US6850426B2 — Synchronous and bi-directional variable frequency…

Claim 1

Independent Claim 98 words

A synchronous and bi-directional power conversion module for use in a variable frequency power conversion system, the power conversion module comprising: a digital controller that receives signals from AC and DC voltage and current sensors and generates gating signals to power switching devices to control power flow between an AC side and a DC side of the power switching devices, wherein the digital controller includes a digital phase lock loop (DPLL) that uses a feed-forward predictive system based on a look-up table to track the system variable frequency, which is a frequency of a variable frequency power source.

Claim 2

Dependent Claim 98 words

A synchronous and bi-directional power conversion module for use in a variable frequency power conversion system, the power conversion module comprising: a digital controller that receives signals from AC and DC voltage and current sensors and generates gating signals to power switching devices to control power flow between an AC side and a DC side of the power switching devices, wherein the digital controller includes a digital phase lock loop (DPLL) that uses a feed-forward predictive system based on a look-up table to track the system variable frequency, which is a frequency of a variable frequency power source.

Claim 3

Dependent Claim 29 words

The synchronous and bi-directional power conversion module according to claim 1 , wherein the power conversion module is configurable to operate as a rectifier (AC-DC) or an inverter (DC-AC).

Claim 4

Dependent Claim 39 words

The synchronous and bi-directional power conversion module according to claim 2 , wherein the power conversion module is configured as a rectifier and is combined with another power conversion module configured as an inverter to provide AC-DC-AC power conversion.

Claim 5

Dependent Claim 26 words

The synchronous and bi-directional power conversion module according to claim 1 , wherein the system frequency varies over a ratio of 2 to 1 or more.

Claim 6

Dependent Claim 32 words

The synchronous and bi-directional power conversion module according to claim 1 , wherein a total number of samples in one system fundamental period is continuously monitored and maintained as an even number.

Claim 7

Dependent Claim 43 words

The synchronous and bi-directional power conversion module according to claim 5 , wherein when the system variable frequency varies between 320 to 800 Hz, the total number of samples is adjusted accordingly to achieve a constant switching frequency for the power switching devices.

Claim 8

Dependent Claim 25 words

The synchronous and bi-directional power conversion module according to claim 1 , wherein a substantially constant switching frequency is maintained for the power switching devices.

Claim 9

Dependent Claim 36 words

The synchronous and bi-directional power conversion module according to claim 7 , wherein the power conversion module operates at a switching frequency of approximately 10 kHz for a system frequency range of 320 to 800 Hz.

Claim 10

Dependent Claim 38 words

The synchronous and bi-directional power conversion module according to claim 8 , further comprising: low-pass filters for active rectifiers having cut-off frequencies on the order of 100 Hz for direct and quadrature components of system voltage and current.

Claim 11

Dependent Claim 121 words

The synchronous and bi-directional power conversion module according to claim 1 , further comprising: a control power supply that internally generates voltages needed for the power conversion module from a single control power source; a DC-link connected to the DC side of the power switching devices; a filter including inductive and capacitive elements connected to the AC side of the power switching devices; and signal conditioning and isolation circuitry for all sensed signals including the sensors for detecting AC voltages and currents on the AC side and DC voltage and current on the DC-link, wherein the digital controller, signal conditioning and isolation circuitry, sensors, filter, DC-link, power switching devices and control power supply are integrated into a common circuit card assembly.

Claim 12

Dependent Claim 124 words

A digital phase lock loop (DPLL) for variable frequency power conversion systems comprising: an input section that determines a reference phase angle error signal based on a reference phase angle of a variable frequency input and an estimated phase angle; a PI controller that determines a measured frequency of the variable frequency input based on the phase angle error signal; and a look-up table that, using the measured frequency, determines a phase angle step, a sampling frequency, and a phase angle delay, wherein the estimated phase angle is generated by a discrete integrator using the phase angle step and a prior value of the estimated phase angle, and a compensated phase angle is generated using the estimated phase angle and the phase angle delay.

Claim 13

Dependent Claim 124 words

A digital phase lock loop (DPLL) for variable frequency power conversion systems comprising: an input section that determines a reference phase angle error signal based on a reference phase angle of a variable frequency input and an estimated phase angle; a PI controller that determines a measured frequency of the variable frequency input based on the phase angle error signal; and a look-up table that, using the measured frequency, determines a phase angle step, a sampling frequency, and a phase angle delay, wherein the estimated phase angle is generated by a discrete integrator using the phase angle step and a prior value of the estimated phase angle, and a compensated phase angle is generated using the estimated phase angle and the phase angle delay.

Claim 14

Dependent Claim 41 words

The digital phase lock loop according to claim 11 , wherein the phase angle step, the sampling frequency, and the phase angle delay are determined at every sample point and wherein the compensated phase angle is generated at every sample point.

Claim 15

Dependent Claim 25 words

The digital phase lock loop according to claim 11 , wherein the variable frequency input varies over a ratio of 2 to 1 or more.

Claim 16

Dependent Claim 19 words

The digital phase lock loop according to claim 11 , wherein the look-up table is a three-dimensional look-up table.

Claim 17

Dependent Claim 37 words

The digital phase lock loop according to claim 14 , wherein stored values in the look-up table relating to the measured frequency and the phase angle step, the sampling frequency, and the phase angle delay are pre-calculated.

Claim 18

Dependent Claim 38 words

The digital phase lock loop according to claim 15 , wherein the stored values in the look-up table are calculated for discrete intervals of the measured frequency, and wherein the intervals ranges from 1 Hz to 40 Hz.

Claim 19

Dependent Claim 29 words

The digital phase lock loop according to claim 15 , wherein the stored values in the look-up table are calculated for each 20 Hz interval of the measured frequency.

Claim 20

Dependent Claim 21 words

The digital phase lock loop according to claim 11 , wherein the variable frequency input ranges from 320 to 800 Hz.

Claim 21

Dependent Claim 30 words

The digital phase lock loop according to claim 11 , wherein a total number of samples in one system fundamental period is continuously monitored and maintained as an even number.

Claim 22

Dependent Claim 41 words

The digital phase lock loop according to claim 19 , wherein when the variable frequency input varies between 320 to 800 Hz, the total number of samples is adjusted accordingly to achieve a constant switching frequency for the power switching devices.

Claim 23

Independent Claim 126 words

A method for implementing a digital phase lock loop (DPLL) for variable frequency power conversion systems, the method comprising: determining a reference phase angle error signal based on a reference phase angle of a variable frequency input and an estimated phase angle; determining a measured frequency of the variable frequency input based on the phase angle error signal; and using the measured frequency as an input to a look-up table that generates a phase angle step, a sampling frequency, and a phase angle delay, wherein the estimated phase angle is generated by a discrete integrator using the phase angle step and a prior value of the estimated phase angle, and a compensated phase angle is generated using the estimated phase angle and the phase angle delay.

Claim 24

Independent Claim 126 words

A method for implementing a digital phase lock loop (DPLL) for variable frequency power conversion systems, the method comprising: determining a reference phase angle error signal based on a reference phase angle of a variable frequency input and an estimated phase angle; determining a measured frequency of the variable frequency input based on the phase angle error signal; and using the measured frequency as an input to a look-up table that generates a phase angle step, a sampling frequency, and a phase angle delay, wherein the estimated phase angle is generated by a discrete integrator using the phase angle step and a prior value of the estimated phase angle, and a compensated phase angle is generated using the estimated phase angle and the phase angle delay.

Claim 25

Dependent Claim 38 words

The method according to claim 21 , wherein the phase angle step, the sampling frequency, and the phase angle delay are determined at every sample point and wherein the compensated phase angle is generated at every sample point.

Claim 26

Dependent Claim 22 words

The method according to claim 21 , wherein the variable frequency input varies over a ratio of 2 to 1 or more.

Claim 27

Dependent Claim 16 words

The method according to claim 21 , wherein the look-up table is a three-dimensional look-up table.

Claim 28

Dependent Claim 33 words

The method according to claim 24 , further comprising: pre-calculating stored values in the look-up table relating the measured frequency and the phase angle step, the sampling frequency, and the phase angle delay.

Claim 29

Dependent Claim 35 words

The method according to claim 25 , wherein the stored values in the look-up table are calculated for discrete intervals of the measured frequency, and wherein the intervals are from 1 Hz to 40 Hz.

Claim 30

Dependent Claim 26 words

The method according to claim 25 , wherein the stored values in the look-up table are calculated for each 20 Hz interval of the measured frequency.

Claim 31

Dependent Claim 18 words

The method according to claim 21 , wherein the variable frequency input ranges from 320 to 800 Hz.

Claim 32

Dependent Claim 27 words

The method according to claim 21 , wherein a total number of samples in one system fundamental period is continuously monitored and maintained as an even number.

Claim 33

Dependent Claim 38 words

The method according to claim 29 , wherein when the variable frequency input varies between 320 to 800 Hz, the total number of samples is adjusted accordingly to achieve a constant switching frequency for the power switching devices.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2008-02-01	2008-08-02	2009-02-01	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2012-02-01	2012-08-02	2013-02-01	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2016-02-01	2016-08-02	2017-02-01	$7700.00	Window Closed / Lapsed

Synchronous and bi-directional variable frequency power conversion systems

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