Magnetic integrated transformer and onboard three-port converter

Abstract

Disclosed in the present invention are a magnetic integrated transformer and an onboard three-port converter. The magnetic integrated transformer comprises a first magnetic core, a second magnetic core and a third magnetic core, wherein the first magnetic core is wound with a first winding and a second winding, the second magnetic core is wound with a third winding, a fourth winding and a fifth winding, and the third magnetic core is communicated with two sides of the magnetic integrated transformer; and the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core flow in the third magnetic core in opposite directions, and the magnetic flux in the third magnetic core is the sum of the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core. Compared with the prior art, the present invention relates to multiplexing the magnetic cores of the transformer, thereby reducing the number of required transformers and obviously reducing the size of a transformer magnetic part; additionally, by using the phase difference between voltages of the windings, the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core are mutually counteracted in the third magnetic core, so that the cross sectional area of the third magnetic core can be reduced, thereby further reducing the size of the magnetic integrated transformer.

Description

A magnetic integrated transformer and a vehicle-mounted three-port converter Technical Field

[0001] The present invention relates to a vehicle-mounted charger, in particular to a magnetic integrated transformer and a vehicle-mounted three-port converter. Background Art

[0002] The on-board charger and on-board DC converter are important components in new energy vehicles. Their functions are to charge the high-voltage battery and low-voltage battery in the new energy vehicle respectively, and when necessary, they also need to transmit the energy in the battery to the external load in the form of AC power.

[0003] On-board chargers typically utilize a cascaded high-voltage DC / DC converter with power factor correction (PFC). To ensure bidirectional energy flow, the AC / DC converter typically employs a totem-pole PFC converter and a three-phase voltage-source rectifier. The high-voltage DC / DC converter typically utilizes an LLC converter and a dual active bridge (DAB) converter. On-board DC converters typically utilize unidirectional DC / DC converters, primarily from the full-bridge converter family.

[0004] As shown in Figure 1, traditional onboard chargers and onboard DC / DC converters operate independently, resulting in significant size and cost disadvantages. Currently, integrated solutions for onboard chargers and onboard DC / DC converters, as shown in Figure 2, are gaining adoption in the automotive electronics industry. This integration significantly reduces cost and size by reusing components. In this integrated solution, the traditional high-voltage DC / DC converter and onboard DC converter are replaced with a bidirectional three-port DC / DC converter, responsible for transferring energy between the high-voltage battery (HV side) and the low-voltage battery (LV side).

[0005] Chinese patent document CN113949282A discloses a three-port on-board charger. This patent adds a bidirectional switch to the LV side to achieve power control, and employs a dual-inductor current-doubling rectifier circuit. This solution undoubtedly increases the complexity of the drive circuit, while the addition of dual inductors increases the system size. Consequently, the power density and cost of the entire device are difficult to manage.

[0006] Chinese patent document CN116191889A discloses an isolated, integrated, three-port, bidirectional DC-DC converter. This patent uses two transformers to decouple the magnetic circuits for high-voltage and low-voltage battery charging, enabling separate control of each charging process and improving control flexibility. Furthermore, all MOS transistors operate in zero voltage switching (ZVS), significantly improving system efficiency. This solution requires two high-frequency transformers, increasing system size and cost. To control system size, the switching frequency needs to be increased, but this undoubtedly increases switching losses, necessitating a design compromise. Therefore, this solution requires further optimization.

[0007] Chinese patent document CN110649813B discloses an isolated, integrated, three-port, bidirectional DC-DC converter. This patent utilizes a single integrated transformer to enable energy transfer between any two ports, offering exceptionally high control flexibility. However, this solution requires a large number of fully controlled components, which increases switching losses and the number of driver circuits required. This, to a certain extent, limits the converter's cost and efficiency optimization.

[0008] Therefore, how to design a magnetically integrated on-board three-port converter that can achieve higher overall efficiency while controlling the transformer volume is a technical problem that the industry urgently needs to solve. Summary of the Invention

[0009] In view of the problem in the prior art that the power density and cost of an on-board charger cannot be well controlled, the present invention proposes a magnetic integrated transformer and an on-board three-port converter.

[0010] The technical solution of the present invention is to propose a magnetic integrated transformer, comprising a first magnetic core, a second magnetic core, and a third magnetic core;

[0011] The first magnetic core is wound with a first winding and a second winding, the second magnetic core is wound with a third winding, a fourth winding, and a fifth winding, and the third magnetic core is connected to both sides of the integrated transformer;

[0012] The magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core flow in opposite directions in the third magnetic core, and the magnetic flux in the third magnetic core is the sum of the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core.

[0013] The present invention also provides an on-vehicle three-port converter using the above-mentioned integrated transformer, comprising a primary circuit connected to the first winding, a first secondary circuit connected to the second winding and the third winding, and a second secondary circuit connected to the fourth winding and the fifth winding;

[0014] The primary circuit adopts a bridge circuit and has a first bridge arm and a second bridge arm;

[0015] The first secondary circuit adopts a three-phase full-bridge circuit and has a third bridge arm, a fourth bridge arm, and a fifth bridge arm;

[0016] The second secondary circuit adopts a power switch circuit and has at least a first power switch group and a second power switch group.

[0017] Furthermore, the same-name end of the first winding is connected in series with a resonant inductor and then connected to the midpoint of the first bridge arm or the second bridge arm;

[0018] The same-name end of the second winding is connected to the midpoint of the third bridge arm;

[0019] The same-name end of the third winding is connected in series to the opposite-name end of the second winding, and a DC blocking capacitor is connected to the series connection point of the second winding and the third winding, and the other end of the DC blocking capacitor is connected to the midpoint of the fourth bridge arm;

[0020] The same-name end of the fourth winding is connected to the drain of the power switch in the second power switch group, and the opposite-name end of the fifth winding is connected to the drain of the power switch in the first power switch group;

[0021] The like-name end of the fifth winding is connected in series to the unlike-name end of the fourth winding, and a filtering inductor is connected to the series connection point between the fourth winding and the fifth winding.

[0022] Furthermore, the first bridge arm, the second bridge arm, the third bridge arm, and the fourth bridge arm operate in a DAB mode, and when the primary circuit transmits energy to the first secondary circuit, the energy transmission is adjusted by lagging the phase angle of the upper arm switch of the third bridge arm behind the phase angle of the upper arm switch of the first bridge arm;

[0023] When the first secondary circuit transmits energy to the primary circuit, the energy transmission is adjusted by a phase angle in which the upper arm switch of the first bridge arm lags behind the upper arm switch of the third bridge arm.

[0024] Furthermore, the fourth bridge arm and the fifth bridge arm operate in a phase-shifted full-bridge mode, and when the first secondary circuit transmits energy to the second secondary circuit, the energy transmission is adjusted by the phase angle of the lower arm switch of the fifth bridge arm lagging behind the upper arm switch of the fourth bridge arm.

[0025] Furthermore, the first power switch group includes a power switch tube S11 and a power switch tube S13, and the second power switch group includes a power switch tube S12 and a power switch tube S14;

[0026] The power switch tube S11 and the power switch tube S12 operate in a synchronous rectification mode, and the power switch tube S11 is turned on when the upper arm switch of the fourth bridge arm or the lower arm switch of the fifth bridge arm is turned on;

[0027] The power switch tube S12 is turned on when the lower arm switch of the fourth bridge arm or the upper arm switch of the fifth bridge arm is turned on;

[0028] The power switch tube S13 and the power switch tube S11 are complementary to each other and the power switch tube S14 and the power switch tube S12 are complementary to each other.

[0029] Furthermore, the fourth bridge arm and the fifth bridge arm operate in a phase-shifted full-bridge mode, and the voltage of the third winding lags behind the voltage of the second winding, and the voltages of the fourth winding and the fifth winding lag behind the voltage of the second winding.

[0030] Furthermore, the upper arm switch of the first bridge arm and the lower arm switch of the second bridge arm have the same first driving signal;

[0031] The lower arm switch of the first bridge arm and the upper arm switch of the second bridge arm have the same second driving signal;

[0032] The duty cycles of the first drive signal and the second drive signal are both 0.5, and the states of the first drive signal and the second drive signal are complementary.

[0033] Furthermore, the upper arm switch of the third bridge arm and the lower arm switch of the fourth bridge arm have the same third driving signal;

[0034] The lower arm switch of the third bridge arm and the upper arm switch of the fourth bridge arm have the same fourth driving signal;

[0035] The duty cycles of the third driving signal and the fourth driving signal are both 0.5, and the states of the third driving signal and the fourth driving signal are complementary.

[0036] Further, the upper arm switch of the fifth bridge arm has a fifth driving signal, and the lower arm switch of the fifth bridge arm has a sixth driving signal;

[0037] The duty cycles of the fifth driving signal and the sixth driving signal are both 0.5, and the states of the fifth driving signal and the sixth driving signal are complementary.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] 1. The present invention reuses the magnetic core of the transformer to reduce the number of required transformers and significantly reduce the volume of transformer magnetic parts;

[0040] 2. When winding the transformer, by designing the magnetic flux flow directions of the first and second magnetic cores, the two magnetic fluxes cancel each other out in the third magnetic core. That is, the peak magnetic flux in the third magnetic core is smaller than that in the first and second magnetic cores. Therefore, the iron core corresponding to the third magnetic core can be selected or designed with a smaller cross-sectional area to reduce the volume of the transformer magnetic components.

[0041] 3. The first and second bridge arms of port A and the third and fourth bridge arms of port B control the power transmission from port A to port B. The fourth and fifth bridge arms of port B can control the power transmission from port B to port C. Therefore, a DC blocking capacitor is preferably connected between the midpoint of the fourth bridge arm and the series connection point of the second winding and the third winding of the transformer. For power transmission between any of the three ports, the DC blocking capacitor will isolate the DC power in the transformer and prevent transformer saturation. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] FIG1 is a circuit block diagram of a conventional on-board charger and an on-board DC converter;

[0044] Figure 2 is a circuit block diagram of a traditional on-board charger and on-board DC converter integrated solution;

[0045] FIG3 is a schematic diagram of the winding of the magnetic integrated transformer in the present invention;

[0046] FIG4 is a circuit diagram of a magnetically integrated vehicle-mounted three-port converter according to the present invention;

[0047] 5 is a schematic diagram of the driving signal timing sequence and three-way magnetic flux of all fully controlled switch devices at port B when energy is transferred from port A to ports B and C of the magnetically integrated on-board three-port converter according to the present invention;

[0048] 6 is a timing diagram of drive signals of various fully controlled components of the magnetically integrated vehicle-mounted three-port converter of the present invention when port A is disconnected from port B and port C simultaneously transmits energy;

[0049] FIG7 is a timing diagram of drive signals of each fully controlled device when energy is transferred from port B to port A and port C simultaneously in the magnetically integrated vehicle-mounted three-port converter of the present invention. DETAILED DESCRIPTION

[0050] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0051] Thus, a feature indicated in this specification is intended to illustrate one of the features of one embodiment of the present invention, rather than to imply that every embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although certain features can be combined together to illustrate possible system designs, these features can also be used in other, not explicitly described, combinations. Thus, unless otherwise noted, the described combinations are not intended to be limiting.

[0052] The principle and structure of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0053] As shown in Figure 1, traditional onboard chargers and onboard DC / DC converters operate independently, resulting in significant size and cost disadvantages. Currently, integrated solutions combining an onboard charger and onboard DC / DC converter, as shown in Figure 2, are gaining adoption in the automotive electronics industry. This integration significantly reduces cost and size by reusing components. In this integrated solution, the traditional high-voltage DC / DC converter and onboard DC converter are replaced with a bidirectional three-port DC / DC converter, responsible for energy transfer between the high-voltage battery (HV side) and the low-voltage battery (LV side). However, current integrated solutions, such as those in patents CN113949282A, CN116191889A, and CN110649813B, lack effective control over the overall power density and cost.

[0054] The idea of ​​the present invention is to reuse the magnetic cores of the transformer, reduce the number of required transformers, significantly reduce the volume of the transformer magnetic parts, and at the same time make the first magnetic core and the second magnetic core cancel each other out in the third magnetic core, thereby reducing the cross-sectional volume of the third magnetic core and thus reducing the volume of the transformer.

[0055] Specifically, the magnetic integrated transformer proposed in the present invention includes a first magnetic core, a second magnetic core, and a third magnetic core;

[0056] The first magnetic core is wound with a first winding and a second winding, the second magnetic core is wound with a third winding, a fourth winding, and a fifth winding, and the third magnetic core is connected to both sides of the integrated transformer;

[0057] The magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core flow in opposite directions in the third magnetic core, and the magnetic flux in the third magnetic core is the sum of the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core.

[0058] Please refer to FIG3 , the winding W1 is also the first winding, the winding W2 is also the second winding, the winding W3 is also the third winding, the winding W4 is also the fourth winding, and the winding W5 is also the fifth winding;

[0059] Magnetic flux 1 is also the magnetic flux path in the first magnetic core, magnetic flux 2 is also the magnetic flux path in the second magnetic core, and magnetic flux 3 is also the magnetic flux path in the third magnetic core;

[0060] First, compared with the prior art in FIG1 , the present invention reuses the cores of two transformers, thereby reducing the number of required transformers and significantly reducing the volume of transformer magnetic components.

[0061] In addition, in the present invention, the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core flow in opposite directions in the third magnetic core, so that the two magnetic fluxes have the effect of canceling each other out in the third magnetic core, that is, the peak value of the magnetic flux in the third magnetic core is smaller than the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core. Therefore, the third magnetic core can be selected or designed with a smaller cross-sectional area to reduce the volume of the transformer magnetic components.

[0062] Referring to FIG4 , the present invention proposes an on-vehicle three-port converter using the aforementioned magnetic integrated transformer, comprising a primary circuit connected to the first winding, a first secondary circuit connected to the second and third windings, and a second secondary circuit connected to the fourth and fifth windings.

[0063] The primary circuit adopts a bridge circuit and has a first bridge arm and a second bridge arm;

[0064] Here, the switch tube S1 and the switch tube S2 form the first bridge arm, and the switch tube S1 is the upper arm switch, and the switch tube S2 is the lower arm switch;

[0065] The switch tube S3 and the switch tube S4 form the second bridge arm, and the switch tube S3 is the upper arm switch, and the switch tube S4 is the lower arm switch;

[0066] Here, the primary circuit is connected to the A port for obtaining the bus voltage BUS, which can convert direct current into alternating current and transmit it to the first winding of the transformer.

[0067] The first secondary circuit adopts a three-phase full-bridge circuit and has a third bridge arm, a fourth bridge arm, and a fifth bridge arm;

[0068] The switch tube S5 and the switch tube S6 form the third bridge arm, and the switch tube S5 is the upper arm switch, and the switch tube S6 is the lower arm switch;

[0069] The switch tube S7 and the switch tube S8 form a fourth bridge arm, wherein the switch tube S7 is an upper arm switch and the switch tube S8 is a lower arm switch;

[0070] The switch tube S9 and the switch tube S10 form a fifth bridge arm, wherein the switch tube S9 is an upper arm switch and the switch tube S10 is a lower arm switch.

[0071] Here, the first secondary circuit is connected to the B port, and can obtain the direct current generated by the transformer through the second winding and the third winding, and convert it into alternating current to output a high-voltage signal from the B port.

[0072] The second secondary circuit adopts a power switch circuit and has at least a first power switch group and a second power switch group.

[0073] The switch tube S11 and the switch tube S13 form a first power switch group, and the switch tube S12 and the switch tube S14 form a second power switch group.

[0074] Here, the second secondary circuit is connected to the C port, and can obtain the AC power generated by the transformer through the fourth winding and the fifth winding, and convert it into DC power to output a low-voltage signal from the C port.

[0075] In order to achieve the effect of the first magnetic core and the second magnetic core canceling each other out, the present invention is provided with:

[0076] The same-name end of the first winding is connected in series with a resonant inductor and then connected to the midpoint of the first bridge arm (or the midpoint of the second bridge arm. The two connection methods can achieve the same control effect, and the only difference is the specific control timing).

[0077] The same-name end of the second winding is connected to the midpoint of the third bridge arm;

[0078] The same-name end of the third winding is connected in series to the opposite-name end of the second winding, and a DC blocking capacitor is connected to the series connection point of the second winding and the third winding, and the other end of the DC blocking capacitor is connected to the midpoint of the fourth bridge arm;

[0079] The same-name end of the fourth winding is connected to the drain of the power switch in the second power switch group, and the opposite-name end of the fifth winding is connected to the drain of the power switch in the first power switch group;

[0080] The like-name end of the fifth winding is connected in series to the unlike-name end of the fourth winding, and a filtering inductor is connected to the series connection point between the fourth winding and the fifth winding.

[0081] In the present invention, the above-mentioned winding setting can ensure that when current flows into the same-name ends of each winding of the integrated transformer, the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core flow in opposite directions in the third magnetic core, and the magnetic flux in the third magnetic core is the sum of the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core. Combined with the subsequent control of the switching tube, the magnetic fluxes in the third magnetic core can offset each other, so that the magnetic flux peak of the third magnetic core is smaller than that of the first magnetic core and the second magnetic core, so that the third magnetic core can be selected or designed with a smaller effective cross-sectional area to reduce the volume of the transformer magnetic parts.

[0082] At the same time, in the present invention, a DC blocking capacitor (capacitor Cb in FIG4 ) is connected to the series connection point of the second winding and the third winding. For power transmission between any of the three ports, the DC blocking capacitor will isolate the DC amount in the transformer, thereby preventing transformer saturation.

[0083] Furthermore, in the present invention, by controlling the fourth bridge arm and the fifth bridge arm, the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core flow in opposite directions in the third magnetic core, thereby achieving a mutual cancellation effect. The specific design is as follows:

[0084] The fourth bridge arm and the fifth bridge arm operate in a phase-shifted full-bridge mode, and when the first secondary circuit transmits energy to the second secondary circuit, the energy transmission is adjusted by a phase angle at which the lower arm switch of the fifth bridge arm lags behind the upper arm switch of the fourth bridge arm.

[0085] With this design, the voltage of the third winding can lag behind the voltage of the second winding, and the voltages of the fourth and fifth windings can lag behind the voltage of the second winding.

[0086] The phase difference between the voltages of the fourth and fifth windings and the voltage of the second winding is 180 degrees.

[0087] Please refer to Figure 5. When the phase difference is 180 degrees, the magnetic flux in the third magnetic core is the smallest. Therefore, the present invention controls the phase difference between the voltage of the fourth winding and the fifth winding and the voltage of the second winding to be 180 degrees, thereby achieving the purpose of reducing the effective cross-sectional area of ​​the third magnetic core.

[0088] Please refer to Figures 5 to 7, the overall working principle of the present invention is:

[0089] 1. The upper arm switch of the first bridge arm and the lower arm switch of the second bridge arm have the same first drive signal;

[0090] The lower arm switch of the first bridge arm and the upper arm switch of the second bridge arm have the same second driving signal;

[0091] The duty cycles of the first driving signal and the second driving signal are both 0.5, and the states of the first driving signal and the second driving signal are complementary.

[0092] As shown in Figure 6, switches S1 and S4 share the same drive signal, while switches S2 and S3 share the same drive signal. Both drive signals have a duty cycle of 0.5, meaning they conduct 180 degrees and are complementary. It's important to note that a dead time should be added between these two drive signals to prevent the input source from short-circuiting due to both upper and lower transistors in the same bridge arm conducting.

[0093] 2. The upper arm switch of the third bridge arm and the lower arm switch of the fourth bridge arm have the same third driving signal;

[0094] The lower arm switch of the third bridge arm and the upper arm switch of the fourth bridge arm have the same fourth driving signal;

[0095] The duty cycles of the third driving signal and the fourth driving signal are both 0.5, and the states of the third driving signal and the fourth driving signal are complementary.

[0096] As shown in Figure 6, switches S5 and S8 share the same drive signal, while switches S6 and S7 share the same drive signal. Both drive signals have a duty cycle of 0.5 and are complementary. It's important to note that a dead time should be added between these two drive signals to prevent a short circuit on the output side caused by both upper and lower transistors in the same bridge arm being turned on.

[0097] 3. The upper arm switch of the fifth bridge arm has a fifth drive signal, and the lower arm switch of the fifth bridge arm has a sixth drive signal;

[0098] The duty cycles of the fifth driving signal and the sixth driving signal are both 0.5, and the states of the fifth driving signal and the sixth driving signal are complementary.

[0099] As shown in Figures 6 and 7, the duty cycle of the drive signals for switch S9 and switch S10 is 0.5, meaning they are on for 180 degrees and complementary. It's worth noting that a dead time should be added between these two drive signals to prevent a short circuit on the output side caused by both upper and lower transistors in the same bridge arm being on.

[0100] 4. The first bridge arm, the second bridge arm, the third bridge arm, and the fourth bridge arm operate in a DAB mode, and when the primary circuit transmits energy to the first secondary circuit, the energy transmission is adjusted by lagging the phase angle of the upper arm switch of the third bridge arm behind the phase angle of the upper arm switch of the first bridge arm;

[0101] When the first secondary circuit transmits energy to the primary circuit, the energy transmission is adjusted by a phase angle in which the upper arm switch of the first bridge arm lags behind the upper arm switch of the third bridge arm.

[0102] As shown in Figure 6, the driving signal of switch tube S5 needs to lag behind switch tube S1 by a certain phase D1p. Adjusting D1p can adjust the energy transmission from port A to port B. As shown in Figure 7, when port B transmits energy to port A, the driving signal of switch tube S1 needs to lag behind switch tube S5 by a certain phase D1n. Adjusting D1n can adjust the energy transmission from port B to port A.

[0103] 5. The fourth bridge arm and the fifth bridge arm operate in a phase-shifted full-bridge mode, and when the first secondary circuit transmits energy to the second secondary circuit, the energy transmission is adjusted by a phase angle at which the lower arm switch of the fifth bridge arm lags behind the upper arm switch of the fourth bridge arm.

[0104] As shown in FIG6 and FIG7, when port B transmits energy to port C, the driving signal of switch tube S10 needs to lag behind switch tube S7 by a certain phase D2p. By adjusting D2p, the energy transmission from port B to port C can be adjusted.

[0105] 6. The first power switch group includes power switch tubes S11 and S13, and the second power switch group includes power switch tubes S12 and S14;

[0106] The power switch tube S11 and the power switch tube S12 operate in a synchronous rectification mode, and the power switch tube S11 is turned on when the upper arm switch of the fourth bridge arm or the lower arm switch of the fifth bridge arm is turned on;

[0107] The power switch tube S12 is turned on when the lower arm switch of the fourth bridge arm or the upper arm switch of the fifth bridge arm is turned on;

[0108] The power switch tube S13 and the power switch tube S11 are complementary to each other and the power switch tube S14 and the power switch tube S12 are complementary to each other.

[0109] As shown in Figures 6 and 7, the power switch tube S11 and the power switch tube S12 operate in a synchronous rectification mode. In this mode, the power switch tube S11 is turned on when the switch tube S7 or the switch tube S10 is turned on, the power switch tube S12 is turned on when the switch tube S8 or the switch tube S9 is turned on, and the power switch tube S13 and the power switch tube S14 are respectively turned on in complement to the power switch tube S11 and the power switch tube S12. The power switch tube S13 and the power switch tube S14 play the role of absorbing the shutdown energy and feeding back the power.

[0110] There are multiple control methods for forward energy transmission from port A to port B. The first bridge arm and the second bridge arm can operate in phase-shift control, frequency conversion control, or a combination of the two.

[0111] In summary, the main improvement of the present invention lies in adjusting the structure of the transformer and the winding of the coil, thereby achieving the effect of reducing the volume of the transformer, and at the same time designing a corresponding control method to ensure the control flexibility and high efficiency of the transformer.

[0112] Compared with the prior art, the present invention has at least the following beneficial effects:

[0113] 1. The present invention reuses the magnetic core of the transformer to reduce the number of required transformers and significantly reduce the volume of transformer magnetic parts;

[0114] 2. When winding the transformer, by designing the flow directions of the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core, the two magnetic fluxes cancel each other out in the third magnetic core. That is, the peak value of the magnetic flux in the third magnetic core is smaller than that in the first magnetic core and the second magnetic core. Therefore, the third magnetic core can be selected or designed with a smaller effective cross-sectional area to reduce the volume of the transformer magnetic components.

[0115] 3. The first and second bridge arms of port A and the third and fourth bridge arms of port B control the power transmission from port A to port B. The fourth and fifth bridge arms of port B can control the power transmission from port B to port C. Therefore, a DC blocking capacitor is preferably connected between the midpoint of the fourth bridge arm and the series connection point of the second winding and the third winding of the transformer. For power transmission between any of the three ports, the DC blocking capacitor will isolate the DC power in the transformer and prevent transformer saturation.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A magnetic integrated transformer, characterized in that, It includes a first magnetic core, a second magnetic core, and a third magnetic core; Among them, the first magnetic core is wound with a first winding and a second winding, the second magnetic core is wound with a third winding, a fourth winding, and a fifth winding, and the third magnetic core connects both sides of the magnetic integrated transformer; The magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core flow in opposite directions in the third magnetic core, and the magnetic flux in the third magnetic core is the sum of the magnetic flux in the first magnetic core and the magnetic flux in the second magnetic core.

2. A vehicle-mounted three-port converter having the magnetic integrated transformer as described in claim 1, characterized in that, It includes a primary circuit connected to the first winding, a first secondary circuit connected to the second winding and the third winding, and a second secondary circuit connected to the fourth winding and the fifth winding; The primary circuit adopts a bridge circuit and has a first bridge arm and a second bridge arm; The first secondary circuit adopts a three-phase full-bridge circuit and has a third bridge arm, a fourth bridge arm, and a fifth bridge arm; The second secondary circuit adopts a power switch circuit and has at least a first power switch group and a second power switch group.

3. The on-vehicle three-port converter according to claim 2, wherein The same-name end of the first winding is connected to the midpoint of the first bridge arm or the second bridge arm after being connected in series with a resonant inductor; The same-name end of the second winding is connected to the midpoint of the third bridge arm; The same-name end of the third winding is connected in series to the opposite-name end of the second winding, and a DC-blocking capacitor is connected at the series connection point of the second winding and the third winding, and the other end of the DC-blocking capacitor is connected to the midpoint of the fourth bridge arm; The same-name end of the fourth winding is connected to the drain of the power switch in the second power switch group, and the opposite-name end of the fifth winding is connected to the drain of the power switch in the first power switch group; The same-name end of the fifth winding is connected in series to the opposite-name end of the fourth winding, and a filter inductor is connected at the series connection point of the fourth winding and the fifth winding.

4. The on-vehicle three-port converter according to claim 3, characterized in that The first bridge arm, the second bridge arm, the third bridge arm, and the fourth bridge arm operate in the DAB mode, and when the primary circuit transfers energy to the first secondary circuit, the phase angle of the upper-arm switch of the third bridge arm lags behind that of the upper-arm switch of the first bridge arm to adjust the transferred energy; When the first secondary circuit transfers energy to the primary circuit, the phase angle of the upper-arm switch of the first bridge arm lags behind that of the upper-arm switch of the third bridge arm to adjust the transferred energy.

5. The on-vehicle three-port converter according to claim 3, characterized in that, The fourth bridge arm and the fifth bridge arm operate in the phase-shifted full-bridge mode, and when the first secondary circuit transfers energy to the second secondary circuit, the phase angle of the lower-arm switch of the fifth bridge arm lags behind that of the upper-arm switch of the fourth bridge arm to adjust the transferred energy.

6. The on-vehicle three-port converter according to claim 3, wherein The first power switch group has a power switch tube S11 and a power switch tube S13, and the second power switch group has a power switch tube S12 and a power switch tube S14; The power switch tube S11 and the power switch tube S12 operate in the synchronous rectification mode, and the power switch tube S11 conducts when the upper-arm switch of the fourth bridge arm or the lower-arm switch of the fifth bridge arm conducts; The power switch tube S12 conducts when the lower-arm switch of the fourth bridge arm or the upper-arm switch of the fifth bridge arm conducts; The power switch tube S13 and the power switch tube S11 conduct complementarily, and the power switch tube S14 and the power switch tube S12 conduct complementarily.

7. The on-vehicle three-port converter according to claim 5, characterized in that The fourth bridge arm and the fifth bridge arm operate in a phase-shifted full-bridge mode, and the voltage of the third winding lags behind the voltage of the second winding, and the voltages of the fourth winding and the fifth winding lag behind the voltage of the second winding.

8. The on-vehicle three-port converter according to claim 2, wherein The upper-arm switch of the first bridge arm and the lower-arm switch of the second bridge arm have the same first driving signal; The lower-arm switch of the first bridge arm and the upper-arm switch of the second bridge arm have the same second driving signal; And the duty cycles of the first driving signal and the second driving signal are both 0.5, and the states of the first driving signal and the second driving signal are complementary.

9. The on-vehicle three-port converter according to claim 2, wherein The upper-arm switch of the third bridge arm and the lower-arm switch of the fourth bridge arm have the same third driving signal; The lower-arm switch of the third bridge arm and the upper-arm switch of the fourth bridge arm have the same fourth driving signal; And the duty cycles of the third driving signal and the fourth driving signal are both 0.5, and the states of the third driving signal and the fourth driving signal are complementary.

10. The on-vehicle three-port converter according to claim 2, characterized in that, The upper-arm switch of the fifth bridge arm has a fifth driving signal, and the lower-arm switch of the fifth bridge arm has a sixth driving signal; And the duty cycles of the fifth driving signal and the sixth driving signal are both 0.5, and the states of the fifth driving signal and the sixth driving signal are complementary.

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