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A Method to Compensate for Errors Caused by the Blanking Time in PWM Systems with High Ripple Currents
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| Author(s) |
Michael Lindgren; Jan Svensson |
| Abstract |
In PWM converters, the non-linearity caused by
the blanking time depends on the direction of the phase current
at the commutations. Previous principles for compensating for
non-linearities have been based on the sign of the phase current
at the sampling instants, and are not able to compensate if the
phase current changes sign between the sampling instant and
the commutations. At a low power level, such a change of sign
occurs for a large part of the line period when PWM
converters are connected to the grid. This paper describes a
method to solve the problem by predicting the sign of the phase
currents at the commutations. Experimental results are
presented for a three-phase grid-connected PWM converter
controlled by a discrete vector-current controller. The method
makes the compensation possible also at low power levels and
in systems with small line filters or low sampling frequencies. |
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| Filename: | Unnamed file |
| Filesize: | 384.2 KB |
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| Type |
Members Only |
| Date |
Last modified 2006-02-21 by System |
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