991 by ChristoPher P.Henze and Hubert C.Martin, Jr. In this embodiment, since there is no additional auxiliary Inductance, so if you want to achieve zero-potential switching, you need to increase the air gap of the transformer so that the peak-to-peak value of the primary magnetizing current of the transformer is greater than the load current reflected from the secondary side to the primary side. This requirement is consistent with Putrice R. Lethellier's invention patent is the same, and it will also cause the transformer to heat abnormally. To solve this problem, the size of the transformer needs to be increased to increase its heat dissipation capacity.

As shown in Figures 8 and 9, it is the circuit embodiment of the U.S. Patent No. 5,402,329 approved by Wittenbreder, Jr. and Ernest H. in March 1995. Since an auxiliary inductance is added in this embodiment, the primary of the transformer The peak-to-peak value of the magnetizing current does not need to be greater than the load current value reflected from the secondary side to the primary side to easily achieve the effect of zero-potential switching. The auxiliary inductance can be a leakage inductance when the transformer is wound in loose cross-connection , can also be an external inductance, but no matter how it is formed, the patent and the aforementioned Imbertson patent will all have side effects caused by ringing. As shown in Figure 10, it is the ringing phenomenon generated by the circuit of Wittenbreder, Jr. and Ernest H. on the primary winding and secondary winding of the transformer.

In view of the parasitic ringing (Parasitic Ringing) generated at the moment of switching of the Power Rectifier Switches of the aforementioned existing power converter when performing zero-potential switching, the effect of induction heating on the magnetic core is generated, As a result, it is greatly limited in efficiency improvement, and at the same time increases the interference signal of electromagnetic interference, and produces a high reverse voltage impact on the rectifier parts. The present invention aims at many shortcomings caused by these ringing phenomena, and develops a A ring-free zero-potential switching system applied to power converters. This technology can address the L-C resonance that will oscillate on the primary side of the transformer during the high-efficiency and high-density zero-potential switching process of the power converter. circuit (inductance-capacitor resonance circuit), when the ringing phenomenon begins to occur, the current on the inductance is short-circuited, and the voltage on the capacitor is clamped, effectively eradicating the parasitic ringing generated by the existing zero-potential switching circuit, so that It is not affected by this parasitic ringing.

Contents of the invention

The main purpose of the present invention is to provide a ringing-free zero-potential switching method and converter applied to power converters, which can avoid the problem of electromagnetic interference signal interference caused by auxiliary inductors and main transformers due to parasitic oscillations, and effectively reduce the impact on The requirements for the reverse voltage rating of the rectifier parts on the secondary side enable the zero-voltage switching circuit with auxiliary inductors to achieve higher energy conversion efficiency and power density, and at the same time it is easier to pass the International EMI regulations (International EMI regulations) ) requirements.

Another object of the present invention is to provide a ringing-free zero-potential switching method and converter applied to power converters, which can prevent its oscillation, effectively avoid ringing, and achieve high efficiency, high density and low interference Signal for zero potential switching purposes.

Another object of the present invention is to provide a ringing-free zero-potential switching method and converter applied to power converters, which can greatly increase the power density, and reduce the heat energy accumulated on the power switch tube and the required heat sink. The small size makes it easier for the power converter to be applied to various miniaturized electronic products, eliminating the need for resonant zero-potential switching circuits without auxiliary inductors, which are too dependent on the leakage inductance of the transformer to achieve zero-potential switching. And during manufacture, it is difficult to reach its design specifications, and it is difficult to produce in large quantities.

The purpose of the present invention is achieved through the following technical solutions: a ringing-free zero-potential switching method applied to power converters, the method is that a zero-potential switching circuit on a power converter is in the process of zero-potential switching, An L-C circuit provided on the primary side of the transformer of the zero-potential switching circuit will short-circuit the current on the inductance of the L-C circuit to clamp the voltage on the capacitor of the L-C circuit when the ringing phenomenon starts to occur.

A half-bridge forward non-ringing zero-potential switching full-wave rectification power converter is characterized in that it includes:

An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, and two power switch tubes connected in series are connected in parallel on it, and the drain of one of the power switch tubes is connected to the input The positive pole of the voltage filter capacitor is connected, the source is connected to the drain of another power switch tube, and the source of the other power switch tube is connected to the negative pole of the input voltage filter capacitor;

A transformer, the transformer is provided with a primary winding and a secondary winding, one end of the primary winding is connected to the negative pole of a capacitor, and the other end is connected to the line between the two power switch tubes through an auxiliary inductance, the capacitor's The anode is connected to the drain of one of the power switch tubes, the source of the power switch tube is connected to the drain of the other power switch tube, and the line between the primary winding and the auxiliary inductance is connected to a The drain of the power switch tube and the source of another power switch tube. These diodes cooperate with the corresponding power switch tubes respectively. When ringing occurs in the circuit, the current on the auxiliary inductor is immediately short-circuited by the corresponding power switch tube and diode. .

In the half-bridge forward type zero-potential switching full-wave rectification power converter without ringing, one end of the secondary winding of the transformer is connected to the negative pole of an output voltage filter capacitor, and the other end is respectively connected to two The positive terminals of the diodes on the secondary side are connected, and the negative terminals of these secondary side diodes are connected to the positive terminal of the output voltage filter capacitor through an inductor. The output voltage filter capacitor provides a stable DC output voltage to the output terminal. load across.

A half-bridge step-up forward type zero-potential switching full-wave rectification power converter without ringing, characterized in that it includes:

An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, two power switch tubes and a capacitor connected in series are connected in parallel, the negative pole of the capacitor is connected to the input voltage The positive pole of the voltage filter capacitor is connected, and the positive pole is connected to the drain of one of the power switch tubes; the source of the power switch tube is connected to the drain of another power switch tube, and the source of the other power switch tube Then connect to the negative pole of the input voltage filter capacitor;

A transformer, the transformer is provided with a primary winding, one end of the primary winding is connected to the negative pole of the capacitor, and the other end is connected to the line between the two power switch tubes through an auxiliary inductance, the connection between the primary winding and the auxiliary inductance The line is connected to the drain of one power switch tube and the source of the other power switch tube through two diodes. These diodes are respectively matched with the corresponding power switch tubes. When the ringing phenomenon occurs in the circuit, the auxiliary inductor is connected to The current is immediately short-circuited by the corresponding power switch tube and diode.

In the half-bridge step-up forward type zero-potential switching full-wave rectification power converter without ringing, one end of the secondary winding of the transformer is connected to the negative pole of an output voltage filter capacitor, and the other end is respectively It is connected to the positive terminals of the two secondary side diodes, and the negative terminals of these secondary side diodes are connected to the positive terminal of the output voltage filter capacitor through an inductor, and the output voltage filter capacitor provides a stable DC output voltage to the load across the output.

A half-bridge forward non-ringing zero-potential switching half-wave rectification power converter is characterized in that it includes:

An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, and two power switch tubes connected in series are connected in parallel on it, and the drain of one power switch tube is connected to the The positive pole of the input voltage filter capacitor is connected, its source is connected to the drain of another power switch tube, and the source of the other power switch tube is connected to the negative pole of the input voltage filter capacitor;

A transformer, the transformer is provided with a primary winding, one end of the primary winding is connected to the negative pole of a capacitor, the other end is connected to the line between two power switch tubes through an auxiliary inductor, the positive pole of the capacitor is connected to one of the power switches The drains of the switching tubes are connected, the source of the power switching tube is connected to the drain of another power switching tube, and the line between the primary winding and the auxiliary inductance is connected to the drain of the other power switching tube through a diode. The diode cooperates with two power switch tubes, and when the ringing phenomenon occurs in the circuit, the current on the auxiliary inductance is immediately short-circuited by the power switch tube and the diode.

In the half-bridge forward non-ringing zero-potential switching half-wave rectification power converter, the transformer further includes a secondary winding, and one end of the secondary winding is respectively connected to the positive side of a diode on the secondary side. terminal and the negative pole of an output voltage filter capacitor, the other end of the secondary winding is connected to one end of the inductor through another diode on the secondary side, the negative pole of the above-mentioned diode is connected to the junction between the other diode and the inductor, and the inductor The other end is connected to the positive pole of the output voltage filter capacitor.

A half-bridge step-up forward type non-ringing zero-potential switching half-wave rectification power converter, characterized in that it includes:

An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, a group of two power switch tubes connected in series and a capacitor are connected in parallel, the negative pole of the capacitor is connected to the input The positive pole of the voltage filter capacitor is connected, its positive pole is connected to the drain of one of the power switch tubes, the source of the power switch tube is connected to the drain of another power switch tube, and the source of the other power switch tube The pole is connected to the negative pole of the input voltage filter capacitor;

A transformer, the transformer is provided with a primary winding, one end of the primary winding is connected to the negative pole of the above-mentioned capacitor, and the other end is connected to the line between the two power switch tubes through an auxiliary inductor, and the drain of one of the power switch tubes The pole is connected to the positive pole of the capacitor, and its source is connected to the drain of another power switch tube. The line between the primary winding and the auxiliary inductance is connected to the drain of another power switch tube through a diode. Cooperating with the power switch tube, when the ringing phenomenon occurs in the circuit, the current on the auxiliary inductance is immediately short-circuited by the power switch tube and the diode together.

In the half-bridge step-up forward type non-ringing zero-potential switching half-wave rectification power converter, the transformer also includes a secondary winding, and one end of the secondary winding is respectively connected to a diode on the secondary side. The positive end and the negative pole of an output voltage filter capacitor, the other end of the secondary winding is connected to one end of the inductor through another diode on the secondary side, and the negative pole of the above-mentioned diode is connected to the junction between the other diode and the inductor. The other end of the inductor is connected to the positive pole of the output voltage filter capacitor.

A half-bridge remagnetization type zero-potential switching power converter without ringing, which includes:

An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, and two power switch tubes connected in series are connected in parallel on it, and the drain of one of the power switch tubes is connected to the The positive pole of the input voltage filter capacitor is connected, the source thereof is connected to the drain of another power switch tube, and the source of the other power switch tube is connected to the negative pole of the input voltage filter capacitor;

A transformer, the transformer is provided with a primary winding, one end of the primary winding is connected to the negative pole of a capacitor, the positive pole of the capacitor is connected to the drain of a power switching tube, and the source of the power switching tube is connected to another The drain of a power switch tube, the other end of the primary winding is connected to the line between two power switch tubes in series through an auxiliary inductor, and the other end is also connected to the source of another power switch tube through a diode, the The diode cooperates with another power switch tube, and when the ringing phenomenon occurs in the circuit, the current on the auxiliary inductance is immediately short-circuited by the other power switch tube and the diode.

In the half-bridge remagnetization type zero-potential switching power converter without ringing, the transformer also includes a secondary winding, one end of the secondary winding is connected to the positive pole of an output voltage filter capacitor through a diode on the secondary side The other end is connected to the negative electrode of the output voltage filter capacitor, and the output voltage filter capacitor provides a stable DC output voltage to the load across the output terminal.

A half-bridge step-up magnetization-free zero-potential switching power converter, characterized in that it includes:

An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, a group of two power switch tubes connected in series and a capacitor are connected in parallel, the negative pole of the capacitor is connected to the input The positive pole of the voltage filter capacitor is connected, its positive pole is connected to the drain of one of the power switch tubes, the source of the power switch tube is connected to the drain of another power switch tube, and the source of the other power switch tube The pole is connected to the negative pole of the input voltage filter capacitor;

A transformer, the transformer is provided with a primary winding, one end of the primary winding is connected to the negative pole of the capacitor, and the other end is respectively connected to the line between the two power switch tubes and a power switch tube through an auxiliary inductor and a diode The source electrode of the diode is matched with a power switch tube. When ringing occurs in the circuit, the current on the auxiliary inductance is immediately short-circuited by a power switch tube and the diode.

In the half-bridge step-up magnetic feedback type zero-potential switching power converter without ringing, the transformer also includes a secondary winding, one end of the secondary winding is connected to the output voltage filter capacitor through a diode on the primary side The positive pole is connected with the other end of which is connected with the negative pole of the output voltage filter capacitor. The output voltage filter capacitor provides a stable DC output voltage to the load across the output terminal.

Because the present invention arranges an auxiliary inductance on the zero-potential switching circuit between the primary winding of the transformer and the series connection line contact of the two field effect power transistors, and then on the line contact between the primary winding of the transformer and the additional inductor, respectively Add at least one diode, these diodes can respectively act with the corresponding power switches when the external inductor starts to ring, short-circuit the current on the auxiliary inductor, and clamp the primary side stray capacitance of the transformer. voltage, to stop its oscillation, effectively avoid the ringing phenomenon, and achieve the purpose of zero potential switching with high efficiency, high density and low interference signal.

Because the present invention arranges an auxiliary inductance on the zero-potential switching circuit between the primary winding of the transformer and the series connection line contact of the two field effect power transistors, and then on the line contact between the primary winding of the transformer and the additional inductor, respectively Add at least one diode, these diodes can respectively act with the corresponding power switch tubes when the external inductor starts to produce ringing, short-circuit the current on the auxiliary inductor, and clamp the stray capacitance on the primary side of the transformer The voltage can prevent it from oscillating, effectively avoid the ringing phenomenon, and achieve the purpose of zero potential switching with high efficiency, high density and low interference signal.

Since the present invention applies the ring-free technology to various flyback, step-up and step-down power converters, these power converters can effectively avoid the occurrence of ringing, so that they can effectively operate under high-frequency switching operations. Reduce power loss, greatly increase its power density, and reduce the heat energy accumulated on the power switch tube and the size of the required heat sink, making it easier for the power converter to be applied to various miniaturized electronic products, eliminating the need for auxiliary The resonant zero-potential switching circuit of the inductor is too dependent on the leakage inductance of the transformer to realize the zero-potential switching, so it is difficult to meet its design specifications during design and manufacture, and it is difficult to produce in large quantities.

Attached content

Figure 1 is the main circuit diagram of the US Patent No. 383,594.

Fig. 2 is the main circuit diagram of the US patent No. 4,975,821.

Fig. 3 is a main circuit diagram of the US patent No. 5,245,520.

Fig. 4 is a main circuit diagram of the US patent No. 5,245,520.

FIG. 5 is a schematic diagram of the spurious ringing phenomenon generated by Imbertson's patented circuit.

Fig. 6 is a main circuit diagram of the US patent No. 5,057,986.

FIG. 7 is a main circuit diagram of the US Patent No. 5,057,986.

Fig. 8 is a main circuit diagram of the US patent No. 5,402,329.

FIG. 9 is a main circuit diagram of the US patent No. 5,402,329.

Fig. 10 is a schematic diagram of the parasitic ringing phenomenon produced by the patent circuit of Wittenbreder, Jr. and Ernest H.

Fig. 11 is a circuit diagram of the first embodiment of the present invention.

FIG. 12 is a schematic diagram of the spurious ringing phenomenon generated when no ringing suppression circuit is added in FIG. 11 .

FIG. 13 is one of the schematic diagrams of the waveforms where the spurious ringing disappears when the non-ringing suppression circuit is added in FIG. 11 .

FIG. 14 is the second schematic diagram of the waveform diagram of the disappearance of spurious ringing when the non-ringing suppression circuit is added in FIG. 11 .

FIG. 15 is one of the equivalent circuit diagrams of FIG. 11 divided into 10 periods.

FIG. 16 is the second equivalent circuit diagram of FIG. 11 divided into 10 periods.

FIG. 17 is the third equivalent circuit diagram of FIG. 11 divided into 10 periods.

FIG. 18 is the fourth equivalent circuit diagram of FIG. 11 divided into 10 periods.

FIG. 19 is the fifth equivalent circuit diagram of FIG. 11 divided into 10 periods.

FIG. 20 is the sixth equivalent circuit diagram of FIG. 11 divided into 10 periods.

FIG. 21 is the seventh equivalent circuit diagram of FIG. 11 divided into 10 periods.

FIG. 22 is the eighth equivalent circuit diagram of FIG. 11 divided into 10 periods.

FIG. 23 is the ninth equivalent circuit diagram of FIG. 11 divided into 10 periods.

FIG. 24 is the tenth equivalent circuit diagram of FIG. 11 divided into 10 periods.

FIG. 25 is one of the period diagrams of the lower arm ringing clamping circuit of the present invention.

Fig. 26 is the second period diagram of the lower arm ringing clamping circuit of the present invention.

FIG. 27 is the third period diagram of the lower arm ringing clamping circuit of the present invention.

Fig. 28 is a voltage and current waveform diagram of the lower arm ringing clamping circuit of the present invention.

Fig. 29 is one of the period diagrams of the upper arm ringing clamping circuit of the present invention.

FIG. 30 is the second time period chart of the upper arm ringing clamping circuit of the present invention.

FIG. 31 is the third time period chart of the upper arm ringing clamping circuit of the present invention.

Fig. 32 is a voltage and current waveform diagram of the upper arm ringing clamping circuit of the present invention.

FIG. 33 is a diagram of the efficiency obtained by the specific embodiment of FIG. 11 of the present invention.

FIG. 34 is a diagram of the results obtained on electromagnetic interference by the specific embodiment of FIG. 11 of the present invention.

Fig. 35 is a circuit diagram of the second embodiment of the present invention.

Fig. 36 is a circuit diagram of a third embodiment of the present invention.

Fig. 37 is a circuit diagram of a fourth embodiment of the present invention.

Fig. 38 is a circuit diagram of a fifth embodiment of the present invention.

Fig. 39 is a circuit diagram of a sixth embodiment of the present invention.

Detailed ways

The present invention is a ring-free zero-potential switching system applied to power converters. The technology is aimed at a zero-potential switching circuit on a power converter. During the process of high-efficiency and high-density zero-potential switching, the transformer An L-C resonant circuit that oscillates on the primary side of the circuit, when it starts to ring, short-circuits the current on its inductance and clamps the voltage on its capacitor, thereby effectively eradicating the parasitic oscillation generated by the zero-potential switching circuit bell.

The present invention re-arranges the zero-potential switching circuit with auxiliary inductor (auxiliary Inductor) and balance capacitor (balance capacitor) on the existing power converter, and arranges an auxiliary inductor on the zero-potential switching circuit on the primary side of the transformer Between the winding and the series connection point of the two field effect power tubes, and then on the line point between the primary winding of the transformer and the external inductor, add a short-circuit diode, or add two short-circuit diodes, the additional auxiliary inductor and the transformer The L-C circuit formed by the stray capacitance (stray capacitance) on the primary side of the primary side, when the ringing starts, these diodes can respectively act with the corresponding power switch tubes, short-circuit the current on the external inductor, and clamp The voltage on the stray capacitance on the primary side of the transformer is controlled to prevent it from oscillating, effectively avoid ringing, and achieve the purpose of zero-potential switching with high efficiency, high density and low interference signals.

As shown in Figure 11, it is the first specific embodiment of the present invention, which applies the zero-potential switching technology without ringing of the present invention to the design of the half-bridge forward full-wave rectifier circuit, which can be referred to as "Half-Bridge Forward Ring-Free Zero-Voltage-Switching Full-Wave Converter" In this embodiment, the circuit includes an input voltage filter capacitor Cin, the positive and negative poles of the capacitor Cin are connected across the positive and negative poles of an input voltage Vin, and a group of series-connected power switch tubes Q1 and Q2 are connected in parallel thereon. The drain of the power switch tube Q2 is connected to the positive pole of the capacitor Cin, its source is connected to the drain of the power switch tube Q1, and the source of the power switch tube Q1 is connected to the negative pole of the capacitor Cin, and the capacitor Cin It can provide a stable input voltage for a transformer. The transformer is mainly used to store and release electric energy. There is a primary winding Np and two secondary windings Ns1 and Ns2 on it. The inductances are Lp and Ls1 and Ls2 respectively. The marks on the windings are shown in Figure 11; the primary windings One end of Np is connected to the negative pole of a balance capacitor Cb, and the other end is connected to the line between the two power switch tubes Q1 and Q2 through an auxiliary inductor La, and the positive pole of the capacitor Cb is connected to the drain of the power switch tube Q2. connection, in this embodiment, the circuit between the primary winding Np and the auxiliary inductance La is respectively connected to the drain of the power switch tube Q2 and the source of Q1 through diodes D4 and D3, and the diode D4 (or D3) can be respectively matched with The power switch tube Q2 (or Q1), when the ringing phenomenon occurs in the circuit, the current ila on the auxiliary inductor La is immediately short-circuited by the power switch tube Q2 and the diode D4 (or the power switch tube Q1 and the diode D3), so as to terminate the oscillation Bell phenomenon; one end of the secondary winding Ns1, Ns2 is connected to the negative pole of an output voltage filter capacitor Co, and the other end is respectively connected to the positive end of the diode D1, D2, and the negative end of the diode D1, D2 is passed through an inductor Lo is connected to the positive electrode of the capacitor Co, and the capacitor Co can provide a stable DC output voltage Vo to the load across the output terminal.

In order to highlight the influence caused by the aforementioned ringing phenomenon, the two diodes D3 and D4 used to short-circuit the inductor La can be removed from the embodiment shown in FIG. 11. After the circuit is stable, an oscilloscope can be used to The waveform diagram of the measured voltage and current is shown in Figure 12. From the waveform diagram, it can be easily known that the ringing phenomenon occurs after time t3 and t8. Then put the diodes D3 and D4 back to their original positions, and the voltage and current waveforms measured at the same measurement point are shown in Figure 13. It can be seen from the waveforms that after the time t3 and t8, although the vibration still occurs at the beginning The bell phenomenon is clamped at time t4 and t9, and there is a very slight aftershock until time t5 and t10. It can be seen that, for the L-C circuit that can generate oscillation in this embodiment, the present invention uses two diodes to short-circuit the current on its inductance, so as to clamp the voltage on its capacitor and prevent it from oscillating, effectively avoiding Ringing occurs.

In order to specifically illustrate the principle that the power switch tubes Q1 and Q2 in this embodiment can interact with the two diodes D3 and D4 respectively when they are turned on, so as to suppress the ringing, the waveform diagram shown in Figure 13 is enlarged and The division is divided into 10 periods, as shown in Figure 14, and in Figures 15-24, the equivalent circuit diagrams of the 10 periods are shown respectively. In these circuit diagrams, the thick line represents the working circuit in the circuit, and the thin line Part of it represents the non-working line in the circuit, and the dotted line part represents the changing state of the circuit when the circuit can be turned on by zero potential. Now, the working state of the circuit in each period is described in detail as follows:

1. t10-t1 period:

As shown in the equivalent circuit in Figure 15, both this period and the previous period are transmitting energy. During this period, the power switch tube Q1 and the diode D1 are in the conduction state, and the current flows in from the positive terminal of the input terminal Vin, and flows to the input terminal Vin after passing through the balance capacitor Cb, the primary winding Np, the auxiliary inductor La and the power switch tube Q1. At this time, the balance capacitor Cb and auxiliary inductor La on the primary side are charged, and the inductor Lo and capacitor Co on the secondary side are also charged.

2. Time period from t1 to t2:

As shown in the equivalent circuit of FIG. 16 , this period is the resonance period in which the power switch Q2 can be turned on with zero potential. At time t1, the power switch tube Q1 is opened, the auxiliary inductance La and the equivalent inductance Lnp on the primary side of the transformer will form an L-C resonance tank (L-C tank) with the parasitic capacitors CQ1 and CQ2 on the power switch tubes Q1 and Q2, and Taking the current iLa on the auxiliary inductor La at time ti as the initial current of resonance, the parasitic capacitors CQ1 and CQ2 are charged respectively. This resonance will enable the power switch Q2 to obtain the possibility of zero-potential switching. When the voltage on the primary winding Np is reduced to zero, the diode D2 starts to conduct, and interacts with the diode D1 that is still conducting, forming a short circuit state for the secondary winding of the transformer. With the help of the auxiliary inductance La, the parasitic capacitance Only CQ1 and CQ2 can be continuously charged, and when the voltage Vds on the capacitor CQ1 is higher than Vin, the parasitic diode DQ2 is turned on, which forms a chance that the power switch Q2 can be turned on with zero potential.

3. Time period from t2 to t3:

As shown in the equivalent circuit of FIG. 17 , this period is the turning period of the current ila on the auxiliary inductor La. During this period, both diodes D1 and D2 are in the conducting state, so there is no voltage on the primary winding Np. At this time, since the parasitic diode DQ2 and the power switch Q2 are both conducting, the voltage on the auxiliary inductor La is equal to The voltage Vcb of the capacitor Cb and the slope of the current icb are -Vcb/La. When the current iLa is still positive, it means that the capacitor Cb is being charged. When the current iLa becomes negative, it means that the capacitor Cb starts to be discharged. .

4. Time period from t3 to t4:

The equivalent circuit shown in Figure 18, this period is the formation period of the upper arm ringing (ringing in upper side). At time t3, due to the discharge of the capacitor Cb, the voltage on the primary winding Np turns from zero to negative, so that the diode D1 is reverse-biased and cut off, and the auxiliary inductance La forms a resonance tank with the stray capacitance Cnp on the primary side of the transformer. , if there is no diode D4, the stray capacitance CNp will be charged and discharged, and the ringing phenomenon will appear.

5. Time period from t4 to t5:

As shown in the equivalent circuit in Figure 19, this period is the short-circuit period of the ringing current of the upper arm. During this period, since the diode D1 is cut off, the voltage Vd3 rises rapidly, and when the voltage Vd3 is higher than the input terminal voltage Vin (that is, time t4), the diode D4 is turned on, and the current on the auxiliary inductor La is immediately driven by the power The switching tube Q2 and the diode D4 are short-circuited together, and the ringing phenomenon stops, and the goal of ringfree in upper side is achieved; at time t5, due to the current on the diode D4, it is not enough to let the diode D4 Therefore, the energy on the auxiliary inductance La is only enough to form a very slight aftershock without affecting the circuit.

6. Time period from t5 to t6:

As shown in the equivalent circuit in Figure 20, this period and the previous period are both energy transmission periods. During this period, both the power switch tube Q2 and the diode D2 are in the conduction state, and the current flows out from the positive terminal of the capacitor Cb, and flows back to the negative terminal of the capacitor Cb after passing through the power switch tube Q2, the auxiliary inductor La and the primary winding Np. At this time, the energy on the capacitor Cb will be cross-connected to the secondary side circuit through the transformer, and charge the inductor Lo and the capacitor Co through the diode D2.

7. Time period from t6 to t7:

As shown in the equivalent circuit of FIG. 21 , this period is a resonance period in which the power switch tube Q1 can be turned on with zero potential. At time t6, the power switch Q2 is opened, the auxiliary inductance La and the equivalent inductance LNp on the primary winding of the transformer will form an L-C resonance tank (L-C tank) with the parasitic capacitances CQ1 and CQ2, and the auxiliary inductance La The current iLa above is the initial current of resonance, which starts to discharge the parasitic capacitors CQ1 and CQ2 respectively. This resonance will make the power switch tube Q1 obtain the possibility of zero-potential switching. When the voltage on the primary winding Np is reduced to zero, the diode D1 starts to conduct, and interacts with the diode D2 that is still conducting, forming a short circuit state for the secondary winding of the transformer. With the help of the auxiliary inductance La, the parasitic capacitance Only CQ1 and CQ2 can be continuously discharged. When the voltage Vds on the parasitic capacitor CQ1 is lower than the zero-crossing point, the parasitic potential DQ1 is turned on, which forms a chance for the power switch Q1 to be turned on with zero potential.

8. t7-t8 period:

As shown in the equivalent circuit of FIG. 22 , this period is the turning period of the current iLa on the auxiliary inductor La. During this period, both diodes D1 and D2 are in the conduction state, therefore, there is no voltage on the primary winding Np. At this time, since the parasitic diode DQ1 and the power switch Q1 are both conducted, the voltage on the auxiliary inductor La is equal to The difference Vin-Vcb between the input terminal voltage Vin and the voltage Vcb on the capacitor Cb, the slope of the current iLa is (Vin-Vcb)/La. When the current iLa is still negative, it means that the capacitor Cb is being discharged. When the current When iLa becomes a positive value, it means that the capacitor Cb starts to be charged.

9. t8-t9 period:

The equivalent circuit shown in Figure 23, this period is the formation period of the lower arm ringing (ringing in lower side). At time t8, since the capacitor Cb is charged, the voltage on the primary winding Np changes from zero to positive, so that the diode D2 is reverse biased and cut off, and the auxiliary inductance La forms a resonance tank with the stray capacitance CNp on the primary side of the transformer. , if there is no diode D3, the stray capacitance CNp will be charged and discharged, and the ringing phenomenon will appear.

10. t9-t10 period:

As shown in the equivalent circuit in Figure 24, this period is the short-circuit period of the ringing current of the lower arm. During this period, since the diode D2 is cut off, the voltage Vd3 drops rapidly, and when the voltage Vd3 is lower than the zero-crossing potential (that is, at time t9), the diode D3 is turned on, and the current on the auxiliary inductor La is immediately controlled by the power switch tube. Q1 and diode D3 are short-circuited together, and the ringing phenomenon stops, realizing the goal of no ringing in the lower arm (Ring free inlower side); at time t10, due to the current on diode D3, it is not enough to make diode D3 conduct Therefore, the energy on the auxiliary inductance La is only enough to form a very slight aftershock without affecting the circuit.

From the above description, it can be seen that in this embodiment, the ringing current of the upper arm can be short-circuited during the period t4-t5, and the ringing current of the lower arm can be short-circuited during the period t9-t10. In this way, this embodiment can In the case of no ringing, zero potential switching is smoothly performed.

In addition, it can be seen from the above description that the ringing effect produced by the general power converter when applying the zero-potential switching technology can be divided into two types: lower arm ringing and upper arm ringing. The present invention further suppresses the two ringing effects The principle and its advantages, combined with the equivalent circuit shown in Figure 25-33, the detailed analysis is as follows:

a. The principle and advantages of lower arm ringing suppression:

(1) During the t7-t8 period:

As shown in the equivalent circuit of FIG. 25 , this period is the turning period of the current iLa on the auxiliary inductor La. In this period, starting from time t7, the transformer is short-circuited by diodes D2 and D1, and the current iLa on the auxiliary inductor La rises rapidly. At time t7a, the current iLa changes from a negative value to a positive value. After time t8, Due to the open circuit of the diode D2, the current iLa changes to a gentler slope and continues to rise.

(2), t8-t9 period:

The equivalent circuit shown in Figure 26, this period is the initial period of the ringing of the lower arm. For the convenience of explanation, Figure 28 shows the voltage and current waveforms of the lower arm ringing clamp circuit, where the current iLa on the auxiliary inductor La can be divided into two parts, and the part marked as ip is the current part flowing through the primary side of the transformer Its size is only related to the load and does not affect the ringing behavior; the parts marked as iCs and iD3 are the current parts flowing through the primary side stray capacitance CS and diode D3 respectively, and its size has nothing to do with the load, only related to ringing related. When the time is t8, the diode D2 is open circuit, the short circuit of the transformer is removed, the auxiliary inductance La and the stray capacitance Cs on the primary side of the transformer form an L-C resonance tank, and V(La)=Vin-VCb, V(Cs>0 ) is the initial condition, and the resonance starts. Since the stray capacitance Cs starts to be charged, the voltage Vd3 on the diode D3 drops rapidly. D3 is short-circuited with the power switch tube Q1, which stops the ringing that will occur. At time t9, the stray capacitance Cs is the same as the energy accumulated on the auxiliary inductance La, both of which are:

E(Cs)＝E(La)＝1/2*Cs(Vin-VCb)*(Vin-VCb) (1)

(3), t9-t10 period:

The equivalent circuit shown in Figure 27, in this period, the ringing of the lower arm is suppressed. If the ringing is not stopped by the diode D3, and the resonance is not damped (damping ratio=0), the voltage of the stray capacitance Cs on the primary side of the transformer will be fully charged to 2 times of Vin-VCb, so that the stray capacitance Cs accumulates to the maximum energy, which is:

E(Cs)＝1/2*Cs[2(Vin-VCb)]*[2(Vin-VCb)] (2)

Also, if the ringing is not stopped by the diode D3, but an RC damper circuit (RC sunbber circuit) is added to the circuit, the maximum energy accumulated on the stray capacitance Cs should be exhausted by the RC damper circuit in order to completely avoid the ringing Impact. After the ringing of the lower arm is stopped by the diode D3, the energy accumulated in the auxiliary inductor La at time t9 will be exhausted by the diode D3 during the period t9-t10. It is calculated from this that since the ringing of the lower arm is stopped, the loss of the circuit will be reduced, and the reduced loss is formula (2) minus formula (1), and we get:

Reduced loss = 3/2Cs(Vin-VCb)*(Vin-VCb) (3)

From the above analysis, it can be known that this embodiment can reduce the energy loss caused by the ringing of the lower arm by 3/4 after adding the ring-free technology of the present invention to the lower arm.

B. The principle and advantages of suppressed upper arm ringing:

The principle that the upper arm ringing is suppressed is basically the same as that of the lower arm ringing, but the energy saved is different. The details are as follows:

(1), t2-t3 period:

As shown in the equivalent circuit of FIG. 29, this period is the turning period of the current iLa on the auxiliary inductor La. In this period, starting from time t2, the transformer is short-circuited by diodes D1 and D2, and the current iLa on the auxiliary inductor La drops rapidly. At time t2a, the current changes from a positive value to a negative value. After time t3, the current iLa Due to the open circuit of diode D1, it changes to a gentler slope and continues to decline.

(2), t3-t4 period:

As shown in the equivalent circuit in Figure 30, this period is the ringing start period. For the convenience of explanation, Figure 32 shows the voltage and current waveforms of the upper arm ringing clamp circuit, in which the current iLa on the auxiliary inductor La can be divided into two parts, and the part marked as 1p is the current part flowing through the primary side of the transformer , its size is only related to the load, and does not affect the ringing behavior; the current part marked as iCs and iD4, its size has nothing to do with the load, but only related to the ringing. When the time is t3, the diode D1 is open circuit, the short circuit of the transformer is released, the auxiliary inductance La and the stray capacitance Cs on the primary side of the transformer form an L-C resonance tank, and V(La)=Vin, V(Cs)=0 is Initial condition, starting to resonate, because the stray capacitance Cs starts to be charged, the voltage Vd3 on the diode D3 rises rapidly, when it rises above the input voltage Vin, the diode D4 is turned on, and the resonance current on the auxiliary inductor La is immediately absorbed by the diode D4 is short-circuited with the power switch tube Q2, which stops the ringing that will occur. At time t4, the stray capacitance Cs is the same as the energy accumulated on the auxiliary inductance La, both are:

E(Cs)＝E(La)＝1/2VCb*VCb (4)

(3), t4-t5 period:

The equivalent circuit shown in Figure 31, in this period, the ringing of the upper arm is suppressed. If the ringing is not stopped by D4, and the resonance is undamped (damoing ratio=0), the voltage of the stray capacitance Cs on the primary side of the transformer will be fully charged to twice the voltage of VCb, so that the stray capacitance Cs will accumulate to the maximum The energy of is:

E(Cs)＝2Cs*VCb*VCb (5)

Also, if the ringing is not stopped by the diode D4, but an RC snubber circuit (RC snubber circuit) is added to the circuit, the maximum energy accumulated on the stray capacitance Cs should be exhausted by the RC snubber circuit in order to completely avoid the ringing Impact. After the ringing of the upper arm is stopped by the diode D4, the energy accumulated in the auxiliary inductor La at time t4 will be consumed by the diode D4 within the time period t4-t5. It is calculated from this that since the ringing of the upper arm is suppressed, the loss of the circuit will be reduced, and the reduced loss is obtained by subtracting formula (4) from formula (5):

Reduced loss = 3/2Cs*VCb*VCb (6)

From the above analysis, it can be known that this embodiment can reduce 3/4 of the energy loss caused by the ringing of the upper arm after adding the ringing-free technology of the present invention to the upper arm.

The sum of formula (2) and formula (5) is the total energy loss caused by the ringing of the upper and lower arms:

Total ringing loss = 2Cs[(Vin-VCb)*(Vin-VCb)+VCb*VCb] (7)

The sum of formula (1) and formula (4) is the total energy loss when the ringing of the upper and lower arms is suppressed:

Total loss without ringing＝1/2Cs[(Vin-VCb)*(Vin-VCb)+VCb*VCb] (8)

In this embodiment, if the stray capacitance Cs on the primary side of the transformer is 100pF, the input voltage Vin is 400V, and the voltage VCb on the capacitor Cb is 100V, then the ringing of the power converter is consumed by the RC damping circuit , the total energy loss is 20 microjoules (uJ), and the energy loss when there is no ringing is 5.0 microjoules, so the energy loss is reduced by 15 microjoules each time when there is no ringing. At this time, if the power converter Working at a frequency of 100KHZ, the power loss of the RC damping circuit is 2.0 watts, and the power loss when there is no ringing is 0.5 watts, so the power loss when there is no ringing is reduced by 1.5 watts. Also, if the operating frequency is increased to 200KHZ, the power loss of the RC damping circuit is 4.0 watts, and the power loss when there is no ringing is 1.0 watts, so the power loss when there is no ringing will be reduced by 3.0 watts. It can be seen that the loss caused by ringing increases with the operating frequency of the circuit. This is also an important factor for the design and manufacturer of traditional power converters. The reason is that after adding the ringing-free mechanism of the present invention, the energy loss caused by ringing can be effectively reduced, so the operating frequency of the zero-potential switching circuit and the power density of the power converter can be greatly improved.

As shown in Figure 33, it is the result obtained in terms of efficiency in the embodiment of Figure 11 of the present invention. In this embodiment, the input voltage Vin is 370V direct current, the output voltage Vout is 12V/5A, and the operating frequency is 60KHZ. The main transformer The inductance LP on the primary winding is 1.2mH, the leakage inductance is 4.5uH, and the auxiliary inductance La is 35uH. The first curve in the figure uses an RC damping circuit to reduce ringing, so the efficiency is only 91%. In the second curve, under the same working conditions as the first curve, the ringing can be suppressed by adding diodes D3 and D4 to eliminate the ringing. Since there is no consumption of the damping circuit, its efficiency is increased to 92%. The third curve is under the same working conditions as the second curve, because there is no ringing, so the rectifier diode on the secondary side is changed to a Schottky diode with a withstand voltage of 100 volts and a forward voltage drop Vf of 0.65 volts. , and its efficiency will thus increase to 94%.

As shown in Figure 34, it is the achievement of the embodiment of Figure 11 of the present invention on the electromagnetic interference interference signal, wherein the upper figure is the frequency spectrum when there is ringing, and the lower figure is the frequency spectrum when there is no ringing, around 2.5MHZ, about 6dB improvement, in fact, 2.5MHZ is about the ringing frequency, after the ringing is suppressed, of course no interference signal can be seen on the spectrum.

In the second specific embodiment of the present invention, the ring-free zero-potential switching technology of the present invention is applied to the design of the half-bridge step-up forward full-wave rectifier circuit, as shown in Figure 35, which can be referred to as "Half-bridge Boost Forward Ring-Free Zero-Voltage-Switching Full-Wave Converter". In this embodiment, the circuit includes an input voltage filter capacitor Cin, the positive and negative poles of the capacitor Cin are connected across the positive and negative poles of an input voltage Vin, and a group of series-connected power switch tubes Q1 and Q2 are connected in parallel and a capacitor Cb, the negative pole of the capacitor Cb is connected to the positive pole of the capacitor Cin, the positive pole is connected to the drain of the power switch tube Q2, the source of the power switch tube Q2 is connected to the drain of the power switch tube Q1, and the power switch The source of the tube Q1 is connected to the negative electrode of the capacitor Cin, and the capacitor Cin can provide a stable input voltage for the transformer. The transformer is provided with a primary winding Np and two secondary windings Ns1, Ns2, the marks on the windings are shown in Figure 35; one end of the primary winding Np is connected to the negative pole of the capacitor Cb, and the other end is connected to the negative pole of the capacitor Cb through an auxiliary inductor La. The line between the two power switch tubes Q1 and Q2, in this embodiment, the line between the primary winding Np and the auxiliary inductance La is connected to the drain electrode of the power switch tube Q2 and the source electrode of Q1 respectively through diodes D4 and D3, Diode D4 (or D3) can respectively cooperate with the power switch tube Q2 (or Q1) when the ringing phenomenon occurs in the circuit, so that the current iLa on the auxiliary inductance La is immediately absorbed by the power switch tube Q2 and diode D4 (or power switch tube Q1). Short circuit together with the diode D3) to terminate the ringing phenomenon; the circuit connection of the two secondary windings NS1, NS2 is exactly the same as the secondary side circuit of the first embodiment.

In the third specific embodiment of the present invention, the no-ringing zero-potential switching technology of the present invention is applied to the design of a half-bridge forward half-wave rectifier circuit, as shown in FIG. Half-Bridge Forward Ring-Free Zero-Voltage-Swit ching Half-Wave Converter". In this embodiment, the circuit includes an input voltage filtering capacitor Cin, the positive and negative poles of the capacitor Cin are connected across the positive and negative poles of an input voltage Vin, and a group of series-connected power switch tubes Q1 and Q2 are connected in parallel thereon. The drain of the power switch tube Q2 is connected to the positive pole of the capacitor Cin, the source is connected to the drain of the power switch tube Q1, and the source of the power switch tube Q1 is connected to the negative pole of the capacitor Cin, and the capacitor Cin can provide a The stable input voltage is used by the transformer. The transformer is provided with a primary winding Np and a secondary winding Ns, and the marks on the windings are shown in Figure 38; one end of the primary winding Np is connected to the negative pole of a capacitor Cb, and the other end is connected to two capacitors through an auxiliary inductance La. In the line between the power switch tubes Q1 and Q2, the anode of the capacitor Cb is connected to the drain of the power switch tube Q2. In this embodiment, the line between the primary winding Np and the auxiliary inductance La is connected to the power switch through the diode D4. The drain of the tube Q2 and the diode D4 can cooperate with the power switch tube Q2. When the ringing phenomenon occurs in the circuit, the current iLa on the auxiliary inductance La is immediately short-circuited by the power switch tube Q2 and the diode D4 to terminate the ringing phenomenon; One end of the secondary winding Ns is respectively connected to the positive end of a diode D2 and the negative end of an output voltage filter capacitor Co in sequence, and the other end is connected to the positive end of the capacitor Co through a diode D1 and an inductor Lo in sequence, The negative end of the diode D2 is connected to the line between the diode D1 and the capacitor Co. Since this embodiment utilizes half-wave rectification, its ringing effect only occurs when D1 is cut off, so it is only necessary to add a diode D4 to achieve the purpose of no ringing.

In the fourth specific embodiment of the present invention, the no-ringing zero-potential switching technology of the present invention is applied to the design of the half-bridge step-up forward half-wave rectifier circuit, as shown in Figure 37, which can be referred to as "Half-Bridge Boost Forward Ring-Free Zero-Voltage-Switching Half-Wave Converter". In this embodiment, the circuit includes an input voltage filtering capacitor Cin, the positive and negative poles of the capacitor Cin are connected across the positive and negative poles of an input voltage Vin, and a group of series-connected power switch tubes Q1, Q2 and A capacitor Cb, the negative electrode of the capacitor Cb is connected to the positive electrode of the capacitor Cin, the positive electrode is connected to the drain of the power switch tube Q2, the source of the power switch tube Q2 is connected to the drain of the power switch tube Q1, and the power switch tube The source of Q1 is connected to the negative pole of the capacitor Cin, and the capacitor Cin can provide a stable input voltage for the transformer. The transformer is provided with a primary winding Np and a secondary winding Ns. The markings on the windings are shown in Figure 37. One end of the primary winding Np is connected to the negative pole of the capacitor Cb, and the other end is connected to two capacitors through an auxiliary inductance La. The line between the power switch tubes Q1 and Q2, in this embodiment, the line between the primary winding Np and the auxiliary inductance La is connected to the drain of the power switch tube Q2 through a diode D4, and the diode D4 can cooperate with the power switch tube Q2 , when the ringing phenomenon occurs in the circuit, the current iLa on the auxiliary inductance La is immediately short-circuited by the power switch tube Q2 and the diode D4 to terminate the ringing phenomenon: the circuit connection mode of the secondary winding Ns is the same as that of the third implementation The secondary side circuit of the example is exactly the same. Since this embodiment utilizes half-wave rectification, its ringing effect only occurs when D1 is cut off, so it is only necessary to add a diode D4 to achieve the purpose of no ringing.

In the fifth specific embodiment of the present invention, the zero-potential switching technology without ringing of the present invention is applied to the design of the half-bridge magnetic return switching circuit, as shown in Figure 38, which can be called "half-bridge magnetic return" Magnetic ring-free zero potential switching circuit (Half-Bridge Flyback Ring-Free Zero-Voltage Switching Converter)". In this embodiment, the circuit includes an input voltage filter capacitor Cin, the positive and negative poles of the capacitor Cin are connected across the positive and negative poles of an input voltage Vin, and a group of series-connected power switch tubes Q1 and Q2 are connected in parallel thereon. The drain of the power switch tube Q2 is connected to the positive pole of the capacitor Cin, the source is connected to the drain of the power switch tube Q1, and the source of the power switch tube Q1 is connected to the negative pole of the capacitor Cin, and the capacitor Cin can provide a The stable input voltage is used for transformer T1. The transformer T1 is provided with a primary winding Np and a secondary winding Ns, the marks on the windings are shown in Figure 38; one end of the primary winding Np is connected to the negative pole of a capacitor Cb, and the other end is respectively passed through an auxiliary inductor La and a Diode D3 is connected to the line between the two power switch tubes Q1 and Q2 and the source of the power switch tube Q1. In this embodiment, since the line between the primary winding Np and the auxiliary inductance La is connected to the power supply through the diode D3 The source of the switching tube Q1, so the diode D3 can cooperate with the power switching tube Q1. When the ringing phenomenon occurs in the circuit, the current iLa on the auxiliary inductor La is immediately short-circuited by the power switching tube Q1 and the diode D3 to stop the ringing Phenomenon: One end of the secondary winding Ns is connected to the positive pole of an output voltage filter capacitor Co through a diode D1, and the other end is connected to the negative pole of the capacitor Co. The capacitor Co can provide a stable DC output voltage Vo to the output The load across the terminal. Since this embodiment utilizes half-wave rectification, its ringing effect only occurs when D1 is cut off, so only a diode D3 is needed to achieve the purpose of no ringing.

In the sixth specific embodiment of the present invention, the no-ringing zero-potential switching technology of the present invention is applied to the design of the half-bridge boost-back magnetic switching circuit, as shown in Figure 39, which can also be referred to as "" Half-Bridge Boost Flyback Ring-Free Zero-Voltage-Switching Converter". In this embodiment, the circuit includes an input voltage filtering capacitor Cin, the positive and negative poles of the capacitor Cin are connected across the positive and negative poles of an input voltage Vin, and a group of series-connected power switch tubes Q1, Q2 and A capacitor Cb, the negative electrode of the capacitor Cb is connected to the positive electrode of the capacitor Cin, the positive electrode is connected to the drain of the power switch tube Q2, the source of the power switch tube Q2 is connected to the drain of the power switch tube Q1, and the power switch The source of the tube Q1 is connected to the negative electrode of the capacitor Cin, and the capacitor Cin can provide a stable input voltage for the transformer. The transformer T1 is provided with a primary winding Np and a secondary winding Ns, the marks on the windings are shown in Figure 39, one end of the primary winding Np is connected to the negative pole of the capacitor Cb, and the other end is respectively passed through an auxiliary inductor La and a The diode D3 is connected to the line between the two power switch tubes Q1 and Q2 and the source of the power switch tube Q1; in this embodiment, since the line between the primary winding Np and the auxiliary inductance La passes through the diode D3, it is connected to the power switch The source of the tube Q1, so the diode D3 can cooperate with the power switch tube Q1. When the ringing phenomenon occurs in the circuit, the current iLa on the auxiliary inductor La is immediately short-circuited by the power switch tube Q1 and the diode D3 to terminate the ringing phenomenon. ; The circuit connection mode of the two secondary windings is exactly the same as the secondary side circuit of the fifth embodiment. Since this embodiment utilizes half-wave rectification, its ringing effect only occurs when D1 is cut off, so only a diode D3 is needed to achieve the purpose of no ringing.

According to the above, using the ringing-free zero-potential switching technology of the present invention, the power converter can perform zero-potential switching operations in a high-frequency environment, avoiding the problem of abnormal heating of the auxiliary inductor due to parasitic oscillations, and effectively reducing power consumption. Loss, and effectively reduce the requirements for the reverse voltage rating of the secondary side rectifier parts, greatly improve its operating frequency and power density, and reduce electromagnetic interference signals, and the heat energy accumulated by the power switch tube and the required The size of the heat sink makes it easier for the power converter to pass international electromagnetic interference regulations, and it is easier to be applied to the design of various miniaturized electronic products.

Claims (18)

1. A half-bridge forward-type zero-potential switching full-wave rectification power converter without ringing, characterized in that: it includes: An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, and two power switch tubes connected in series are connected in parallel on it, and the drain of one of the power switch tubes is connected to the input The positive pole of the voltage filter capacitor is connected, the source is connected to the drain of another power switch tube, and the source of the other power switch tube is connected to the negative pole of the input voltage filter capacitor; A transformer, the transformer is provided with a primary winding and two secondary windings, one end of the primary winding is connected to the negative pole of a capacitor, and the other end is connected to the line between the two power switch tubes through an auxiliary inductance, the capacitor The anode of the power switch is connected to the drain of one of the power switches, the source of the power switch is connected to the drain of the other power switch, and the line between the primary winding and the auxiliary inductance is connected to the The drain of one power switch tube and the source of the other power switch tube. These diodes cooperate with the corresponding power switch tubes. When ringing occurs in the circuit, the current on the auxiliary inductance is immediately absorbed by the corresponding power switch tube and diode. short circuit. 2. The half-bridge forward non-ringing zero-potential switching full-wave rectification power converter as claimed in claim 1, characterized in that: one end of the secondary winding of the transformer is connected to an output voltage filter capacitor The negative pole of the diode is connected to the positive pole of the two secondary side diodes respectively, and the negative poles of these secondary side diodes are connected to the positive pole of the output voltage filter capacitor through an inductor. The output voltage filter capacitor provides A stable DC output voltage to the load across the output. 3. The half-bridge forward-type zero-potential switching full-wave rectification power converter without ringing as claimed in claim 1 or 2, characterized in that: said power switch tube is a field effect power tube. 4. A half-bridge step-up forward type zero-potential switching full-wave rectification power converter without ringing, characterized in that it includes: An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, two power switch tubes and a capacitor connected in series are connected in parallel, the negative pole of the capacitor is connected to the input voltage The positive pole of the voltage filter capacitor is connected, and the positive pole is connected to the drain of one of the power switch tubes; the source of the power switch tube is connected to the drain of another power switch tube, and the source of the other power switch tube Then connect to the negative pole of the input voltage filter capacitor; A transformer, the transformer is provided with a primary winding, one end of the primary winding is connected to the negative pole of the capacitor, and the other end is connected to the line between the two power switch tubes through an auxiliary inductance, the connection between the primary winding and the auxiliary inductance The line is connected to the drain of one power switch tube and the source of the other power switch tube through two diodes. These diodes are respectively matched with the corresponding power switch tubes. When the ringing phenomenon occurs in the circuit, the auxiliary inductor is connected to The current is immediately short-circuited by the corresponding power switch tube and diode. 5. The half-bridge step-up forward type non-ringing zero-potential switching full-wave rectification power converter as claimed in claim 4, characterized in that: said transformer includes two secondary windings, one end of the two secondary windings It is connected to the negative pole of an output voltage filter capacitor, and the other end is respectively connected to the positive terminals of two secondary side diodes, and the negative terminals of these secondary side diodes are connected to the output voltage filter capacitor through an inductor. The positive pole is connected, and the output voltage filter capacitor provides a stable DC output voltage to the load connected across the output terminal. 6. The half-bridge step-up forward type zero-potential switching full-wave rectification power converter without ringing as claimed in claim 4 or 5, characterized in that: said power switch tube is a field effect power tube. 7. A half-bridge forward non-ringing zero-potential switching half-wave rectifier power converter, characterized in that it includes: An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, and two power switch tubes connected in series are connected in parallel on it, and the drain of one power switch tube is connected to the The positive pole of the input voltage filter capacitor is connected, its source is connected to the drain of another power switch tube, and the source of the other power switch tube is connected to the negative pole of the input voltage filter capacitor; A transformer, the transformer is provided with a primary winding, one end of the primary winding is connected to the negative pole of a capacitor, the other end is connected to the line between two power switch tubes through an auxiliary inductor, the positive pole of the capacitor is connected to one of the power switches The drains of the switching tubes are connected, the source of the power switching tube is connected to the drain of another power switching tube, and the line between the primary winding and the auxiliary inductance is connected to the drain of one of the power switching tubes through a diode. The diode cooperates with two power switch tubes, and when the ringing phenomenon occurs in the circuit, the current on the auxiliary inductance is immediately short-circuited by the power switch tube and the diode. 8. The half-bridge forward non-ringing zero-potential switching half-wave rectifier power converter as claimed in claim 7, characterized in that: said transformer also includes a secondary winding, one end of which is respectively connected to To the positive terminal of a diode on the secondary side and the negative terminal of an output voltage filter capacitor, the other end of the secondary winding is connected to one end of the inductor through another diode on the secondary side, and the negative terminal of the above-mentioned diode is connected to another diode and the inductor The other end of the inductor is connected to the positive pole of the output voltage filter capacitor. 9. The half-bridge forward non-ringing zero-potential switching half-wave rectification power converter as claimed in claim 7 or 8, characterized in that: said power switch tube is a field effect power tube. 10. A half-bridge step-up forward type non-ringing zero-potential switching half-wave rectification power converter, characterized in that it includes: An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, a group of two power switch tubes connected in series and a capacitor are connected in parallel, the negative pole of the capacitor is connected to the input The positive pole of the voltage filter capacitor is connected, its positive pole is connected to the drain of one of the power switch tubes, the source of the power switch tube is connected to the drain of another power switch tube, and the source of the other power switch tube The pole is connected to the negative pole of the input voltage filter capacitor; A transformer, the transformer is provided with a primary winding, one end of the primary winding is connected to the negative pole of the above-mentioned capacitor, and the other end is connected to the line between the two power switch tubes through an auxiliary inductor, and the drain of one of the power switch tubes The pole is connected to the positive pole of the capacitor, and its source is connected to the drain of another power switch tube. The line between the primary winding and the auxiliary inductance is connected to the drain of one of the power switch tubes through a diode. The diode cooperates with the power switch tube, and when the ringing phenomenon occurs in the circuit, the current on the auxiliary inductance is immediately short-circuited by the power switch tube and the diode together. 11. The half-bridge step-up forward type non-ringing zero-potential switching half-wave rectification power converter according to claim 10, characterized in that: said transformer also includes a secondary winding, and one end of the secondary winding Connect to the positive terminal of a diode on the secondary side and the negative terminal of an output voltage filter capacitor, the other end of the secondary winding is connected to one end of the inductor through another diode on the secondary side, and the negative terminal of the above-mentioned diode is connected to another diode The junction between the inductor and the inductor, the other end of the inductor is connected to the positive pole of the output voltage filter capacitor. 12. The half-bridge step-up forward type non-ringing zero-potential switching half-wave rectification power converter according to claim 10 or 11, characterized in that the power switch tube is a field effect power tube. 13. A half-bridge remagnetization-free zero-potential switching power converter, characterized in that it includes: An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, and two power switch tubes connected in series are connected in parallel on it, and the drain of one of the power switch tubes is connected to the The positive pole of the input voltage filter capacitor is connected, the source thereof is connected to the drain of another power switch tube, and the source of the other power switch tube is connected to the negative pole of the input voltage filter capacitor; A transformer, the transformer is provided with a primary winding, one end of the primary winding is connected to the negative pole of a capacitor, the positive pole of the capacitor is connected to the drain of a power switching tube, and the source of the power switching tube is connected to another The drain of a power switch tube, the other end of the primary winding is connected to the line between the two power switch tubes through an auxiliary inductor, and the other end is also connected to the source of another power switch tube through a diode, and the diode cooperates Another power switch tube, when ringing occurs in the circuit, the current on the auxiliary inductance is immediately short-circuited by another power switch tube and the diode. 14. The half-bridge remagnetization type zero-potential switching power converter without ringing according to claim 13, characterized in that: said transformer also includes a secondary winding, and one end of the secondary winding passes through a The diode is connected to the anode of an output voltage filter capacitor, and the other end is connected to the cathode of the output voltage filter capacitor. The output voltage filter capacitor provides a stable DC output voltage to the load across the output terminal. 15. The half-bridge remagnetization type zero-potential switching power converter without ringing according to claim 13 or 14, characterized in that the power switch tube is a field effect power tube. 16. A half-bridge step-up magnetization-free zero-potential switching power converter, characterized in that it includes: An input voltage filter capacitor, the positive and negative poles of the input voltage filter capacitor are connected across the positive and negative poles of an input voltage, a group of two power switch tubes connected in series and a capacitor are connected in parallel, the negative pole of the capacitor is connected to the input The positive pole of the voltage filter capacitor is connected, its positive pole is connected to the drain of one of the power switch tubes, the source of the power switch tube is connected to the drain of another power switch tube, and the source of the other power switch tube The pole is connected to the negative pole of the input voltage filter capacitor; A transformer, the transformer is provided with a primary winding, one end of the primary winding is connected to the negative pole of the capacitor, the other end is connected to the line between the two power switch tubes through an auxiliary inductor, and the other end is also connected through a diode Connected to the source of another power switch tube, the diode cooperates with a power switch tube, and when the ringing phenomenon occurs in the circuit, the current on the auxiliary inductance is immediately short-circuited by a power switch tube and the diode. 17. The half-bridge step-up magnetic return type zero-potential switching power converter without ringing according to claim 16, characterized in that: said transformer also includes a secondary winding, and one end of the secondary winding passes through a secondary The diode on the side is connected to the positive pole of the output voltage filter capacitor, and the other end is connected to the negative pole of the output voltage filter capacitor. The output voltage filter capacitor provides a stable DC output voltage to the load across the output terminal. . 18. The half-bridge step-up magnetization-free zero-potential switching power converter according to claim 16 or 17, characterized in that the power switch tube is a field effect power tube.

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