Power conditioning system for use with two PWM inverters and at least one other load
First Claim
1. A combined electric drive and charging system comprising:
- a source of electrical energy;
a first pulse width modulated (PWM) inverter circuit for driving a first load with power obtained from said source of electrical energy, said first (PWM) inverter circuit having means for switchably applying a first drive current pulse to said first load, said first drive current pulse having a pulse width and polarity controlled by a first carrier signal and at least one first phase control signal, whereby the electrical power delivered to said first load is controlled by said first PWM inverter circuit;
a second PWM inverter circuit for driving a second load with power obtained from said source of electrical energy, said second PWM inverter circuit having means for switchably applying a second drive current pulse to have second load, said second drive current pulse having a pulse width and polarity controlled by a second carrier signal and at least one second phase control signal, whereby the electrical power delivered to said second load is controlled by said second PWM inverter circuit;
generating means for generating said first and second carrier signals and said at least one first and second phase control signals;
phase adjustment means for selectively adjusting the phase between said first and second carrier signals, whereby the relative phase difference between said first and second drive current pulses can be selectively controlled; and
extraction means for generating a drive current phase difference signal and extracting the energy contained therein for powering a third load, said drive current phase difference signal having a maximum energy content when the phase difference between said first and second drive current pulses is a maximum, and a minimum energy content when the phase difference between said first and second drive current pulses is a minimum, whereby the power delivered to said first load is also obtained from said source of electrical energy and is controlled by said phase adjustment means.
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Accused Products
Abstract
A coupling circuit (30) connects two three-phase pulse width modulated (PWM) inverter circuits (16, 18), used in conventional manner to power a first load (12), in order to independently power a second load (32). In a preferred embodiment, the two PWM inverter circuits propel an armored vehicle, such as a tank, with one motor driving the right side, and the other motor driving the left side. The propulsion of the vehicle represents the first load. The second load is a pulse forming network (PFN), which PFN powers an electrothermal gun system carried by the vehicle. The coupling circuit includes a transformer (TA, TB, TC) and rectifier circuit (34) for each phase output of the PWM inverters. A primary winding (32) of each transformer is connected between corresponding phase outputs of the two PWM inverters. A secondary winding of each transformer is connected to a respective rectifier circuit. The output of each rectifier circuit is joined with the other rectifier outputs to charge the PFN. Charging of the PFN is controlled using a phase shift network (28) that selectively adjusts the phase shift between the carrier signals applied to the two PWM inverters, with a zero phase shift reducing the charging current to zero, and a 180° phase shift increasing the charging current to a maximum. A feedback sensor (38) detects the current, voltage and/or power of the PFN output, and these sensed parameters in turn control the phase shift between the two carrier signals so as to produce and/or maintain a specified PFN charging current.
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Citations
20 Claims
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1. A combined electric drive and charging system comprising:
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a source of electrical energy; a first pulse width modulated (PWM) inverter circuit for driving a first load with power obtained from said source of electrical energy, said first (PWM) inverter circuit having means for switchably applying a first drive current pulse to said first load, said first drive current pulse having a pulse width and polarity controlled by a first carrier signal and at least one first phase control signal, whereby the electrical power delivered to said first load is controlled by said first PWM inverter circuit; a second PWM inverter circuit for driving a second load with power obtained from said source of electrical energy, said second PWM inverter circuit having means for switchably applying a second drive current pulse to have second load, said second drive current pulse having a pulse width and polarity controlled by a second carrier signal and at least one second phase control signal, whereby the electrical power delivered to said second load is controlled by said second PWM inverter circuit; generating means for generating said first and second carrier signals and said at least one first and second phase control signals; phase adjustment means for selectively adjusting the phase between said first and second carrier signals, whereby the relative phase difference between said first and second drive current pulses can be selectively controlled; and extraction means for generating a drive current phase difference signal and extracting the energy contained therein for powering a third load, said drive current phase difference signal having a maximum energy content when the phase difference between said first and second drive current pulses is a maximum, and a minimum energy content when the phase difference between said first and second drive current pulses is a minimum, whereby the power delivered to said first load is also obtained from said source of electrical energy and is controlled by said phase adjustment means. - View Dependent Claims (2, 3, 4)
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5. A power system for delivering electrical power to at least two loads comprising:
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a primary power source; means for generating first and second carrier signals, said first and second carrier signals having the same frequency, but having a phase difference therebetween that is selectively adjustable; first and second inverter circuits, each of said inverter circuits having input means for receiving;
(1) input power from said primary power source, (2) a respective one of said first or second carrier signals, and (3) at least one phase control signal;
each of said inverter circuits further having at least one phase output for delivering output power to a first load as controlled by said respective carrier signal and said at least one phase control signal;combining means for combining corresponding phase outputs from said first and second inverter circuits and for delivering power obtained through said combining means to a second load, the amount of power delivered to said second load being controlled by the phase difference between said first and second carrier signals. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A power system for providing controlled electrical power to first and second subsystems within an electrically powered apparatus, said power system comprising:
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a primary power source; first delivery means for delivering a controlled amount of electrical power from said primary power source to said first subsystem comprising; at least two pulse width modulator (PWM) inverter circuits for delivering power pulses having a controlled pulse width and repetition rate from said primary power source to respective loads, and means for generating respective carrier signals and at least one phase control signal for each of said PWM inverter circuits, said carrier signal and phase control signal being used by each PWM inverter circuit to control the pulse width and repetition rate of the power pulses delivered by said PWM inverter circuit; and second delivery means for extracting a controlled amount of electrical power from the power made available for delivery to said first subsystem and delivering said extracted electrical power to said second subsystem; whereby controlled amounts of electrical power are delivered to both said first and second subsystems. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A power delivery system comprising:
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at least a pair of inverters, each inverter driving a respective load with multiple phase drive signals, each inverter having a carrier signal associated therewith; a DC power source coupled to said inverters; and combining means for combining the drive signals associated with each phase of each inverter for driving an additional load; the amount of power delivered to the additional load being controllable by changing the relative phase shift between the carrier signals applied to each inverter of said pair of inverters.
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Specification