WO2020112051A2

WO2020112051A2 - A wireless power transfer system

Info

Publication number: WO2020112051A2
Application number: PCT/TR2019/050684
Authority: WO
Inventors: Navid TAYEBI; Nader TAYEBI
Original assignee: Wi Energy Elektrik Sanayi Ve Ticaret Anonim Sirketi
Priority date: 2018-08-15
Filing date: 2019-08-14
Publication date: 2020-06-04
Also published as: WO2020112051A3

Abstract

The present invention is a wireless power transfer system (10) for charging batteries in a wireless manner, wherein said wireless power transfer system (10) comprises an inverter (150) connected to a first end where DC input voltage is provided and arranged to transform said input voltage into sinusoidal waveform at a f1 frequency; and a transmitter circuit (160) associated with the inverter (150) which receives the voltage in sinusoidal waveform received from said inverter (150); said transmitter circuit (160) comprises a first winding (161) for providing transferring of the voltage, received from the inverter (150), in a wireless manner; said wireless power transfer system (10) further comprises a receiver circuit (210) having a second winding (211) associated with the battery (300) to be charged; a control unit arranged to monitor the phase difference angle between the first voltage and the inverter (150); and the control unit is arranged to gradually increase the f1 frequency until the phase difference exceeds 0 and to provide continuation of the power transfer process with the obtained f1 frequency when the phase difference exceeds 0 or is equal to 0.

Description

A WIRELESS POWER TRANSFER SYSTEM

TECHNICAL FIELD

The present invention relates to a wireless power transfer system for providing charging of batteries in a wireless manner.

PRIOR ART

Electrical automobiles are becoming more popular and frequent in our lives every passing day. As electricity is begun to be used in automobile sector, vehicles, which operate with electricity, are begun to be produced in different countries worldwide. Besides providing fuel saving, they move in a silent manner and they provide extra comfort for the driver and for the passengers.

As the number of electrical vehicles increase every passing day and as the movement distance of electrical vehicles is short, electrical vehicles need continuous charge and pluralities of charging stations are needed. However, in charging stations like parking areas, shopping centers where pluralities of vehicles exist, the usage of wired charging stations leads to wire dirt and the mixing of these wires, and even crushing of these wires lead to safety problems. Moreover, when the population existing in big cities is taken into consideration, the problem of wire number leads to problems everywhere as mentioned above since residences are not generally detached.

In the present art, in the studies made in wireless charging systems, the receiver and the transmitter are together. However, as these wireless charging points become frequent, problems occur in the compliancy between the wireless charging stations produced in different structures from different producers and the wireless charging receiver fixed onto the vehicle.

As a result, because of all of the abovementioned problems, an improvement is required in the related technical field. BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a wireless power transfer system, for eliminating the above mentioned disadvantages and for bringing new advantages to the related technical field.

An object of the present invention is to provide a wireless power transfer system which provides power transfer with increased efficiency.

Another object of the present invention is to provide a wireless power transfer system which provides charging of batteries at different modes.

Another object of the present invention is to provide a wireless power transfer system which provides power transfer with increased efficiency even if there is shift in the position of the vehicle with respect to the power transfer system.

In order to realize all of the abovementioned objects and the objects which are to be deducted from the detailed description below, the present invention is a wireless power transfer system for charging batteries in a wireless manner. Accordingly, said wireless power transfer system comprises an inverter connected to a first end where DC input voltage is provided and arranged to transform said input voltage into sinusoidal waveform at a f1 frequency; and a transmitter circuit associated with the inverter which receives the voltage in sinusoidal waveform received from said inverter; said transmitter circuit comprises a first winding for providing transferring of the voltage, received from the inverter, in a wireless manner; said wireless power transfer system further comprises a receiver circuit having a second winding associated with the battery to be charged; a control unit arranged to monitor the phase difference angle between the first voltage and the inverter; and the control unit is arranged to gradually increase the f1 frequency until the phase difference exceeds 0 and to provide continuation of the power transfer process with the obtained f1 frequency when the phase difference exceeds 0 or is equal to 0. Thus, even if the positions of the receiver and transmitter shift from the desired resonance region, an efficient power transfer is provided.

In a preferred embodiment of the present invention, said transmitter circuit comprises a first capacitor group comprising pluralities of capacitors connected in a parallel manner to each other by means of pluralities of switches and a second capacitor group comprising pluralities of capacitors connected in a parallel manner to each other by means of pluralities of switches and associated with said first capacitor group; and the control unit is configured to provide transmitting of at least one each of the capacitors in the first capacitor group and in the second capacitor group according to the obtained f1 frequency value. Thus, the inverter is arranged so as to operate in a compliant manner to the selected frequency value.

In another preferred embodiment of the present invention, a power supply, which is associated with the first end, is provided.

In another preferred embodiment of the present invention, said power supply is a DC power supply.

In another preferred embodiment of the present invention, said power supply is an AC power supply and it comprises AC/DC converter provided between the AC power supply and the first end.

In another preferred embodiment of the present invention, said AC/DC converter is configured to rectify the power factor.

In another preferred embodiment of the present invention, a filter is provided between the AC power supply and the AC/DC converter.

In another preferred embodiment of the present invention, the receiver circuit comprises a first compensation circuit associated with the second winding for providing charging of the battery in fixed current mode and a second compensation circuit for providing charging of the battery in fixed voltage mode; a control unit is provided arranged to selectively control the operation of the first compensation circuit and the second compensation circuit. Thus, the battery can be charged at different charge modes.

In another preferred embodiment of the present invention, the first control unit comprises a first communication unit for providing communication with a server in order to send the charging information.

In another preferred embodiment of the present invention, client devices are provided which are arranged to communicate with the server in a manner receiving the charge information.

In another preferred embodiment of the present invention, the control unit is arranged to detect the fullness proportion of the battery and the control unit comprises a second communication unit for providing sending of the charge fullness proportion to the first control unit. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a representative view of the power transfer system.

Figure 2 is a representative view of the circuit form of the receiver unit and the transmitter unit.

Figure 3 is the flow schema of realization of frequency adjustment by the control unit.

Figure 4 is a representative view of the compensation circuits in the receiver unit.

Figure 3 is a representative view of the first compensation circuit.

Figure 3 is a representative view of the second compensation circuit.

DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the subject matter is explained with references to examples without forming any restrictive effect only in order to make the subject more understandable.

With reference to Figure 1 , the subject matter is a wireless power transfer system (10) for charging batteries (300) of electrical vehicles in a wireless manner. Basically, it comprises a transmitter unit (100) which receives power from a power supply (110) and a receiver unit (200) which transfers the energy, received from the transmitter unit (100) in a wireless manner, to the battery (300).

The transmitter unit (100) comprises an inverter which receives an input voltage as DC from a first end (120). Said inverter (150) transforms DC voltage into wave with sinusoidal form. In order to transfer power to the receiver unit (200) in a wireless manner, a transmitter circuit (160) is provided which is associated with the inverter (150) and which comprises a first winding (161).

The first end (120) is associated with a power supply (110). The power supply (110) can be a network, etc. which provides AC voltage or a battery (300), solar battery (solar panel), etc. which provides DC voltage. In case the power supply (110) provides AC voltage, an AC/DC converter is provided between the power supply (110) and the first end (120). A filter (140) can also be provided between AC/DC converter and the power supply (110). The AC power supply (110) can have a type which rectifies the power factor. The power supply (110) can have 2 phases or 3 phases. Moreover, the power factor drawn from the supply must be close to 1. The filter (140) and the power factor rectification AC/DC inverter (150) meet these conditions and any topology can be used.

In case the power supply provides DC voltage, a DC/DC converter (not illustrated in the figures) can be provided between the first end (120) and the power supply (110).

The inverter transforms the voltage, received from the first end (120), into sinusoidal wave at f1 frequency. A control unit is provided in a manner controlling the inverter (150).

The phase difference between the input voltage, received as input by the inverter (150), and the current taken as output from the inverter (150), is monitored. The control unit increases frequency f1 gradually. When the fi angle which describes the phase difference exceeds 0 (or becomes equal), the obtained frequency value is defined as the rezonance frequency, and the inventor (150) provides transformation with this frequency. Thus, even if the receiver and the transmitter are placed in a shifted manner, an efficient power transfer is provided. In Figure 3, the flow schema of the steps realized by the first control unit (170) related to finding of the resonance frequency is given.

Thus, in order for the charge efficiency and the performance thereof not to be dependent on the position of the electrical vehicle, the resonance frequency is optimized to the frequency of the fixed voltage gain. Normally, electrical vehicles are parked at a different position in any time. This leads to shift of the center points of the transmitter and receiver windings with respect to each other. Because of this shift, the coupling coefficient between the receiver and the transmitter changes and the charging efficiency decreases. In this case, the inverter follows the frequency with respect to the fixed voltage gain point of the voltage and applies optimized frequency for maximum power transfer. When the resonance frequency has value f, the frequency change is in the vicinity of f±10%. This frequency change is realized only once before charging process is started and it does not change during charging.

With reference to Figure 2, in a more detailed manner, the transmitter circuit (160) comprises a first capacitor group (163) and a second capacitor group (164). The first capacitor group (163) comprises pluralities of capacitors connected to each other in a parallel manner by means of pluralities of switching elements. The second capacitor group (164) comprises pluralities of capacitors connected to each other in a parallel manner by means of pluralities of switching elements. The control unit provides power transfer in a suitable manner by providing transmitting by at least one each capacitor from the first capacitor group (163) and the second capacitor group (164) according to the resonance frequency, in other words, according to the resonance frequency obtained by means of increasing gradually. A coil is provided between the capacitor groups and the first input. Thus, a suitable LC circuit is formed by selecting suitable capacitors from capacitor groups.

With reference to Figure 2, 5, 6 and 7, the receiver unit (200) comprises a first compensation circuit (212) provided between the second winding (211) and the battery (300) and a second compensation circuit (213). A second control unit (220) selectively operates one of the second compensation cricuit (213) and the first compensation circuit (212). The first compensation circuit (212) comprises capacitors and coils in a manner providing charging of the battery (300) in fixed current mode, in other words, with fixed current, and the second compensation circuit (213) comprises capacitors and coils in a manner providing charging of the battery (300) by being subjected to a fixed voltage, in other words, in fixed voltage mode.

The compensation networks are used for minimizing VA value of the power supply (110), for obtaining high efficiency, for improving power transfer capacity and the input power factor.

The receiver unit also comprises an AC/DC converter for transforming the received voltage into DC voltage and for transferring said received voltage to the battery (300).

The first control unit (170) comprises a communication unit. The first communication unit (171) provides data exchange with a server (400). The server (400) is configured in a manner providing data exchage with client devices (500). The client devices (500) can be cellular phone, tablet computer, computer, etc. The first control unit (170) moreover provides transfer of information like the charging duration, frequency values and the current amount, transferred to the battery (300), to the client devices (500) by means of the server (400). This information can be accessed by means of an application in the client device (500).

The second control unit (220) is associated with a second communication unit (221). The second communication unit (221) provides transfer of the information, related to the charging like fullness proportion, charging duration, etc. of the battery (300), to the client device (500) by means of the server (400).

The protection scope of the present invention is set forth in the annexed claims and cannot be restricted to the illustrative disclosures given above, under the detailed description. It is because a person skilled in the relevant art can obviously produce similar embodiments under the light of the foregoing disclosures, without departing from the main principles of the present invention.

REFERENCE NUMBERS

10 Wireless power transfer system

100 Transmitter unit

110 Power supply

120 First end

130 AC/DC converter

140 Filter

150 Inverter

160 Transmitter circuit

161 First winding

162 First coil

163 First capacitor group

164 Second capacitor group

170 First control unit

171 First communication unit 200 Receiver unit

210 Receiver circuit

211 Second winding

212 First compensation circuit

213 Second compensation circuit

220 Second control unit

221 Second communication unit 230 AC/DC converter

300 Battery

400 Server

500 Client device

Claims

1. A wireless power transfer system (10) for charging batteries in a wireless manner, wherein said wireless power transfer system (10) comprises an inverter (150) connected to a first end where DC input voltage is provided and arranged to transform said input voltage into sinusoidal waveform at a f1 frequency; and a transmitter circuit (160) associated with the inverter (150) which receives the voltage in sinusoidal waveform received from said inverter (150); said transmitter circuit (160) comprises a first winding (161) for providing transferring of the voltage, received from the inverter (150), in a wireless manner; said wireless power transfer system (10) further comprises a receiver circuit (210) having a second winding (211) associated with the battery (300) to be charged; a control unit arranged to monitor the phase difference angle between the first voltage and the inverter (150); and the control unit is arranged to gradually increase the f1 frequency until the phase difference exceeds 0 and to provide continuation of the power transfer process with the obtained f1 frequency when the phase difference exceeds 0 or is equal to 0.

2. The wireless power transfer system (10) according to claim 1 , wherein said transmitter circuit (160) comprises a first capacitor group (163) comprising pluralities of capacitors connected in a parallel manner to each other by means of pluralities of switches and a second capacitor group (164) comprising pluralities of capacitors connected in a parallel manner to each other by means of pluralities of switches and associated with said first capacitor group (163); and the control unit is configured to provide transmitting of at least one each of the capacitors in the first capacitor group (163) and in the second capacitor group according to the obtained f1 frequency value.

3. The wireless power transfer system (10) according to claim 1 , wherein a power supply (110), which is associated with the first end (120), is provided.

4. The wireless power transfer system (10) according to claim 3, wherein said power supply (110) is a DC power supply (110).

5. The wireless power transfer system (10) according to claim 3, wherein said power supply (110) is AC power supply (110) and an AC/DC converter is provided between the AC power supply (110) and the first end (120).

6. The wireless power transfer system (10) according to claim 5, wherein said AC/DC converter is configured to rectify the power factor.

7. The wireless power transfer system (10) according to claim 5, wherein a filter (140) is provided between the AC power supply (110) and the AC/DC converter.

8. The wireless power transfer system (10) according to claim 1 , wherein the receiver circuit (210) comprises a first compensation circuit (212) associated with the second winding (211) for providing charging of the battery (300) in fixed current mode and a second compensation circuit (213) for providing charging of the battery (300) in fixed voltage mode; a control unit is provided arranged to selectively control the operation of the first compensation circuit (212) and the second compensation circuit (213).

9. The wireless power transfer system (10) according to claim 1 , wherein the first control unit (170) comprises a first communication unit (171) for providing communication with a server (400) in order to send the charging information.

10. The wireless power transfer system (10) according to claim 1 , wherein client devices (500) are provided which are arranged to communicate with the server (400) in a manner receiving the charge information.

11. The wireless power transfer system (10) according to claim 1 , wherein the control unit is arranged to detect the fullness proportion of the battery (300) and the control unit comprises a second communication unit (221) for providing sending of the charge fullness proportion to the first control unit (170).