The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 06, 1987
Filed:
Nov. 16, 1984
Sampat S Shekhawat, Rockford, IL (US);
P John Dhyanchand, Rockford, IL (US);
Pierre Thollot, Rockford, IL (US);
Sundstrand Corporation, Rockford, IL (US);
Abstract
Prior types of neutral point clamped PWM inverters have included memories for storing a plurality of PWM waveforms, one of which is utilized to control switches in the inverter to maintain an output parameter within prescribed limits. Such types of inverter controls, however, cannot provide the necessary degree of regulation in some applications. To overcome this problem, an inverter control according to the present invention permits on-line generation of PWM patterns for a neutral point clamped PWM inverter. The control includes circuitry for generating a depth of modulation signal representing the deviation of the output of the inverter from a desired level. A microprocessor and memory are coupled to the generating circuitry for calculating switching points for the inverter switches during operation of the inverter based upon the depth of modulation signal for a given number of pulses to be produced during each half cycle of the output. Timer modules are coupled to the microprocessor for developing switch control signals for each switch from the switching points so that the switches are operated to reduce the deviation of the output from the desired level.