Solid state motor starter with energy recovery
First Claim
1. For use with a multi-phase motor and a multi-phase power source providing source voltage in the form of positive and negative voltage alternations resulting in a load current in the motor having positive and negative alternations, a starter circuit for the motor comprising:
- a first pair of switch-diode combinations electrically connected in series with the multi-phase power source and the multi-phase motor, each of the switches having an open state and a closed state;
a second pair of switch-diode combinations electrically connected in parallel with the multi-phase power source and the multi-phase motor, each of the switches having an open state and a closed state;
a controller programmed to control the state of the switches of the switch-diode combinations, based on the relative polarities of the supply voltage and the load current, so as to provide pulse-width modulated current to the motor when the supply voltage and the load current have similar polarities and to recover energy trapped in the motor and transfer it back to the multi-phase source when the supply voltage and load current have opposite polarities.
1 Assignment
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Accused Products
Abstract
A motor starter circuit providing recovery of the energy trapped in the motor windings when the supply voltage and current have opposite polarities by selectively controlling actuation of a plurality of high speed switches. The circuit, for use with a multiphase motor and power source that provides positive and negative voltage alternations which result in the generation of a load current in the motor having positive and negative alternations, includes a plurality of switch-diode combinations electrically configured such that for a given pair of supply voltage/load current polarities, only one diode of each combination may be forward biased.
36 Citations
16 Claims
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1. For use with a multi-phase motor and a multi-phase power source providing source voltage in the form of positive and negative voltage alternations resulting in a load current in the motor having positive and negative alternations, a starter circuit for the motor comprising:
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a first pair of switch-diode combinations electrically connected in series with the multi-phase power source and the multi-phase motor, each of the switches having an open state and a closed state; a second pair of switch-diode combinations electrically connected in parallel with the multi-phase power source and the multi-phase motor, each of the switches having an open state and a closed state; a controller programmed to control the state of the switches of the switch-diode combinations, based on the relative polarities of the supply voltage and the load current, so as to provide pulse-width modulated current to the motor when the supply voltage and the load current have similar polarities and to recover energy trapped in the motor and transfer it back to the multi-phase source when the supply voltage and load current have opposite polarities. - View Dependent Claims (2, 3, 4, 5)
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6. For use with a multi-phase motor and a multi-phase power source providing positive and negative voltage alternations resulting in a load current in the motor having positive and negative alternations, a starter circuit for the motor comprising:
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a first pair of switch-diode combinations electrically connected in series with the multi-phase power source and the multi-phase motor; a second pair of switch-diode combinations electrically connected in parallel with the multi-phase power source and the multi-phase motor; a controller programmed, based on the relative polarities of the supply voltage and the load current, to maintain the switches of two switch-diode combinations in an open position, to maintain the switch from one of the switch-diode combinations in a closed position, and to cycle the switch from one of the switch-diode combinations between an open state and a closed state, so as to provide pulse-width-modulated current to the motor during starting. - View Dependent Claims (7, 8, 9, 10)
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11. For use with a multi-phase motor and a multi-phase power source providing source voltage in the form of positive and negative voltage alternations resulting in a load current in the motor having positive and negative alternations, a starter circuit for the motor comprising, for each phase:
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a first pair of switch-diode combinations electrically connected in series with the multi-phase power source and the multi-phase motor, each of the switches having an open state and a closed state; a second pair of switch-diode combinations electrically connected in parallel with the multi-phase power source and the multi-phase motor, each of the switches having an open state and a closed state; a controller programmed to control the state of the switches of the switch-diode combinations, based on the relative polarities of the supply voltage and the load current, so as to provide pulse-width modulated current to the motor when the supply voltage and the load current have similar polarities and to recover energy trapped in the motor back to the multi-phase source when the supply voltage and load current have opposite polarities. - View Dependent Claims (12, 13)
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- 14. A method, for use with a starter circuit for a multi-phase motor and a multi-phase power source providing source voltage in the form of positive and negative voltage alternations resulting in a load current in the motor having positive and negative alternations, the starter circuit including a first pair of switch-diode combinations electrically connected in series with the multi-phase power source and the multi-phase motor, a second pair of switch-diode combinations electrically connected in parallel with the multi-phase power source and the multi-phase motor, each of the switches having an open state and a closed state, and a controller, the method comprising the step of controlling the state of the switches of the switch-diode combinations based on the relative polarities of the supply voltage and the load current so as to provide pulse-width modulated current to the motor during starting and to recover energy trapped in the motor back to the multi-phase source when the supply voltage and load current have opposite polarities.
Specification