Bradley J Recker

US Patent:

50124374, Apr 30, 1991

Filed:

Nov 29, 1989

Appl. No.:

7/442899

Inventors:

Bradley J. Recker - Rockford IL
Derrick I. Roe - Rockford IL
Christopher J. Rozman - Park Ridge IL

Assignee:

Sundstrand Corporation - Rockford IL

International Classification:

G06F 1520

US Classification:

364701

Abstract:

A digitally controlled oscillator (DCO) includes a binary full adder having a first set of inputs coupled to input lines, a second set of inputs, a set of summation outputs and a carry output. A latch is provided having a set of latch inputs each coupled to one of the outputs of the binary full adder, a clock input and a set of latched outputs each coupled to one of the second set of inputs of the binary full adder wherein the binary full adder sums the bits of a latched period command signal which is provided on the input lines with bits appearing at the latched outputs and provides a summed value to the summation and carry outputs. A finite state machine is coupled to the carry output of the binary full adder and to the clock input of the latch wherein the machine produces the oscillator signal having a period determined by the period command signal.

US Patent:

48751499, Oct 17, 1989

Filed:

Dec 16, 1988

Appl. No.:

7/285118

Inventors:

Christopher J. Rozman - Delavan WI
Derrick I. Roe - Rockford IL
Bradley J. Recker - Rockford IL

Assignee:

Sundstrand Corporation - Rockville IL

International Classification:

H02M 112

US Classification:

363 41

Abstract:

Polyphase inverters for converting AC power into polyphase AC output power typically experience phase shifts due to unbalanced phase loading. The resulting phase error is undesirable and should be eliminated, if possible. In order to overcome the foregoing problem, a control for maintaining N-1 phase outputs at desired angular displacements relative to a reference phase output determines the angular deviation of each of the N-1 phase outputs from the desired angular displacement for such phase output and adjusts a control waveform in time for each of a number of switches based upon the angular deviation of the phase output produced by such switch so that the angular deviations are minimized.

US Patent:

48751480, Oct 17, 1989

Filed:

Dec 16, 1988

Appl. No.:

7/285117

Inventors:

Derrick I. Roe - Rockford IL
Christopher J. Rozman - Delavan WI
Bradley J. Recker - Rockford IL

Assignee:

Sundstrand Corporation - Rockville IL

International Classification:

H02M 144

US Classification:

363 41

Abstract:

At times, it may be necessary to operate switches of a PWM inverter to provide a low output voltage. However, in order to produce such a low voltage, it may be necessary to operate the switches near their minimum on time limit, which can in turn lead to damage or destruction of the switches. In order to overcome this problem, a control for an inverter which produces an output voltage having two levels wherein the inverter includes first and second switches coupled to an inverter output produces first and second switch control signals each having alternating switch on and switch off portions wherein each switch on portion is of a duration in excess of the minimum on time limit of the switches. The first and second switches are operated in accordance with the first and second switch control signals, respectively, to produce the output voltage wherein the switches are operated in a particular switch state for a duration less than the minimum on time limit of the switches to cause the output voltage to assume one of the levels during such time. Inasmuch as the switches are operated for periods of time in excess of the minimum on time limit, the risk of damage to or destruction of the switches is minimized.

US Patent:

51989719, Mar 30, 1993

Filed:

Aug 15, 1991

Appl. No.:

7/745413

Inventors:

Bradley J. Recker - Rockford IL
Derrick Roe - Rockford IL

International Classification:

H02M 108
H02M 112

US Classification:

363 71

Abstract:

A system for receiving DC input and for providing AC output is disclosed having first and second inverters. The first inverter has an input for receiving DC input and an output for providing a first inverter output and the second inverter has an input for receiving DC input and an output for providing a second inverter output. An inverter controller is connected to the first and second inverters for controlling the first and second inverters such that the first and second inverter outputs are separated in phase by a predetermined number of degrees in order to suppress harmonics in the AC output. An output circuit is arranged to combine the first inverter output and the second inverter output into the AC output.

US Patent:

49374621, Jun 26, 1990

Filed:

Jan 23, 1989

Appl. No.:

7/300820

Inventors:

Bradley J. Recker - Rockford IL
Christopher J. Rozman - Delavan WI
Derrick I. Roe - Rockford IL

Assignee:

Sundstrand Corporation - Rockford IL

International Classification:

H02J 906
H02J 900

US Classification:

307 19

Abstract:

In aircraft applications, it may be necessary or desirable to transfer one or more loads between a variable speed, constant frequency (VSCF) power generating system and a further source of AC power. Prior controls for effecting such transfer, however, have been unduly complex. In order to overcome this problem, a control for a VSCF system senses the deviation of a parameter of the power developed by an inverter of the system relative to a parameter of the power developed by an AC power source and controls the inverter in accordance with such deviation to cause the parameter of the power developed thereby to approach the parameter of the power developed by the AC power source. The inverter and the AC power source are connected in parallel across one or more loads when the parameter deviation is within a certain range. Either the inverter or the AC power source is thereafter disconnected a certain time after the two were connected in parallel to complete the power transfer.

US Patent:

48821209, Nov 21, 1989

Filed:

Dec 16, 1988

Appl. No.:

7/285119

Inventors:

Derrick I. Roe - Rockford IL
Christopher J. Rozman - Delavan WI
Bradley J. Recker - Rockford IL

Assignee:

Sundstrand Corporation - Rockford IL

International Classification:

H02P 1318
H02M 5458

US Classification:

363 98

Abstract:

Power inverters for converting DC power into AC power often produce a DC component in the inverter output which is objectionable. In order to overcome this problem, an inverter control according to the present invention detects the magnitude of the DC component in the inverter AC output power and adjusts the time of selected rising and falling edges of control waveforms for switches in the inverter to reduce the magnitude of the DC component.

US Patent:

49565982, Sep 11, 1990

Filed:

Dec 16, 1988

Appl. No.:

7/285423

Inventors:

Bradley J. Recker - Rockford IL
Thong-Meng Cheng - Rockford IL
Derrick I. Roe - Rockford IL
Christopher J. Rozman - Delavan WI

Assignee:

Sundstrand Corporation - Rockford IL

International Classification:

H02P 942
H02M 532
H02J 300

US Classification:

322 28

Abstract:

Prior variable speed constant frequency (VSCF) generating systems which utilize an inverter to derive constant frequency power from variable frequency power developed by a generator driven by a prime mover have controlled system output voltage by controlling the excitation of the generator. Such a control technique, however, does not provide voltage regulation of individual phases and minimize undesirable distortion in the system output. In order to overcome the foregoing problem, a control for a VSCF system having a generator and an inverter which receives DC power from a rectifier coupled to the generator controls switches in the inverter to maintain the voltage of the AC power developed by the inverter at a desired level and controls the power applied to an exciter of the generator to maintain the voltage of the DC power at a particular level relative to the voltage of the AC power developed thereby. Distortion in the inverter output is thereby minimized.

US Patent:

49051342, Feb 27, 1990

Filed:

Dec 29, 1988

Appl. No.:

7/291501

Inventors:

Bradley J. Recker - Rockford IL
Christopher J. Rozman - Delavan WI
Derrick I. Roe - Rockford IL

Assignee:

Sundstrand Corporation - Rockford IL

International Classification:

H02M 542
H02V 316

US Classification:

363 98

Abstract:

Prior variable speed constant frequency (VSCF) system controls which operate the VSCF system while it is coupled in parallel with an external AC source across a load have controlled inverter output voltage based only upon the reactive current level supplied by the inverter. This has in turn resulted in the possibility of unstable system operation under load. In order to overcome the foregoing problem, a control for controlling the supply of power to a load from an inverter coupled in parallel with an AC power source across the load senses the real and reactive components of the current supplied by the inverter and the phase displacement of the power developed by the inverter relative to the power developed by the AC power source to derive an angular displacement signal. The frequency and phase of the inverter output are controlled in dependence upon the real current component supplied by the inverter and the angular displacement signal while the magnitude of the inverter output is controlled in dependence upon the real and reactive current components. The present control is capable of operating a VSCF inverter in a stable fashion under load.