Regenerative braking protection for an electrically-propelled traction vehicle

摘要

An electric propulsion system for a traction vehicle includes a controllable power converter operable in either a propulsion or an electric braking mode in which power is withdrawn from a wayside source or returned to the source, respectively. The wayside source utilizes certain preselected frequencies for power generation and for signaling. It is desirable to detect these frequencies quickly and to be able to disconnect the vehicle from the source if some frequencies are being generated by the vehicle and others are not present on the system. Bandpass filters are coupled to the power converter to detect the preselected frequencies. Wayside transients sometimes encroach on these frequencies with large power spikes causing ringing of the filter circuits and delay in detecting the preselected frequencies. The system includes an active power limiter for limiting the peak amplitude of the signals coupled to the filters without interfering with the signal frequency content or affecting filter operation.