Magnetic resonance wireless power transfer device
View Patent ↗[PROBLEM] To provide a magnetic resonance wireless power transfer device which allows constant transmission power and high transmission efficiency to be maintained over a long transmission distance even when the distance (transmission distance) between a transmitter coil and a receiver coil changes. [SOLUTION] In a magnetic resonance wireless power transfer device wherein a negative resistance circuit 20 , a transmitter resonant circuit 10 having a transmitter coil 11 , and a receiver resonant circuit 30 having a receiver coil 11 are configured so that the parity-time symmetry is preserved, out of two resonant loops (Loop I and Loop II) in which a resonant current is circulatable when the transmitter resonant circuit 10 and the receiver resonant circuit 30 are regarded as a double resonant circuit coupled with a mutual inductance, Q value of the Loop II is set to be higher than Q value of the Loop I, so that oscillation occurs in the Loop II in which a leakage inductance component of the coil and a capacitance component of a capacitor resonate.
1. A magnetic resonance wireless power transfer device, wherein
a negative resistance circuit,
a transmitter resonant circuit having a transmitter coil, and
a receiver resonant circuit having a receiver coil are configured so that a parity-time symmetry is preserved, and wherein
out of two resonant loops (hereinafter referred to as “Loop I” and “Loop II”) in which a resonant current is circulatable when the transmitter resonant circuit and the receiver resonant circuit are regarded as a double resonant circuit coupled with a mutual inductance, Q value of the Loop II is set to be higher than Q value of the Loop I, so that oscillation occurs in a loop in which a leakage inductance component of the coil and a capacitance component of a capacitor resonate.
2. The magnetic resonance wireless power transfer device according to claim 1 , wherein a driving frequency is 100 kHz or lower.
3. The magnetic resonance wireless power transfer device according to claim 1 , wherein the transmitter coil and the receiver coil are each wound on a magnetic core.
4. The magnetic resonance wireless power transfer device according to claim 1 , wherein
a capacitor is connected in parallel with the receiver coil, and
the receiver coil is configured with a plurality of windings cumulatively connected in parallel with each other, or a bundle of wires.
5. The magnetic resonance wireless power transfer device according to claim 1 , wherein the negative resistance circuit is provided with a trigger mechanism for activation.
6. The magnetic resonance wireless power transfer device according to claim 1 , wherein
the negative resistance circuit comprises
a current sensor,
a zero-crossing comparator for receiving a current waveform signal of the transmitter coil detected by the current sensor,
a gate signal generation circuit for generating a gate signal for transistors based on an output voltage of the zero-crossing comparator, and
a switching circuit configured with a plurality of transistors for driving the transmitter coil with an alternating current in response to the gate signal output by the gate signal generation circuit.
7. The magnetic resonance wireless power transfer device according to claim 6 , wherein the negative resistance circuit further comprises a phase lead compensation circuit for lead compensation of delay of said gate signal.
8. The magnetic resonance wireless power transfer device according to claim 6 , wherein the negative resistance circuit further comprises a direct current offset adjustment circuit for adjusting a duty ratio of said gate signal.