Siemens Aktiengesellschaft

Metallgesellschaft Aktiengesellschaft

Hermann Mickal

Hartmut Gaul

Helmut Schummer

Franz Neulinger

Walter Schmidt

Dietmar Fischer

Adolf Haboeck

A method and apparatus for monitoring the operational state (C.sub.R) and stand-by (t.sub.St) of a battery averages battery currents (I.sub.B) and battery voltages (U.sub.B) and determines the operating mode (charging L.sub.A, or discharging, E.sub.n) from the direction of the battery current (I.sub.B). When discharging (E.sub.n), a discharge power (P.sub.En) is calculated form the average battery current (I.sub.Bm) and battery voltage (U.sub.Bm). The average cell voltage (U.sub.BZ) is determined by dividing the average battery voltage (U.sub.B) by the number of cells (Z.sub.Z) in the battery. The cell discharge power (P.sub.EnZ) is determined by dividing the discharge power (P.sub.En) by the number of cells (Z.sub.z) in the battery. Consequently, the cell discharge time (t.sub.p) is known since it is proportional to the cell discharge power (P.sub.EnZ). The cell discharge power (P.sub.EnZ) is then compared with stored families of curves of cell voltage versus withdrawn capacity (C.sub.En) and cell discharge power (P.sub.EnZ). The withdrawn capacity (C.sub.En) is determined from the average cell voltage (U.sub.BZ) and the previously determined cell discharge power (P.sub.EnZ). The withdrawn capacity (C.sub.En) is subtracted from the maximum capacity (C.sub.max) to determine the residual capacity (C.sub.R), which is multiplied by the discharge time (t.sub.p). Consequently with the aid of only one family of curves and without large expenses, the operational state (C.sub.R) and the stand-by (t.sub.St) of a battery can be monitored.

Method and apparatus for monitoring the operational state and stand-by

In order to scrub a waste gas, for example, of foreign matter by means of an electrostatic filter, a power supply is provided which contains a converter whose output feeds the primary winding of a high-voltage transformer. The secondary winding is connected to the electrostatic filter via a high-voltage rectifier. Disposed in the intermediate circuit of the converter is a control element for the intermediate circuit current. This shields the supply network against the effects of the power converter commutations and of short-circuits in the filter to a great extent. A limiter for the filter voltage and a temporary separation of the transformer from the inverter in case of filter short-circuits may be provided to reduce the stress on the components which can be made small if a high-frequency working cycle for the setter and the inverter is used.

Power supply for an electrostatic filter

To supply various loads connected to a uninterruptible bus, a power supply system N is connected (when functioning normally) by means of a mechanical switch, keeping an energy storage unit charged by means of a static converter which also functions preferrably as a phase shifter to stabilize the supply voltage. In the event of a power system malfunction, the storage unit is discharged by means of the static converter arrangement, and the mechanical switch is opened. The opening of this switch is not critical since between the switch and uninterruptible bus there is an inductance arrangement and an auxiliary switch. In case of a power system malfunction (auxiliary switch open), a large inductance and its large corresponding impedance of the inductive impedance arrangement becomes effective which during proper operation of the power system is shunted. Thus, during proper operation of the system only low inductive impedances (11, 12) and their correspondingly low impedances are effective via which a high current can flow from power supply system N, which suffices to trigger the load unit fuses in the event of a load unit short-circuit thus allowing such loads to self disconnect and not interrupt the bus by dragging it down with a heavy current malfunction.

Procedure and apparatus for uninterruptible power supply

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Erlangen, Germany

Hermann Mickal