CN116552273A - Bidirectional wireless power transmission system of electric automobile - Google Patents

Bidirectional wireless power transmission system of electric automobile Download PDF

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Publication number
CN116552273A
CN116552273A CN202310572838.7A CN202310572838A CN116552273A CN 116552273 A CN116552273 A CN 116552273A CN 202310572838 A CN202310572838 A CN 202310572838A CN 116552273 A CN116552273 A CN 116552273A
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CN
China
Prior art keywords
power switch
switch
inductance
power
frequency conversion
Prior art date
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Pending
Application number
CN202310572838.7A
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Chinese (zh)
Inventor
邓钧君
张保坤
王震坡
林倪
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Beijing Institute of Technology BIT
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Beijing Institute of Technology BIT
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Application filed by Beijing Institute of Technology BIT filed Critical Beijing Institute of Technology BIT
Priority to CN202310572838.7A priority Critical patent/CN116552273A/en
Publication of CN116552273A publication Critical patent/CN116552273A/en
Pending legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/10—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by the energy transfer between the charging station and the vehicle
    • B60L53/12—Inductive energy transfer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/10—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by the energy transfer between the charging station and the vehicle
    • B60L53/12—Inductive energy transfer
    • B60L53/122—Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/20—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by converters located in the vehicle
    • B60L53/22—Constructional details or arrangements of charging converters specially adapted for charging electric vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L55/00—Arrangements for supplying energy stored within a vehicle to a power network, i.e. vehicle-to-grid [V2G] arrangements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/005—Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/40—Circuit arrangements or systems for wireless supply or distribution of electric power using two or more transmitting or receiving devices
    • H02J50/402—Circuit arrangements or systems for wireless supply or distribution of electric power using two or more transmitting or receiving devices the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33573—Full-bridge at primary side of an isolation transformer
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/02—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc
    • H02M5/04—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters
    • H02M5/10—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The invention discloses a bidirectional wireless power transmission system of an electric automobile, and relates to the technical field of wireless charging of electric automobiles. According to the invention, the first high-frequency conversion unit and the second high-frequency conversion unit are arranged as the full-bridge converter, so that bidirectional flow of power can be realized, the switch is arranged on the connecting branch of the first high-frequency conversion unit and the ground-end compensation network, and the switch is also arranged on the connecting branch of the second high-frequency conversion unit and the vehicle-mounted-end compensation network, and the power transmission can be performed in a higher efficiency in a wide working range from light load to heavy load of the whole electric vehicle bidirectional wireless power transmission system by controlling the opening and closing of the switch.

Description

Bidirectional wireless power transmission system of electric automobile
Technical Field
The invention relates to the technical field of wireless charging of electric automobiles, in particular to a bidirectional wireless electric energy transmission system of an electric automobile.
Background
The wireless power transmission technology realizes non-contact energy transmission through magnetic field coupling, and is particularly widely applied to the field of wireless charging of electric automobiles by virtue of the advantages of convenience, safety and the like. In recent years, in order to fully develop the potential of an electric automobile as a mass distributed energy storage resource, the vehicle network interaction technology is widely focused, and under the background, the research of a wide-power efficient bidirectional wireless electric energy transmission system has important significance.
Based on this, the design schemes of the existing wireless power transmission system generally have the following several schemes:
scheme (1), bidirectional wireless charging topology
Patent CN107404135a proposes a wireless charging topology with energy flowing in both directions, as shown in fig. 7, which has a two-stage buck-boost circuit, so that the gain is the square of the gain of the common buck-boost topology, which can realize both high-gain boost and high-gain buck, and can realize a wide-range voltage class bidirectional charging occasion. And a channel is provided for bidirectional flow of energy, and the wireless power transmission requirements of special environments such as underwater are met.
Although the scheme can realize the bidirectional flow of power under a wide range of voltage levels, the two-step-up/step-down circuit is used, and more devices such as a switch tube, a diode, an inductor and the like are introduced, so that the system has high cost and large volume.
Scheme (2), constant-current constant-voltage device
Patent CN115489349a proposes a constant-current and constant-voltage device applied to a wireless charging system of an electric automobile. As shown in fig. 8, the topology is operated in a constant voltage charging mode and a constant current charging state, respectively, by changing the off or off state of the secondary side ac switch. The output power of the system ranges from 1.5 to 6kW.
The scheme can realize the switching of constant-current and constant-voltage modes, but has a narrow output power range (1.5 kW-6 kW), and is not suitable for a high-power bidirectional charging and discharging scene of an electric automobile.
Scheme (3), constant-current constant-voltage wireless charging system
Patent CN109980757a proposes a constant-current and constant-voltage wireless charging system based on topology switching, as shown in fig. 9, in this scheme, a switch switching part is added in a transmitting part (or a receiving part), a controller (K1) is used to control the opening or closing of a switch (S1), and the system is operated in a constant-current mode or a constant-voltage mode, and is suitable for charging a battery.
The scheme can realize the switching of constant-current and constant-voltage modes, but three inductors and one capacitor are needed to be reserved at the transmitting end or the ground end, so that the cost and the volume of the system are increased.
Scheme (4), wide-load-range efficient WPT system and optimization method thereof
Patent CN113629895a discloses a high-efficiency WPT system with a wide load range based on hybrid load matching and an optimization method thereof, the structure of which is shown in fig. 10, which solves the problem that the WPT system in the prior art is difficult to always keep working in a high-efficiency area, and the optimal load can be changed by hybrid reconstruction circuit topology (S-S, S-LCC) and rectification operation mode (full bridge, half bridge), so that the system always works in the high-efficiency area.
The scheme can realize the switching of constant current and constant voltage modes, and fully utilizes the half-bridge and full-bridge working modes, so that the system ensures high efficiency under various load conditions. However, the secondary side converter of this solution is a rectifier, not supporting power bi-directional flow; secondly, the invention can not realize the charging of light load high power, medium load medium power and heavy load low power.
Scheme (5), constant-current-constant-voltage charging wireless power transmission system
Patent CN113794287a proposes a constant-current-constant-voltage charging wireless power transmission system based on a dual-channel T-type circuit, whose structure is shown in fig. 11, and the system works in a constant-current or constant-voltage mode respectively by switching on a switch and a power tube.
The scheme can realize the switching of constant-current and constant-voltage modes, however, the converter mainly works in a half-bridge mode, and the maximum output power is limited, so that the scheme is not suitable for a high-power bidirectional charging and discharging scene of an electric automobile.
Disclosure of Invention
The invention aims to provide the bidirectional wireless electric energy transmission system of the electric automobile, which can perform power transmission with higher efficiency in a wide working range from light load to heavy load.
In order to achieve the above object, the present invention provides the following solutions:
a bi-directional wireless power transfer system for an electric vehicle, comprising: the system comprises a PFC module, a first high-frequency conversion unit, a ground end compensation network, a magnetic coupling coil, a vehicle-mounted end compensation network and a second high-frequency conversion unit;
the PFC module is respectively connected with a power grid and the first high-frequency conversion unit; the first high-frequency conversion unit is connected with the ground end compensation network; the ground end compensation network and the vehicle-mounted end compensation network form resonance through the magnetic coupling coil; the vehicle-mounted end compensation network is connected with the second high-frequency conversion unit; the second high-frequency conversion unit is connected with the battery of the electric automobile;
the first high-frequency conversion unit and the second high-frequency conversion unit are full-bridge converters; a switch is arranged on a connecting branch of the first high-frequency conversion unit and the ground end compensation network; and a switch is also arranged on a connecting branch of the second high-frequency conversion unit and the vehicle-mounted end compensation network.
Optionally, the first high frequency transforming unit includes: power switch S 1 Power switch S 2 Power switch S 3 And a power switch S 4 ；
The power switch S 1 And the power switch S 3 Is connected to the ground DC bus at one endA positive electrode of the wire; the power switch S 2 And power switch S 4 One end of the two ends are connected to the negative electrode of the ground direct current bus; the power switch S 1 And the other end of the power switch S 2 Is connected with the other end of the connecting rod; the power switch S 3 And the other end of the power switch S 4 Is connected with the other end of the connecting rod.
Optionally, the second high frequency transforming unit includes: power switch Q 1 Power switch Q 2 Power switch Q 3 And power switch Q 4 ；
The power switch Q 1 And the power switch Q 3 One end of the battery is connected to the anode of the battery of the electric automobile; the power switch Q 2 And power switch Q 4 One end of the battery is connected to the negative electrode of the electric automobile battery; the power switch Q 1 Is connected with the other end of the power switch Q 2 Is connected with the other end of the connecting rod; the power switch Q 3 Is connected with the other end of the power switch Q 4 Is connected with the other end of the connecting rod.
Optionally, the ground-side compensation network includes: main inductance L 1 Compensating capacitor C 1 Compensating capacitor C f1 And compensating inductance L f1 ；
The main inductance L 1 Through switch K 3 Is connected to the power switch S 1 And the power switch S 2 Is connected with the connecting branch of the connecting branch; the main inductance L 1 One end of (2) is also passed through switch K 2 Is connected to a power switch S 3 And the power switch S 4 Is connected with the connecting branch of the connecting rod;
the main inductance L 1 And the other end of the compensation capacitor C 1 Is connected with one end of the connecting rod; the compensation capacitor C 1 Respectively with the other end of the compensation capacitor C f1 And compensating inductance L f1 Is connected with one end of the connecting rod; the compensating inductance L f1 The other end of the switch K 1 Is connected to the power switch S 1 And the power switch S 2 Is connected with the connecting branch of the connecting rod; the compensation capacitor C f1 Is connected to the other end of the switch K 2 And a connection branch to the first high frequency conversion unit.
Optionally, the vehicle-mounted end compensation network includes: main inductance L 2 Compensating capacitor C 2 Compensating capacitor C f2 And compensating inductance L f2 ；
The main inductance L 2 Through switch K 5 Is connected to the power switch Q 3 And the power switch Q 4 Is connected with the connecting branch of the connecting branch; the main inductance L 2 One end of (2) is also passed through switch K 6 Connected to the power switch Q 2 A connecting branch with the negative electrode of the electric automobile battery;
the main inductance L 2 And the other end of the compensation capacitor C 2 Is connected with one end of the connecting rod; the compensation capacitor C 2 Respectively with the other end of the compensation capacitor C f2 And compensating inductance L f2 Is connected with one end of the connecting rod; the compensating inductance L f2 The other end of the switch K 4 Is connected to the power switch Q 1 And the power switch Q 2 Is connected with the connecting branch of the connecting rod; the compensation capacitor C f2 Is connected to the other end of the switch K 5 And a connection branch to the first high frequency conversion unit.
Optionally, the ground-side compensation network includes: main inductance L 1 Compensating capacitor C 1 Compensating capacitor C f1 And compensating inductance L f1 ；
The main inductance L 1 Through switch K 3 Is connected to the power switch S 1 And the power switch S 2 Is connected with the connecting branch of the connecting branch; the main inductance L 1 One end of (2) is also passed through switch K 2 Is connected to a power switch S 3 And the power switch S 4 Is connected with the connecting branch of the connecting rod; the main inductance L 1 Through switch K 4 Is connected to the power switch S 4 The connecting branch is connected with the negative electrode of the ground direct current bus;
the main inductance L 1 And the other end of the compensation capacitor C 1 Is connected with one end of the connecting rod; the compensation capacitor C 1 Respectively with the other end of the compensation capacitor C f1 One end and compensation of (2)Inductance L f1 Is connected with one end of the connecting rod; the compensating inductance L f1 The other end of the switch K 1 Is connected to the power switch S 1 And the power switch S 2 Is connected with the connecting branch of the connecting rod; the compensation capacitor C f1 Is connected to the other end of the switch K 2 And a connection branch to the first high frequency conversion unit.
Optionally, the vehicle-mounted end compensation network includes: main inductance L 2 Compensating capacitor C 2 Compensating capacitor C f2 And compensating inductance L f2 ；
The main inductance L 2 Through switch K 5 Is connected to the power switch Q 3 And the power switch Q 4 Is connected with the connecting branch of the connecting branch;
the main inductance L 2 And the other end of the compensation capacitor C 2 Is connected with one end of the connecting rod; the compensation capacitor C 2 Respectively with the other end of the compensation capacitor C f2 And compensating inductance L f2 Is connected with one end of the connecting rod; the compensating inductance L f2 Is connected to the other end of the power switch Q 1 And the power switch Q 2 Is connected with the connecting branch of the connecting rod; the compensation capacitor C f2 Is connected to the other end of the switch K 5 And a connection branch to the first high frequency conversion unit.
Optionally, the magnetic coupling coil comprises a unipolar coil and a bipolar coil;
the unipolar coil and the bipolar coil are both symmetrically disposed about a centerline.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
according to the bidirectional wireless power transmission system of the electric automobile, the first high-frequency conversion unit and the second high-frequency conversion unit are arranged as the full-bridge converter, so that bidirectional flow of power can be realized, the switch is arranged on the connecting branch of the first high-frequency conversion unit and the ground-end compensation network, the switch is also arranged on the connecting branch of the second high-frequency conversion unit and the vehicle-mounted-end compensation network, and the power transmission can be performed in high efficiency in a wide working range from light load to heavy load by controlling the on-off of the switch.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a bidirectional wireless power transmission system for an electric vehicle according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a magnetic coupling coil according to an embodiment of the present invention; fig. 2 (a) is a schematic structural diagram of a rectangular coil, fig. 2 (b) is a schematic structural diagram of a DD coil, and fig. 2 (c) is a schematic structural diagram of a DDQ coil;
fig. 3 is a schematic diagram of magnetic flux distribution of a magnetic coupling coil according to an embodiment of the present invention; wherein (a) of fig. 3 is a schematic diagram of magnetic flux in a vertical mode, and (b) of fig. 3 is a schematic diagram of distribution of magnetic flux in a parallel mode;
FIG. 4 is a schematic diagram of a compensation network according to an embodiment of the present invention; fig. 4 (a) is a schematic diagram of different topologies of the ground-side compensation network, and fig. 4 (b) is a schematic diagram of different topologies of the vehicle-mounted compensation network;
fig. 5 is a schematic diagram of a compensation network type commonly used in an electric vehicle according to an embodiment of the present invention; wherein (a) of fig. 5 is a schematic diagram of an S-S type compensation network, (b) of fig. 5 is a schematic diagram of an S-LCC type compensation network, (c) of fig. 5 is a schematic diagram of an LCC-S type compensation network, and (d) of fig. 5 is a schematic diagram of an LCC-LCC type compensation network;
FIG. 6 is a graph of power versus efficiency for a wireless power transfer system according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a wireless charging topology proposed by the scheme (1) provided in the embodiment of the present invention;
fig. 8 is a schematic structural diagram of a constant-current and constant-voltage device of a wireless charging system according to the scheme (2) provided by the embodiment of the invention;
fig. 9 is a schematic structural diagram of a constant-current constant-voltage wireless charging system according to the scheme (3) provided by the embodiment of the invention;
fig. 10 is a schematic structural diagram of a WPT system with a wide load range and high efficiency according to scheme (4) provided in an embodiment of the present invention;
fig. 11 is a schematic structural diagram of a constant-current and constant-voltage wireless power transmission system according to the scheme (5) provided by the embodiment of the invention;
FIG. 12 is a schematic diagram illustrating an analysis of output characteristics of each resonance compensation network according to an embodiment of the present invention; fig. 12 (a) is an analysis schematic diagram of an S-S type compensation network output characteristic, fig. 12 (b) is an analysis schematic diagram of an S-LCC type compensation network output characteristic, fig. 12 (c) is an analysis schematic diagram of an LCC-S type compensation network output characteristic, and fig. 12 (d) is an analysis schematic diagram of an LCC-LCC type compensation network output characteristic;
fig. 13 is a schematic diagram of three schemes of an orthogonal decoupling coil according to an embodiment of the present invention; the main inductor (a) in fig. 13 is a DD coil, the auxiliary inductor is a schematic structure of a rectangular coil, the main inductor (b) in fig. 13 is a schematic structure of a rectangular coil, the auxiliary inductor is a schematic structure of a DD coil, and the main inductor and the auxiliary inductor (c) in fig. 13 are schematic structures of DD coils;
fig. 14 is a schematic diagram of a topology structure of a bidirectional wireless power transmission system of a first electric vehicle according to an embodiment of the present invention;
fig. 15 is a schematic diagram of each working mode in the first bidirectional wireless power transmission system for an electric vehicle according to the embodiment of the present invention; fig. 15 (a) is a schematic diagram of an operation mode of the bidirectional wireless power transmission system of the first electric vehicle when the voltage of the vehicle-mounted battery is low, fig. 15 (b) is a schematic diagram of an operation mode of the bidirectional wireless power transmission system of the first electric vehicle when the voltage of the vehicle-mounted battery is raised to a certain extent, fig. 15 (c) is a schematic diagram of an operation mode of the bidirectional wireless power transmission system of the first electric vehicle when the voltage of the vehicle-mounted battery is raised to a larger value, and fig. 15 (d) is a schematic diagram of an operation mode of the bidirectional wireless power transmission system of the first electric vehicle when the voltage of the vehicle-mounted battery is high;
fig. 16 is a schematic diagram of a topology structure of a second bidirectional wireless power transmission system for an electric vehicle according to an embodiment of the present invention;
fig. 17 is a schematic diagram of each working mode in a second bidirectional wireless power transmission system for an electric vehicle according to an embodiment of the present invention; fig. 17 (a) is a schematic diagram of an operation mode of the second bidirectional wireless power transmission system of the electric vehicle when the voltage of the vehicle-mounted battery is low, fig. 17 (b) is a schematic diagram of an operation mode of the second bidirectional wireless power transmission system of the electric vehicle when the voltage of the vehicle-mounted battery is raised to a certain extent, fig. 17 (c) is a schematic diagram of an operation mode of the second bidirectional wireless power transmission system of the electric vehicle when the voltage of the vehicle-mounted battery is raised to a larger value, and fig. 17 (d) is a schematic diagram of an operation mode of the second bidirectional wireless power transmission system of the electric vehicle when the voltage of the vehicle-mounted battery is high;
fig. 18 is a constant-current constant-voltage phase charging graph during forward power transmission according to an embodiment of the present invention;
fig. 19 is a graph showing power variation during forward power transmission according to an embodiment of the present invention;
FIG. 20 is a graph showing current variation during reverse power transmission according to an embodiment of the present invention;
fig. 21 is a graph showing power variation during reverse power transmission according to an embodiment of the present invention.
Reference numerals illustrate:
the system comprises a 1-PFC module, a 2-first high-frequency conversion unit, a 3-ground end compensation network, a 4-magnetic coupling coil, a 5-vehicle-mounted end compensation network and a 6-second high-frequency conversion unit.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide the bidirectional wireless electric energy transmission system of the electric automobile, which can perform power transmission with higher efficiency in a wide working range from light load to heavy load.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
As shown in fig. 1, the bidirectional wireless power transmission system for an electric automobile provided by the invention comprises: the Power Factor Correction (PFC) module 1, a first high-frequency conversion unit 2, a ground-side compensation network 3, a magnetic coupling coil 4, a vehicle-mounted-side compensation network 5 and a second high-frequency conversion unit 6.
The PFC module 1 is connected to the power grid and to the first high-frequency conversion unit 2, respectively. The first high frequency conversion unit 2 is connected to a ground-side compensation network 3. The ground-side compensation network 3 resonates with the vehicle-mounted-side compensation network 5 via the magnetic coupling coil 4. The on-board compensation network 5 is connected to the second high-frequency conversion unit 6. The second high frequency conversion unit 6 is connected to an electric vehicle battery.
The first high frequency transforming unit 2 and the second high frequency transforming unit 6 are both full bridge converters. A switch is arranged on the connection branch of the first high-frequency conversion unit 2 and the ground-side compensation network 3. A switch is also provided on the connection leg of the second high-frequency conversion unit 6 to the vehicle-mounted compensation network 5.
Based on the above structure, when the electric network charges the battery of the electric vehicle (defined as power forward transmission), the power frequency ac voltage from the electric network is converted into the intermediate dc voltage through the rectification of the PFC module 1. The first high-frequency conversion unit 2 behind the PFC module 1 works in an inversion mode, inverts the intermediate-stage direct current to generate high-frequency alternating current, and injects the high-frequency alternating current into a resonance network formed by the ground-end compensation network 3 and the magnetic coupling coil 4. Under the influence of the alternating magnetic field, the magnetic coupling coil 4 induces a high-frequency alternating voltage, resonates with the vehicle-mounted end compensation network 5, and transmits energy to the battery of the electric vehicle through the second high-frequency conversion unit 6 (working in a rectification mode, converting high-frequency alternating current into direct current).
When the battery discharges to the power grid (defined as power reverse transmission), the second high-frequency conversion unit 6 operates in an inversion mode, inverts the direct current of the battery of the electric vehicle to generate high-frequency alternating current, and injects the high-frequency alternating current into a resonance network composed of the vehicle-mounted terminal compensation network 5 and the magnetic coupling coil 4. Under the influence of the alternating magnetic field, the magnetic coupling coil 4 induces high-frequency alternating voltage, resonates with the ground-end compensation network 3, converts energy into power frequency alternating current through the first high-frequency conversion unit 2 (working in an inversion mode and converting the high-frequency alternating current into direct current), inverts the power frequency alternating current into power frequency alternating current through the PFC module 1, and finally transmits the power to a power grid.
The determination of the specific structure of each part in the bidirectional wireless power transmission system for electric vehicles provided by the invention is described below in terms of technical conception and technical purpose achieved.
The magnetic coupling coil 4 and the compensation network are important components of the wireless charging system.
The magnetic coupling coil 4 of the existing wireless charging system is mainly divided into a unipolar coil, a bipolar coil and a composite coil. In the unipolar coil, since the rectangular shape can more fully utilize the space of the vehicle chassis, it is applied more. The bipolar coil is mainly represented by a DD coil. The DDQ coil can be obtained by placing the DD coil and the rectangular coil in a quadrature lamination manner, as shown in fig. 2.
As shown in fig. 3, the magnetic flux distribution of the unipolar coil is mainly represented by a vertical mode, and the bipolar coil is represented by a parallel mode. Therefore, coils of the same polarity are often used for power transfer. Since the DDQ coil is composed of unipolar and bipolar coils, decoupling of the two coils can be achieved if properly arranged. Taking a unipolar coil as an example, when the magnitude of the magnetic flux flowing into the unipolar coil by the bipolar coil is equal to that of the magnetic flux flowing out of the unipolar coil, the magnetic flux coupling between the two coils is approximately 0, so as to realize decoupling.
The typical coupling coefficient k of the magnetic coupling coil 4 of the electric automobile is about 0.2-0.4, and in order to enable the coupling system to efficiently transmit electric energy, reactive compensation needs to be performed on the magnetic coupling coil 4, so that a high-frequency resonant network is formed together. The compensation network can effectively reduce the apparent power level of the transmitting-end inverter and the reactive power of the resonant cavity, improve the power transmission capacity, realize constant current/constant voltage output, improve the transmission efficiency and resist the frequency bifurcation phenomenon.
As shown in fig. 4, according to the connection mode of the compensation capacitor/inductor and the magnetic coupling coil 4, there are mainly Series (S) compensation, parallel (P) compensation, series-Parallel (LCL) compensation, LCC compensation derived on the basis of these, and the like. In FIG. 4, L is a magnetic coupling coil 4, C, L f 、C f Are compensation elements, and subscripts 1 and 2 represent a ground end and a vehicle-mounted end respectively. For the electric automobile application scenario, the common compensation networks are S-S, S-LCC, LCC-S and LCC-LCC, respectively, as shown in FIG. 5. Wherein, the S-S, LCC-LCC can realize natural constant-current charging, and the S-LCC and LCC-S can realize natural constant-voltage charging.
Furthermore, existing systems are difficult to maintain efficient over a wide power range. As shown in fig. 6, for a general wireless power transmission system, the transmission efficiency is also improved with the increase of the transmission power, that is, the efficiency of the system is generally not high in light load, and the transmission efficiency is high in medium and heavy load.
Further, the compensation network parameter design method and the output characteristic are analyzed.
The output characteristics of the various types of compensation networks are shown in figure 12, wherein the various types of compensation networks are used as research objects and are sequentially S-S, S-LCC and LCC-S, LCC-LCC. Wherein R is eq Is equivalent to load resistance, U p And U s Respectively the effective values of the excitation voltage of the converter, if the voltage of the ground-end direct current bus and the voltage of the battery are respectively V 1 And V 2 The high-frequency converters at two ends are all full-bridge circuits, and the maximum effective values of fundamental waves of excitation voltages are respectively as follows:
if the high-frequency converters at two ends are all half-bridge circuits, the maximum effective values of fundamental waves of excitation voltages are respectively as follows:
the maximum output voltage of the half-bridge converter is half that of the full-bridge converter. Referring to table 1, the output power is proportional to the double-ended voltage.
Thus at DC bus voltage V 1 And battery voltage V 2 A timing:
if the two-terminal converters are in full-bridge mode, the maximum output power is P max 。
If the two-terminal converters are in half-bridge mode, the maximum output power is P max /4。
If the two-terminal converter is in full-bridge mode and half-bridge mode respectively, the maximum output power is P max /2。
Therefore, the maximum output power can be limited by controlling the operation mode of the inverter.
In FIG. 12, L 1 、L 2 Is the main inductance, C f1 、C 1 ，C f2 、C 2 To compensate for capacitance, L f1 、L f2 To compensate for the inductance. M is M 1-2 And M f1-f2 Representing the mutual inductance between the main coils and the mutual inductance between the auxiliary coils, respectively.
The invention makes each resonant cavity work under pure resonance condition omega 0 Is the nominal angular frequency.
For S compensation, satisfy
For LCC compensation, satisfy
For conventional LCC compensation, the conventional LCC compensation uses only the main inductance L as the energy-transfer coil (see (d) of fig. 5), while the auxiliary inductance L f Only the compensation element is acting. Auxiliary inductor L in the invention f1 And L f2 The wireless power transmission system has the functions of compensation and energy transmission, so that two coils at the ground end/vehicle-mounted end in the wireless power transmission system can transmit energy.
In addition, in order to reduce the space between the coils on the same side and the coils on the different sideThe present invention uses an orthogonal decoupling coil as a magnetic coupling coil, as shown in fig. 13, and the three coil designs are: (1) the main inductance L is DD coil, the auxiliary inductance L f Is a rectangular coil as shown in fig. 13 (a). (2) The main inductance is a rectangular coil, and the auxiliary inductance is a DD coil, as shown in fig. 13 (b). (3) The main inductance and the auxiliary inductance are DD coils, but the directions are different by 90 °, as shown in fig. 13 (c). Wherein the same-side coils are symmetrically placed about the center line to achieve decoupling.
The output characteristics and maximum transmission power of each compensation network are summarized in Table 1 below, where M represents the mutual inductance between the inductances, I out Representing the resonant cavity output current. It is readily apparent that as the excitation voltage increases, the transmission power also increases.
Table 1 analysis table of output characteristics of each resonance compensation network
Further, based on the above description, taking the DC-DC link from the DC bus output by the PFC module 1 to the power battery in fig. 1 as a research object, taking the first type of orthogonal decoupling coil as an example, two different topologies of the bidirectional wireless power transmission system for electric vehicles are proposed.
The topology structure of the first two-way wireless power transmission system of the electric automobile is shown in fig. 14. V (V) 1 、V 2 The high-frequency conversion units (namely the first high-frequency conversion unit 2 and the second high-frequency conversion unit 6) of the ground-side compensation network 3 and the vehicle-side compensation network 5 are respectively voltage sources representing a direct-current bus and a power battery and are respectively full-bridge converters, and are respectively formed by MOSFET power switches S 1 ～S 4 、Q 1 ～Q 4 The composition (for simplicity, the dc support capacitance between the voltage source and the full bridge converter is not drawn). L (L) 1 、L 2 Main inductances of the ground-side compensation network 3 and the vehicle-side compensation network 5, C f1 、C 1 ，C f2 、C 2 Compensation capacitors L of the ground-side compensation network 3 and the vehicle-side compensation network 5 respectively f1 、L f2 The compensating inductances of the ground compensating network 3 and the vehicle compensating network 5 are respectively.
On six branches of the ground-side compensation network 3 and the vehicle-mounted compensation network 5, switches K are respectively added 1 、K 2 、K 3 ，K 4 、K 5 、K 6 The above-mentioned change-over switch K 1 ～K 6 May be a relay or a bi-directional power switch. If the switch is closed, the corresponding branch is turned on. If the switch is opened, the corresponding branch circuit is opened.
Based on the above description, in the first bidirectional wireless power transmission system of electric automobile, the main inductance L 1 Through switch K 3 Is connected to a power switch S 1 And a power switch S 2 Is provided. Main inductance L 1 One end of (2) is also passed through switch K 2 Is connected to a power switch S 3 And power switch S 4 Is connected to the connecting branch of the (c).
Main inductance L 1 And the other end of (C) is connected with a compensation capacitor C 1 Is connected to one end of the connecting rod. Compensating capacitor C 1 Respectively with the other end of the compensation capacitor C f1 And compensating inductance L f1 Is connected to one end of the connecting rod. Compensating inductance L f1 The other end of the switch K 1 Is connected to a power switch S 1 And a power switch S 2 Is connected to the connecting branch of the (c). Compensating capacitor C f1 Is connected to the switch K 2 A connection branch to the first high frequency conversion unit 2.
Main inductance L 2 Through switch K 5 Connected to the power switch Q 3 And a connection leg of the power switch Q4. Main inductance L 2 One end of (2) is also passed through switch K 6 Connected to the power switch Q 2 And a connecting branch with the negative electrode of the electric automobile battery.
Main inductance L 2 And the other end of (C) is connected with a compensation capacitor C 2 Is connected to one end of the connecting rod. Compensating capacitor C 2 Respectively with the other end of the compensation capacitor C f2 And compensating inductance L f2 Is connected to one end of the connecting rod. Compensating inductance L f2 The other end of the switch K 4 Connected to the power switch Q 1 And power switch Q 2 Is connected to the connecting branch of the (c). Compensating capacitor C f2 Is connected to the switch K 5 A connection branch to the first high frequency conversion unit 2.
Unlike conventional unidirectional wireless power transmission systems, the receiving-side converter often adopts uncontrolled rectification (composed of diodes), so that only forward energy transmission can be performed. In the topological structure of the bidirectional wireless electric energy transmission system of the electric automobile, the full-bridge converter is composed of full-control devices, so that bidirectional flow of power can be realized.
Fig. 15 illustrates various modes of operation of the first system topology. Wherein:
(1) When the voltage of the vehicle-mounted battery is low, the power is transmitted forward to charge the battery, and constant current charging is needed. As shown in fig. 15 (a), the switch K is made 1 、K 4 When the other switches are closed and the other switches are opened, the ground-side compensation network 3 (hereinafter referred to as ground-side) and the vehicle-side compensation network 5 (hereinafter referred to as vehicle-side) form an S-S compensation network, and the auxiliary coil L f1 And L f2 Is used for energy transmission. The ground-side high-frequency converter (i.e., the first high-frequency conversion unit 2) operates in a full-bridge inversion mode, and the vehicle-side high-frequency converter (i.e., the second high-frequency conversion unit 6) operates in a full-bridge rectification mode.
As the bus voltage and battery voltage increase, the power transferred increases. In the S-S mode, constant current charging can be realized. On the other hand, because the self inductance and mutual inductance of the auxiliary coil are smaller, the transmission power of the system is larger, thereby realizing light-load high-power transmission.
(2) When the voltage of the vehicle-mounted battery rises to a certain degree, the power is transmitted forward to charge the battery, and the constant-current mode is still maintained but the required current is reduced. As shown in fig. 15 (b), the switch K is made 1 、K 2 、K 4 、K 5 When the other switches are closed and the other switches are opened, the ground end compensation network 3 and the vehicle end compensation network 5 form a double-coupling LCC-LCC compensation network L 1 、L 2 Auxiliary coil L f1 、L f2 All are used for energy transmission. The ground-side high-frequency converter (namely, the first high-frequency conversion unit 2) works in a full-bridge inversion mode, and the vehicle-mounted-side high-frequency converter (namely, the second high-frequency converterThe frequency conversion unit 6) operates in a full bridge rectification mode.
As the bus voltage and battery voltage increase, the power transferred increases. Constant current charging can be realized in a double-coupling LCC-LCC mode. On the other hand, mutual inductance parameters are designed to enable the transmission power of the system to be in a target range, so that medium-load medium-power transmission is realized.
(3) When the voltage of the vehicle-mounted battery rises to a larger value, the power forward transmission charges the battery, the constant voltage mode is changed to charge, and the charging current continuously drops. As shown in fig. 15 (c), the switch K is made 1 、K 2 、K 6 When the other switches are closed and the other switches are opened, the ground end and the vehicle-mounted end form an LCC-S compensation network, and the main coil L 1 And L 2 Is used for energy transmission. In the LCC-S mode, constant voltage charging can be achieved. The ground-side high-frequency converter works in a full-bridge inversion mode. Power switch Q 1 And Q 2 Is always in an off state by controlling the power switch Q 3 And Q 4 The on/off of the vehicle-mounted high-frequency converter is enabled to work in a half-bridge rectification mode. Thus, the excitation voltage of the converter port becomes 1/2 in full bridge mode, limiting the output capability, thus adapting to low power transmission at heavy loads.
(4) When the vehicle battery voltage is high, the power is reversely transmitted to discharge to the power grid. As shown in fig. 15 (d), the switch K is made 3 、K 4 、K 5 When the other switches are closed and the other switches are opened, the ground end and the vehicle-mounted end form an S-LCC compensation network, and the main coil L 1 And L 2 Is used for energy transmission. In the S-LCC mode, a constant voltage discharge can be realized. The vehicle-mounted high-frequency converter works in a full-bridge inversion mode, and the ground-side high-frequency converter works in a full-bridge rectification mode. Thus, reverse high power transmission can be achieved.
The topology of the second type of electric vehicle bidirectional wireless power transmission system is shown in fig. 16. The scheme is characterized in that a switch K is respectively added on four branches of a ground end and one branch of a vehicle-mounted end 1 ～K 4 And switch K 5 。
Specifically, the main inductance L 1 Through switch K 3 Is connected to a power switch S 1 And a connection leg of the power switch S2. Main inductance L 1 One end of (2) is also passed through switch K 2 Is connected to a power switch S 3 And power switch S 4 Is connected to the connecting branch of the (c). Main inductance L 1 Through switch K 4 Is connected to a power switch S 4 And a connecting branch with the negative electrode of the ground direct current bus.
Main inductance L 1 And the other end of (C) is connected with a compensation capacitor C 1 Is connected to one end of the connecting rod. Compensating capacitor C 1 Respectively with the other end of the compensation capacitor C f1 And compensating inductance L f1 Is connected to one end of the connecting rod. Compensating inductance L f1 The other end of the switch K 1 Is connected to a power switch S 1 And a power switch S 2 Is connected to the connecting branch of the (c). Compensating capacitor C f1 Is connected to the switch K 2 A connection branch to the first high frequency conversion unit 2.
Main inductance L 2 Through switch K 5 Connected to the power switch Q 3 And a connection leg of the power switch Q4.
Main inductance L 2 And the other end of (C) is connected with a compensation capacitor C 2 Is connected to one end of the connecting rod. Compensating capacitor C 2 Respectively with the other end of the compensation capacitor C f2 And compensating inductance L f2 Is connected to one end of the connecting rod. Compensating inductance L f2 Is connected to the power switch Q 1 And power switch Q 2 Is connected to the connecting branch of the (c). Compensating capacitor C f2 Is connected to the switch K 5 A connection branch to the first high frequency conversion unit 2.
Fig. 17 illustrates various modes of operation of the second system topology. Wherein:
(1) When the voltage of the vehicle-mounted battery is low, the power is transmitted forward to charge the battery, and constant current charging is needed. As shown in fig. 17 (a), the switch K is made 1 When the other switches are closed and the other switches are opened, the ground end and the vehicle-mounted end form an S-S compensation network, and the auxiliary coil L f1 And L f2 Is used for energy transmission. The ground-side high-frequency converter works in a full-bridge inversion mode, and the vehicle-mounted-side high-frequency converter works in a full-bridge rectification mode.
As the bus voltage and battery voltage increase, the power transferred increases. In the S-S mode, constant current charging can be realized. On the other hand, because the self inductance and mutual inductance of the auxiliary coil are smaller, the transmission power of the system is larger, thereby realizing light-load high-power transmission.
(2) When the voltage of the vehicle-mounted battery rises to a certain degree, the power is transmitted forward to charge the battery, the constant-current mode charge is still kept, and the required current is reduced. As shown in fig. 17 (b), the switch K is made 1 、K 2 、K 5 When the other switches are closed and the other switches are opened, the ground end and the vehicle-mounted end form a double-coupling LCC-LCC compensation network, and the main coil L 1 、L 2 Auxiliary coil L f1 、L f2 All are used for energy transmission. The ground-side high-frequency converter works in a full-bridge inversion mode, and the vehicle-mounted-side high-frequency converter works in a full-bridge rectification mode.
As the bus voltage and battery voltage increase, the power transferred increases. Constant current charging can be realized in a double-coupling LCC-LCC mode. On the other hand, mutual inductance parameters are designed to enable the transmission power of the system to be in a target range, so that medium-load medium-power transmission is realized.
(3) When the voltage of the vehicle-mounted battery rises to a higher value, the power forward transmission charges the battery, the constant voltage mode is changed to charge, and the charging current continuously drops. As shown in fig. 17 (c), the switch K is made 4 、K 5 When the other switches are closed and the other switches are opened, the ground end and the vehicle-mounted end form an S-LCC compensation network, and the main coil L 1 And L 2 Is used for energy transmission. In the S-LCC mode, constant voltage charging can be achieved. Power switch S 1 And S is 2 Always in the off state by controlling S 3 And S is 4 The ground-side high-frequency converter is enabled to work in a half-bridge inversion mode. Power switch Q 1 Always in the off state, Q 2 Always in an on state by controlling Q 3 And Q 4 The on/off of the vehicle-mounted high-frequency converter is enabled to work in a half-bridge rectification mode. Therefore, the excitation voltage of the ports of the double-ended converter is 1/2 of that of the full-bridge mode, and the output capacity is limited, so that the double-ended converter is suitable for low-power transmission in heavy load.
(4) When the voltage of the vehicle-mounted battery is relatively highAt high, the power is discharged to the grid in reverse. As shown in fig. 17 (d), let K 3 、K 5 When the other switches are closed and the other switches are opened, the ground end and the vehicle-mounted end form an S-LCC compensation network, and the main coil L 1 And L 2 Is used for energy transmission. In the S-LCC mode, a constant voltage discharge can be realized. The vehicle-mounted high-frequency converter works in a full-bridge inversion mode, and the ground-side high-frequency converter works in a full-bridge rectification mode. Thus, reverse high power transmission can be achieved.
According to the above operation mode, the charging curve at the time of forward power transmission is shown in fig. 18. And when the battery is lightly loaded, an S-S mode (a first working mode of the first topological structure or the second topological structure) is adopted to charge the battery at a constant current stage (high current). The LCC-LCC mode (the second operation mode of the first or second topology) is used for constant current stage (low current charging) when the battery is loaded. When the battery is reloaded, the LCC-S (third working mode of the first topological structure) or the S-LCC mode (third working mode of the second topological structure) is adopted and is used as a constant voltage stage (current is continuously reduced).
The power change curve at the time of power forward transmission is shown in fig. 19. And when the bus voltage and the battery voltage rise, the transmitted power is increased. The LCC-LCC mode is adopted when the battery is in the middle load state, and when the bus voltage and the battery voltage rise, the transmitted power is increased. When the battery is reloaded, the LCC-S or S-LCC mode is adopted, and the charging current and the power are continuously reduced along with the increase of the equivalent resistance of the battery.
For the conventional wireless power transmission system, the conventional wireless power transmission system is subjected to a light-load-heavy-load charging process in the same working mode, so that inefficiency in the light-load stage is unavoidable. For the topology structure provided by the invention, the system always works in the corresponding medium-load and heavy-load range under each working mode (for example, the maximum output capacity of the S-S mode is 30kW, the maximum output capacity of the LCC-LCC mode is only 11kW and only 5-11 kW in the system of the invention), so that the transmission efficiency can always be kept at high efficiency.
The current and power curves at the time of power reverse transmission are shown in fig. 20 and 21. The system provided by the invention works in an S-LCC mode (a fourth mode of two topologies), and as the voltage of a battery is reduced, the magnitude of discharge current is gradually reduced, and the discharge power is also reduced. The reverse discharge is terminated when the battery voltage drops to a medium voltage.
Based on the above description, the bidirectional wireless power transmission system for the electric automobile provided by the invention has the following advantages compared with the prior art:
1) The invention provides three orthogonal decoupling coil schemes, wherein the main inductor and the auxiliary inductor can transmit energy, and bidirectional power flow is realized.
2) The invention provides two switchable bidirectional wireless power transmission system topologies, which are switched into different compensation networks through the closing or the closing of a switch, so that a constant current/constant voltage output mode is realized.
3) In the forward power transmission mode, the battery is charged with high power in light load, is charged with medium power in medium load and is charged with low power in heavy load, and in the reverse power transmission mode, the battery is discharged with high power in high voltage, so that the battery realizes the charging modes of light load with high power, medium load with medium power and heavy load with low power, and can realize reverse high power discharge, thereby being suitable for the bidirectional charging and discharging scene of the electric automobile.
4) The system provided by the invention can efficiently transmit energy in a wide power working range. The maximum output capacity is high, and the transmission efficiency in a wide working range is high.
5) Compared with a common wireless power transmission system based on LCC-LCC compensation, the invention does not add any redundant inductance or capacitance, and can complete the switching of the constant-current constant-voltage mode by only adding a plurality of switches on the branch.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.

Claims (8)

1. A bi-directional wireless power transfer system for an electric vehicle, comprising: the system comprises a PFC module, a first high-frequency conversion unit, a ground end compensation network, a magnetic coupling coil, a vehicle-mounted end compensation network and a second high-frequency conversion unit;
the PFC module is respectively connected with a power grid and the first high-frequency conversion unit; the first high-frequency conversion unit is connected with the ground end compensation network; the ground end compensation network and the vehicle-mounted end compensation network form resonance through the magnetic coupling coil; the vehicle-mounted end compensation network is connected with the second high-frequency conversion unit; the second high-frequency conversion unit is connected with the battery of the electric automobile;
the first high-frequency conversion unit and the second high-frequency conversion unit are full-bridge converters; a switch is arranged on a connecting branch of the first high-frequency conversion unit and the ground end compensation network; and a switch is also arranged on a connecting branch of the second high-frequency conversion unit and the vehicle-mounted end compensation network.
2. The electric car bidirectional wireless power transmission system according to claim 1, wherein the first high-frequency conversion unit includes: power switch S 1 Power switch S 2 Power switch S 3 And a power switch S 4 ；
The power switch S 1 And the power switch S 3 One end of each of the two ends is connected to the positive electrode of the ground direct current bus; the power switch S 2 And power switch S 4 One end of the two ends are connected to the negative electrode of the ground direct current bus; the power switch S 1 And the other end of the power switch S 2 Is connected with the other end of the connecting rod; the power switch S 3 Is connected with the other end of the powerSwitch S 4 Is connected with the other end of the connecting rod.
3. The electric car bidirectional wireless power transmission system according to claim 2, wherein the second high-frequency conversion unit includes: power switch Q 1 Power switch Q 2 Power switch Q 3 And power switch Q 4 ；
The power switch Q 1 And the power switch Q 3 One end of the battery is connected to the anode of the battery of the electric automobile; the power switch Q 2 And power switch Q 4 One end of the battery is connected to the negative electrode of the electric automobile battery; the power switch Q 1 Is connected with the other end of the power switch Q 2 Is connected with the other end of the connecting rod; the power switch Q 3 Is connected with the other end of the power switch Q 4 Is connected with the other end of the connecting rod.
4. The electric car bi-directional wireless power transfer system of claim 3, wherein the ground-side compensation network comprises: main inductance L 1 Compensating capacitor C 1 Compensating capacitor C f1 And compensating inductance L f1 ；
The main inductance L 1 Through switch K 3 Is connected to the power switch S 1 And the power switch S 2 Is connected with the connecting branch of the connecting branch; the main inductance L 1 One end of (2) is also passed through switch K 2 Is connected to a power switch S 3 And the power switch S 4 Is connected with the connecting branch of the connecting rod;
the main inductance L 1 And the other end of the compensation capacitor C 1 Is connected with one end of the connecting rod; the compensation capacitor C 1 Respectively with the other end of the compensation capacitor C f1 And compensating inductance L f1 Is connected with one end of the connecting rod; the compensating inductance L f1 The other end of the switch K 1 Is connected to the power switch S 1 And the power switch S 2 Is connected with the connecting branch of the connecting rod; the compensation capacitor C f1 Is connected to the other end of the switch K 2 Connection branch with first high-frequency conversion unitOn the road.
5. The bi-directional wireless power transfer system of an electric vehicle of claim 4, wherein the on-board compensation network comprises: main inductance L 2 Compensating capacitor C 2 Compensating capacitor C f2 And compensating inductance L f2 ；
The main inductance L 2 Through switch K 5 Is connected to the power switch Q 3 And the power switch Q 4 Is connected with the connecting branch of the connecting branch; the main inductance L 2 One end of (2) is also passed through switch K 6 Connected to the power switch Q 2 A connecting branch with the negative electrode of the electric automobile battery;
the main inductance L 2 And the other end of the compensation capacitor C 2 Is connected with one end of the connecting rod; the compensation capacitor C 2 Respectively with the other end of the compensation capacitor C f2 And compensating inductance L f2 Is connected with one end of the connecting rod; the compensating inductance L f2 The other end of the switch K 4 Is connected to the power switch Q 1 And the power switch Q 2 Is connected with the connecting branch of the connecting rod; the compensation capacitor C f2 Is connected to the other end of the switch K 5 And a connection branch to the first high frequency conversion unit.
6. The electric car bi-directional wireless power transfer system of claim 3, wherein the ground-side compensation network comprises: main inductance L 1 Compensating capacitor C 1 Compensating capacitor C f1 And compensating inductance L f1 ；
The main inductance L 1 Through switch K 3 Is connected to the power switch S 1 And the power switch S 2 Is connected with the connecting branch of the connecting branch; the main inductance L 1 One end of (2) is also passed through switch K 2 Is connected to a power switch S 3 And the power switch S 4 Is connected with the connecting branch of the connecting rod; the main inductance L 1 Through switch K 4 Is connected to the power switch S 4 The connecting branch is connected with the negative electrode of the ground direct current bus;
the main inductance L 1 And the other end of the compensation capacitor C 1 Is connected with one end of the connecting rod; the compensation capacitor C 1 Respectively with the other end of the compensation capacitor C f1 And compensating inductance L f1 Is connected with one end of the connecting rod; the compensating inductance L f1 The other end of the switch K 1 Is connected to the power switch S 1 And the power switch S 2 Is connected with the connecting branch of the connecting rod; the compensation capacitor C f1 Is connected to the other end of the switch K 2 And a connection branch to the first high frequency conversion unit.
7. The bi-directional wireless power transfer system of an electric vehicle of claim 6, wherein the on-board compensation network comprises: main inductance L 2 Compensating capacitor C 2 Compensating capacitor C f2 And compensating inductance L f2 ；
The main inductance L 2 Through switch K 5 Is connected to the power switch Q 3 And the power switch Q 4 Is connected with the connecting branch of the connecting branch;
the main inductance L 2 And the other end of the compensation capacitor C 2 Is connected with one end of the connecting rod; the compensation capacitor C 2 Respectively with the other end of the compensation capacitor C f2 And compensating inductance L f2 Is connected with one end of the connecting rod; the compensating inductance L f2 Is connected to the other end of the power switch Q 1 And the power switch Q 2 Is connected with the connecting branch of the connecting rod; the compensation capacitor C f2 Is connected to the other end of the switch K 5 And a connection branch to the first high frequency conversion unit.
8. The electric vehicle bidirectional wireless power transmission system of claim 1, wherein the magnetically coupled coil comprises a unipolar coil and a bipolar coil;
the unipolar coil and the bipolar coil are both symmetrically disposed about a centerline.
CN202310572838.7A 2023-05-22 2023-05-22 Bidirectional wireless power transmission system of electric automobile Pending CN116552273A (en)

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