Control unit for controlling a direct-current load

Details Control unit for controlling a direct-current load Control unit for controlling a direct-current load

2003-01-28

2004-02-24

Nguyen, Matthew V. (Department: 2838)

Electric power conversion systems

Current conversion

With condition responsive means to control the output...

C363S132000

Reexamination Certificate

active

06697273

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a control unit for controlling a direct-current load, said control unit comprising a DC/DC bridge provided with controllable semiconductor switches, said bridge having two bridge sections, one of which bridge sections conducts direct current while the other one is controlled via PWM to regulate the current magnitude.
BACKGROUND OF THE INVENTION
Elevator motor drives may be either alternating-current or direct-current motor drives. The drives may be controlled e.g. via PWM (Pulse Width Modulation). Today, alternating-current motor drives are fairly common, especially because of the simple construction of alternating-current motors. However, direct-current motor drives are still in use. Neither is it always appropriate to replace a direct-current motor drive with an alternating-current motor drive, because e.g. gearless direct-current motor drives and the direct-current motors used in them are durable and it is therefore unnecessary to replace them with alternating-current motor drives. Besides, replacing the motor entails relatively high costs.
Since the trend is towards alternating-current motor drives, it is also hardly rational to specifically develop power electronics systems for use in the control of direct-current drives. In addition, semiconductor components, such as IGBTs, used in alternating-current drives are all the time becoming increasingly efficient and economical. Moreover, it is to be expected that especially new regulations concerning network harmonics may alter the situation in future so that the use of traditional thyristor bridges used in direct-current drives will become more difficult.
SUMMARY OF THE INVENTION
The object of the invention is to eliminate the drawbacks of prior-art technology and achieve a new type of PWM-controlled control unit for controlling a direct-current load, such as a direct-current motor. The solution of the invention is based on a new principle of power electronics topology, wherein it is possible to utilize the technology of alternating-current drives in the control off direct-current motors. In the solution of the invention, a PWM-controlled bridge section consists of two bridge arms, and the semiconductor switches of the bridge arms are turned alternately into the conducting state.
The preferred embodiments of the solution of the invention are presented in the claims below.
By using the technology of the invention, it is possible to manufacture modern and economical PWM-controlled direct-current motor drives e.g. for elevator applications. By applying the invention, the power electronics technology and components of alternating-current drives manufactured in large production series can be utilized in direct-current drives. The conductor rails and other structures of the power stage can be identical to those used in alternating-current drives. In addition, the use of semiconductor switches, such as IGBTs can be optimized even in direct-current applications. And, in particular, cost savings are achieved in development and production methods as the same methods can be used in both alternating-current and direct-current drives.


REFERENCES:
patent: 5107190 (1992-04-01), Schultz et al.
patent: 5703768 (1997-12-01), Kanna et al.
patent: 5757636 (1998-05-01), Fletcher
patent: 5912813 (1999-06-01), Kerkman et al.
patent: 6131692 (2000-10-01), Kawasuji
patent: 6172882 (2001-01-01), Tanaka et al.
patent: 6486632 (2002-11-01), Okushima et al.
patent: 3428239 (1985-03-01), None
“Single-Phase DC Drive System Controlled by Sinusoidal PWM Full-Bridge DC-DC Converter with Improved Input Current Waveform” by T.H. Abdelharnid, Department of Electrical Engineering, University of Alexandria, Egypt IEEE 1999 pp. 670-672.

Affiliated with

Also associated with

Rating

Control unit for controlling a direct-current load does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Control unit for controlling a direct-current load, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control unit for controlling a direct-current load will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3305834