Power conversion system including an improved filter for attenuating harmonics
AssigneeGeneral Electric Company
InventorsRonald B. Bailey, Ajith K. Kumar, David L. Plette
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Abstract
For connecting the d-c terminals of a voltage-source inverter to a direct current (d-c) power source, a d-c link capacitor is connected directly between the d-c terminals, a line capacitor is connected in parallel with the d-c link capacitor, and a series inductor is connected between the line capacitor and the source. A dynamic brake resistor and an electric power chopper are connected in series with one another across the line capacitor. Between the two capacitors, no inductance is provided but a resistor is inserted in the braking current path during electrical braking operation of the inverter.
Claims10
An electric power conversion system for conveying power between a d-c power source and an electric motor, comprising:
- a. an electric power converter having a set of load terminals on its motor side for connection to at least one motor and a pair of d-c terminals on its source side, said converter having alternative motoring and electrical braking modes of operation;
- b. means for connecting said d-c terminals to a d-c power source;
- c. said connecting means including an electrical filter for attenuating harmonics generated by operation of said converter during motoring and electrical braking, said filter comprising:
- (i) line-filter inductance means connected in the path of current between said source and said converter,
- (ii) first capacitance means directly connected between said d-c terminals,
- (iii) second capacitance means, and
- (iv) interconnecting means characterized by the absence of appreciable inductance for connecting said second capacitance means in parallel with said first capacitance means;
- d. dynamic braking circuit connected across said second capacitance means and comprising the series combination of a dynamic braking resistance and an electric power chopper that can be repetitively turned on and off during electrical braking to control current in said dynamic braking resistance;
- e. said interconnecting means of said filter including additional ohmic resistance means in the path of current between said first and second capacitance means so that during electrical braking a substantially higher voltage is developed across said first capacitance means than across said second capacitance means;
- and
- f. means for effectively removing said additional resistance means from said interconnecting means during the motoring mode of converter operation.
Dependencies are inferred from the claim text.