TWI895062B - Multiple-port bidirectional converter - Google Patents

Abstract

A multiple-port bidirectional converter is provided. The multiple-port bidirectional converter includes a transformer, a primary full-bridge converter, a first high voltage (HV) power converting unit, a second HV power converting unit, a first low voltage (LV) power converting unit, a second LV power converting unit, a full-bridge diode rectifier, and a full-bridge inverter. The transformer includes a core, one primary winding and five secondary windings. The primary full-bridge converter is coupled to the first primary winding and receives an input voltage. The first/second HV power converting unit, coupled to the first/second secondary winding, outputs a first/second high DC voltage to a first/second HV battery. The first/second LV power converting unit, coupled to the third/fourth secondary winding, outputs a first/second low DC voltage to a first/second LV battery. The full-bridge diode rectifier is coupled to the fifth secondary winding and the full-bridge diode rectifier to output an AC output voltage.

Description

Multi-port bidirectional converter

The present invention relates to a multi-port bidirectional converter.

International efforts to combat global warming have begun, driving the development of electric vehicles (EVs) to reduce fuel consumption. Combo onboard chargers have traditionally been used to charge EVs. However, this approach presents challenges such as increased size and cost. Furthermore, to ensure safe redundant operation, multiple converters and transformers are required to provide redundant outputs, which incurs additional cost and space. Therefore, finding ways to reduce the cost and size of onboard chargers has become crucial.

According to one aspect of the present invention, a multi-port bidirectional converter is provided, comprising a transformer, a primary full-bridge converter, a first high-voltage (HV) power conversion unit, a second high-voltage power conversion unit, a first low-voltage (LV) power conversion unit, a second low-voltage power conversion unit, a full-bridge diode rectifier, and a full-bridge inverter. The transformer includes a magnetic core, a first primary winding, a first secondary winding, a second secondary winding, a third secondary winding, a fourth secondary winding, and a fifth secondary winding. A primary full-bridge converter is coupled to the first primary winding and receives an input voltage from a primary direct current (DC) voltage source. A first high-voltage power conversion unit is coupled to the first secondary winding and outputs a first high DC voltage to a first high-voltage battery. A second high-voltage power conversion unit is coupled to the second secondary winding and outputs a second high DC voltage to a second high-voltage battery. The first low-voltage power conversion unit is coupled to the third secondary winding and outputs a first low-voltage direct current voltage to a first low-voltage battery. The second low-voltage power conversion unit is coupled to the fourth secondary winding and outputs a second low-voltage direct current voltage to a second low-voltage battery. The full-bridge diode rectifier is coupled to the fifth secondary winding. The full-bridge inverter is coupled to the full-bridge diode rectifier and outputs an alternating current (AC) output voltage to an AC load.

In order to better understand the above and other aspects of the present invention, the following embodiments are specifically described in detail with reference to the accompanying drawings:

100,300: Multi-port bidirectional converter

102,302: Transformer

104,204: Input power conversion unit

106,206: Load power conversion unit

108, 208, 308, 508: First high-voltage power conversion unit

110, 210, 310, 510: Second high-voltage power conversion unit

112, 212, 312, 512: First low-voltage power conversion unit

114,214,314,514: Second low-voltage power conversion unit

116,316: First high-voltage battery

118,318: Second Highest Voltage Battery

120,320: First low-voltage battery

122,322: Second low-voltage battery

124: Power

126: AC load

128,228: First microcontroller

130,230: Second microcontroller

132,232: Third microcontroller

204_1: Input relay

204_2: AC electromagnetic interference filter

204_3: Power Factor Correction Converter

204_4: Large capacitor

204_5: Basic LLC Circuit

206_1: V2L filter

206_2: Single-phase inverter

206_3, 208_1, 210_1, 212_1, 214_1: Secondary LLC circuit

208_2,210_2: High-pressure filter

212_2,214_2: Low-pressure filter

234: AC voltage

236: AC terminal

238:V2L terminal

240,242: High voltage terminals

244,246: Low voltage terminals

303: Primary Full-Bridge Converter

305: Full-bridge diode rectifier

307,507: Full-bridge inverter

308_1: First high-voltage full-bridge converter

308_2: First High-Voltage Bidirectional Buck-Boost Half-Bridge Converter

310_1: Second high-voltage full-bridge converter

310_2: Second High-Voltage Bidirectional Buck-Boost Half-Bridge Converter

312_1: First synchronous rectifier

312_2: The First Bidirectional Low-Voltage Buck-Boost Half-Bridge Converter

314_1: Second synchronous rectifier

314_2: Second Bidirectional Low-Voltage Buck-Boost Half-Bridge Converter

323: Primary DC voltage source

326: AC load

502: AC input circuit

504: T-type converter

532,534: High Voltage DC EMI Filter

536,538: Low Voltage DC EMI Filter

540:V2L EMI Filter

542: AC EMI Filter

544:V2L terminal

600: Magnetic core

602: First magnetic core column

604: Second magnetic core column

PW1: First Beginner Winding

PW2: Second Primary Winding

SW1: First secondary winding

SW2: Secondary Winding

SW3: Third secondary winding

SW4: Fourth secondary winding

SW5: Fifth secondary winding

F1~F6: Fuse

C1~C12: Capacitors

T1~T18: Switch

L1: Primary resonant inductor

Lhv1: First high-voltage buck/boost inductor

Lhv2: Second high voltage buck/boost inductor

Llv2: Second low voltage buck/boost inductor

Llv1: First low voltage buck/boost inductor

FIG1 shows a block diagram of a multiple-port bidirectional converter in an on-board power unit (OPU) of an electric vehicle (EV) according to an embodiment of the present disclosure.

FIG2 is a block diagram illustrating an example of a multi-port bidirectional converter in an onboard power unit of an electric vehicle according to an embodiment of the present disclosure.

Figure 3 shows a block diagram of a multi-port bidirectional converter used in an electric vehicle's onboard power unit.

FIG4 shows an example of a redundant mode of a multi-port bidirectional converter 300 used in an on-board power unit of an electric vehicle according to an embodiment of the present disclosure.

Figure 5 shows a block diagram of a multi-port bidirectional converter used in an on-board power unit of an electric vehicle according to another embodiment of the present disclosure.

FIG6A shows the magnetic core structure of a transformer in a multi-port bidirectional converter used in an on-board power unit of an electric vehicle according to another embodiment of the present disclosure.

Figure 6B shows an example of the first primary winding in a multi-port bidirectional converter.

Figure 6C shows an example of the first primary winding and the second primary winding in a multi-port bidirectional converter.

Please refer to Figure 1, which shows a block diagram of a multi-port bidirectional converter in an on-board power unit (OPU) of an electric vehicle (EV) according to one embodiment of the present disclosure. The OPU is responsible for managing the charging and discharging of the battery and providing power to various vehicle systems such as the motor and electronic devices. The multi-port bidirectional converter has multiple ports for connecting to multiple power sources and loads. These power sources can include, for example, the public power grid, photovoltaic panels, wind turbines, batteries, fuel cells, etc. As shown in FIG. 1 , a multi-port bidirectional converter 100 includes, for example, a transformer 102, an input power conversion unit 104, a load power conversion unit 106, a first high-voltage (HV) power conversion unit 108, a second high-voltage power conversion unit 110, a first low-voltage (LV) power conversion unit 112, and a second low-voltage power conversion unit 114. The first high-voltage power conversion unit 108 outputs a first high direct current (DC) voltage HVlt1 to a first high-voltage battery 116. The second high-voltage power conversion unit 110 outputs a second high DC voltage HVlt2 to a second high-voltage battery 118. The first low-voltage power conversion unit 112 outputs a first low-voltage direct current voltage LVlt1 to a first low-voltage battery 120. The second low-voltage power conversion unit 114 outputs a second low-voltage direct current voltage LVlt2 to a second low-voltage battery 122. The input power conversion unit 104 receives input power from a power source 124. The load power conversion unit 106 can output power to an alternating current (AC) load 126.

For example, power source 124 may be a utility grid. Multi-port bidirectional converter 100 may operate in a first operating mode. In the first operating mode, input power conversion unit 104 may transfer power to first high-voltage battery 116, second high-voltage battery 118, first low-voltage battery 120, second low-voltage battery 122, and AC load 126. Thus, in the first operating mode, first high-voltage battery 116 and second high-voltage battery 118 may receive power. Multi-port bidirectional converter 100 may also operate in a second operating mode. In the second operating mode, first high-voltage power conversion unit 108 and second high-voltage power conversion unit 110 may transfer power to first low-voltage battery 120, second low-voltage battery 122, power source 124, and AC load 126. Therefore, in the second operating mode, the first high-voltage battery 116 and the second high-voltage battery 118 can transfer power. Because the first high-voltage battery 116 and the second high-voltage battery 118 can receive or transfer power, the multi-port bidirectional converter 100 is bidirectional.

Transformer 102 includes a magnetic core (not shown in FIG. 1 ), a first primary winding PW1, a first secondary winding SW1, a second secondary winding SW2, a third secondary winding SW3, a fourth secondary winding SW4, and a fifth secondary winding SW5. Input power conversion unit 104 is coupled to first primary winding PW1. First high-voltage power conversion unit 108 is coupled to first secondary winding SW1. Second high-voltage power conversion unit 110 is coupled to second secondary winding SW2. First low-voltage power conversion unit 112 is coupled to third secondary winding SW3. Second low-voltage power conversion unit 114 is coupled to fourth secondary winding SW4.

A first microcontroller (MCU) 128 controls the input power conversion unit 104 and the load power conversion unit 106. A second microcontroller 130 controls the first high-voltage power conversion unit 108 and the first low-voltage power conversion unit 112. A third microcontroller 132 controls the second high-voltage power conversion unit 110 and the second low-voltage power conversion unit 114.

Referring to FIG. 2 , FIG. 2 illustrates a block diagram of an exemplary multi-port bidirectional converter in an onboard power unit of an electric vehicle according to an embodiment of the present disclosure. The input power conversion unit 204 includes, for example, an input relay 204_1 , an AC electromagnetic interference (EMI) filter 204_2 , a power factor correction (PFC) converter 204_3 , a large capacitor 204_4 , and a primary inductor-inductor-capacitor (LLC) circuit 204_5 . The load power conversion unit 206, for example, includes a vehicle-to-load (V2L) filter 206_1, a single-phase inverter 206_2, and a secondary LLC circuit 206_3. The first high-voltage power conversion unit 208, for example, includes a secondary LLC circuit 208_1 and a high-voltage filter 208_2. The second high-voltage power conversion unit 210, for example, includes a secondary LLC circuit 210_1 and a high-voltage filter 210_2. The first low-voltage power conversion unit 212, for example, includes a secondary LLC circuit 212_1 and a low-voltage filter 212_2. The second low-voltage power conversion unit 214 includes, for example, a secondary LLC circuit 214_1 and a low-voltage filter 214_2.

The first microcontroller 228 controls the PFC converter 204_3 and the single-phase inverter 206_2. The second microcontroller 230 controls the secondary LLC circuit 208_1 and the secondary LLC circuit 212_1. The third microcontroller 232 controls the secondary LLC circuit 210_1 and the secondary LLC circuit 214_1.

AC voltage 234 is input to input power conversion unit 204 via AC terminal 236. Load power conversion unit 206 outputs power to V2L terminal 238. First high-voltage power conversion unit 208 outputs voltage to high-voltage terminal 240. Second high-voltage power conversion unit 210 outputs voltage to high-voltage terminal 242. First low-voltage power conversion unit 212 outputs voltage to low-voltage terminal 244. Second low-voltage power conversion unit 214 outputs voltage to low-voltage terminal 246.

Please refer to Figure 3, which shows a block diagram of a multi-port bidirectional converter used in an on-board power unit of an electric vehicle. Multi-port bidirectional converter 300 includes a transformer 302, a primary full-bridge converter 303, a first high-voltage power conversion unit 308, a second high-voltage power conversion unit 310, a first low-voltage power conversion unit 312, a second low-voltage power conversion unit 314, a full-bridge diode rectifier 305, and a full-bridge inverter 307.

Transformer 302 includes a core (not shown in FIG. 3 ), a first primary winding PW1, a first secondary winding SW1, a second secondary winding SW2, a third secondary winding SW3, a fourth secondary winding SW4, and a fifth secondary winding SW5. The primary full-bridge converter 303 is coupled to the first primary winding PW1 and receives an input voltage Vin from a primary DC voltage source 323.

The first high-voltage power conversion unit 308 is coupled to the first secondary winding SW1 and outputs a first high DC voltage HVlt1 to a first high-voltage battery 316. The second high-voltage power conversion unit 310 is coupled to the second secondary winding SW2 and outputs a second high DC voltage HVlt2 to a second high-voltage battery 318. The first low-voltage power conversion unit 312 is coupled to the third secondary winding SW3 and outputs a first low DC voltage LVlt1 to a first low-voltage battery 320. The second low-voltage power conversion unit 314 is coupled to the fourth secondary winding SW4 and outputs a second low DC voltage LVlt2 to a second low-voltage battery 322. The full-bridge diode rectifier 305 is coupled to the fifth secondary winding SW5. The full-bridge inverter 307 is coupled to the full-bridge diode rectifier 305 and outputs an AC output voltage Vac to the AC load 326.

The multi-port bidirectional converter 300 further includes a first fuse F1, a second fuse F2, a third fuse F3, a fourth fuse F4, a fifth fuse F5, and a sixth fuse F6. The first fuse F1 is coupled between the first primary winding PW1 and the primary full-bridge converter 303. The second fuse F2 is coupled between the first secondary winding SW1 and the first high-voltage power conversion unit 308. The third fuse F3 is coupled between the second secondary winding SW2 and the second high-voltage power conversion unit 310. The fourth fuse F4 is coupled between the third secondary winding SW3 and the first low-voltage power conversion unit 312. The fifth fuse F5 is coupled between the fourth secondary winding SW4 and the second low-voltage power conversion unit 314. The sixth fuse F6 is coupled between the fifth secondary winding SW5 and the full-bridge diode rectifier 305.

Fuses F1 through F6 can be used to isolate failed or malfunctioning power conversion units. For example, when excessive current flows through the first high-voltage power conversion unit 308, fuse F2 melts to stop the current flow. Fuse F2 also isolates the first high-voltage power conversion unit 308 from the other power conversion units and other components of the multi-port bidirectional converter 300. Thus, the other power conversion units and other components of the multi-port bidirectional converter 300 are protected.

The multi-port bidirectional converter 300 further includes a first capacitor C1 and a primary resonant inductor L1. One end of the first capacitor C1 is coupled to one end of the first primary winding PW1. One end of the primary resonant inductor L1 is coupled to the other end of the first primary winding PW1. One end of the primary full-bridge converter 303 is coupled to the other end of the first capacitor C1. The other end of the primary full-bridge converter 303 is coupled to the other end of the primary resonant inductor L1.

The first high-voltage power conversion unit 308 includes a first high-voltage full-bridge converter 308_1, a second capacitor C2, and a third capacitor C3. The second capacitor C2 is coupled between the first high-voltage full-bridge converter 308_1 and the first secondary winding SW1. The third capacitor C3 is coupled between two terminals of the first high-voltage full-bridge converter 308_1.

The first high-voltage power conversion unit 308 further includes a first high-voltage bidirectional buck-boost half-bridge converter 308_2 coupled to a third capacitor C3. The first high-voltage power conversion unit 308 further includes a first high-voltage buck-boost inductor Lhv1 and a fourth capacitor C4. The first high-voltage buck-boost inductor Lhv1 is coupled to the first high-voltage bidirectional buck-boost half-bridge converter 308_2, and the fourth capacitor C4 is coupled to the first high-voltage buck-boost inductor Lhv1. The voltage across the fourth capacitor C4 serves as the first high DC voltage HVlt1.

The second high-voltage power conversion unit 310 includes a second high-voltage full-bridge converter 310_1, a fifth capacitor C5, and a sixth capacitor C6. The fifth capacitor C5 is coupled between the second high-voltage full-bridge converter 310_1 and the second secondary winding SW2. The sixth capacitor C6 is coupled between two terminals of the second high-voltage full-bridge converter 310_1. The second high-voltage power conversion unit 310 further includes a second high-voltage bidirectional buck-boost half-bridge converter 310_2, which is coupled to the sixth capacitor C6.

The second high-voltage power conversion unit 310 further includes a second high-voltage buck-boost inductor Lhv2 and a seventh capacitor C7. The second high-voltage buck-boost inductor Lhv2 is coupled to the second high-voltage bidirectional buck-boost half-bridge converter 310_2, and the seventh capacitor C7 is coupled to the second high-voltage buck-boost inductor Lhv2. The voltage across the seventh capacitor C7 serves as the second high DC voltage HVlt2.

The first low-voltage power conversion unit 312 includes a first synchronous rectifier (SR) 312_1 and an eighth capacitor C8. The eighth capacitor C8 is coupled to the first synchronous rectifier 312_1. The first low-voltage power conversion unit 312 further includes a first bidirectional low-voltage buck-boost half-bridge converter 312_2, a first low-voltage buck-boost inductor Llv1, and a ninth capacitor C9. The first low-voltage buck-boost inductor Llv1 is coupled between the first bidirectional low-voltage buck-boost half-bridge converter 312_2 and the ninth capacitor C9. The voltage across the ninth capacitor C9 serves as the first low-voltage DC voltage LVlt1.

The second low-voltage power conversion unit 314 includes a second synchronous rectifier 314_1 and a tenth capacitor C10. The tenth capacitor C10 is coupled to the second synchronous rectifier 314_1. The second low-voltage power conversion unit 314 further includes a second bidirectional low-voltage buck-boost half-bridge converter 314_2, a second low-voltage buck-boost inductor Llv2, and an eleventh capacitor C11. The second low-voltage buck-boost inductor Llv2 is coupled between the second bidirectional low-voltage buck-boost half-bridge converter 314_2 and the eleventh capacitor C11. The voltage of the eleventh capacitor C11 serves as the second low-voltage DC voltage LVlt2.

The multi-port bidirectional converter 300 further includes a twelfth capacitor C12. One end of the full-bridge diode rectifier 305 is coupled to one end of the fifth secondary winding SW5. One end of the full-bridge diode rectifier 305 is coupled to the other end of the fifth secondary winding SW5. The twelfth capacitor C12 is coupled between two terminals of the full-bridge diode rectifier 305, and the full-bridge inverter 307 is coupled to the twelfth capacitor C12.

The number of turns of the first secondary winding SW1 is greater than the number of turns of the third secondary winding SW3. Therefore, the voltage value of the first high DC voltage HVlt1 is greater than the voltage value of the first low DC voltage LVlt1. Similarly, the number of turns of the second secondary winding SW2 is greater than the number of turns of the fourth secondary winding SW4. Therefore, the voltage value of the second high DC voltage HVlt2 is greater than the voltage value of the second low DC voltage LVlt2. For example, the number of turns of the first secondary winding SW1 can be 14, the number of turns of the second secondary winding SW2 can be 14, the number of turns of the third secondary winding SW3 can be 2, and the number of turns of the fourth secondary winding SW4 can be 2.

When the multi-port bidirectional converter 300 operates in a first operating mode, such as an AC charging mode, the primary full-bridge converter 303 transfers electrical energy to the first high-voltage battery 316, the second high-voltage battery 318, the first low-voltage battery 320, the second low-voltage battery 322, and the AC load 326. In other words, electrical energy input from the AC grid is converted into an input voltage Vin, a DC voltage, by, for example, an AC/DC converter, a PFC converter, or a T-type converter. This input voltage Vin is then input to the primary full-bridge converter 303. By switching switches T1 through T4 on and off in a specific sequence, primary full-bridge converter 303 generates an AC voltage, which is input to first primary winding PW1 via first capacitor C1 and primary resonant inductor L1. This electrical energy is then transferred from first primary winding PW1 to first secondary winding SW1, second secondary winding SW2, third secondary winding SW3, fourth secondary winding SW4, and fifth secondary winding SW5 through magnetic coupling in transformer 302. The electrical energy is then transferred to the first high-voltage battery 316, the second high-voltage battery 318, the first low-voltage battery 320, the second low-voltage battery 322, and the AC load 326 through the first high-voltage power conversion unit 308, the second high-voltage power conversion unit 310, the first low-voltage power conversion unit 312, the second low-voltage power conversion unit 314, the full-bridge diode rectifier 305, and the full-bridge inverter 307. The first high-voltage battery 316, the second high-voltage battery 318, the first low-voltage battery 320, the second low-voltage battery 322, and the AC load 326 are coupled to the first secondary winding SW1 to the fifth secondary winding SW5, respectively.

To convert the input voltage Vin into an AC voltage in the primary full-bridge converter 303, switches T1 and T4 may be turned on, and switches T2 and T3 may be turned off, for example, during a first time period. For example, the first time period may be half a switching cycle of switches T1 through T4. Subsequently, during a second time period, switches T1 and T4 are turned off, and switches T2 and T3 are turned on. The first and second time periods repeat and alternate. The switching frequency of switches T1 through T4 can be adjusted, or the first and second time periods can be adjusted to generate AC voltages of different frequencies or amplitudes. For example, the first time segment may be the first half of a switching cycle of switches T1 to T4, and the second time segment may be the second half of a switching cycle of switches T1 to T4.

The operation of the first high-voltage power conversion unit 308 is described below. By turning switches T5 through T8 on and off in a specific sequence, the AC voltage generated by the first secondary winding SW1 is converted into a DC voltage across the third capacitor C3. For example, during the positive voltage period of the AC voltage generated by the first secondary winding SW1, switches T5 and T8 are conductive, while switches T6 and T7 are non-conductive, charging the third capacitor C3 and increasing the voltage across the third capacitor C3. Subsequently, during the negative voltage period of the AC voltage generated by the first secondary winding SW1, switches T6 and T7 are conductive, while switches T5 and T8 are non-conductive, charging the third capacitor C3 and continuing to increase the voltage across the third capacitor C3.

Subsequently, by turning on switch T9, the energy in the third capacitor C3 is transferred to the fourth capacitor C4. When switch T10 turns on, the fourth capacitor C4 discharges, causing the voltage across the fourth capacitor C4 to decrease. The on-time of switches T9 and T10 determines the voltage across the fourth capacitor C4. By controlling the on-time of switches T9 and T10, or the on-time ratio of switches T9 and T10, the voltage across the fourth capacitor C4 can be determined. By varying the on-time of switches T9 and T10, or the on-time ratio of switches T9 and T10, different voltages across the fourth capacitor C4 can be achieved, providing a wide voltage range for the fourth capacitor C4. In some embodiments, when the wide voltage range of the fourth capacitor C4 is not required, the first high-voltage bidirectional buck-boost half-bridge converter 308_2 can be omitted.

The electrical energy stored in the fourth capacitor C4 is used to charge the first high-voltage battery 316. The above process is repeated while the first high-voltage battery 316 is charging. The operation of the second high-voltage power conversion unit 310 is similar to that of the first high-voltage power conversion unit 308 and will not be repeated here.

The operation of the first low-voltage power conversion unit 312 is described below. By turning switches T11 and T12 on and off in a specific sequence, the AC voltage generated by the third-secondary winding SW3 is converted into a DC voltage across the eighth capacitor C8. For example, during a positive period of the AC voltage generated by the third-secondary winding SW3, one of switches T11 and T12 is turned on to charge the eighth capacitor C8. Then, during a negative period of the AC voltage generated by the third-secondary winding SW3, the other of switches T11 and T12 is turned on to charge the eighth capacitor C8. Subsequently, by turning on switch T13, the energy in the eighth capacitor C8 is transferred to the ninth capacitor C9, where it is stored in the first low-voltage buck-boost inductor Llv1. When switch T13 is off and switch T14 is on, the ninth capacitor C9 discharges, releasing the energy in the first low-voltage buck-boost inductor Llv1 and reducing the voltage across the ninth capacitor C9. The voltage across the ninth capacitor C9 can be determined by controlling the on-time of switches T13 and T14, or by controlling the on-time ratio of switches T13 and T14. By providing different on-times for switches T13 and T14 or different on-time ratios for switches T13 and T14, different voltages can be achieved for the ninth capacitor C9, providing a wide voltage range for the ninth capacitor C9. The energy stored in the ninth capacitor C9 is used to charge the first low-voltage battery 320. In some embodiments, when the wide voltage range of the ninth capacitor C9 is not required, the first bidirectional low-voltage buck-boost half-bridge converter 312_2 can be omitted.

The above process is repeated while the first low-voltage battery 320 is charging. The operation of the second low-voltage power conversion unit 314 is similar to that of the first low-voltage power conversion unit 312 and will not be repeated here.

The operation of the full-bridge diode rectifier 305 and the full-bridge inverter 307 is described as follows. When the AC voltage output from the fifth secondary winding SW5 is positive, diodes D1 and D4 conduct, and current flows through diodes D1 and D4 to charge the twelfth capacitor C12. When the AC voltage output from the fifth secondary winding SW5 is negative, diodes D2 and D3 conduct, and current flows through diodes D2 and D3 to charge the twelfth capacitor C12.

Then, during the first time period, switches T15 and T18 are turned on, while switches T16 and T17 are turned off. During the second time period, switches T15 and T18 are turned off, while switches T16 and T17 are turned on. In this way, the DC voltage across the twelfth capacitor C12 is converted into an AC output voltage Vac.

In addition, switches T1 to T18 can be implemented with transistors. Other switches shown in the diagrams of this disclosure can also be implemented with transistors.

When the multi-port bidirectional converter 300 operates in a second operating mode, such as a reverse operating mode, at least one of the first high-voltage power conversion unit 308 and the second high-voltage power conversion unit 310 transmits power to at least one of the first low-voltage battery 320, the second low-voltage battery 322, the primary DC voltage source 323, and the AC load 326.

Taking the first high-voltage power conversion unit 308 as an example, the power stored in the first high-voltage battery 316 is transferred to the fourth capacitor C4. Then, by turning on switch T9, the power in the fourth capacitor C4 is transferred to the third capacitor C3. The on-time of switch T9 determines the voltage of the third capacitor C3. When switch T10 is on, energy is stored in the first high-voltage buck-boost inductor Lhv1. When switch T10 is off and switch T9 is on, the energy in the first high-voltage buck-boost inductor Lhv1 is released, charging the third capacitor C3. The voltage of the third capacitor C3 is determined by controlling the on-time and off-time of switches T9 and T10.

By turning switches T5 through T8 on and off in a specific sequence, an AC voltage is generated and output to the first secondary winding SW1. For example, switches T5 and T8 are turned on, while switches T6 and T7 are turned off, to generate a positive AC voltage across the first secondary winding SW1. Then, switches T6 and T7 are turned on, while switches T5 and T8 are turned off, to generate a negative AC voltage across the first secondary winding SW1. The electrical energy in the first secondary winding SW1 is transferred to at least one of the second secondary winding SW2, the third secondary winding SW3, the fourth secondary winding SW4, the fifth secondary winding SW5, and the first primary winding PW1 through magnetic coupling of the transformer. Then, the electrical energy in at least one of the second secondary winding SW2, the third secondary winding SW3, the fourth secondary winding SW4, the fifth secondary winding SW5, and the first primary winding PW1 is transferred to at least one of the second high-voltage battery 318, the first low-voltage battery 320, the second low-voltage battery 322, the primary DC voltage source 323, and the AC load 326.

Furthermore, if one of the first high-voltage power conversion unit 308, the second high-voltage power conversion unit 310, the first low-voltage power conversion unit 312, or the second low-voltage power conversion unit 314 fails, the multi-port bidirectional converter 300 can operate in a third operating mode, such as a redundant mode. If either the first high-voltage power conversion unit 308 or the second high-voltage power conversion unit 310 fails, the other of the first high-voltage power conversion unit 308 and the second high-voltage power conversion unit 310 transfers power to at least one of the first low-voltage battery 320 and the second low-voltage battery 322. Furthermore, if one of the first low-voltage power conversion unit 312 and the second low-voltage power conversion unit 314 fails, at least one of the first high-voltage power conversion unit 308 and the second high-voltage power conversion unit 310 transfers power to the first low-voltage battery 320 or the second low-voltage battery 322 corresponding to the other of the first low-voltage power conversion unit 312 and the second low-voltage power conversion unit 314. The redundancy mode of the multi-port bidirectional converter 300 will be further explained in FIG. 4.

Please refer to Figure 4, which shows an example of a redundant mode for a multi-port bidirectional converter 300 used in an on-board power unit of an electric vehicle according to an embodiment of the present disclosure. In the table shown in Figure 4, the label "IN" indicates a corresponding unit that serves as an input unit providing power to other units. The label "OUT" indicates a corresponding unit that serves as an output unit receiving power from other units. The label "X" indicates that the corresponding unit is inactive.

In scenario 1, the first high-voltage battery 316 fails, and the first high-voltage power conversion unit 308 is inoperative. Alternatively, in scenario 1, the first high-voltage power conversion unit 308 fails. The second high-voltage power conversion unit 310 supplies power to the first low-voltage power conversion unit 312 and the second low-voltage power conversion unit 314. The first low-voltage power conversion unit 312 and the second low-voltage power conversion unit 314 then supply power to the first low-voltage battery 320 and the second low-voltage battery 322, respectively.

In scenario 2, the second high-voltage battery 318 fails, and the second high-voltage power conversion unit 310 is inoperative. Alternatively, in scenario 2, the second high-voltage power conversion unit 310 fails. The first high-voltage power conversion unit 308 supplies power to the first low-voltage power conversion unit 312 and the second low-voltage power conversion unit 314. The first low-voltage power conversion unit 312 and the second low-voltage power conversion unit 314 then supply power to the first low-voltage battery 320 and the second low-voltage battery 322, respectively.

In scenario 3, the first low-voltage power conversion unit 312 fails and is inoperative. Both the first high-voltage power conversion unit 308 and the second high-voltage power conversion unit 310 supply power to the second low-voltage power conversion unit 314. The second low-voltage power conversion unit 314 then supplies power to the second low-voltage battery 322.

In scenario 4, the second low-voltage battery 322 fails, and the second low-voltage power conversion unit 314 is inoperative. Alternatively, in scenario 4, the second low-voltage power conversion unit 314 fails. Both the first high-voltage power conversion unit 308 and the second high-voltage power conversion unit 310 supply power to the first low-voltage power conversion unit 312. The first low-voltage power conversion unit 312 then supplies power to the first low-voltage battery 320.

In scenario 5, both the first high-voltage battery 316 and the first low-voltage battery 320 fail, and both the first high-voltage power conversion unit 308 and the first low-voltage power conversion unit 312 are inoperative. Alternatively, in scenario 5, both the first high-voltage power conversion unit 308 and the first low-voltage power conversion unit 312 fail. The second high-voltage power conversion unit 310 and the second low-voltage power conversion unit 314 operate normally. The second high-voltage power conversion unit 310 supplies power to the second low-voltage power conversion unit 314, and the second low-voltage power conversion unit 314 supplies power to the second low-voltage battery 322.

In scenario 6, both the second high-voltage battery 318 and the second low-voltage battery 322 fail, and the second high-voltage power conversion unit 310 and the second low-voltage power conversion unit 314 are inoperative. Alternatively, in scenario 6, the second high-voltage power conversion unit 310 and the second low-voltage power conversion unit 314 fail. The first high-voltage power conversion unit 308 and the first low-voltage power conversion unit 312 operate normally. The first high-voltage power conversion unit 308 supplies power to the first low-voltage power conversion unit 312, and the first low-voltage power conversion unit 312 supplies power to the first low-voltage battery 320.

In summary, when the multi-port bidirectional converter 300 operates in a first operating mode (or AC charging mode), the primary full-bridge converter 303 transfers power received from the AC grid to the first high-voltage battery 316, the second high-voltage battery 318, the first low-voltage battery 320, the second low-voltage battery 322, and the AC load 326. When the multi-port bidirectional converter 300 operates in a second operating mode (or reverse operating mode), at least one of the first high-voltage power conversion unit 308 and the second high-voltage power conversion unit 310 transfers power to at least one of the first low-voltage battery 320, the second low-voltage battery 322, the primary DC voltage source 323, and the AC load 326. The reverse operation mode provides flexible power sharing between the first high-voltage battery 316, the second high-voltage battery 318, the first low-voltage battery 320, and the second low-voltage battery 322. This reverse operation mode allows for automatic battery balancing. In the event of a failure or malfunction in any power conversion unit or battery, the multi-port bidirectional converter 300 will operate in a third operation mode (or redundant mode). In redundant mode, if any power conversion unit or battery fails, other power conversion units can be used to charge the remaining batteries. Even if the electric vehicle has been traveling for an extended period and cannot find a charging station, the multi-port bidirectional converter 300 can be operated in redundant mode to charge the remaining batteries using the remaining functioning power conversion units. This improves user convenience.

Referring to FIG. 5 , FIG. 5 shows a block diagram of a multi-port bidirectional converter for use in an on-board power unit of an electric vehicle according to another embodiment of the present disclosure. Multi-port bidirectional converter 500 differs from multi-port bidirectional converter 300 in FIG. 3 in that multi-port bidirectional converter 500 further includes an AC input circuit 502, a T-type converter 504, a high-voltage DC EMI filter 532, a high-voltage DC EMI filter 534, a low-voltage DC EMI filter 536, a low-voltage DC EMI filter 538, and a V2L EMI filter 540. In the AC input circuit 502, the three phase signals L1, L2, and L3 of the AC input or grid, as well as the neutral point signal N, are transmitted to the AC EMI filter 542. The symbol "PE" in Figure 5 indicates ground. These phase signals are then sent to the T-type converter 504 to be converted into a DC voltage.

Furthermore, the DC voltage output from the first high-voltage power conversion unit 508 is transmitted to a high-voltage DC EMI filter 532 to generate a first high DC voltage HVlt1′. The DC voltage output from the second high-voltage power conversion unit 510 is transmitted to a high-voltage DC EMI filter 534 to generate a second high DC voltage HVlt2′. The DC voltage output from the first low-voltage power conversion unit 512 is transmitted to a low-voltage DC EMI filter 536 to generate a first low DC voltage LVlt1′. The DC voltage output from the second low-voltage power conversion unit 514 is transmitted to a low-voltage DC EMI filter 538 to generate a second low DC voltage LVlt2′. The AC voltage output from the full-bridge inverter 507 is transmitted to the V2L EMI filter 540 and then to the V2L terminal 544.

Please refer to Figures 6A to 6C. Figure 6A shows the magnetic core structure of a transformer in a multi-port bidirectional converter used in an on-board power unit of an electric vehicle according to another embodiment of the present disclosure. Figure 6B shows an example of a first primary winding in the multi-port bidirectional converter. Figure 6C shows examples of a first primary winding and a second primary winding in the multi-port bidirectional converter.

As shown in FIG. 6A , the magnetic core 600 of the transformer 102 or 302 includes a first magnetic core leg 602 and a second magnetic core leg 604. As shown in FIG. 6B , a first primary winding PW1 is wound around the first magnetic core leg 602. In one embodiment, as shown in FIG. 6C , the transformer 102 or 302 further includes a second primary winding PW2, wherein the first primary winding PW1 is wound around the first magnetic core leg 602, and the second primary winding PW2 is wound around the second magnetic core leg 604. The first primary winding PW1 and the second primary winding PW2 are coupled in parallel. The parallel-coupled first and second primary windings PW1 and PW2 can receive an input voltage Vin from a primary DC voltage source or power supply.

According to one embodiment of the present disclosure, a multi-port bidirectional converter provides a multi-port integrated power supply with redundant operation for a combined vehicle charger having one primary AC input port, two high-voltage DC output ports, two low-voltage DC output ports, and one V2L output port. Power can be flexibly shared among these multiple ports through magnetic coupling via a shared transformer with multiple windings. Compared to a converter with six transformers for six ports, the multi-port bidirectional converter according to one embodiment of the present disclosure saves five transformers and five corresponding full-bridge converters. Consequently, the cost and size of the multi-port bidirectional converter according to this embodiment of the present disclosure can be reduced by reducing the number of key components.

A multi-port bidirectional converter according to an embodiment of the present disclosure also provides bidirectional power flow between these multiple ports and offers wide output voltage regulation for high-voltage DC batteries and low-voltage DC batteries, or for a high-voltage DC battery pack and a low-voltage DC battery pack. Furthermore, the multi-port bidirectional converter according to an embodiment of the present disclosure enables redundant operation in the event of battery failure or power conversion unit failure.

Furthermore, according to one embodiment of the present disclosure, a multi-port bidirectional converter has the advantages of high power efficiency, flexible power flow control, and wide voltage range operation. According to one embodiment of the present disclosure, the multi-port bidirectional converter can operate at a fixed switching frequency to provide a fixed output voltage at each port. According to one embodiment of the present disclosure, the multi-port bidirectional converter can be designed to operate at a frequency slightly above the resonant frequency (corresponding to the capacitors and inductors in the multi-port bidirectional converter) to achieve zero voltage switching (ZVS) in the power conversion unit and reduce magnetizing losses in the transformer. Consequently, the efficiency of the multi-port bidirectional converter is optimized.

Furthermore, according to one embodiment of the present disclosure, a multi-port bidirectional converter can implement droop control through flexible power sharing. Droop control can be performed by controlling the power conversion unit via an MCU. Droop control involves reducing voltage or frequency when grid load increases. To ensure grid stability, the multi-port bidirectional converter can employ flexible power sharing between the power source, high-voltage battery, low-voltage battery, and AC load as needed to mitigate grid impacts. By dynamically adjusting the output power of the power conversion unit to achieve shared power usage, grid load can be reduced and grid load balancing and stability can be effectively managed.

Furthermore, a bidirectional buck/boost half-bridge converter in a multi-port bidirectional converter according to one embodiment of the present disclosure is used to provide a wide voltage range on both the high-voltage port and the low-voltage port. Therefore, a high-voltage battery and a low-voltage battery, or a high-voltage battery pack and a low-voltage battery pack, can have a wide voltage range and accommodate various battery voltage ranges from different automakers.

Furthermore, a multi-port bidirectional converter according to an embodiment of the present disclosure may include a transformer with an additional secondary winding and may include an additional power conversion unit to connect to an energy source, such as a solar photovoltaic module or a wind turbine.

In summary, although the present invention has been disclosed above through the use of embodiments, these are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and improvements can be made to the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of protection for the present invention shall be determined by the scope of the patent application appended hereto.

100: Multi-port bidirectional converter 102: Transformer 104: Input power conversion unit 106: Load power conversion unit 108: First high-voltage power conversion unit 110: Second high-voltage power conversion unit 112: First low-voltage power conversion unit 114: Second low-voltage power conversion unit 116: First high-voltage battery 118: Second high-voltage battery 120: First low-voltage battery 122: Second low-voltage battery 124: Power supply 126: AC load 128: First microcontroller 130: Second microcontroller 132: Third microcontroller

Claims (19)

A multi-port bidirectional converter includes: a transformer, a primary full-bridge converter, a first high voltage (HV) power conversion unit, a second high voltage power conversion unit, a first low voltage (LV) power conversion unit, a second low voltage power conversion unit, a full-bridge diode rectifier, and a full-bridge inverter; wherein the transformer includes a core, a first primary winding, a first secondary winding, and a first high voltage (HV) power conversion unit. Winding), a second secondary winding, a third secondary winding, a fourth secondary winding, and a fifth secondary winding; wherein the primary full-bridge converter is coupled to the first primary winding and receives an input voltage from a primary direct current (DC) voltage source; wherein the first high-voltage power conversion unit is coupled to the first secondary winding, and the first high-voltage power conversion unit outputs a first high direct current voltage to a first high-voltage battery; wherein the second high-voltage power conversion unit is coupled to the second secondary winding, and the second high-voltage power conversion unit outputs a second high direct current voltage to a second high-voltage battery; wherein the first low-voltage power conversion unit is coupled to the third secondary winding, The first low-voltage power conversion unit outputs a first low-voltage direct current voltage to a first low-voltage battery. The second low-voltage power conversion unit is coupled to the fourth secondary winding and outputs a second low-voltage direct current voltage to a second low-voltage battery. The full-bridge diode rectifier is coupled to the fifth secondary winding. The full-bridge inverter is coupled to the full-bridge diode rectifier and outputs an alternating current (AC) output voltage to an AC load. A multi-port bidirectional converter as described in claim 1, wherein the magnetic core includes a first magnetic core leg and a second magnetic core leg; wherein the transformer further includes a second primary winding, the first primary winding is wound on the first magnetic core leg, and the second primary winding is wound on the second magnetic core leg. The multi-port bidirectional converter as claimed in claim 2, wherein the first primary winding and the second primary winding are connected in parallel. The multi-port bidirectional converter as claimed in claim 1, wherein the number of turns of the first secondary winding is greater than the number of turns of the third secondary winding. The multi-port bidirectional converter as described in claim 1 further includes: a first fuse coupled between the first primary winding and the primary full-bridge converter; a second fuse coupled between the first secondary winding and the first high-voltage power conversion unit; a third fuse coupled between the second secondary winding and the second high-voltage power conversion unit; a fourth fuse coupled between the third secondary winding and the first low-voltage power conversion unit; a fifth fuse coupled between the fourth secondary winding and the second low-voltage power conversion unit; and a sixth fuse coupled between the fifth secondary winding and the full-bridge diode rectifier. The multi-port bidirectional converter as described in claim 1 further includes a first capacitor and a primary resonant choke; wherein one end of the first capacitor is coupled to one end of the first primary winding, and one end of the primary resonant choke is coupled to the other end of the first primary winding; wherein one end of the primary full-bridge converter is coupled to the other end of the first capacitor, and the other end of the primary full-bridge converter is coupled to the other end of the primary resonant choke. A multi-port bidirectional converter as described in claim 6, wherein the first high-voltage power conversion unit includes a first high-voltage full-bridge converter, a second capacitor, and a third capacitor, the second capacitor being coupled between the first high-voltage full-bridge converter and the first secondary winding, and the third capacitor being coupled between two terminals of the first high-voltage full-bridge converter. The multi-port bidirectional converter as described in claim 7, wherein the first high-voltage power conversion unit further includes a first high-voltage bidirectional buck/boost half-bridge converter, and the first high-voltage bidirectional buck/boost half-bridge converter is coupled to the third capacitor. A multi-port bidirectional converter as described in claim 8, wherein the first high-voltage power conversion unit further includes a first high-voltage buck/boost inductor and a fourth capacitor, the first high-voltage buck/boost inductor is coupled to the first high-voltage bidirectional buck/boost half-bridge converter, the fourth capacitor is coupled to the first high-voltage buck/boost inductor, and the voltage of the fourth capacitor is the first high DC voltage. A multi-port bidirectional converter as described in claim 9, wherein the second high-voltage power conversion unit includes a second high-voltage full-bridge converter, a fifth capacitor, and a sixth capacitor, the fifth capacitor being coupled between the second high-voltage full-bridge converter and the second secondary winding, and the sixth capacitor being coupled between two terminals of the second high-voltage full-bridge converter. The multi-port bidirectional converter as described in claim 10, wherein the second high-voltage power conversion unit further includes a second high-voltage bidirectional buck/boost half-bridge converter, and the second high-voltage bidirectional buck/boost half-bridge converter is coupled to the sixth capacitor. A multi-port bidirectional converter as described in claim 11, wherein the second high-voltage power conversion unit further includes a second high-voltage buck/boost inductor and a seventh capacitor, the second high-voltage buck/boost inductor is coupled to the second high-voltage bidirectional buck/boost half-bridge converter, the seventh capacitor is coupled to the second high-voltage buck/boost inductor, and the voltage of the seventh capacitor is the second high DC voltage. The multi-port bidirectional converter as described in claim 12, wherein the first low-voltage power conversion unit includes a first synchronous rectifier (SR) and an eighth capacitor, and the eighth capacitor is coupled to the first synchronous rectifier. A multi-port bidirectional converter as described in claim 13, wherein the first low-voltage power conversion unit further includes a first low-voltage bidirectional buck/boost half-bridge converter, a first low-voltage buck/boost inductor and a ninth capacitor, the first low-voltage buck/boost inductor is coupled between the first low-voltage bidirectional buck/boost half-bridge converter and the ninth capacitor, and the voltage of the ninth capacitor is the first low-voltage DC voltage. The multi-port bidirectional converter as described in claim 14, wherein the second low-voltage power conversion unit includes a second synchronous rectifier and a tenth capacitor, and the tenth capacitor is coupled to the second synchronous rectifier. A multi-port bidirectional converter as described in claim 15, wherein the second low-voltage power conversion unit further includes a second low-voltage bidirectional buck/boost half-bridge converter, a second low-voltage buck/boost inductor and an eleventh capacitor, the second low-voltage buck/boost inductor is coupled between the second low-voltage bidirectional buck/boost half-bridge converter and the eleventh capacitor, and the voltage of the eleventh capacitor is the second low-voltage DC voltage. The multi-port bidirectional converter as described in claim 16 further includes a twelfth capacitor; wherein one end of the full-bridge diode rectifier is coupled to one end of the fifth secondary winding, one end of the full-bridge diode rectifier is coupled to the other end of the fifth secondary winding, the twelfth capacitor is coupled between two ends of the full-bridge diode rectifier, and the full-bridge inverter is coupled to the twelfth capacitor. The multi-port bidirectional converter as described in claim 6, wherein in a first operating mode, the primary full-bridge converter generates an AC voltage and inputs it to the first primary winding through the first capacitor and the primary resonant inductor; wherein in a second operating mode, the first high-voltage power conversion unit generates an AC voltage that is output to the first secondary winding. The multi-port bidirectional converter of claim 18, wherein in the second operating mode, the second high-voltage power conversion unit generates an AC voltage that is output to the second secondary winding.