| 摘要 |
The present invention relates to a circuit for use with a stator winding of a rotating or linear electrical machine. The stator winding will normally have a number of coils linked by the same number of points of common coupling (PCC1 to PCC8). The circuit of the invention includes an electronic commutator circuit having the same number of switching stages, each switching stage being connected between a respective one of the points of common coupling (PCC1 to PCC8) and first and second main dc lines (DC1, DC2). Each switching stage include a first reverse blocking semiconductor power device (GTO1, GTO3) capable of being turned on and off by gate control having its cathode connected to the first main dc line (DC1) and a second reverse blocking semiconductor power device (GTO2, GTO4) capable of being turned on and off by gate control having its anode connected to the second main dc line (DC2). A voltage clamping circuit includes the same number of clamping stages, each clamping stage being connected between a respective one of the points of common coupling (PCC1 to PCC8) and first and second auxiliary dc lines (DC3, DC4). Each clamping stage includes a first diode (D1, D3) having its cathode connected to the first auxiliary dc line (DC3) and a second diode (D2, D4) having its anode connected to the second auxiliary dc line (DC4). The voltage clamping circuit also includes a first capacitor (C1) connected between the first main dc line (DC1) and the first auxiliary dc line (DC3) and a second capacitor (C2) connected between the second main dc line (DC2) and the second auxiliary dc line (DC4); the first and second capacitors (C1, C2) being common the various clamping stages. An energy recovery circuit includes a dc to dc converter means (i.e. switches (GTO5 GTO6) and inductors (L1 and L2)) for selectively discharging the first and second capacitors (C1, C2) to the first and second main dc lines (DC1, DC2). |
