Base drive and overlap protection circuit
First Claim
1. A base drive and overlap protection circuit comprising:
- power switching means;
means operative to monitor current flow through said power switching means and to generate a negative current signal as a function thereof; and
gating means operative to receive said negative current signal, switch command signals from a control circuit and an enable signal from an enabling circuit, and to generate a switching signal in response thereto, said power switching means being operative to switch from a first state to a second state in response to said switching signal.
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Accused Products
Abstract
An inverter (34) which provides power to an A. C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A. C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A. C. machine is optimized. The control circuit includes a microcomputer and memory element which receive various parametric inputs and calculate optimized machine control data signals therefrom. The control data is asynchronously loaded into the inverter through an intermediate buffer (38). A base drive and overlap protection circuit is included to insure that both transistors of a complimentary pair are not conducting at the same time. In its preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack (32) and a three-phase induction motor (18).
87 Citations
30 Claims
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1. A base drive and overlap protection circuit comprising:
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power switching means; means operative to monitor current flow through said power switching means and to generate a negative current signal as a function thereof; and gating means operative to receive said negative current signal, switch command signals from a control circuit and an enable signal from an enabling circuit, and to generate a switching signal in response thereto, said power switching means being operative to switch from a first state to a second state in response to said switching signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A base drive and overlap protection circuit for an inverter of the type having a plurality of complimentary power switching means arranged to reciprocally energize a common load in response to switch command signals generated by a control circuit, said base drive and overlap protection circuit comprising:
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means operative to monitor current flow through said complimentary power switching means and to generate negative current signals as a function thereof; means operative to monitor the voltage drop across said complimentary power switching means and to generate voltage sense signals as a function thereof; means operative to generate distinct enabling signals for each said switching means as a function of said negative current signals and said voltage sense signals; and gating means operative to selectively actuate one of said power switching means in response to receipt of enable signals from another of said switching means, said switch command signals and negative current signals, whereby at least one of said complimentary switching means is in a nonconductive state at all times. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A base drive and overlap protection circuit for an inverter of the type having first and second complimentary power switching means arranged to reciprocally energize a common load in response to switch command signals generated by a control circuit, said base drive and overlap protection circuit comprising:
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means operative to monitor current flow through said first and second power switching means and to generate first and second negative current signals respectively as a function thereof; means operative to monitor the voltage drops across said first and second power switching means and to generate first and second voltage sense signals respectfully as a function thereof; means operative to generate a first enabling signal as a function of said first negative current signal and said first voltage sense signal; means operative to generate a second enabling signal as a function of said second negative current signal and said second voltage sense signal; first gating means operative to selectively actuate said first power switching means in response to receipt of said switch command signals, said first negative current signal and said second enabling signal; and second gating means operative to selectively actuate said second power switching means in response to receipt of said switch command signals, said second negative current signal and said first enabling signal. - View Dependent Claims (19, 20, 21)
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22. An inverter for controlling a multi-phase A. C. machine comprising:
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a control circuit operative to receive parametric inputs and generate switch command signals as a function thereof; a complimentary pair of power transistors associated with each phase of said machine, each said pair operative to reciprocally energize said associated phase in response to said switch command signals; current sensors operative to monitor the current flowing through each of the transistors and to generate corresponding negative current signals as a function thereof; voltage level sensors operative to monitor the voltage drop across each of the transistors and to generate voltage sense signals as a function thereof; means associated with each transistor operative to generate an enabling signal as a function of the corresponding negative current signal and voltage sense signal; and gating means associated with each transistor operative to switch said associated transistor from a nonconductive state to a conducting state in response to receipt of; said switch command signals; the negative current singal from said associated transistor; and the enabling signal from the compliment of said associated transistor.
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23. A drivetrain adapted for use with an electric vehicle having at least one tractive wheel, said drivetrain comprising:
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a D. C. power source; a three-phase induction motor; an inverter for providing a power input from said power source and a power output to each phase of said motor at a preselectable frequency and a preselectable voltage, said inverter comprising; a control circuit operative to receive parametric inputs and generate switch command signals as a function thereof; a complimentary pair of power transistors associated with each phase of said motor, each said pair operative to reciprocally energize said associated phase in response to said switch command signals; current sensors operative to monitor the current flowing through each of the transistors and to generate corresponding negative current signals as a function thereof; voltage level sensors operative to monitor the voltage drop across each of the transistors and to generate voltage sense signals as a function thereof; means associated with each transistor operative to generate an enabling signal as a function of the corresponding negative current signal and voltage sense signal; and gating means associated with each transistor operative to switch said associated transistor from a nonconducting state to a conducting state in response to receipt of; said switch command signals; the negative current signal from said associated transistor; and the enabling signal from the compliment of said associated transistor.
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24. A base drive and overlap protection circuit for an inverter of the type having complimentary power switching means arranged to reciprocally energize a common load in response to switch command signals generated by a control circuit, said base drive and overlap protection circuit comprising:
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means operative to monitor current flow through said complimentary power switching means and to generate negative current signals as a function thereof; means operative to monitor the voltage drop across said complimentary power switching means and to generate voltage sense signals as a function thereof; means operative to generate enabling signals as a function of said negative current signals and said voltage sense signals; gating means operative to selectively actuate said power switching means in response to receipt of said switch command signals, negative current signals and enable signals, whereby at least one of said complimentary switching means is in a nonconductive state at all times; and overcurrent latch means operative to interrupt activation of said power switching means when the current flow through said power switching means exceeds a predetermined value, and to reset upon receipt of a subsequent switch command signal. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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Specification