US 2022/0278563 A1 · INCOMPLETELY COMPENSATED WIRELESS POWER TRANSFER SYSTEM

Abstract

Disclosed in the present application is an incompletely compensated wireless power transfer system. On the basis of an SS compensated wireless power transfer system topology, a primary side capacitor C1 and a secondary side capacitor C2 take specific values, and in combination with a phase shift frequency modulation control method, a coupling range of a system output rated power is improved. According to the present application, by finding an appropriate combination of the primary side capacitor C1 and the secondary side capacitor C2, the system can output a required rated power in a larger coupling range under the condition of incomplete compensation.

An incompletely compensated wireless power transfer system, wherein on basis of an SS compensated wireless power transfer system topology, a primary side capacitance C1 and a secondary side capacitance C2 take specific values, and a phase shift frequency modulation control method is combined, to increase a coupling range of rated output power of the system;

values of the primary side capacitance C1 and the secondary side capacitance C2 are taken as follows:
restrictions that are met are as follows:
1. circuit equations of a wireless charging transfer system:
(R1+jX1)I1+jωM12I2=V1 (1)
jωM12I1+(R2+RL+jX2)I2=0 (2)
where Ri, i=1 or 2, is parasitic resistance in the circuit, generally including coil resistance and equivalent series resistance of a capacitor;
Xi=ωLi−1/(ωCi), i=1 or 2, is reactance of a harmonic oscillator i;
Li, Ci, i=1 or 2, are coil inductance and compensation capacitance, I1 and I2 are current phasors of a primary loop and a secondary loop respectively;
V1 is input voltage phasor;
M12 is mutual inductance of two coils;
RL is equivalent load resistance;
ω=2πf is angular frequency, and f is frequency of a power supply;
2. rated output direct current voltage Vout and power Pout, that is
R
L
=
8
π
2
⁢
V
out
P
out
(
3
)
3. range of operating frequency:
fmin≤f≤fmax (4)
4. coupling range of the coil:
M12min≤M12≤M12max (5)
5. direct current input voltage VDC, through phase shift control, the effective value V1 of a fundamental wave of a square wave actually acting on a primary LC harmonic oscillator must meet:
V
1
≤
2
⁢
2
π
⁢
V
D
⁢
C
(
6
)
6. maximum primary current I1max, that is
I1≤I1max (7)
where, I1 is an effective value of the current phasor I1;
7. a primary input current should lag behind the input square wave to achieve zero voltage turn-on, that is
θ
+
90
⁢
°
-
arcsin
⁡
(
π
⁢
V
1
2
⁢
2
·
V
D
⁢
C
)
<
0
(
8
)
where θ is a phase angle of the primary input current I1 with respect to an input voltage V1, and V1 is the effective value of a fundamental wave of an inverter output square wave:
V
1
=
2
⁢
2
π
⁢
V
D
⁢
C
⁢
sin
⁡
(
α
2
)
;
(
9
)
α is an angle occupied by half wave of the square wave, and is 180° when duty ratio is 1;
8. calculating the coil resistance via finite element simulation;
the equivalent series resistance of a compensation capacitor can be estimated by the following method:
the coil inductance is L1, then the compensation capacitance C1 is near resonance capacitance value C10, and the calculation method of the resonance capacitance value and the corresponding equivalent series resistance is as follows:
C
1
⁢
0
=
1
ω
2
⁢
L
1
;
(
10
)
R
C
⁢
1
≈
tan
⁢
δ
ω
⁢
C
1
⁢
0
;
(
11
)
where tan δ is a tangent value of a loss angle of the capacitor;
in simplified calculation, the parasitic resistance of the circuit is negligible;
for given coils L1 and L2, in combination with the above operating conditions, the ranges of C1 and C2 that can simultaneously meet all the above conditions can be obtained by a numerical solution method.

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Incompletely compensated wireless power transfer system

Life of this patent

Incompletely compensated wireless power transfer system

Life of this patent

Abstract

Claims5