Predictive control system and method

• US 20070021873A1
• Filed: 08/16/2006
• Published: 01/25/2007
• Est. Priority Date: 02/28/2002
• Status: Active Grant

• Current Assignee: Zetacon Corporation
• Original Assignee: Zetacon Corporation
• Inventors: Richards, Michael
• Granted Patent: US 7,286,906 B2
• Time in Patent Office: Days
• US Class Current: 700/286
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods
• CPC Class Codes: H02M 7/53873 with digital control
• CPC Class Codes: H02P 21/09 Field phase angle calculation based on rotor voltage equation by adding slip frequency and speed proportional frequency
• CPC Class Codes: H02P 21/16 Estimation of constants, e.g. the rotor time constant

Abstract

A control system and control method provides improved control of various loads by selecting the switch configuration of an associated power circuit having N binary switches, based in part on a finite state machine. The control system includes an embedded simulator, a present state contemplator and a next state contemplator to predict the operation of the load based on various switch configurations of the power circuit. The various switch states of the power circuit are modeled by the finite state machine (having up to 2^N switch states) such that at any time, the power circuit switches are in a Present State and there are a plurality of Next States which are one or more switch transitions away from the Present State. The embedded simulator estimates the operating conditions of the load based on measured operational characteristics and the Present State. The present state contemplator determines, based on the operating conditions, whether a switch state transition should be contemplated. If so, then the next state contemplator determines the optimal next state based on a set of performance criterion and sends a state switch command to the power circuit.

Claims

1. A method for determining the voltage provided by a power circuit having N switches in a circuit configuration, where each switch includes a unidirectional current element having a connected node that is coupled to a voltage source and an opposite node, each switch having a present current direction, said method comprising the steps:

(a) for each switch that opens;

(i) determining the direction of the present current direction with respect to a free-wheeling current path of the unidirectional current element;

(ii) if the present current direction is positive with respect to the free-wheeling current path, then the voltage at the opposite node is a determined voltage and is equal to the voltage at the connected node; and

,

(iii) if the present current direction is negative with respect to the free-wheeling current path, then the voltage at the opposite node is an undetermined voltage; and

(b) combining the values of all determined voltages present at the opposite nodes of each switch in accordance with the circuit configuration of the power circuit to form a vector representing the voltage provided by the power circuit.