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A PWM 3-phase on-line controller for A.C. drives
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| Author(s) |
J. Richardson; G. Bezanov |
| Abstract |
The laws governing the commutation angles of optimal PWM strategies invariably describe a non-linear relationship to the fundamental component magnitude. For this reason these strategies cannot be realised using natural sampling techniques and are therefore entirely software-based. A considerable disadvantage of software based optimal strategies is that they cannot be described by an analytical expression which can be executed in real-time. In this investigation an analytic expression is defined which describes the modulation process of the harmonic elimination strategy. This modulation process is reduced to a fast algorithm for on-line calculation of the required pulse widths for eliminating the first four non-triplen harmonics and controlling the fundamental component. Results shown include the harmonic content of the waveforms supplied to a three phase induction motor load at selected operating frequencies. Also shown are selected open loop responses to sudden changes in supply frequency. |
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| Filename: | Unnamed file |
| Filesize: | 3.117 MB |
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| Type |
Members Only |
| Date |
Last modified 2019-08-16 by System |
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