Control of series-resonant inductive pickups
First Claim
1. An inductive power pickup device having a series resonant circuit comprising a pickup coil and a resonating capacitor selected so that the pickup is capable of resonance at a system-wide frequency, the power pickup device further including power conditioning means capable of converting electricity that has been picked up into a conditioned form suitable for consumption by a load, characterised-in-that apparatus capable of controlling the amount of power picked up by the power pickup device comprises switching means in series with the pickup coil and in series with the resonating capacitor, together with switch controlling means causing the switching means to repetitively be in either an open or a closed state, so that by varying the respective proportion of time that the switching means is either open or is closed the time-averaged amount of power picked up by the power pickup device can be controlled, the pickup coil positioned adjacent a primary inductive conductor for intercepting a magnetic field surrounding the primary inductive conductor.
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Accused Products
Abstract
A series resonant inductive pickup has a bi-directional solid state switch in series with an inductor and a capacitor is controlled by switch control elements capable of causing the switching elements to repetitively be in either an open or a closed state, so that by varying the closed: open ratio of the switch the time-averaged amount of power picked up by the power pickup can be controlled. Switch is controlled by output of a voltage comparing circuit. A reference voltage source provides a basis for comparison of some fraction of a supply voltage in order to cause the switch to operate. The magnitude of capacitance in relation to the current drawn by the load determines the repetition rate of ON or OFF commands to the switch. If the current drawn by the load tends to zero, the proportion of time during which the switch is open will tend to 100%.
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Citations
20 Claims
- 1. An inductive power pickup device having a series resonant circuit comprising a pickup coil and a resonating capacitor selected so that the pickup is capable of resonance at a system-wide frequency, the power pickup device further including power conditioning means capable of converting electricity that has been picked up into a conditioned form suitable for consumption by a load, characterised-in-that apparatus capable of controlling the amount of power picked up by the power pickup device comprises switching means in series with the pickup coil and in series with the resonating capacitor, together with switch controlling means causing the switching means to repetitively be in either an open or a closed state, so that by varying the respective proportion of time that the switching means is either open or is closed the time-averaged amount of power picked up by the power pickup device can be controlled, the pickup coil positioned adjacent a primary inductive conductor for intercepting a magnetic field surrounding the primary inductive conductor.
- 9. An inductive power pickup device having a series resonant circuit comprising a pickup coil and a resonating capacitor selected so that the pickup is capable of resonance at a system-wide frequency, the power pickup device further including power conditioning means capable of converting electricity that has been picked up into a conditioned form suitable for consumption by a load, characterized in that an apparatus capable of controlling the amount of power picked up by the power pickup device comprises switching means in series with the pickup coil and in series with the resonating capacitor, together with switch controlling means capable of causing the switching means to repetitively be in either an open or a closed state, so that by varying the respective proportion of time that the switching means is either open or is closed the time-averaged amount of power picked up by the power pickup device can be controlled and wherein the switch controlling means is capable of responding to the voltage of the conditioned power.
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19. An inductive power pickup device, comprising:
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a series resonant circuit comprising a switch in series with a pickup coil positioned for intercepting a magnetic field surrounding a primary inductive conductor, the pickup coil in series with a resonating capacitor, the capacitor selected to provide a pickup capable of resonance at a system-wide frequency;
a power conditioner connected across the pickup coil and capacitor for converting electricity that has been picked up by the series resonant circuit into a conditioned power, the conditioned power being at an output of the power conditioner at a supply voltage and in a form suitable for load consumption;
a switch controlling circuit connected to open and close the switch, the switch controlling circuit being responsive to the supply voltage of the conditioned power in opening and closing the switch, the switch controlling circuit repetitively opening and closing the switch to vary a time that the switch is open so that a time-averaged amount of power picked up by the series resonant circuit is controlled. - View Dependent Claims (20)
a switching rate determining capacitor connected across the output of the power conditioner;
a voltage comparing circuit having on output connected to the switch to control the opening and closing of the switch;
a reference voltage connected as a first input to the voltage comparing circuit; and
a fractional voltage of the supply voltage of the conditioned power connected as a second input to the voltage comparing circuit, wherein the voltage comparing circuit compares the reference voltage to the fractional voltage of the supply voltage as a basis for controlling the opening and closing of the switch, and a capacitance of the switching rate determining capacitor, in relation to a current drawn from the power conditioner by a load, determines a repetition rate of opening and closing of the switch.
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Specification