| 摘要 |
The problem of minimizing DC content in a dual converter system (18) is addressed with dual inverters (36,38) having outputs connected in parallel through an interphase transformer (42). In order to minimize DC current flow through the transformer (42) caused by non-ideal switching characteristics, a current transducer (44) senses primary current out of each inverter (36,38). Particularly, the current transducer (44) comprises a current transformer which senses the currents differentially. This sensing removes load current so that the sensed current represents interphase transformer excitation current and DC current. The excitation current is eliminated by filtering and averaging resulting in a DC signal proportional to DC current through the interphase transformer (42), which is transferred to a control processor (40) which modifies PWM patterns sent to the inverters (36,38) to reduce the DC current.
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