Multi-phase electric drive and power unit thereof for use with a multi-phase AC load
AssigneeABB Schweiz AG
InventorsAndreas Voegeli, Jukka Palomaki
Life of this patent
Estimating the term…
Abstract
It is provided a multi-phase electric drive for use with a multi-phase AC load and the power unit thereof. The multi-phase electric drive includes a multi-phase power transformer with at least one primary winding and a plurality of secondary windings. The primary winding may be electrically connected to a source of multi-phase AC power. Power units may have an input connected with a corresponding one of said plurality of secondary windings and may have a single-phase controllable output to such multi-phase AC load. The power units may be serially connected with respective others of said power units in each phase output line and are connectable to said multi-phase AC load.
Claims18
A multi-phase electric drive for use with a multi-phase AC load, including:
- a multi-phase power transformer, including at least one primary winding and a plurality of secondary windings, said primary winding being electrically connectable to a source of multi-phase AC power;
- a multiple of power units including a first number of power units having an input connected with a corresponding one of said plurality of secondary windings, each of said first number of power units having a single-phase controllable output to such multi-phase AC load, and said first number of power units in a first single phase output line connectable to said multi-phase AC load;
- said power unit each includes:
- a rectifier, being adapted for converting incoming power from the corresponding secondary windings into a DC voltage;
- and
- a capacitor bank, being connected to an output of said rectifier through DC+ and DC−;
- wherein:
- said capacitor bank includes a plurality of capacitor sets connected in series;
- and
- each of said capacitor sets includes one capacitor or a multiple of capacitor elements connected in parallel;
- a voltage measurement device, being adapted for measuring respective voltages, as regards to a potential at one of DC+ and DC− of the capacitor bank, at the other of DC+ and DC- and connection points among the capacitor sets connected in series;
- a control system, being adapted for controlling said plurality of power units based on the measured voltage between DC+ and DC− of the capacitor bank and monitoring a fault on said plurality of capacitor sets based on the measured respective voltages;
- and
- said control system is adapted for calculating a magnitude of voltage across each of said plurality of capacitor sets based on magnitudes of said respective measured voltages, calculating an amplitude of unbalanced voltages among said magnitudes of said voltages across said capacitor sets, and determining said fault based on said calculated magnitude of said unbalanced voltages and a second threshold.
A power unit used in a multi-phase electric drive, including:
- a rectifier, being adapted for converting incoming power from the corresponding secondary windings into a DC voltage;
- and
- a capacitor bank, being connected to an output of said rectifier through DC+ and DC−;
- wherein:
- said capacitor bank includes a plurality of capacitor sets connected in series;
- and each of said capacitor sets includes one capacitor or a multiple of capacitor elements connected in parallel;
- a voltage measurement device, being adapted for measuring respective voltages, as regards to a potential at one of DC+ and DC− of the capacitor bank, at the other of DC+ and DC− and connection points among the capacitor sets connected in series;
- a control system, being adapted for controlling said plurality of power units based on the measured voltage between DC+ and DC− of the capacitor bank and monitoring a fault on said plurality of capacitor sets based on the measured respective voltages;
- and
- said control system is adapted for calculating a magnitude of voltage across each of said plurality of capacitor sets based on magnitudes of said respective measured voltages, calculating an amplitude of unbalanced voltages among said magnitudes of said voltages across said capacitor sets, and determining said fault based on said calculated magnitude of said unbalanced voltages and a second threshold.
The power unit according to 15, wherein:
- said control system is adapted for calculating a magnitude of said voltage across each of said plurality of capacitor sets based on a difference between two of the measured voltages for two of said connection points respectively electrically connected to said capacitor set.
Dependencies are inferred from the claim text.