Control of electrical machines
First Claim
1. A method of compensating for differences between an applied DC link voltage and a predetermined DC link voltage in an electrical machine comprising a rotor, at least one phase winding, and a controller configured to energize the phase winding in dependence on an angular position of the rotor, wherein the controller comprises a memory storing a voltage compensation map comprising a plurality of correction factors, the method comprising:
- measuring the applied DC link voltage;
obtaining a correction factor by addressing the voltage compensation map using the applied DC link voltage; and
applying the obtained correction factor to the angular position of energization of the phase winding.
2 Assignments
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Accused Products
Abstract
An electrical machine, such as a switched reluctance motor, has a rotor and a controller arranged to energize at least one electrically energizable phase winding in dependence on the angular position of the rotor. The controller may employ a control law table derived by applying a predetermined DC link voltage to the windings. Differences between an applied DC link voltage and the predetermined DC link voltage may be compensated by applying a predetermined correction to the angular position of energization of the phase winding in dependence on the value applied DC link voltage. Such a compensation factor may be derived from a relationship held in memory.
58 Citations
16 Claims
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1. A method of compensating for differences between an applied DC link voltage and a predetermined DC link voltage in an electrical machine comprising a rotor, at least one phase winding, and a controller configured to energize the phase winding in dependence on an angular position of the rotor, wherein the controller comprises a memory storing a voltage compensation map comprising a plurality of correction factors, the method comprising:
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measuring the applied DC link voltage; obtaining a correction factor by addressing the voltage compensation map using the applied DC link voltage; and applying the obtained correction factor to the angular position of energization of the phase winding. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A controller for an electrical machine, wherein the electrical machine comprises a rotor and at least one phase winding and the controller comprises a memory storing a voltage compensation map comprising a plurality of correction factors, the controller being configured to:
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energize the phase winding in dependence on an angular position of the rotor; obtain a correction factor by addressing the voltage compensation map using a value of an applied DC link voltage; and apply the obtained correction factor to the angular position of energization of the phase winding. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification