Method for implementing bootstrap-supply charging in a motor controller at energized motor and motor controller using such a method
First Claim
1. A method of recharging a controller with inoperative switching elements comprising a bootstrap capacitor and having at least two output phases, the controller being connected to a load generating back-EMFs at the output terminals of the controller, wherein the load is a motor and the controller is a motor controller, the method comprising a recharge sequence for the bootstrap capacitor of each output phase, and selecting each recharge sequence from a set of at least two recharge sequences in relation to or as a function of the back-EMFs of the load, where the choice is based on the spinning of the load in relation to a base frequency, or alternatively the amplitude of the back-EMFs in relation to a base amplitude of the back-EMFs.
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Abstract
The present invention relates to a motor controller employing bootstrap-capacitor supplies and in particular to the situation where the bootstrap supplies have to be charged, while the motor controller is connected to a spinning and energized motor. The present invention introduces a method of recharging based on choosing a recharging sequence from a set of recharging sequences, where the choice depends on the state of the connected motor and in particular on the back-EMF voltages of the motor.
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14 Claims
- 1. A method of recharging a controller with inoperative switching elements comprising a bootstrap capacitor and having at least two output phases, the controller being connected to a load generating back-EMFs at the output terminals of the controller, wherein the load is a motor and the controller is a motor controller, the method comprising a recharge sequence for the bootstrap capacitor of each output phase, and selecting each recharge sequence from a set of at least two recharge sequences in relation to or as a function of the back-EMFs of the load, where the choice is based on the spinning of the load in relation to a base frequency, or alternatively the amplitude of the back-EMFs in relation to a base amplitude of the back-EMFs.
Specification