Duty cycle for inductive position sensors
A duty cycle is used in conjunction with a powered oscillator to electronically reduce the current draw by reducing the average current and thus reducing the sensor radiated emissions without altering an inductive position sensor. The duty cycle and the switching of the oscillation drive enable an on and an off cycling of the inductive position sensor such that an oversampling may occur without altering the hardware, but providing the improvements. As such, the inductive position sensor may only have an oscillation signal long enough to capture a stable sample and remain off for the duration of the sampling period. As such, a reduction in radiated emissions is achieved.
1. A position sensor system comprising:
an inductive position sensor having a transmitting coil and at least one receiving coil;
a coupler configured to move relative to the transmitting coil and the at least one receiving coil;
an electronic control unit comprising an oscillator drive, the electronic control unit operably connected to the oscillator drive, the oscillator drive enables an oscillation signal configured to enable the inductive position sensor at a predetermined time;
a pulse-width modulation controlled by the electronic control unit, the pulse-width modulation having a start duty cycle and a stop duty cycle controlled by the electronic control unit at a predetermined period of time, the pulse-width modulation operating at a predefined frequency and at a predefined ratio;
wherein, the inductive position sensor transmits a sample to the electronic control unit when the oscillation signal and the start duty cycle are both enabled, the sample being a position of the coupler relative to the inductive position sensor;
wherein, the start duty cycle and the stop duty cycle are configured to reduce an average radiated emission of the inductive position sensor.
2. The position sensor system of claim 1 , wherein the predetermined time is a minimum time required for the inductive position sensor to transmit a stable sample.
3. The position sensor system of claim 1 , wherein the sample is held by the electronic control unit until a second sample is taken during a next period of time when the oscillation signal and the start duty cycle are both enabled.
4. The position sensor system of claim 1 , wherein the coupler is spaced apart from the transmitting coil and the at least one receiving coil so to form an airgap.
5. The position sensor system of claim 4 , wherein the air gap between the transmitter coil and the coupler is greater than 1.0 millimeter.
6. The position sensor system of claim 1 , wherein the pulse-width modulation is at the predefined frequency of 400 hertz.
7. The position sensor system of claim 1 , wherein the pulse-width modulation is at the predefined frequency of 200 hertz.
8. The position sensor system of claim 1 , wherein the pulse-width modulation is at the predefined frequency of 800 hertz.
9. The position sensor system of claim 1 , wherein the predetermined period of time between the start duty cycle to the stop duty cycle is equal to 10 percent.
10. The position sensor system of claim 1 , wherein the predetermined period of time between the start duty cycle to the stop duty cycle is greater than 10 percent.
11. The position sensor system of claim 1 , wherein the predetermined period of time between the start duty cycle to the stop duty cycle is less than 10 percent.
12. A sensor system comprising:
an inductive position sensor having a transmitting coil and at least one receiving coil;
a coupler configured to move relative to the transmitting coil and the at least one receiving coil;
an electronic control unit comprising an oscillator drive, the electronic control unit operably connected to the oscillator drive, the oscillator drive operably connected to the inductive position sensor so to transmit an oscillating signal;
a pulse width modulation signal having a duty cycle, the pulse width modulation signal controlled by the electronic control unit at a predetermined period of time, the duty cycle operating at a predefined proportion of time;
wherein a sample of the inductive position sensor position is obtained when the oscillating signal and the duty cycle are both enabled such that only a single sample is required for the predefined proportion of time, the sample being a position of the coupler relative to the inductive position sensor,
wherein the oscillator drive is inhibited a remaining time of the predefined proportion of time so to reduce power consumption and emissions of the inductive position sensor.
13. The position sensor system of claim 12 , wherein the predetermined time is a minimum time required for the inductive position sensor to transmit a stable sample.
14. The position sensor system of claim 13 , wherein the sample is held by the electronic control unit until a second sample is taken during a next period of time when the oscillation signal and the duty cycle are both enabled.
15. The position sensor system of claim 12 , wherein the coupler is spaced apart from the transmitting coil and the at least one receiving coil so to form an airgap.
16. The position sensor system of claim 15 , wherein the air gap between the transmitter coil and the coupler is greater than 1.0 millimeter.
17. The position sensor system of claim 12 , wherein the duty cycle is a periodic clock signal, the predetermined period of time of the periodic clock signal is 10 percent.
18. The position sensor system of claim 12 , wherein the duty cycle is a periodic clock signal the predetermined period of time of the periodic clock signal is greater than 10 percent.
19. The position sensor system of claim 12 , wherein the duty cycle is a periodic clock signal, the predetermined period of time of the periodic clock signal is less than 10 percent.
20. The position sensor system of claim 12 , wherein repeat multiples of the sample of the inductive position sensor position are processed by the electronic control unit until the oscillation signal and the duty cycle both change states.