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AssigneeYork International Corporation
InventorsIvan Jadric, Harold Schnetzka
Estimating the term…
A variable speed drive (VSD) having a rectifier, an inverter, an inverter modulator, an inverter controller, and a control loop, for controlling a motor load, wherein the control loop reduces an amount of power transferred to the inverter during a voltage sag. The control loop may include a reference generator, a filter, a regulator, and a ride-through corrective algorithm. A method for controlling a VSD to improve voltage sag ride-through by monitoring a voltage applied to the VSD, generating a control signal representative of losses in a motor load when a voltage sag is detected in the voltage applied to the VSD and applying less power to the load of the inverter.
A variable speed drive comprising:
A variable speed drive comprising:
A method for controlling a variable speed drive for a load, the drive including a rectifier, DC link, inverter, and an inverter control, the method comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
With automatic control of output voltage or current: with digital control
Using devices of a triode or transistor type requiring continuous application of a control signal: using semiconductor devices only
Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters: the disturbance parameters being…
Apparatus for conversion between ac and ac, between ac and dc, or
Term ended 27 Nov 2021 (estimated)
1. Field of the Invention
This invention relates to a control loop and method for enabling variable speed drives (VSDs) with an intermediate DC stage to ride through supply voltage sags.
2. Background of the Invention
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate different embodiments of the invention and together with the description, serve to explain the principles of the invention.
FIG. 1 is a schematic diagram of a generic embodiment of a three stage variable speed drive with a controller that provides ride through control;
FIG. 2 is a schematic diagram of a more specific embodiment of a three stage variable speed drive with a ride through control loop comprising of various individual components.
Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings.
One purpose of a VSD is to take three-phase power at a fixed voltage and frequency, which may be provided from a utility for example, and convert it to three-phase power at a desired variable voltage and frequency for use in variable-speed electric motors. In the United States, power utilities often provide power at around 460 Volts and at about 60 Hz. In Europe, power is typically supplied at around 380 V and at about 50 Hz. VSDs can convert various input power voltages and frequencies to desired voltages and frequencies for operating motors. Many motors in large-tonnage heating, ventilation, air-conditioning and refrigeration (HVAC&R) applications operate at frequencies around 30 to 60 Hz, but VSDs are not limited to outputting power at or between those frequencies.
The attached drawings show block diagrams of a typical variable speed drive system. Control signals and components in the drawing have been numbered for ease of understanding. These numbers will be referred to throughout this text.