Abstract: A control and regulation system for use with a harmonic neutralization frequency changer system. In the generalized frequency changer system, a direct converter frequency changer is used to convert bulk power, but unwanted harmonics are introduced. Input and output power distortion is monitored by a control system, and groups of high performance inverters inject shunt/series harmonic currents/voltages into a specially designed transformer to neutralize the power distortion to a specific acceptable level. Two control strategies are used including one that is based on discrete narrow band harmonic regulation and another that is based on wide band harmonic control. Each of these control strategies can be used at the input and/or output of the frequency changer and can be injected using shunt-current and series-voltage schemes.

Abstract: The present invention provides a device for feeding pulverized coal to a furnace, such as a drop tube furnace. The feeding system consists of a feed hopper, a pneumatic vibrator positioned on the periphery of the feeder hopper, a needle valve arrangement in the said feed hopper, a depth gauge micrometer, a distribution chamber with primary and secondary airline at the bottom of the said feed hopper. Adjusting the pressure of compressed air allows setting of the frequency of vibration of the pneumatic vibrator. The needle valve arrangement in conjunction with the vibratory hopper controls the feed rate. The rate of coal flow is measured by the depth gauge micrometer. The distribution chamber with primary and secondary airline at the bottom of the said feed hopper allows uniform mixing of air with coal before being charged into the furnace reactor.

Abstract: A multi-line power flow transformer implements power flow control among multiple transmission lines in an n-phase power system. The transformer has an exciter unit with n primary windings. Each primary winding is on a core and receives a transmission voltage of a respective one of the phases of the power system. The transformer also has a series compensating unit for each transmission line. Each series compensating unit has n secondary windings on the core of each primary winding. Each secondary winding has a voltage induced thereon by the corresponding primary winding. For each phase, the secondary windings of the series compensating unit assigned to the phase are coupled in series to sum the induced voltages formed thereon. The summed voltage is a compensating voltage for the phase.