Vacon Oyj

Semikron Elektronik Gmbh

The Switch Drive Systems Oy

Pertti Tapani Silventoinen

Risto Komulainen

Juha Pyrhönen

Dejan Schreiber

Olli Pyrhönen

Mikko Pekka Juhani Kuisma

Valentin Dzhankhotov

A filter appliance comprises first electrical terminals (-) for connecting to a multiphase electrical converter device, second electrical terminals (-) for connecting to a load, main current coils formed of foil conductors and connected between the first and the second electrical terminals, and shielding coils whose first ends are electrically connected to a third electrical terminal () of the filter appliance. Each of the shielding coils is formed of foil conductor that is alongside and a distance apart from the foil conductor of the corresponding main current coil so as to form a capacitive shield between successive turns of the main current coil. When the third electrical terminal is connected to constant electrical potential, the shielding coils reduce the common mode voltage applied to the load and, for example, a risk of bearing damages in an electrical motor driven by a multiphase electrical converter device is reduced.

Filter appliance for a multiphase electrical converter device

Method of controlling a voltage controlled PWM (Pulse Width Modulated) frequency converter comprising a single phase rectifier bridge () connectable to a sinusoidal single phase supply, a DC intermediate circuit () and a controlled inverter bridge () for generating an AC output voltage with varying amplitude and frequency to a load, said inverter bridge () having PWM controlled semiconductor switches (VV) and flywheel diodes (DD) connected in inverse-parallel with the semiconductor switches, wherein the DC intermediate circuit () is provided with a DC capacitor unit, and wherein the frequency converter is controlled so that the supply line current (I) is essentially sinusoidal and in phase with the supply line voltage (U). The inverter bridge is controlled so that the curve of filtered average current (I) in the DC intermediate circuit follows essentially the curve of the rectified AC supply voltage (U), the rectifier bridge is () connected to the inverter bridge () directly without a DC capacitor unit acting as an intermediate energy storage, and the curve of the power fed to the load has essentially the form sin(2&#x3c0;ft) (f=line frequency t=time).

Frequency converter and its control method

Growing community of inventors

Lappeenranta, Finland

Pertti Tapani Silventoinen