High-resolution and low-resolution sensors for phase detection
AssigneeHamilton Sundstrand Corporation
InventorsSouren G. Fattal, John Duward Sagona
Life of this patent
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Abstract
A phase detection system includes a low-resolution sensor and a high-resolution sensor for monitoring an alternating current (AC) voltage. A phase detector receives voltage samples from both the low-resolution sensor and the high-resolution sensor. The phase detector monitors the low-resolution sensor to detect approaching zero cross events (i.e., monitored voltage values approaching zero). In response to an approaching zero-cross event, the phase detector uses the magnitude of the high-resolution voltage samples measured on either side of the zero cross event to determine the phase of the monitored AC voltage.
Claims16
A phase detection system comprising:
- a low-resolution sensor for monitoring an alternating current (AC) voltage;
- a high-resolution sensor for monitoring the AC voltage;
- and
- a phase detector that receives voltage samples from the low-resolution sensor and the high-resolution sensor, wherein the phase detector employs high-resolution voltage samples when the low-resolution voltage samples indicate an approaching zero-cross event, wherein the phase detector employs magnitude of the high-resolution voltage samples received on either side of a zero-cross event to determine a phase associated with the monitored AC voltage.
A zero-cross based method of phase detection, the method comprising:
- monitoring an alternating current (AC) voltage with a low-resolution sensor;
- monitoring the AC voltage with a high-resolution sensor when the low-resolution sensor indicates the AC voltage is nearing a zero-cross event;
- storing a previous voltage value and a current voltage value provided by the high-resolution sensor;
- detecting a zero-cross event between the previous voltage value and the current voltage value;
- estimating an initial phase of the AC voltage based on the current voltage value, the previous voltage value, and an estimated phase difference between successive voltage values provided by the high-resolution sensor;
- and
- estimating subsequent phase values associated with the AC voltage based on the initial phase estimate.
An active rectification system comprising:
- an active rectifier having a plurality of switching elements selectively controlled to convert an alternating current (AC) input voltage to a direct current (DC) output voltage;
- a high-resolution sensor connected to monitor the AC input voltage provided to the active rectifier;
- a low-resolution sensor connected to monitor the AC input voltage provided to the active rectifier;
- a controller connected to receive high-resolution voltage samples measured by the high-resolution sensor and low-resolution voltage samples measured by the low-resolution sensor, the controller including:
- a phase/frequency detector that detects phase and frequency information associated with the AC input voltage, wherein the phase/frequency detector employs the high-resolution voltage samples when the low-resolution voltage samples indicate an approaching zero-cross event, wherein the phase/frequency detector employs a magnitude of the high-resolution voltage samples received on either side of a zero-cross event to determine a phase associated with the AC input voltage;
- and
- a controller that receives phase and frequency information provided by the phase/frequency detector, and in response generates signals to selectively control the active switching elements within the active rectifier.
Dependencies are inferred from the claim text.