Integrated control system and method for controlling mode, synchronization, power factor, and utility outage ride-through for micropower generation systems
First Claim
1. A power generation control system having a plurality of control states for electric power transformation having a full wave rectifier connected to a generator, a DC bus connected to the output of the full wave rectifier, an inverter connected to the DC bus, an inductor unit connected to the output of the inverter, a first contactor unit connecting and disconnecting the inductor unit to and from a grid, and a precharge circuit connected to the DC bus;
- the power generation control system comprising;
an initialization state for initializing the state machine;
a first neutral state for idling the state machine while monitoring commands and system parameters;
a pre-charge state for enabling and monitoring the precharge circuit to pre-charge the DC bus to a pre-charge DC voltage;
a second neutral state for disabling the pre-charge circuit and closing the first contactor;
an engine start state for verifying DC link voltage, sending a speed command to the start inverter unit, enabling the start inverter, updating the speed command being sent to the start inverter unit, and determining successful engine start;
a power on-line state for enabling a current mode in said inverter and controlling the inverter to deliver power at a level determined by a power level command;
a power off-line state for opening the first contactor, switching the inverter to a voltage mode, and setting the power level command to a nominal power level;
a shutdown state for disabling the inverter, opening the first contactor after waiting for a cool-down time period, and reinitializing the state machine,a state controller for controlling the following permitted transitions between said control states;
said initialization state →
said first neutral state ←
→
said pre-charge state →
said second neutral state ←
→
said start engine state ←
→
said power on-line state →
said power off-line state →
said shutdown state.
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Accused Products
Abstract
An integrated system for comprehensive control of an electric power generation system utilizes state machine control having particularly defined control states and permitted control state transitions. In this way, accurate, dependable and safe control of the electric power generation system is provided. Several of these control states may be utilized in conjunction with a utility outage ride-through technique that compensates for a utility outage by predictably controlling the system to bring the system off-line and to bring the system back on-line when the utility returns. Furthermore, a line synchronization technique synchronizes the generated power with the power on the grid when coming back on-line. The line synchronization technique limits the rate of synchronization to permit undesired transient voltages. The line synchronization technique operates in either a stand-alone mode wherein the line frequency is synthesized or in a connected mode which sensed the grid frequency and synchronizes the generated power to this senses grid frequency. The system also includes power factor control via the line synchronization technique or via an alternative power factor control technique. The result is an integrated system providing a high degree of control for an electric power generation system.
121 Citations
13 Claims
-
1. A power generation control system having a plurality of control states for electric power transformation having a full wave rectifier connected to a generator, a DC bus connected to the output of the full wave rectifier, an inverter connected to the DC bus, an inductor unit connected to the output of the inverter, a first contactor unit connecting and disconnecting the inductor unit to and from a grid, and a precharge circuit connected to the DC bus;
- the power generation control system comprising;
an initialization state for initializing the state machine; a first neutral state for idling the state machine while monitoring commands and system parameters; a pre-charge state for enabling and monitoring the precharge circuit to pre-charge the DC bus to a pre-charge DC voltage; a second neutral state for disabling the pre-charge circuit and closing the first contactor; an engine start state for verifying DC link voltage, sending a speed command to the start inverter unit, enabling the start inverter, updating the speed command being sent to the start inverter unit, and determining successful engine start; a power on-line state for enabling a current mode in said inverter and controlling the inverter to deliver power at a level determined by a power level command; a power off-line state for opening the first contactor, switching the inverter to a voltage mode, and setting the power level command to a nominal power level; a shutdown state for disabling the inverter, opening the first contactor after waiting for a cool-down time period, and reinitializing the state machine, a state controller for controlling the following permitted transitions between said control states;
said initialization state →
said first neutral state ←
→
said pre-charge state →
said second neutral state ←
→
said start engine state ←
→
said power on-line state →
said power off-line state →
said shutdown state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
- the power generation control system comprising;
Specification