Auxiliary winding for extended current measurement

摘要

A power controller controls power to a load and includes a primary current sensor, a controller and a current source. The primary current sensor includes a primary conductor and an auxiliary conductor. The primary conductor carries a primary current to the load and the auxiliary conductor carries an auxiliary current in the opposite direction of the primary current to provide partial flux cancellation. The primary current sensor provides an output voltage based upon a magnetic field generated by the primary current and auxiliary current. The controller determines the primary current based upon the output voltage and the auxiliary current. The current source provides the auxiliary current. The controller controls the current source to provide the auxiliary current to the auxiliary conductor if the primary current is greater than a threshold value.

主权项

1. A power controller that controls power to a load, the power controller comprising:
a primary current sensor that includes a primary conductor and an auxiliary conductor, wherein the primary conductor carries a primary current to the load and the auxiliary conductor carries an auxiliary current in the opposite direction of the primary current to provide partial flux cancellation, and wherein the primary current sensor provides an output voltage based upon a magnetic field generated by the primary current and the auxiliary current; a controller that determines the primary current based upon the output voltage and the auxiliary current; a power switch, wherein the controller controls the power switch to control the power to the load based upon the primary current; and a current source that provides the auxiliary current, wherein the controller controls the current source to only provide the auxiliary current to the auxiliary conductor if the primary current is greater than a first threshold value; wherein the controller is configured to command the power switch off to disable the power to the load if a total power to the load over a time period is greater than a second threshold value.