ELECTRIC VEHICLE FAST CHARGING STATION WITH SOLAR ENERGY SYSTEM AND IT'S METHOD

Abstract

A high power EV fast charging station with solar energy system (EVFCS-SES) having a HV DC bus, several EVFCS-SES cells connecting in parallel and with their universal battery interfaces, and a storage battery system provides the following functions: solar energy generation; solar energy generation plus a direct storage battery charging; high power EV fast charging with either solar energy or storage battery or AC grid power. These functions enable EVFCS-SES system to charge any EV battery with solar energy in minutes, convert solar energy to AC grid power, and supply electricity to building loads at same time. In addition, it stores unused solar energy into storage battery for supplementing solar energy in cloudy days or at night. Combining EV fast charging system and solar energy generation system into one system achieves a low cost, high efficient and high power EV fast charging station with solar energy generation system. Furthermore, this system takes full advantage of solar energy and eliminates or reduces AC grid power usage effectively. As a result, it makes both EV fast charger and solar energy generation system more desirable and economical.

Claims

1. An EV Fast Charging Station with Solar Energy System (EVFCS-SES) maximizing solar energy usage to charge EV battery in minutes and produce building electricity, said system comprising: a system architecture with a HV DC bus, multiple EVFCS-SES cells connecting in parallel, operation switches, solar energy sources, a storage battery system, and an AC grid power source; an EVFCS-SES cell operable in, such as but not limited to following operation modes: solar energy generation mode (Mode 1), solar energy generation plus direct storage battery charging mode (Mode 2), EV battery charger using solar energy mode (Mode 3), EV battery charger using storage battery and AC grid power mode (Mode 4), and PWM rectifier battery charger mode (Mode 5).

2. The said EVFCS-SES cell of claim 1 further comprising a Multi-Function Power Conversion System (MFPCS), LCL filters plus isolation transformer, AC power grid, solar energy source, a universal battery interface, and three operation mode switches, operates as either a High Frequency (HF) isolated EV battery charger or a PWM rectifier storage battery charger or a three-phase solar power converter.

3. The said MFPCS system of claim 2 further comprising a three phase IGBT module on a liquid cooled heatsink, connected to a DC-link capacitor and controlled by a IGBT gate drive circuit card, a DSP interface circuit card, a Texas Instrument (TI) DSP control Card, provides DC/AC, AC/DC, and DC/DC power conversion hardware functions .

4. The said TI DSP control Card of claim 3 further comprising Mode 1 control library comprising three-phase grid-tied inverter control algorithms, Mode 2 control library comprising three-phase grid-tied inverter control plus direct storage battery charger control algorithms, Mode 3 control library comprising HF EV charger control and three-phase grid-tied inverter control plus optimized solar power generation control algorithms, Mode 4 control library comprising HF EV charger control and PWM rectifier control algorithms, Mode 5 control library comprising PWM rectifier battery charger control algorithms, provides power conversion and battery charging/discharging software functions.

5. The said three-phase grid-tied inverter control algorithms of claim 4 further comprises Maximum Power Point Tracking (MPPT) means to extract the maximum solar energy, DC voltage control means to regulate the output voltage of said solar energy, AC current reference generation means, AC current control means, Space Vector Modulation (SVM) means to convert said solar energy to said AC grid power.

6. The said three-phase grid-tied inverter control plus direct storage battery control algorithms and three-phase grid-tied inverter control plus optimized solar power generation control algorithms of claim 4 further comprise said MPPT means, said DC voltage control means, battery charging power calculation means, inverter command generation means, said AC current reference generation means, said AC current control means, said SVM means to produce said AC grid power plus directly charge said storage battery or to provide enough solar energy for EV battery chargers.

7. The said HF EV charger control algorithms of claim 4 further comprises EV battery data base of voltages, currents, temperatures, State of Charge (SOC), age, chemistry, charging requirements for all EV battery systems, battery voltage and current control means, DC current control means, full bridge PWM means to charge said EV battery with HV DC bus.

8. The said PWM rectifier control algorithms of claim 4 further comprises Minimum Grid Power Import means, said DC voltage control means, said current reference generation means, said AC current control means and said SVM means to charge EV battery with both storage battery and AC grid power.

9. The said PWM rectifier battery charger control algorithms of claim 4 further comprises said battery voltage and current control means, said AC current reference generation means, said current control means and said SVM means to convert AC grid power to DC charging said storage battery.

10. The said operation switches of claim 2 operable to set operation modes are controlled by a controller based on the operation mode table.

11. The said solar energy generation mode (Mode 1) of claim 1 further comprises said EVFCS-SES cells all configured as three phase grid-tied inverters when said MFPCS connecting to said solar power sources and said LCL filters plus transformers which also connecting to said AC grid power source through said operation switches and activation of Mode 1 control library.

12. The said solar energy generation plus direct storage battery charging mode (Mode 2) of claim 1 further comprises said EVFCS-SES cells all configured as three phase grid-tied inverters plus direct storage battery (which connects to HV DC bus through operation switches) chargers using their solar power energy sources and activation of Mode 2 control library.

13. The said EV battery charger using solar energy mode (Mode 3) of claim 1 further comprises one EVFCS-SES cell, for example cell 1, configured as an isolated EV battery charger when its MFPCS connecting to all solar energy sources via said HV DC bus and said universal battery interface which also connecting to said EV battery through operation switches, the rest of said EVFCS-SES cells configured as three phase grid-tied inverters and activation of Mode 3 control library.

14. The said EV battery charger using storage battery and AC grid power mode (Mode 4) of claim 1 further comprises one EVFCS-SES cell, for example cell 1, configured as an isolated EV battery charger when its MFPCS connecting to HV DC bus which further connecting to said storage battery, another EVFCS-SES cell, for example cell 2, configured as a PWM rectifier to maintain HV DC bus voltages through said operation switches and activation of Mode 4 control library.

15. The said PWM rectifier battery charger mode (Mode 5) of claim 1 further comprises one EVFCS-SES cell, for example cell 1, configured as a PWM rectifier battery charger when its MFPCS connecting to HV DC bus which further connecting to said storage battery through said operation switches and activation of Mode 5 control library.

16. The said universal battery interface of claim 2 further comprises two identical re-configurable HF transformers, transformer re-configuration switches, diode rectifier circuit, and output L-C filter circuit, to provide the battery interface with EV battery system of any voltage range.

17. The said re-configurable HF transformers of claim 16 further comprising one primary winding and two separated secondary windings with a turns ratio of n, primary windings connected in parallel while the secondary windings operated in combination of series and/or parallel connections so that the effective transformer turns ratio is rescaled to match EV battery voltage range, provides galvanic isolation and universal battery voltage arrangement.

18. The said transformer re-configuration switches of claim 16 connecting transformer secondary windings in series and/or parallel, are controlled by a controller based on transformer re-configuration control table.

19. An optimized solar energy method to reduce utility bill, the said method comprising minimum AC grid power import means through charge/discharge storage battery to maximize solar energy and minimize AC grid power usage during on-peak hour period.

20. A EV fast charging station with solar energy generation along with the method of maximizing solar power usage for EV battery charger and building loads by means of storage battery and unique system configurations of an EVFCS-SES system comprising: Mode 1 operating EVFCS-SES as solar energy generation system, Mode 2 operating EVFCS-SES as solar energy generation plus direct storage battery charger, Mode 3 operating EVFCS-SES as solar energy EV battery charger, Mode 4 operating EVFCS-SES as EV battery charger with storage battery and AC gird power, Mode 5 operating EVFCS-SES as PWM rectifier battery charger; a method optimizing solar energy usage during on-peak hour period by (1) utilizing as much solar energy as possible charging EV battery, (2) storing unused solar energy into storage battery for later use, (3) powering building loads when EV charger is unused and storage battery is full.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention is pointed out with particularity in the appended claims. However, other features of the present invention will become more apparent and present invention will be best understood by referring to the following detailed description in conjunction with the accompany drawings in which:

[0028] FIG. 1 illustrates the functional block diagram of an EV Fast Charging Station/Solar Energy System (EVFCS-SES) architecture incorporating a HV DC bus, multiple EVFCS-SES cells connecting in parallel and a storage battery system as contemplated by one non-limiting aspect of the present invention.

[0029] FIG. 2 schematically illustrates a Multi-Function Power Conversion System (MFPCS) as contemplated by one non-limiting aspect of the present invention.

[0030] FIG. 3 illustrates an operation mode switch control table as contemplated by one non-limiting aspect of the present invention.

[0031] FIG. 4 illustrates the functional block diagram of solar energy generation mode (Mode 1) and its control library as contemplated by one non-limiting aspect of the present invention.

[0032] FIG. 5 illustrates the functional block diagram of solar energy generation plus direct storage battery charger mode (Mode 2) and its control library as contemplated by one non-limiting aspect of the present invention.

[0033] FIG. 6a illustrates the functional block diagram of EV battery charger using solar energy mode (Mode 3) as contemplated by one non-limiting aspect of the present invention.

[0034] FIG. 6b illustrates the block diagram of control library for EV battery charger using solar energy as contemplated by one non-limiting aspect of the present invention.

[0035] FIG. 7 illustrates the functional block diagram of EV battery charger using storage battery and AC grid power mode (Mode 4) and its control library as contemplated by one non-limiting aspect of the present invention.

[0036] FIG. 8 illustrates the functional block diagram of PWM rectifier battery charger mode (Mode 5) and its control library as contemplated by one non-limiting aspect of the present invention.

[0037] FIGS. 9a and 9b illustrate the detailed schematic circuit diagram of EVFCS-SES system as contemplated by one non-limiting aspect of the present invention.

[0038] FIG. 10 illustrates High Frequency transformer re-configuration control table as contemplated by one non-limiting aspect of the present invention.

[0039] FIG. 11 illustrates the structure and mechanism of optimized solar energy software environment as contemplated by one non-limiting aspect of the present invention.

DETAILED DESCRIPTION

[0040] As required, detailed embodiments of the present invention are disclosed herein; However, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0041] The EV Fast Charging Station/Solar Energy System (EVFCS-SES) 10 as illustrated in FIG. 1 comprising a HV DC bus 12, a number of parallel connected EVFCS-SES cells (cell-1 14, cell-2 90, and cell-n 92) and a storage battery system 16, may provide the following functions: (1) Converting solar power to AC grid power; (2) Charging EV battery with either solar power or storage battery power or AC grid power.

[0042] The EVFCS-SES cell 14 comprising a MFPCS 18, a solar energy source 20, LCL filters plus isolation transformer 22, AC grid power 24, operation mode switches SW11 26, SW12 28, SW13 30, an universal battery interface 32 and a EV battery 34, may be configured as either a solar energy generation system which operates with solar power source 20, MFPCS 18, SW12 28, LCL filters plus isolation transformer 22 and AC grid power 24; or a High Frequency (HF) transformer isolated Full Bridge(FB) DC/DC battery charger which operates with solar power source 20, MFPCS 18, SW11 26, universal battery interface 32 and a EV battery 34; or a PWM rectifier which operates with MFPCS 18, SW12 28, SW13 30, LCL filters plus isolation transformer 22, AC grid power 24 and HV DC bus 12.

[0043] The HV DC bus 12 supported either by AC grid power 24 when EVFCS-SES cell 14 is operated as PWM rectifier or by solar power source 20 when switch SW13 30 is closed or by storage battery 16 when SWs 36 is closed, may be used as energy buffer to support different system operation modes.

[0044] FIG. 2 schematically illustrates MFPCS 18 having an IGBT module 40 mounted on a liquid cooled heatsink 42 and connected to DC-link capacitor 44 as contemplated by one non-limiting aspect of the present invention. The MFPCS 18 is shown for exemplary and non-limiting purpose being as a power electronic converter to facilitate AC/DC, DC/AC, DC/DC conversions utilized in EVFCS-SES cell 14 (FIG. 1).

[0045] An AC current sensing system 46 and DC current sensing system 48 may be included to sense currents to LCL filter plus isolation transformer 22 (FIG. 1) in solar energy generator/PWM rectifier, or to HF transformer primaries in universal battery interface 32 (FIG. 1) and to DC-link capacitor 44 such as to facilitate control of AC/DC, DC/AC and DC/DC power conversion processes. The DSP interface card 52 may condition and filter feedback currents from current sensors 46, 48 and other sensing devices within the system, and provide the conditioned feedback signals to TI DSP control card 54 for further processing. TI DSP control card 54 with Mode 1 control library 56, Mode 2 control library 58, Mode 3 control library 60, Mode 4 control library 62, and Mode 5 control library 64 may cooperate with DSP interface card 52 and IGBT drive card 50 to control IGBT module 40 such that opening and closing of switches 72, 74, 76, 78, 80, 82 can be coordinated to produce desired voltage/current waveform patterns for AC/DC, DC/AC and DC/DC power conversions.

[0046] FIG. 3 illustrates operation mode switch control table 84 used by a controller to select operation mode of EVFCS-SES system. When SWs=0, SW11=0, SW12=1, SW13=0, SW21=0, SW22=1, SW23=0, SWn1=0, SWn2=1, SWn3=0,EVFCS-SES system is operated in solar power generation mode (Mode 1); When SWs=1, SW11=0, SW12=1, SW13=1, SW21=0, SW22=1, SW23=1,SWn1=0, SWn2=1, SWn3=1, EVFCS-SES system is operated in solar energy generation plus direct storage battery charger mode (Mode 2); When SWs=0, SW11=1, SW12=0, SW13=1, SW21=0, SW22=1, SW23=1, SWn1=0, SWn2=1, SWn3=1, EVFCS-SES system is operated in EV battery charger using solar energy mode (Mode 3); When SWs=1, sW11=1, SW12=0, SW13=1, SW21=0, SW22=1,SW23=1 . . . SWn1=0 SWn2=0, SWn3=0, EVFCS-SES system is operated in EV battery charger using storage battery and AC grid power mode (Mode 4); When SWs=1, SW11=0, SW12=1, SW13=1, SW21=0, SW22=0, SW23=0 SWn1=0 SWn2=0, SWn3=0, EVFCS-SES system is operated in PWM rectifier battery charger mode (Mode 5).

[0047] FIG. 4 illustrates functional block diagram of EVFCS-SES system 10 operated in Mode 1 configuration when solar power is present, EV battery is not present, and storage battery is full. In EVFCS-SES system 10, each EVFCS-SES cells 14, 92 has same connection patterns. For example, EVFCS-SES cell 14 having MFPCS 18 connecting to solar power 20 and through switch SW12 28 to LCL filters plus isolation transformer 22 which further connecting to AC grid power 24, is configured as three-phase grid-tied inverter converting solar power to AC gird power. In Mode 1 control library which comprises three-phase grid-tied inverter control algorithm 100, the Maximum Power Point Tracking (MPPT) 102 extracts the maximum solar power by producing a dynamic voltage reference to DC voltage control 104 which regulates solar power output voltage by generating an inverter power command for AC current reference generation 106. The reference generation 106 produces current reference for AC current control 108 which regulates AC current by commanding SVM 110 to generate PWM signals controlling IGBT 112 to convert solar energy to AC grid power.

[0048] FIG. 5 illustrates functional block diagram of EVFCS-SES system 10 operated in Mode 2 configuration when solar power is present, EV battery is not present, and storage battery is not full. In system 10, EVFCS-SES cells 14, 92 are configured as three-phase grid-tied inverter with connections to HV DC bus 12 when switches SW13 30 and SWn3 98 are closed and to storage battery 16 when switch SWs 36 is closed so that part of energy from solar cells 20, 38 is used to directly charge storage battery 16 and the rest is converted to AC grid power. Mode 2 control library comprises three-phase grid-tied inverter control plus direct storage battery charger control algorithms 218 used for EVFCS-SES cells 14, 92. In control algorithm 218, MPPT 118 extracts the maximum solar power by producing dynamic voltage reference to DC voltage control 120. DC voltage control 120 regulates DC voltage by generating solar power command 122. It is then subtracted from required storage battery charging power 124 calculated by block 224 based on storage battery charging current reference I.sub.BR 220 and storage battery voltage V.sub.B 222 to get inverter power command 126. Inverter power command 126 is fed to AC current reference generation 128 to create current reference for AC current control 130 which regulates AC current by commanding SVM 132 to generate PWM signals controlling IGBT 134 to provide storage battery charging power through HV bus 12 with part of solar energy 20, 38 and convert the rest to AC grid power.

[0049] FIG. 6a illustrates functional block diagram of EVFCS-SES system 10 operated in Mode 3 configuration when solar power and EV battery are present. In system 10, EVFCS-SES cell 14 is configured as HF transformer isolated FB DC/DC converter with connection to HV DC bus 12 when switch SW13 30 is closed and EVFCS-SES cells 90, 92 are configured as three-phase grid-tied inverters with connections to HV DC bus 12 when switches SW23 94, SWn3 98 are closed. When solar cell 20 has enough energy, EVFCS-SES cell 14 charges EV battery 34 with its energy and EVFCS-SES cells 90, 92 convert their solar energy 96, 38 to AC grid power. When solar cell 20 does not have enough energy, EVFCS-SES cell 14 charges EV battery 34 with the energy from solar cells 20, 96, 38 and EVFCS-SES cells 90, 92 convert rest energy from their solar cells 96, 38 to AC grid power.

[0050] Mode 3 control block diagram 168 in FIG. 6b comprises control algorithms 172, 174. The FB DC/DC converter based EV battery charging control 172 is used for EVSCS-SES cell 14 (FIG. 6a). Control algorithms 172 incorporates EV battery data base 140 providing battery voltage reference and battery current reference to battery voltage control 142 and battery current control 144 based on the battery information including but not limiting to EV model number and manufacturer, chemistry, voltage/current range, State of Charge (SOC), temperature and charging requirements. While battery voltage is regulated by battery voltage control 142 in constant voltage mode, the battery current is regulated by battery current control 144 in constant current mode. Using the output of either voltage control 142 or current control 144, DC current control current 146 regulates DC current by commanding FB PWM 216 to generate PWM signals controlling IGBT 170 to produce AC voltage pulse trains for universal battery interface 32 which produces optimal charging voltage and current for EV battery 34. Control algorithms 172 including a communication interface 272 which establishes an immediate communication between EV fast charging station and EV when they are connected, may automatically reconfigure hardware and select battery charging control algorithms before battery charging process begins.

[0051] The three-phase grid-tied inverter control plus optimized solar power generation control algorithms 174 is used for EVFCS-SES cells 90, 92 (FIG. 6a). In control algorithm 174, MPPT 102 extracts the maximum solar power by producing dynamic voltage reference to DC voltage control 104. DC voltage control 104 regulates DC voltage by generating solar power command 180. It is then subtracted from required EV battery charging power 182 calculated by block 184 based on EV battery charging current reference I.sub.BR 186 and EV battery voltage V.sub.B 188 to get inverter power command 190. Inverter power command 190 is fed to AC current reference generation 106 to create current reference for AC current control 108 which regulates AC current by commanding SVM 110 to generate PWM signals controlling IGBT 112 to provide EV battery charging power through HV bus 12 (FIG. 6a) with part of solar energy 96, 38 (FIG. 6a) and convert the rest to AC grid power.

[0052] FIG. 7 illustrates functional block diagram of EVFCS-SES system 10 operated in Mode 4 configuration when solar power is not present and EV battery is present. In system 10, EVFCS-SES cell 14 is configured as HF transformer isolated FB DC/DC converter connecting to HV DC bus 12 with switch SW13 30 closed to charge EV battery 34 with HV DC bus 12; EVFCS-SES cell 90 is configured as a PWM rectifier connecting to HV DC bus 12 with switch SW23 150 closed to support HV DC bus 12; storage battery 16 supports HV DC bus 12 with switch SWs 36 closed. Mode 4 control library comprises HF EV charger control algorithms 172 used for EVFCS-SES cell 14 and PWM rectifier control algorithm 308 used for EVFCS-SES cell 90. Control algorithm 172 is the same as that of Mode 3. In control algorithm 308, using information of EV battery charging power and storage battery discharging power, MIPT 310 import minimum AC grid power by providing a dynamic voltage reference to DC control 104 which regulates HV DC bus 12 by generating inverter power command for AC current reference generation 106. Reference generation 106 produces current reference for current control 108 which regulates AC current by commanding SVM 110 to generate PWM signals controlling IGBT 112 to import minimum AC grid power supporting EV battery 34 charging process.

[0053] FIG. 8 illustrates functional block diagram of EVFCS-SES system 10 operated in Mode 5 configuration when solar power is not present and storage battery charging is needed. In system 10, EVFCS-SES cell 14 is configured as PWM rectifier based battery charger connecting to HV DC bus 12 with switch SW13 30 closed to charge storage battery 16 which is also connected to HV DC bus 12 with switch SWs 36 closed. Mode 5 control library comprises PWM rectifier battery charger control algorithms 238. In battery charger control 238, while battery voltage is regulated by battery voltage control 240 in constant voltage mode, battery current is regulated by battery current control 242 in constant current mode. Using the output of either voltage control 240 or current control 242, AC current reference generation 106 produces current reference for AC current control 108 which regulates AC current by commanding SVM 110 to generate PWM signals controlling IGBT 112 to charge storage battery 16.

[0054] FIGS. 9a and 9b illustrate the detailed schematic circuit diagram of EVFCS-SES cell-1 14 and cell-n 92 in system 10. IGBT based MFPCS 18 is used for AC/DC, DC/AC and DC/DC power conversions. LCL filter 326 is used to interface MFPCS 18 with AC grid power 24. Isolation transformer 330 provides the galvanic isolation and voltage matching between MFPCS 18 and AC grid power 24. Operation mode switches SW11 26, SW12 28, SW13 30 configure system 10 in either Mode 1 or Mode 2 or Mode 3 or Mode 4 or Mode 5 operations.

[0055] Universal battery interface system 32 in FIG. 9a having two identical HF transformers 334 with one primary winding and two separated secondary windings, a set of transformer re-configuration On-Off switches CT1 336, CT2 338, CT3 340, CT4 342, CT5 344, CT6 346, CT7 348, CT8 350, CT9 352 connecting those secondary windings to a diode rectifier circuit 354 converting AC voltage pulse trains to DC ones, and an output L-C filter 356 eliminating HF switching harmonic components, may be re-configured automatically such that it interfaces with EV battery 34 with any voltage ranges.

[0056] The output voltage of universal battery interface 32 in FIG. 9a is determined by transformer turns ratio n, connections of transformer primary windings and secondary windings and PWM control of MFPCS 18. Two HF transformers with turns ratio n are configured in such way that primary windings are connected in parallel while the secondary windings are operated in combination of series and /or parallel with opening and closing of switches CT1 336, CT2 338, CT3 340, CT4 342, CT5 344, CT6 346, CT7 348, CT8 350, CT9 352 under DSP control, to match voltage level with EV battery 34.

[0057] FIG. 10 illustrates transformer re-configuration control table 366 used by a controller to achieve optimal voltage level for solar power/HV DC bus voltage range of 300V-500V and transformer turns ratio of 1.5. When CT1=0, CT2=1, CT3=1, CT4=0, CT5=1, CT6=1, CT7=0, CT8=1, CT9=1, the EV fast charging station operates in battery voltage range of 150V-210V. When CT1=1, CT2=0, CT3=0, CT4=0, CT5=1, CT6=1, CT7=1, CT8=0, CT9=0, the EV fast charging station operates in battery voltage range of 300v- 420v. When CT1=1, CT2=0, CT3=0, CT4=1, CT5=0, CT6=0, CT7=1, CT8=0, CT9=0, the EV super charging station operates in battery voltage range of 600V-840V.

[0058] FIG. 11 illustrates the structure and mechanism of optimized solar energy software environment 368 used in EVFCS-SES system. The optimized solar energy software 376 inside of MFPCS 18 determines the system operation modes based on internal datas from MFPCS, the weather condition information from internet weather channel 370, and peak hour electricity rate from the data base 372.

[0059] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention, rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without depart from the sprit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.