| 摘要 |
<p>This invention discloses a power supply and inverters for a broadband signal distribution system in which electrical power is coupled with broadband signals and transmitted through a coaxial cable. The system includes a head-end for providing the broadband signals and a trunk for coupling the broadband signals to a plurality of distribution nodes, each of which are coupled to a distribution network of feeder lines for delivering broadband signals to a plurality of consumer sites. The distribution nodes further include an electrical switching power supply for the generation of electrical power having a slowly varying AC waveform. Preferably, the AC waveform is trapezoidal so the RMS value of power delivered is greater than that previously achieved with sinusoidal waveforms with the same peak voltage. Because a trapezoidal waveform has smoother transitions, the trapezoidal waveform results in reduced harmonics, thus less change of interference. Furthermore, compared to DC, an AC waveform results in lower probability of switch corrosion. The inverters of the power supply include a regulator for controlling a switching network of the power supply. Each regulator includes a processor, a feed forward circuit to efficiently regulate the voltage of the AC waveform, and a current overshoot circuit. The processor and current overshoot circuit enable the switching network to receive control signals from the feed forward circuit to reduce current overshoot on said inverter outputs. The inverters are coupled together through a synchronization line and polarity lines to control the timing for the output of the trapezoidal waveforms so that ramp up and ramp down portions of the waveform start at approximately the same time. The synchronization of the output waveforms reduce the likelihood of inducing noise in the broadband signals coupled with the AC power onto the feeder lines.</p> |
