Файл: wirelesspowerspecificationpart1.pdf

System Description

Wireless Power Transfer

3.2.2.1.2Shielding

As shown in Figure 3-7, soft-magnetic material protects the Base Station from the magnetic field that is generated in the Primary Coil. The Shielding extends to at least 2 mm beyond the outer diameter of the Primary Coil, has a thickness of at least 0.20 mm and is placed below the Primary Coil at a distance of at most mm. This version 1.1.1 of the System Description Wireless Power Transfer, Volume I, Part 1, limits the composition of the Shielding to a choice from the following list of materials:

DPR-MF3 — Daido Steel

HS13-H — Daido Steel

Figure 3-7: Primary Coil assembly of Power Transmitter design A2

3.2.2.1.3Interface Surface

As shown in Figure 3-7, the distance from the Primary Coil to the Interface Surface of the Base Station is mm, across the top face of the Primary Coil. In addition, the Interface Surface of the Base

Station extends at least 5 mm beyond the outer diameter of the Primary Coil.

3.2.2.1.4Positioning stage

The positioning stage shall have a resolution of 0.1 mm or better in each of the two orthogonal directions parallel to the Interface Surface.

3.2.2.2Electrical details

As shown in Figure 3-8, Power Transmitter design A2 uses a full-bridge inverter to drive the Primary Coil and a series capacitance. At the fixed Operating Frequency of 140 kHz, the assembly of Primary Coil and Shielding has a self inductance μH. The value of the series capacitance is nF. (Informative) Near resonance, the voltage developed across the series capacitance can reach levels up to 50 V pk-pk.

Power Transmitter design A2 uses the input voltage to the full-bridge inverter to control the amount of power that is transferred. For this purpose, the input voltage range is 3…12 V, where a lower input voltage results in the transfer of a lower amount of power. In order to achieve a sufficiently accurate adjustment of the power that is transferred, a type A2 Power Transmitter shall be able to control the input voltage with a resolution of 50 mV or better.

When a type A2 Power Transmitter first applies a Power Signal (Digital Ping; see Section 5.2.1), it shall use an initial input voltage of 8 V.

3.2.3Power Transmitter design A3

Power Transmitter design A3 enables Free Positioning, and has a design similar to Power Transmitter design A2. See Section 3.2.2 for an overview.

3.2.3.1Mechanical details

Power Transmitter design A3 includes a single Primary Coil as defined in Section 3.2.3.1.1, Shielding as defined in Section 3.2.3.1.2, an Interface Surface as defined in Section 3.2.3.1.3, and a positioning stage as defined in Section 3.2.3.1.4.

3.2.3.1.1Primary Coil

The Primary Coil is of the wire-wound type, and consists of litz wire having 11 strands of 0.20 mm diameter, or equivalent. As shown in Figure 3-9, the Primary Coil has a circular shape and consists of a single layer. Table 3-7 lists the dimensions of the Primary Coil.

do

di

dc

Figure 3-9: Primary Coil of Power Transmitter design A3

Table 3-7: Primary Coil parameters of Power Transmitter design A3

System Description

Wireless Power Transfer

3.2.3.1.2Shielding

As shown in Figure 3-10: Primary Coil assembly of Power Transmitter design A3, soft-magnetic material protects the Base Station from the magnetic field that is generated in the Primary Coil. The Shielding extends to at least 1 mm beyond the outer diameter of the Primary Coil, has a thickness of at least 0.60 mm and is placed below the Primary Coil at a distance of at most mm. This version 1.1.1 of the System Description Wireless Power Transfer, Volume I, Part 1, limits the composition of the Shielding to a choice from the following list of materials:

HS13-H — Daido Steel

KNZWA20B356 — Panasonic

Figure 3-10: Primary Coil assembly of Power Transmitter design A3

3.2.3.1.3Interface Surface

As shown in Figure 3-10, the distance from the Primary Coil to the Interface Surface of the Base Station is mm, across the top face of the Primary Coil. In addition, the Interface Surface of the Base

Station extends at least 5 mm beyond the outer diameter of the Primary Coil.

3.2.3.1.4Positioning stage

The positioning stage shall have a resolution of 0.1 mm or better in each of the two orthogonal directions parallel to the Interface Surface.

3.2.3.2Electrical details

As shown in Figure 3-11, Power Transmitter design A3 uses a full-bridge inverter to drive the Primary Coil and a series capacitance. At an Operating Frequency range between 105 kHz and 140 kHz, the

Power Transmitter design A3 uses the input voltage to the full-bridge inverter to control the amount of power that is transferred. For this purpose, the input voltage range is 3…12 V, where a lower input voltage results in the transfer of a lower amount of power. In order to achieve a sufficiently accurate adjustment of the power that is transferred, a type A3 Power Transmitter shall be able to control the input voltage with a resolution of 50 mV or better.

When a type A3 Power Transmitter first applies a Power Signal (Digital Ping; see Section 5.2.1), it shall use an initial input voltage of 6 V. It is recommended that the Power Transmitter uses an Operating Frequency of 140 kHz when first applying the Power Signal. If the Power Transmitter does not to receive a Signal Strength Packet from the Power Receiver, the Power Transmitter shall remove the Power Signal as defined in Section 5.2.1. The Power Transmitter may reapply the Power Signal multiple times at