A bidirectional dual-polarity input-output dc converter topology

Abstract

This invention discloses a bidirectional bipolar input / output DC-DC converter topology, which is an asymmetric structure centered on a high-frequency transformer T1 with a center tap. It includes a first circuit unit, the high-frequency transformer T1, and a second circuit unit connected in sequence. The first circuit unit employs a half-bridge or full-bridge structure, and the second circuit unit also employs a half-bridge or full-bridge structure. At least one of the first and second circuit units uses a bidirectional switching structure with two switches connected in reverse series, enabling mutual conversion between the bipolar voltages of the first and second circuit units, thus multiplying the voltage variation range on the output side. This invention improves upon traditional bipolar DC-DC converters, achieving stable and adjustable voltage gain by changing the switching frequency while realizing high-frequency, high-efficiency bipolar DC-DC conversion, significantly improving the converter's wide-range voltage supply capability.

Description

Technical Field

[0001] This invention relates to the technical field of power electronics applications, and in particular to a bidirectional bipolar input-output DC-DC converter topology. Background Technology

[0002] Energy devices such as distributed renewable energy sources and energy storage batteries with DC power output require a larger voltage span and a wider voltage range, leading to an increasing demand for DC-DC converters that can adapt to bipolar voltages and wider voltage ranges.

[0003] A traditional bidirectional DC-DC converter is a DC-DC converter that enables bidirectional energy flow while maintaining the same polarity of the DC voltages on both sides. However, the output voltage of such a converter is limited by the unipolar voltage and its own voltage gain range, making it difficult to adapt to the wide range of voltage requirements of distributed renewable energy and energy storage battery systems.

[0004] To overcome the shortcomings of traditional bidirectional DC-DC converters, bipolar output bidirectional DC-DC converters have emerged. This type of converter can achieve controllable bipolar voltage output through a single device without affecting the connection methods of traditional circuits. Bipolar output bidirectional DC-DC converters broaden the voltage output range and possess the advantages of high efficiency and small size found in high-frequency converters.

[0005] Bipolar output bidirectional DC-DC converters can further widen the voltage and output voltage range, significantly improving the converter's wide voltage range supply capability.

[0006] Against the backdrop of global environmental change and the widespread application of new energy sources, bipolar output bidirectional DC-DC converters have shown broad application prospects in fields such as energy storage power supplies and DC power distribution of renewable energy. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a bidirectional bipolar input-output DC-DC converter topology. It improves upon the traditional bipolar DC-DC converter by achieving stable and adjustable voltage gain through changing the switching frequency, while realizing high-frequency and high-efficiency bipolar bidirectional DC-DC conversion, and significantly improving the converter's wide voltage range supply capability.

[0008] To achieve the above objectives, the technical solution provided by the present invention is as follows: a bidirectional bipolar input-output DC-DC converter topology, which is an asymmetric structure centered on a high-frequency transformer T1 with a center tap, comprising a first circuit unit, a high-frequency transformer T1, and a second circuit unit connected in sequence; the first circuit unit is connected to the high-turns end of the high-frequency transformer T1 and adopts a half-bridge or full-bridge structure, and the second circuit unit is connected to the low-turns end of the high-frequency transformer T1 and adopts a half-bridge or full-bridge structure;

[0009] At least one of the first and second circuit units adopts a bidirectional switching structure with two switching transistors connected in reverse series to realize bipolar voltage conversion and bidirectional power flow. Specifically, when power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), it can convert the positive or negative voltage of the high-voltage side to the positive or negative voltage of the low-voltage side; when power flows from the low-voltage side to the high-voltage side (i.e., power flows in the reverse direction), it can convert the positive or negative voltage of the low-voltage side to the positive or negative voltage of the high-voltage side.

[0010] Preferably, the first circuit unit is one of the following six structures:

[0011] In structure one, the first circuit unit includes a filter capacitor C1, an inverter half-bridge, and a resonant cavity. The inverter half-bridge includes series-connected switching transistors Q1 and Q2, and the resonant cavity is composed of series-connected capacitors C1 and Q2. r L r L m Composition, C r For the resonant network, series capacitor L r For the resonant network series inductor, L m The magnetizing inductance of the high-frequency transformer T1; the switching transistors Q1 and Q2 in the inverter half-bridge can be replaced by bidirectional switches Q1 and Q2 respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0012] In structure two, the first circuit unit includes a filter capacitor C1, an inverter full-bridge, and a resonant cavity. The inverter full-bridge includes a first inverter half-bridge and a second inverter half-bridge connected in parallel. The first inverter half-bridge includes series-connected switches Q1 and Q2, and the second inverter half-bridge includes series-connected switches Q3 and Q4. The resonant cavity is formed by a series-connected capacitor C1. r L r L m Composition, C r For the resonant network, series capacitor L r For the resonant network series inductor, L mThe magnetizing inductance of the high-frequency transformer T1; the switching transistors Q1, Q2, Q3, and Q4 in the inverter half-bridge can be replaced with bidirectional switches Q1, Q2, Q3, and Q4 respectively. 11 and Q 12 Q 21 and Q 22 Q 31 and Q 32 Q 41 and Q 42 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0013] In structure three, the first circuit unit includes a filter capacitor C1 and an inverter full bridge. The inverter full bridge includes a first inverter half bridge and a second inverter half bridge connected in parallel. The first inverter half bridge includes switches Q1 and Q2 connected in series, and the second inverter half bridge includes switches Q3 and Q4 connected in series. The switches Q1, Q2, Q3, and Q4 in the inverter full bridge can be replaced with bidirectional switches Q1, Q2, Q3, and Q4, respectively. 11 and Q 12 Q 21 and Q 22 Q 31 and Q 32 Q 41 and Q 42 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0014] In structure four, the first circuit unit includes a push-pull half-bridge composed of a filter capacitor C1 and switching transistors Q1 and Q2. Switch Q1 is the upper transistor of the push-pull half-bridge, and switching transistor Q2 is the lower transistor. The filter capacitor C1 is connected to the center tap of the primary side of the high-frequency transformer T1 and the lower transistor of the push-pull half-bridge. Switches Q1 and Q2 in the push-pull half-bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0015] In structure five, the first circuit unit includes an inverter full-bridge, which comprises a first inverter half-bridge and a second inverter half-bridge connected in parallel. The first inverter half-bridge includes a series-connected switch Q1 and a series-connected switch Q2; the second inverter half-bridge includes a series-connected capacitor C. Q1 and capacitor C Q2 The switching transistors Q1 and Q2 in the inverter full-bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0016] In structure six, the first circuit unit includes an inverter full-bridge and an inductor L1. The inverter full-bridge includes a first inverter half-bridge and a second inverter half-bridge connected in parallel. The first inverter half-bridge includes a switch Q1 and a switch Q2 connected in series. The second inverter half-bridge includes a capacitor C connected in series. Q1 and capacitor C Q2 The inductor L1 is connected to the midpoint of the second inverter half-bridge arm; the switching transistors Q1 and Q2 in the inverter full-bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0017] Preferably, the second circuit unit is one of the following six structures:

[0018] In structure one, the second circuit unit includes a filter capacitor C2, a rectifier half-bridge, and a resonant cavity. The rectifier half-bridge includes series-connected switching transistors Q5 and Q6, and the resonant cavity is composed of series-connected C... r L r Composition, C r For the resonant network, series capacitor L r The resonant network is connected in series with an inductor; the switching transistors Q5 and Q6 in the rectifier half-bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0019] In structure two, the second circuit unit includes a filter capacitor C2, a rectifier bridge, and a resonant cavity. The rectifier bridge includes a first rectifier half-bridge and a second rectifier half-bridge connected in parallel. The first rectifier half-bridge includes switches Q5 and Q6 connected in series, and the second rectifier half-bridge includes switches Q7 and Q8 connected in series. The resonant cavity is formed by a filter capacitor C2 connected in series. r L r Composition, C r For the resonant network, series capacitor L r The resonant network is connected in series with an inductor; the switching transistors Q5, Q6, Q7, and Q8 in the rectifier bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 51 and Q 52 Q 61 and Q 62 Q 71 and Q 72 Q 81 and Q 82 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0020] In structure three, the second circuit unit includes a filter capacitor C2 and a rectifier full bridge. The rectifier full bridge includes a first rectifier half bridge and a second rectifier half bridge connected in parallel. The first rectifier half bridge includes switches Q5 and Q6 connected in series, and the second rectifier half bridge includes switches Q7 and Q8 connected in series. The switches Q5, Q6, Q7, and Q8 in the rectifier full bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 51 and Q 52 Q 61 and Q 62 Q 71 and Q 72 Q 81 and Q 82 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0021] In structure four, the second circuit unit includes a push-pull half-bridge composed of a filter capacitor C2 and switching transistors Q5 and Q6. Switch Q5 is the upper transistor of the push-pull half-bridge, and switching transistor Q6 is the lower transistor. The filter capacitor C2 is connected to the center tap of the secondary side of the high-frequency transformer T1 and the lower transistor of the push-pull half-bridge. Switches Q5 and Q6 in the push-pull half-bridge can be replaced with bidirectional switches Q6. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0022] In structure five, the second circuit unit includes a full-bridge rectifier, which comprises a first half-bridge and a second half-bridge connected in parallel. The first half-bridge includes a series-connected switch Q5 and a series-connected switch Q6; the second half-bridge includes a series-connected capacitor C. Q5 and capacitor C Q6 The switching transistors Q5 and Q6 in the rectifier bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0023] In structure six, the second circuit unit includes a rectifier full-bridge and an inductor L2. The rectifier full-bridge includes a first rectifier half-bridge and a second rectifier half-bridge connected in parallel. The first rectifier half-bridge includes a switch Q5 and a switch Q6 connected in series. The second rectifier half-bridge includes a capacitor C connected in series. Q5 and capacitor C Q6 The inductor L2 is connected to a node in the second rectifier half-bridge; the switches Q5 and Q6 in the rectifier full-bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 51 and Q52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0024] Firstly, the fundamental wave analysis method is used to model the converter to obtain an equivalent simplified model;

[0025] Points E and F in the second circuit unit are defined as follows: In a half-bridge, point E is the source of the upper bridge switch or the drain of the lower bridge switch, and point F is the source of the lower bridge switch; in a full-bridge, point E is the source of the upper bridge switch or the drain of the lower bridge switch in the left bridge arm, and point F is the source of the upper bridge switch or the drain of the lower bridge switch in the right bridge arm. When power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), the output equivalent resistance is:

[0026]

[0027] In the formula, R e U is the output equivalent resistance when power flows in the forward direction. EF-rms U is the effective value of the equivalent voltage between points E and F in the second circuit unit, P is the total transmitted power, and U is the effective value of the equivalent voltage between points E and F in the second circuit unit. o For the output voltage, R o Let n be the load resistance and n be the turns ratio of the high-frequency transformer T1.

[0028] The voltage conversion gain is:

[0029]

[0030]

[0031]

[0032]

[0033]

[0034] In the formula, M is the voltage conversion gain, and U in Where k is the input voltage and k is the magnetizing inductance value L' m With resonant inductance value L' r The ratio, f n For the switching frequency f s With resonant frequency f r The ratio of C r ' is the resonant capacitance value, and Q is the quality factor when power flows in the forward direction;

[0035] Points C and D in the first circuit unit are defined as follows: In a half-bridge, point C is the source of the upper bridge switch or the drain of the lower bridge switch, and point D is the source of the lower bridge switch; in a full-bridge, point C is the source of the upper bridge switch or the drain of the lower bridge switch in the left bridge arm, and point D is the source of the upper bridge switch or the drain of the lower bridge switch in the right bridge arm. When power flows from the low-voltage side to the high-voltage side (i.e., power flows in reverse), the output equivalent resistance is:

[0036]

[0037] In the formula, R′ e U is the output equivalent resistance when power flows in the reverse direction. CD-rms This is the effective value of the equivalent voltage between points C and D in the first circuit unit;

[0038] The voltage conversion gain is:

[0039]

[0040]

[0041] In the formula, M′ is the voltage conversion gain when power flows in reverse, and Q′ is the quality factor when power flows in reverse.

[0042] Preferably, when the first circuit unit is structure one, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), in the first circuit unit, the switching transistor Q... 11 Q 21 As the resonant switching transistors are complementary to each other in conduction, the switching transistor Q... 12 Q 22 Turn off, C connected in series r L r L m Forming a resonant cavity;

[0043] When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure.

[0044] When a positive voltage is output, the switching transistor Q... 12 Q 11 On, the switching transistor Q 21 Q 22 Turn off;

[0045] When the output voltage is negative, the switching transistor Q... 21 Q 22 On, the switching transistor Q 12 Q 11 Turn off.

[0046] Preferably, when the first circuit unit is structure two, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), in the first circuit unit, the switching transistor Q... 11 Q 41 As the resonant switching transistors are complementary to each other in conduction, the switching transistor Q... 21 Q 31 As the resonant switching transistors are complementary to each other in conduction, the switching transistor Q... 12 Q 22 Q 32 Q 42 Turn off;

[0047] When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure.

[0048] When a positive voltage is output, the switching transistor Q... 12 Q 42 Complementary conduction, switching transistor Q 22 Q 32 Complementary conduction, switching transistor Q 11 Q 21 Q 31 Q 41 Constant off, using the switching diode D 11 D 21 D 31 D 41 It constitutes the positive voltage output of the rectifier circuit;

[0049] When the output voltage is negative, the switching transistor Q... 11 Q 41 Complementary conduction, switching transistor Q 21 Q 31 Complementary conduction, switching transistor Q 12 Q 22 Q 32 Q 42 Constant off, using the switching diode D 12 D 22 D 32 D 42 It forms the rectifier circuit and outputs a negative voltage.

[0050] Preferably, when the first circuit unit is structure three, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), in the first circuit unit, the switching transistor Q... 11 Q 41 Complementary conduction, switching transistor Q 21 Q 31 Complementary conduction, switching transistor Q 12 Q 22 Q 32 Q42 Turn off;

[0051] When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure.

[0052] When a positive voltage is output, the switching transistor Q... 12 Q 42 Complementary conduction, switching transistor Q 22 Q 32 Complementary conduction, switching transistor Q 11 Q 21 Q 31 Q 41 Constant off, using the switching diode D 11 D 21 D 31 D 41 It constitutes the positive voltage output of the rectifier circuit;

[0053] When the output voltage is negative, the switching transistor Q... 11 Q 41 Complementary conduction, switching transistor Q 21 Q 31 Complementary conduction, switching transistor Q 12 Q 22 Q 32 Q 42 Constant off, using the switching diode D 12 D 22 D 32 D 42 It forms the rectifier circuit and outputs a negative voltage.

[0054] Preferably, when the first circuit unit is structure four, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), in the first circuit unit, the switching transistor Q... 11 Q 21 On, the switching transistor Q 12 Q 22 As a complementary conduction of push-pull resonant switches;

[0055] When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure.

[0056] When a positive voltage is output, the switching transistor Q... 11 Q 21 On, the switching transistor Q 12 Q 22 Constant off, using the switching diode D 12 D 22 It constitutes the positive voltage output of the rectifier circuit;

[0057] When the output voltage is negative, the switching transistor Q... 12 Q 22 On, the switching transistor Q 11 Q 21 Constant off, using the switching diode D 11 D 21 It forms the rectifier circuit and outputs a negative voltage.

[0058] Preferably, when the first circuit unit is structure five, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), in the first circuit unit, the switching transistor Q... 11 Q 21 Complementary conduction, switching transistor Q 12 Q 22 Constantly off;

[0059] When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure.

[0060] When a positive voltage is output, the switching transistor Q... 12 Q 22 On, the switching transistor Q 11 Q 22 Constantly off;

[0061] When the output voltage is negative, the switching transistor Q... 11 Q 21 On, the switching transistor Q 12 Q 22 Constantly off.

[0062] Preferably, when the first circuit unit is structure six, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), in the first circuit unit, the switching transistor Q... 11 Q 21 Complementary conduction, switching transistor Q 12 Q 22 Constantly off;

[0063] When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure.

[0064] When a positive voltage is output, the switching transistor Q... 12 Q 22 On, the switching transistor Q 11 Q 22 Constantly off;

[0065] When the output voltage is negative, the switching transistor Q... 11 Q 21On, the switching transistor Q 12 Q 22 Constantly off.

[0066] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0067] 1. At least one of the first and second circuit units adopts a bidirectional switching structure with two switching transistors connected in reverse series, which enables the bipolar voltage of the first circuit unit and the bipolar voltage of the second circuit unit to be mutually converted, thus multiplying the voltage variation range on the output side. This is suitable for applications requiring bipolar voltage conversion and a wide voltage variation range.

[0068] 2. This invention improves upon traditional bipolar DC-DC converters, enabling not only stable and adjustable voltage gain by changing the switching frequency, but also high-frequency and high-efficiency bipolar DC-DC conversion by controlling the conduction state of the switching transistors, thus significantly improving the converter's wide-range voltage supply capability. Attached Figure Description

[0069] Figure 1 This is a structural framework diagram of the present invention.

[0070] Figure 2 This is a structural framework diagram of the forward power flow in an embodiment of the present invention.

[0071] Figure 3 This is a structural framework diagram of reverse power flow in an embodiment of the present invention.

[0072] Figure 4 This is a schematic diagram of the equivalent model of the fundamental wave analysis method used in an embodiment of the present invention.

[0073] Figure 5a , 5b This is a topology diagram of another first circuit unit provided in an embodiment of the present invention.

[0074] Figure 6a , 6b This is a topology diagram of another first circuit unit provided in an embodiment of the present invention.

[0075] Figure 7a , 7b This is a topology diagram of another first circuit unit provided in an embodiment of the present invention.

[0076] Figure 8a , 8b This is a topology diagram of another first circuit unit provided in an embodiment of the present invention.

[0077] Figure 9a , 9b This is a topology diagram of another first circuit unit provided in an embodiment of the present invention.

[0078] Figure 10a , 10b This is a topology diagram of another second circuit unit provided in an embodiment of the present invention.

[0079] Figure 11a , 11b This is a topology diagram of another second circuit unit provided in an embodiment of the present invention.

[0080] Figure 12a , 12b This is a topology diagram of another second circuit unit provided in an embodiment of the present invention.

[0081] Figure 13a , 13b This is a topology diagram of another second circuit unit provided in an embodiment of the present invention.

[0082] Figure 14a , 14b This is a topology diagram of another second circuit unit provided in an embodiment of the present invention.

[0083] Figure 15a , 15b This is a topology diagram of another second circuit unit provided in an embodiment of the present invention. Detailed Implementation

[0084] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0085] like Figure 1 As shown, this embodiment provides a bidirectional bipolar input / output DC-DC converter topology, which is an asymmetric structure centered on a high-frequency transformer T1 with a center tap. It includes a first circuit unit, the high-frequency transformer T1, and a second circuit unit connected sequentially. The first circuit unit is connected to the high-turns end of the high-frequency transformer T1, and the second circuit unit is connected to the low-turns end of the high-frequency transformer T1.

[0086] The first circuit unit includes a filter capacitor C1, an inverter full-bridge, and a resonant cavity. The inverter full-bridge includes a first inverter half-bridge and a second inverter half-bridge connected in parallel. The first inverter half-bridge includes series-connected switches Q1 and Q2, and the second inverter half-bridge includes series-connected switches Q3 and Q4. The resonant cavity is formed by a filter capacitor C1 connected in series. r L r L m Composition, C r For the resonant network, series capacitor L r For the resonant network series inductor, L m This is the magnetizing inductance of the high-frequency transformer T1;

[0087] The second circuit unit includes a push-pull half-bridge composed of a filter capacitor C2 and switching transistors Q5 and Q6. Switching transistor Q5 is the upper transistor of the push-pull half-bridge, and switching transistor Q6 is the lower transistor. The filter capacitor C2 is connected to the center tap of the secondary side of the high-frequency transformer T1 and the lower transistor of the push-pull half-bridge. Switching transistors Q5 and Q6 in the push-pull half-bridge can be replaced with bidirectional switches Q6 and Q7, respectively. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0088] Furthermore, such as Figure 2 As shown, when power flows from the high-voltage side to the low-voltage side, i.e., power flows in the forward direction, in the first circuit unit, the switching transistor Q... 11 Q 41 Variable frequency control is adopted, with complementary conduction. The duty cycle of the control drive signal is slightly less than 50%, and the switching transistor Q... 21 Q 31 Variable frequency control is adopted, with complementary conduction. The duty cycle of the control drive signal is slightly less than 50%, and the switching transistor Q... 12 Q 22 Q 32 Q 42 Constant conduction;

[0089] When a positive voltage is output, the switching transistor Q... 51 Q 61 On, the switching transistor Q 52 Q 62 Constant off, using the switching diode D 52 D 62 It constitutes the positive voltage output of the rectifier circuit;

[0090] When the output voltage is negative, the switching transistor Q... 52 Q 62 On, the switching transistor Q 51 Q 61 Constant off, using the switching diode D 51 D 61 It constitutes the negative polarity voltage output by the rectifier circuit;

[0091] Furthermore, such as Figure 3 As shown, when power flows from the low-voltage side to the high-voltage side (i.e., power flows in reverse), in the first circuit unit, when the input is positive, the switching transistor Q... 51 Q 61 As a push-pull resonant switch, it employs frequency conversion control and complementary conduction. The duty cycle of the control drive signal is slightly less than 50%, and the switching transistor Q... 52 Q 62 Constant conduction; when the input is negative, the switching transistor Q...52 Q 62 As a push-pull resonant switch, it employs frequency conversion control and complementary conduction. The duty cycle of the control drive signal is slightly less than 50%, and the switching transistor Q... 51 Q 61 Constant conduction;

[0092] When a positive voltage is output, the switching transistor Q... 12 Q 42 On, the switching transistor Q 11 Q 21 Q 22 Q 31 Q 32 Q 41 Constant off, using the switching diode D 11 D 41 It constitutes the positive voltage output of the rectifier circuit;

[0093] When the output voltage is negative, the switching transistor Q... 21 Q 31 On, the switching transistor Q 11 Q 12 Q 22 Q 32 Q 41 Q 42 Constant off, using the switching diode D 22 D 32 It constitutes the negative polarity voltage output by the rectifier circuit;

[0094] Furthermore, such as Figure 4 As shown, the converter is modeled using the fundamental frequency analysis method to obtain an equivalent simplified model. The voltage U at the midpoint of the first circuit unit is then analyzed. CD Fourier decomposition yields:

[0095]

[0096] In the formula, ω is the phase angular frequency.

[0097] Points C and D in the first circuit unit are defined as follows: In a half-bridge, point C is the source of the upper bridge switch or the drain of the lower bridge switch, and point D is the source of the lower bridge switch; in a full-bridge, point C is the source of the upper bridge switch or the drain of the lower bridge switch in the left bridge arm, and point D is the source of the upper bridge switch or the drain of the lower bridge switch in the right bridge arm. CD The fundamental effective value is:

[0098]

[0099] Considering the transformer turns ratio, the midpoint voltage U of the second circuit unit EF The effective values ​​of the fundamental components can be written as:

[0100]

[0101] Points E and F in the second circuit unit are defined as follows: In a half-bridge, point E is the source of the upper bridge switch or the drain of the lower bridge switch, and point F is the source of the lower bridge switch; in a full-bridge, point E is the source of the upper bridge switch or the drain of the lower bridge switch in the left bridge arm, and point F is the source of the upper bridge switch or the drain of the lower bridge switch in the right bridge arm. When power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), the output equivalent resistance is:

[0102]

[0103] In the formula, R e U is the output equivalent resistance when power flows in the forward direction. EF-rms U is the effective value of the equivalent voltage between points E and F in the second circuit unit, P is the total transmitted power, and U is the effective value of the equivalent voltage between points E and F in the second circuit unit. o For the output voltage, R o Let n be the load resistance and n be the turns ratio of the high-frequency transformer T1.

[0104] The voltage division relationship between the output and input impedances is as follows:

[0105]

[0106] The voltage conversion gain is:

[0107]

[0108]

[0109]

[0110]

[0111]

[0112] In the formula, is the voltage conversion gain, U in Where k is the input voltage and k is the magnetizing inductance value L' m With resonant inductance value L' r The ratio, f n For the switching frequency f s With resonant frequency f r The ratio, C′ r Where is the resonant capacitance value, and Q is the quality factor when power flows in the forward direction.

[0113] When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the output equivalent resistance is:

[0114]

[0115] In the formula, R′ e U is the output equivalent resistance when power flows in the reverse direction. CD-rms It is the effective value of the equivalent voltage between points C and D in the first circuit unit.

[0116] The gain of the electro-conversion system for reverse power flow is:

[0117]

[0118]

[0119] In the formula, M′ is the voltage conversion gain when power flows in reverse, and Q′ is the quality factor when power flows in reverse.

[0120] As a preferred embodiment, such as Figure 5a As shown, a first circuit unit structure for another application of the present invention is illustrated. The first circuit unit includes a filter capacitor C1, an inverter half-bridge, and a resonant cavity. The inverter half-bridge includes series-connected switching transistors Q1 and Q2, and the resonant cavity is formed by series-connected capacitor C1. r L r L m Composition, C r For the resonant network, series capacitor L r For the resonant network series inductor, L m For example, the magnetizing inductance of T1; Figure 5b As shown, the switching transistors Q1 and Q2 in the inverter half-bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0121] As a preferred embodiment, such as Figure 6a As shown, a first circuit unit structure for another application of the present invention is illustrated. The first circuit unit includes a filter capacitor C1 and an inverter full-bridge. The inverter full-bridge includes a first inverter half-bridge and a second inverter half-bridge connected in parallel. The first inverter half-bridge includes series-connected switches Q1 and Q2, and the second inverter half-bridge includes series-connected switches Q3 and Q4. Figure 6b As shown, the switching transistors Q1, Q2, Q3, and Q4 in the inverter full-bridge can be replaced with bidirectional switches Q1, Q2, Q3, and Q4, respectively. 11 and Q 12 Q 21 and Q 22 Q 31 and Q 32 Q 41 and Q 42The bidirectional switch is composed of two switching transistors connected in reverse series.

[0122] As a preferred embodiment, such as Figure 7a As shown, a first circuit unit structure for another application of the present invention is illustrated. The first circuit unit includes a push-pull half-bridge composed of a filter capacitor C1, switching transistors Q1 and Q2. Switch Q1 is the upper transistor of the push-pull half-bridge, and switching transistor Q2 is the lower transistor. The filter capacitor C1 is connected to the center tap of the primary side of the high-frequency transformer T1 and the lower transistor of the push-pull half-bridge. Figure 7b As shown, the switching transistors Q1 and Q2 in the push-pull half-bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0123] As a preferred embodiment, such as Figure 8a As shown, a first circuit unit structure for another application of the present invention is illustrated. The first circuit unit includes an inverter full-bridge, which comprises a first inverter half-bridge and a second inverter half-bridge connected in parallel. The first inverter half-bridge includes switching transistors Q1 and Q2 connected in series. The second inverter half-bridge includes a capacitor C connected in series. Q1 Capacitor C Q2 ;like Figure 8b As shown, the switching transistors Q1 and Q2 in the inverter full-bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0124] As a preferred embodiment, such as Figure 9a As shown, a first circuit unit structure for another application of the present invention is illustrated. The first circuit unit includes an inverter full-bridge and an inductor L1. The inverter full-bridge includes a first inverter half-bridge and a second inverter half-bridge connected in parallel. The first inverter half-bridge includes switching transistors Q1 and Q2 connected in series. The second inverter half-bridge includes a capacitor C connected in series. Q1 Capacitor C Q2 The inductor L1 is connected to the midpoint of the second inverter half-bridge arm; as shown... Figure 9b As shown, the switching transistors Q1 and Q2 in the inverter full-bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0125] As a preferred embodiment, such as Figure 10a As shown, a second circuit unit structure for another application of the present invention is illustrated. The second circuit unit includes a filter capacitor C2, a rectifier half-bridge, and a magnetizing inductor L. m The resonant cavity and rectifier half-bridge consist of series-connected switching transistors Q5 and Q6, and the resonant cavity consists of series-connected C... r L r Composition, C r For the resonant network, series capacitor L r For a resonant network, series inductor; such as Figure 10b As shown, the switching transistors Q5 and Q6 in the rectifier half-bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0126] As a preferred embodiment, such as Figure 11a As shown, a second circuit unit structure for another application of the present invention is illustrated. The second circuit unit includes a filter capacitor C2, a rectifier bridge, and a resonant cavity. The rectifier bridge includes a first rectifier half-bridge and a second rectifier half-bridge connected in parallel. The first rectifier half-bridge includes series-connected switches Q5 and Q6, and the second rectifier half-bridge includes series-connected switches Q7 and Q8. The resonant cavity is formed by a filter capacitor C2 connected in series. r L r Composition, C r For the resonant network, series capacitor L r For a resonant network, series inductor; such as Figure 11b As shown, the switching transistors Q5, Q6, Q7, and Q8 in the rectifier bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 51 and Q 52 Q 61 and Q 62 Q 71 and Q 72 Q 81 and Q 82 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0127] As a preferred embodiment, such as Figure 12a As shown, a second circuit unit structure for another application of the present invention is illustrated. The second circuit unit includes a filter capacitor C2 and a rectifier bridge. The rectifier bridge includes a first rectifier half-bridge and a second rectifier half-bridge connected in parallel. The first rectifier half-bridge includes switches Q5 and Q6 connected in series, and the second rectifier half-bridge includes switches Q7 and Q8 connected in series. Figure 12bAs shown, the switching transistors Q5, Q6, Q7, and Q8 in the rectifier bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 51 and Q 52 Q 61 and Q 62 Q 71 and Q 72 Q 81 and Q 82 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0128] As a preferred embodiment, such as Figure 13a As shown, a second circuit unit structure for another application of the present invention is illustrated. This second circuit unit includes a push-pull half-bridge composed of a filter capacitor C2, switching transistors Q5 and Q6. Switch Q5 is the upper transistor of the push-pull half-bridge, and switching transistor Q6 is the lower transistor. The filter capacitor C2 is connected to the center tap of the secondary side of the high-frequency transformer T1 and the lower transistor of the push-pull half-bridge. Figure 13b As shown, the switching transistors Q5 and Q6 in the push-pull half-bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0129] As a preferred embodiment, such as Figure 14a As shown, a second circuit unit structure for another application of the present invention is illustrated. The second circuit unit includes a full-bridge rectifier, comprising a first half-bridge and a second half-bridge connected in parallel. The first half-bridge includes switching transistors Q5 and Q6 connected in series. The second half-bridge includes a capacitor C connected in series. Q5 Capacitor C Q6 ;like Figure 14b As shown, the switching transistors Q5 and Q6 in the rectifier bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0130] As a preferred embodiment, such as Figure 15a As shown, a second circuit unit structure for another application of the present invention is illustrated. The second circuit unit includes a rectifier bridge and an inductor L. The rectifier bridge includes a first rectifier half-bridge and a second rectifier half-bridge connected in parallel. The first rectifier half-bridge includes a switch Q5 and a switch Q6 connected in series. The second rectifier half-bridge includes a capacitor C connected in series. Q5 Capacitor C Q6The inductor L2 is connected to a node in the second rectifier half-bridge; as shown... Figure 15b As shown, the switching transistors Q5 and Q6 in the rectifier bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series.

[0131] The embodiments and descriptions above are merely illustrative of the principles and preferred embodiments of the present invention. Various changes and modifications may be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A bidirectional bipolar input / output DC-DC converter topology, characterized in that: The structure is an asymmetric structure centered on a high-frequency transformer T1 with a center tap, comprising a first circuit unit, a high-frequency transformer T1, and a second circuit unit connected in sequence; the first circuit unit is connected to the high-turns end of the high-frequency transformer T1 and adopts a half-bridge or full-bridge structure, and the second circuit unit is connected to the low-turns end of the high-frequency transformer T1 and adopts a half-bridge or full-bridge structure. At least one of the first and second circuit units adopts a bidirectional switching structure with two switching transistors connected in reverse series to realize bipolar voltage conversion and bidirectional power flow. Specifically, when power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), it can convert the positive or negative voltage on the high-voltage side to the positive or negative voltage on the low-voltage side; when power flows from the low-voltage side to the high-voltage side (i.e., power flows in the reverse direction), it can convert the positive or negative voltage on the low-voltage side to the positive or negative voltage on the high-voltage side. The first circuit unit is one of the following six structures: In structure one, the first circuit unit includes a filter capacitor C1, an inverter half-bridge, and a resonant cavity. The inverter half-bridge includes series-connected switching transistors Q1 and Q2, and the resonant cavity is composed of series-connected capacitors C1 and Q2. r L r L m Composition, C r For the resonant network, series capacitor L r For the resonant network series inductor, L m The magnetizing inductance of the high-frequency transformer T1; the switching transistors Q1 and Q2 in the inverter half-bridge can be replaced by bidirectional switches Q1 and Q2 respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series. In structure two, the first circuit unit includes a filter capacitor C1, an inverter full-bridge, and a resonant cavity. The inverter full-bridge includes a first inverter half-bridge and a second inverter half-bridge connected in parallel. The first inverter half-bridge includes series-connected switches Q1 and Q2, and the second inverter half-bridge includes series-connected switches Q3 and Q4. The resonant cavity is formed by a series-connected capacitor C1. r L r L m Composition, C r For the resonant network, series capacitor L r For the resonant network series inductor, L m The magnetizing inductance of the high-frequency transformer T1; the switching transistors Q1, Q2, Q3, and Q4 in the inverter half-bridge can be replaced with bidirectional switches Q1, Q2, Q3, and Q4 respectively. 11 and Q 12 Q 21 and Q 22 Q 31 and Q 32 Q 41 and Q 42 The bidirectional switch is composed of two switching transistors connected in reverse series. In structure three, the first circuit unit includes a filter capacitor C1 and an inverter full bridge. The inverter full bridge includes a first inverter half bridge and a second inverter half bridge connected in parallel. The first inverter half bridge includes switches Q1 and Q2 connected in series, and the second inverter half bridge includes switches Q3 and Q4 connected in series. The switches Q1, Q2, Q3, and Q4 in the inverter full bridge can be replaced with bidirectional switches Q1, Q2, Q3, and Q4, respectively. 11 and Q 12 Q 21 and Q 22 Q 31 and Q 32 Q 41 and Q 42 The bidirectional switch is composed of two switching transistors connected in reverse series. In structure four, the first circuit unit includes a push-pull half-bridge composed of a filter capacitor C1 and switching transistors Q1 and Q2. Switch Q1 is the upper transistor of the push-pull half-bridge, and switching transistor Q2 is the lower transistor. The filter capacitor C1 is connected to the center tap of the primary side of the high-frequency transformer T1 and the lower transistor of the push-pull half-bridge. Switches Q1 and Q2 in the push-pull half-bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series. In structure five, the first circuit unit includes an inverter full-bridge, which comprises a first inverter half-bridge and a second inverter half-bridge connected in parallel. The first inverter half-bridge includes a series-connected switch Q1 and a series-connected switch Q2; the second inverter half-bridge includes a series-connected capacitor C. Q1 and capacitor C Q2 The switching transistors Q1 and Q2 in the inverter full-bridge can be replaced with bidirectional switches Q1 and Q2, respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series. In structure six, the first circuit unit includes an inverter full-bridge and an inductor L1. The inverter full-bridge includes a first inverter half-bridge and a second inverter half-bridge connected in parallel. The first inverter half-bridge includes a switch Q1 and a switch Q2 connected in series. The second inverter half-bridge includes a capacitor C connected in series. Q1 and capacitor C Q2 The inductor L1 is connected to the midpoint of the second inverter half-bridge arm; the switching transistors Q1 and Q2 in the inverter full-bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 11 and Q 12 Q 21 and Q 22 The bidirectional switch is composed of two switching transistors connected in reverse series.

2. The bidirectional bipolar input / output DC-DC converter topology according to claim 1, characterized in that: The second circuit unit is one of the following six structures: In structure one, the second circuit unit includes a filter capacitor C2, a rectifier half-bridge, and a resonant cavity. The rectifier half-bridge includes series-connected switching transistors Q5 and Q6, and the resonant cavity is composed of series-connected C... r L r Composition, C r For the resonant network, series capacitor L r The resonant network is connected in series with an inductor; the switching transistors Q5 and Q6 in the rectifier half-bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series. In structure two, the second circuit unit includes a filter capacitor C2, a rectifier bridge, and a resonant cavity. The rectifier bridge includes a first rectifier half-bridge and a second rectifier half-bridge connected in parallel. The first rectifier half-bridge includes switches Q5 and Q6 connected in series, and the second rectifier half-bridge includes switches Q7 and Q8 connected in series. The resonant cavity is formed by a filter capacitor C2 connected in series. r L r Composition, C r For the resonant network, series capacitor L r The resonant network is connected in series with an inductor; the switching transistors Q5, Q6, Q7, and Q8 in the rectifier bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 51 and Q 52 Q 61 and Q 62 Q 71 and Q 72 Q 81 and Q 82 The bidirectional switch is composed of two switching transistors connected in reverse series. In structure three, the second circuit unit includes a filter capacitor C2 and a rectifier full bridge. The rectifier full bridge includes a first rectifier half bridge and a second rectifier half bridge connected in parallel. The first rectifier half bridge includes switches Q5 and Q6 connected in series, and the second rectifier half bridge includes switches Q7 and Q8 connected in series. The switches Q5, Q6, Q7, and Q8 in the rectifier full bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 51 and Q 52 Q 61 and Q 62 Q 71 and Q 72 Q 81 and Q 82 The bidirectional switch is composed of two switching transistors connected in reverse series. In structure four, the second circuit unit includes a push-pull half-bridge composed of a filter capacitor C2 and switching transistors Q5 and Q6. Switch Q5 is the upper transistor of the push-pull half-bridge, and switching transistor Q6 is the lower transistor. The filter capacitor C2 is connected to the center tap of the secondary side of the high-frequency transformer T1 and the lower transistor of the push-pull half-bridge. Switches Q5 and Q6 in the push-pull half-bridge can be replaced with bidirectional switches Q6. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series. In structure five, the second circuit unit includes a full-bridge rectifier, which comprises a first half-bridge and a second half-bridge connected in parallel. The first half-bridge includes a series-connected switch Q5 and a series-connected switch Q6; the second half-bridge includes a series-connected capacitor C. Q5 and capacitor C Q6 The switching transistors Q5 and Q6 in the rectifier bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series. In structure six, the second circuit unit includes a rectifier full-bridge and an inductor L2. The rectifier full-bridge includes a first rectifier half-bridge and a second rectifier half-bridge connected in parallel. The first rectifier half-bridge includes a switch Q5 and a switch Q6 connected in series. The second rectifier half-bridge includes a capacitor C connected in series. Q5 and capacitor C Q6 The inductor L2 is connected to a node in the second rectifier half-bridge; the switches Q5 and Q6 in the rectifier full-bridge can be replaced with bidirectional switches Q1 and Q2 respectively. 51 and Q 52 Q 61 and Q 62 The bidirectional switch is composed of two switching transistors connected in reverse series.

3. The bidirectional bipolar input / output DC-DC converter topology according to claim 1, characterized in that: The converter is modeled using the fundamental wave analysis method to obtain an equivalent simplified model; Points E and F in the second circuit unit are defined as follows: In a half-bridge, point E is the source of the upper bridge switch or the drain of the lower bridge switch, and point F is the source of the lower bridge switch; in a full-bridge, point E is the source of the upper bridge switch or the drain of the lower bridge switch in the left bridge arm, and point F is the source of the upper bridge switch or the drain of the lower bridge switch in the right bridge arm. When power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), the output equivalent resistance is: ； In the formula, This is the output equivalent resistance when power flows in the forward direction. This represents the effective value of the equivalent voltage between points E and F in the second circuit unit. To transmit total power, For output voltage, For load resistance, This refers to the turns ratio of the high-frequency transformer T1; The voltage conversion gain is: ； ； ； ； ； In the formula, For voltage conversion gain, Input voltage, The value of the magnetizing inductance With resonant inductance value The ratio, Switching frequency With resonant frequency The ratio, This is the resonant capacitance value. This is the quality factor when power flows in the forward direction; Points C and D in the first circuit unit are defined as follows: In a half-bridge, point C is the source of the upper bridge switch or the drain of the lower bridge switch, and point D is the source of the lower bridge switch; in a full-bridge, point C is the source of the upper bridge switch or the drain of the lower bridge switch in the left bridge arm, and point D is the source of the upper bridge switch or the drain of the lower bridge switch in the right bridge arm. When power flows from the low-voltage side to the high-voltage side (i.e., power flows in reverse), the output equivalent resistance is: ； In the formula, This is the output equivalent resistance when power flows in the reverse direction. This is the effective value of the equivalent voltage between points C and D in the first circuit unit; The voltage conversion gain for reverse power flow is: ； ； In the formula, This represents the voltage conversion gain when power flows in the reverse direction. This is the quality factor when power flows in reverse.

4. The bidirectional bipolar input / output DC-DC converter topology according to claim 1, characterized in that: When the first circuit unit is structure one, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), the switching transistor Q in the first circuit unit... 11 Q 21 As the resonant switching transistors are complementary to each other in conduction, the switching transistor Q... 12 Q 22 Turn off, C connected in series r L r L m Forming a resonant cavity; When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure. When a positive voltage is output, the switching transistor Q... 12 Q 11 On, the switching transistor Q 21 Q 22 Turn off; When the output voltage is negative, the switching transistor Q... 21 Q 22 On, the switching transistor Q 12 Q 11 Turn off.

5. The bidirectional bipolar input / output DC-DC converter topology according to claim 1, characterized in that: When the first circuit unit is structure two, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), the switching transistor Q in the first circuit unit... 11 Q 41 As the resonant switching transistors are complementary to each other in conduction, the switching transistor Q... 21 Q 31 As the resonant switching transistors are complementary to each other in conduction, the switching transistor Q... 12 Q 22 Q 32 Q 42 Turn off; When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure. When a positive voltage is output, the switching transistor Q... 12 Q 42 Complementary conduction, switching transistor Q 22 Q 32 Complementary conduction, switching transistor Q 11 Q 21 Q 31 Q 41 Constant off, using the switching diode D 11 D 21 D 31 D 41 It constitutes the positive voltage output of the rectifier circuit; When the output voltage is negative, the switching transistor Q... 11 Q 41 Complementary conduction, switching transistor Q 21 Q 31 Complementary conduction, switching transistor Q 12 Q 22 Q 32 Q 42 Constant off, using the switching diode D 12 D 22 D 32 D 42 It forms the rectifier circuit and outputs a negative voltage.

6. The bidirectional bipolar input / output DC-DC converter topology according to claim 1, characterized in that: When the first circuit unit is structure three, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), the switching transistor Q in the first circuit unit... 11 Q 41 Complementary conduction, switching transistor Q 21 Q 31 Complementary conduction, switching transistor Q 12 Q 22 Q 32 Q 42 Turn off; When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in reverse, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure. When a positive voltage is output, the switching transistor Q... 12 Q 42 Complementary conduction, switching transistor Q 22 Q 32 Complementary conduction, switching transistor Q 11 Q 21 Q 31 Q 41 Constant off, using the switching diode D 11 D 21 D 31 D 41 It constitutes the positive voltage output of the rectifier circuit; When the output voltage is negative, the switching transistor Q... 11 Q 41 Complementary conduction, switching transistor Q 21 Q 31 Complementary conduction, switching transistor Q 12 Q 22 Q 32 Q 42 Constant off, using the switching diode D 12 D 22 D 32 D 42 It forms the rectifier circuit and outputs a negative voltage.

7. The bidirectional bipolar input / output DC-DC converter topology according to claim 1, characterized in that: When the first circuit unit is structure four, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), the switching transistor Q in the first circuit unit... 11 Q 21 On, the switching transistor Q 12 Q 22 As a complementary conduction of push-pull resonant switches; When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure. When a positive voltage is output, the switching transistor Q... 11 Q 21 On, the switching transistor Q 12 Q 22 Constant off, using the switching diode D 12 D 22 It constitutes the positive voltage output of the rectifier circuit; When the output voltage is negative, the switching transistor Q... 12 Q 22 On, the switching transistor Q 11 Q 21 Constant off, using the switching diode D 11 D 21 It forms the rectifier circuit and outputs a negative voltage.

8. The bidirectional bipolar input / output DC-DC converter topology according to claim 1, characterized in that: When the first circuit unit is structure five, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), the switching transistor Q in the first circuit unit... 11 Q 21 Complementary conduction, switching transistor Q 12 Q 22 Constantly off; When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure. When a positive voltage is output, the switching transistor Q... 12 Q 22 On, the switching transistor Q 11 Q 22 Constantly off; When the output voltage is negative, the switching transistor Q... 11 Q 21 On, the switching transistor Q 12 Q 22 Constantly off.

9. The bidirectional bipolar input / output DC-DC converter topology according to claim 1, characterized in that: When the first circuit unit is structure six, and power flows from the high-voltage side to the low-voltage side (i.e., power flows in the forward direction), the switching transistor Q in the first circuit unit... 11 Q 21 Complementary conduction, switching transistor Q 12 Q 22 Constantly off; When power flows from the low-voltage side to the high-voltage side, i.e., when power flows in the reverse direction, the first circuit unit achieves bipolar voltage output by controlling the bidirectional switching structure. When a positive voltage is output, the switching transistor Q... 12 Q 22 On, the switching transistor Q 11 Q 22 Constantly off; When the output voltage is negative, the switching transistor Q... 11 Q 21 On, the switching transistor Q 12 Q 22 Constantly off.

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