Patent EP-2100851-B1 (EP)
Inventor: WALLMEIER PETER DR
IPC: G05D23/19
Filed: 2009-03-10
Granted: 2013-08-14
Abstract: The device comprises an inlet for connecting the device to an electric power grid for supplying electric energy, an output, to which silicon rods (3) are connected, an alternative current controller (1) and a frequency converter (2), which are arranged for supplying the silicon rods connected to the output with electrical current from the electric power grid, nodes, at which the voltages provided by the controller and by the frequency converter are connectable for mixing the voltage provided at the output, and a regulating unit. The frequency converter has a high frequency. The device comprises an inlet for connecting the device to an electric power grid for supplying electric energy, an output, to which silicon rods (3) are connected, an alternative current controller (1) and a frequency converter (2), which are arranged for supplying the silicon rods connected to the output with electrical current from the electric power grid, nodes, at which the voltages provided by the controller and by the frequency converter are connectable for mixing the voltage provided at the output, and a regulating unit. The frequency converter has a high frequency than the current provided by the alternative current controller and is a medium frequency converter. The controller is a network-controlled alternative current controller. A first decoupling means (4) for electrically decoupling the controller from the frequency converter is arranged between the controller and the output of the device, and a second decoupling means (5) for electrically decoupling the frequency converter from the controller is arranged between the frequency converter and the output of the device. An electrical voltage mixed from voltage portions having different frequencies is provided by the device at the output of the device. The controller and the frequency converter have an output. The outputs of the controller, the frequency converter and the device are arranged in a row. The arrangements made of the controller and the first decoupling means on one hand and the frequency converter and the second decoupling means on the other hand are electrically arranged in a parallel manner. The device has one pair of the outputs for a corresponding silicon rod, and one pair of frequency converters arranged with the pair of outputs. Each of the two outputs of the pair of outputs is connected with a corresponding output of the frequency converter of the pair of frequency converters. The two frequency converters of a pair of frequency converters are identical with respect to their electric output quantities. Each frequency converter has a pair of outputs forming a chain, in which the outputs of the converter are chained with opposite phase. The chain has a first external port, a middle port and a second external port. The output of the first frequency converter pair is connected to the first external port and the middle port and the output of the second frequency converter pair is connected to the middle port and the second external port. The output of the controller is connected to the first and second external ports. The frequency converter is arranged at the output of the device to provide a mixture of superimposed currents having different medium frequencies, and for adjusting the frequency and/or frequencies of the current and/or currents provided at the output of the device. The regulating unit is arranged for adjusting the ratios of the output provided by the controller to the output provided by the frequency converter, and for adjusting the frequency and/or frequencies in dependent of the diameter and/or cross-sectional area of the silicon rods. An independent claim is included for a method for supplying current to silicon rods during precipitation of silicon according to Siemens process.