Power electronics charge coupler for vehicle-to-vehicle fast energy sharing
View Patent ↗A power electronics charge coupler (PECC) unit allows vehicle-to-vehicle (V2V) energy transfer by forming a bidirectional buck/boost converter for supplying rapid energy transfer with wide input-output battery voltage and battery voltage levels. The PECC unit embeds DC-DC converter modules into the charging handles of the PECC unit. Each of the charging handles includes a half-bridge of the DC-DC converter and parasitic inductance of a cable between charging handles is utilized as a portion of the filter inductor for the converter. The PECC unit handles are each configured to connect to an electric vehicle and are dynamically configurable in one of four modes of operation based on the battery voltage of the electric vehicles to which the PECC unit is connected and based on which of the electric vehicles is designated as the receiver vehicle and which is designated as the supplier vehicle.
1. A power electronics charge coupler (PECC) unit, comprising:
a first charging handle comprising a first DC-DC half-bridge converter;
a second charging handle comprising a second DC-DC half-bridge converter; and
a cable configured to electrically couple the first charging handle with the second charging handle, wherein the first charging handle and the second charging handle are coupled by the cable to form a DC-DC full-bridge converter, where a portion of a filter inductor of the DC-DC full-bridge converter is provided by parasitic inductance of the cable.
2. The PECC unit of claim 1 , wherein the cable comprises a charge line and a ground line separated by a dielectric membrane.
3. The PECC unit of claim 1 , wherein the first and second DC-DC half-bridges each comprise:
a smoothing capacitor connected across a charge line and a ground line of the first charging handle; and
a pair of switches in series with each other and connected in parallel to the smoothing capacitor across the charge line and the ground line of the first charging handle; and
a filter inductor with a first side of the filter inductor connected between the pair of switches and a second side of the filter inductor connected to a charge line of the cable.
4. The PECC unit of claim 3 , wherein each of the pair of switches is a power MOSFET.
5. The PECC unit of claim 4 , wherein the power MOSFET switch is a SiC MOSFET.
6. The PECC unit of claim 5 , wherein the SiC MOSFET is two paralleled 25 m Ω SiC MOSFETs.
7. The PECC unit of claim 5 , wherein the SiC MOSFET is a 15 m Ω SiC MOSFET.
8. The PECC unit of claim 4 , wherein the power MOSFET is contained in a four-lead TO-247 package.
9. The PECC unit of claim 1 , wherein the first DC-DC half-bridge converter comprises a first pair of switches and the first charging handle comprises a first digital signal processor (DSP) adapted to configure the pair of switches to operate the first charging handle as a charge supplier or a charge receiver.
10. The PECC unit of claim 9 , wherein the first DSP is adapted to configure one of the first pair of switches to actively modulate a transfer of charge across the PECC unit and the other of the first pair of switches to operate as a synchronous rectifier.
11. The PECC unit of claim 10 , wherein the second DC-DC half-bridge converter comprises a second pair of switches and the second charging handle comprises a second DSP adapted to configure the second pair of switches to operate the second charging handle as a charge supplier or a charge receiver.
12. The PECC unit of claim 11 , wherein the second DSP is adapted to configure one of the second pair of switches to statically remain on and the other of the second pair of switches to statically remain off.
13. The PECC unit of claim 12 , wherein the first DC-DC half-bridge converter is configured to switch between operating between a buck mode of operation and a boost mode of operation.
14. A method of charging a receiver electric vehicle from a supplier electric vehicle with a PECC unit, the method comprising:
receiving, by a first DSP in a first charging handle of the PECC unit coupled to the supplier electric vehicle, a first message comprising a first value of a voltage of a battery pack of the supplier electric vehicle;
receiving, by the first DSP, a second message comprising a second value of a voltage of a battery pack of the receiver electric vehicle;
comparing, by the first DSP, the first value to the second value to determine which is larger; and
configuring, by the first DSP, a first pair of switches in a first DC-DC half-bridge converter in the first charging handle based on the comparison, wherein the PECC unit further comprises a second charging handle with a second DC-DC half-bridge converter and a cable configured to electrically couple the first charging handle with the second charging handle, wherein the first charging handle and the second charging handle are coupled by the cable to form a DC-DC full-bridge converter, where a portion of a filter inductor of the DC-DC full-bridge converter is provided by parasitic inductance of the cable.
15. The method of claim 14 , further comprising:
receiving, by a second DSP in the second charging handle of the PECC unit coupled to the receiver electric vehicle, a third message comprising the second value of the voltage of the battery pack of the receiver electric vehicle;
receiving, by the second DSP, a fourth message comprising the first value of the voltage of the battery pack of the supplier electric vehicle;
comparing, by the second DSP, the first value to the second value to determine which is larger; and
configuring, by the second DSP, a second pair of switches in a second DC-DC half-bridge converter in the second charging handle based on the comparison.
16. The method of claim 14 , wherein configuring the first pair of switches in the first DC-DC half-bridge converter comprises configuring one of the first pair of switches to actively modulate a transfer of charge from the supplier electric vehicle to the receiver electric vehicle and the other of the first pair of switches to operate as a synchronous rectifier.
17. The method of claim 14 , wherein configuring the first pair of switches in the first DC-DC half-bridge converter comprises configuring one of the first pair of switches to statically remain on and the other of the first pair of switches to statically remain off.
18. The method of claim 14 , further comprising:
receiving, by the first DSP, fifth message with a value of a minimum allowed voltage of the battery pack of the supplier electric vehicle.
19. The method of claim 15 , further comprising:
receiving, by the second DSP, a sixth message with a value of a maximum voltage of the battery pack of the receiver electric vehicle.