Universal Power Converter

Abstract

Methods and systems for transforming electric power between two or more portals. Any or all portals can be DC, single phase AC, or multi-phase AC. Conversion is accomplished by a plurality of bi-directional conducting and blocking semiconductor switches which alternately connect an inductor and parallel capacitor between said portals, such that energy is transferred into the inductor from one or more input portals and/or phases, then the energy is transferred out of the inductor to one or more output portals and/or phases, with said parallel capacitor facilitating “soft” turn-off, and with any excess inductor energy being returned back to the input. Soft turn-on and reverse recovery is also facilitated. Said hi-directional switches allow for two power transfers per inductor/capacitor cycle, thereby maximizing inductor/capacitor utilization as well as providing for optimum converter operation with high input/output voltage ratios. Control means coordinate the switches to accomplish the desired power transfers.

What is claimed is: 
     
         1 . A Buck-Boost Converter, comprising:
 an energy-transfer reactance;   first and second power portals, each with two or more ports by which electrical power is input from or output to said portals;   first and second bridge switch arrays interposed between said reactance and respective ones of said portals, and each comprising one bidirectional switching device for each said port of each said power portal.   
     
     
         2 . The converter of  claim 1 , wherein said bridge arrays are symmetrically connected to said energy-transfer reactance. 
     
     
         3 . The converter of  claim 1 , wherein said bridge arrays are full-bridge arrays. 
     
     
         4 . The converter of  claim 1 , further comprising a third switch array, which is connected to said reactance in parallel with said first and second switch arrays. 
     
     
         5 . The converter of  claim 1 , wherein each said portal is shunted by a capacitor which provides a low-impedance voltage source thereat. 
     
     
         6 . The converter of  claim 1 , wherein said reactance comprises a transformer. 
     
     
         7 . The converter of  claim 1 , wherein said reactance comprises a parallel combination of an inductor with a capacitor. 
     
     
         8 . The converter of  claim 1 , wherein said reactance is driven at a base frequency which is less than half its resonant frequency. 
     
     
         9 . A Buck-Boost Converter, comprising:
 an energy-transfer reactance;   a first bridge switch array comprising at least two bidirectional switching devices which are jointly connected to operatively connect at least one terminal of said reactance to a power input, with reversible polarity of connection;   a second bridge switch array comprising at least two bidirectional switching devices which are jointly connected to operatively connect at least one terminal of said reactance to a power output, with reversible polarity of connection;   wherein said first switch array drives said reactance with a nonsinusoidal voltage waveform.   
     
     
         10 . The converter of  claim 9 , wherein said bridge arrays are symmetrically connected to said energy-transfer reactance. 
     
     
         11 . The converter of  claim 9 , wherein said bridge arrays are full-bridge arrays. 
     
     
         12 . The converter of  claim 9 , further comprising a third switch array, which is connected to said reactance in parallel with said first and second switch arrays. 
     
     
         13 . The converter of  claim 9 , wherein said input is shunted by a capacitor which provides a low-impedance voltage source thereat. 
     
     
         14 . The converter of  claim 9 , wherein said input and output are both shunted by respective capacitors which provide low-impedance voltage sources thereat. 
     
     
         15 . The converter of  claim 9 , wherein said reactance comprises a transformer. 
     
     
         16 . The converter of  claim 9 , wherein said reactance comprises a parallel combination of an inductor with a capacitor. 
     
     
         17 . The converter of  claim 9 , wherein said reactance is driven at a base frequency which is less than half its resonant frequency. 
     
     
         18 . The converter of claim, wherein said bridge arrays are symmetrically connected to said energy-transfer reactance. 
     
     
         19 . A Full-Bridge Buck-Boost Converter, comprising:
 first and second full bridge switch arrays, each comprising at least four bidirectional switching devices;   a substantially parallel inductor-capacitor combination symmetrically connected to be driven separately by either said switch array;   one of said switch arrays being operatively connected to a power input, and the other thereof being operatively connected to supply a power output.   
     
     
         20 . The converter of  claim 19 , wherein said power input is shunted by a capacitor which provides a low-impedance voltage source thereat. 
     
     
         21 . The converter of  claim 19 , wherein said power output is shunted by a capacitor which provides a low-impedance voltage sink thereat. 
     
     
         22 . The converter of  claim 19 , wherein said reactance comprises a transformer. 
     
     
         23 . The converter of  claim 19 , wherein said bridge arrays are full-bridge arrays. 
     
     
         24 . The converter of  claim 19 , further comprising a third switch array, which is connected to said reactance in parallel with said first and second switch arrays. 
     
     
         25 . The converter of  claim 19 , wherein said reactance comprises a parallel combination of an inductor with a capacitor. 
     
     
         26 . The converter of  claim 19 , wherein said reactance is driven at a base frequency which is less than half its resonant frequency. 
     
     
         27 . A Buck-Boost Converter, comprising:
 first and second switch arrays, each comprising least two bidirectional switching devices;   a substantially parallel inductor-capacitor combination connected to each said switch array;   wherein a first one of said switch arrays is operatively connected to a power input, and is operated to drive power into said inductor-capacitor combination with a non-sinusoidal waveform;   and wherein a second one of said switch arrays is operated to extract power from said inductor-capacitor combination to an output.   
     
     
         28 . The converter of  claim 27 , wherein said bridge arrays are full-bridge arrays. 
     
     
         29 . The converter of  claim 27 , wherein said bridge arrays are symmetrically connected to said energy-transfer reactance. 
     
     
         30 . The converter of  claim 27 , further comprising a third switch array, which is connected to said reactance in parallel with said first and second switch arrays. 
     
     
         31 . The converter of  claim 27 , wherein said power input is shunted by a capacitor which provides a low-impedance voltage source thereat. 
     
     
         32 . The converter of  claim 27 , wherein said power output is shunted by a capacitor which provides a low-impedance voltage sink thereat. 
     
     
         33 . The converter of  claim 27 , wherein said inductor is implemented by a transformer. 
     
     
         34 . A Buck-Boost Converter, comprising:
 first and second switch arrays, each comprising at least two bidirectional switching devices;   an energy-transfer reactance connected to each said switch array;   wherein a first one of said switch arrays is connected through respective capacitive reactances to a polyphase power input, and operated to drive power into said reactance from multiple different legs of said power input in succession with a non-sinusoidal waveform;   and wherein a second one of said switch arrays is operated to extract power from said reactance to an output.   
     
     
         35 . The converter of  claim 34 , wherein said bridge arrays are full-bridge arrays. 
     
     
         36 . The converter of  claim 34 , wherein said bridge arrays are symmetrically connected to said energy-transfer reactance. 
     
     
         37 . The converter of  claim 34 , further comprising a third switch array, which is connected to said reactance in parallel with said first and second switch arrays. 
     
     
         38 . The converter of  claim 34 , wherein said power input is shunted by a capacitor which provides a low-impedance voltage source thereat  39 . The converter of  claim 34 , wherein said power output is shunted by a capacitor which provides a low-impedance voltage sink thereat. 
     
     
         39 . The converter of  claim 34 , wherein said reactance comprises a transformer. 
     
     
         40 . A power converter, comprising:
 an energy-transfer reactance comprising at least one inductor;   an input switch array configured to drive AC current through said reactance; and   an output network connected to extract energy from said reactance;   wherein said input switch array performs at least two drive operations, in the same direction but from different sources, during a single half-cycle of said reactance.   
     
     
         41 . The converter of  claim 40 , wherein said inductance is implemented by a transformer. 
     
     
         42 . The converter of  claim 40 , wherein said inductance is paralleled by a capacitor. 
     
     
         43 . A power converter, comprising:
 an energy-transfer reactance comprising at least one inductor, and operating at a primary AC magnetic field frequency which is less than half of the reactance's resonant frequency;   an input switch array configured to drive AC current through said reactance; and   an output network switch array connected to extract energy from said reactance;   wherein said input switch array performs at least two drive operations, in the same direction but from different sources, during a single half-cycle of said reactance.   
     
     
         44 . The converter of  claim 43 , wherein said switch arrays are full-bridge arrays. 
     
     
         45 . The converter of claim, wherein said reactance comprises a transformer. 
     
     
         46 . A power converter, comprising:
 an energy-transfer reactance comprising at least one inductor, and operating at a primary AC magnetic field frequency which is less than half of the reactance's resonant frequency;   an input switch array configured to drive current through said reactance; and an output switch array to extract energy from said reactance;   wherein said input switch array performs at least two different drive operations at different times during a single cycle of said reactance,   and wherein said output switch array performs at least two different drive operations at different times during a single cycle of said reactance.   
     
     
         47 . The converter of  claim 46 , wherein said switch arrays are full-bridge arrays. 
     
     
         48 . The converter of  claim 46 , wherein said first array connects said reactance to a power input which is shunted by a capacitor which provides a low-impedance voltage source thereat. 
     
     
         49 . The converter of  claim 46 , wherein said first array connects said reactance to a power input which is shunted by a capacitor which provides a low-impedance voltage source thereat. 
     
     
         50 . The converter of  claim 46 , wherein said reactance comprises a transformer. 
     
     
         51 . A Buck-Boost Converter, comprising:
 an energy-transfer reactance comprising at least one inductor;   an input switch array configured to drive AC current, with no average DC current, through said reactance; and   an output network connected to extract energy from said reactance.   
     
     
         52 . The converter of  claim 51 , wherein said switch arrays are full-bridge arrays. 
     
     
         53 . The converter of  claim 51 , wherein said reactance comprises a transformer. 
     
     
         54 . A Buck-Boost Converter, comprising:
 an energy-transfer reactance comprising at least one inductor;   a plurality of input switch arrays, each said array configured to drive AC current, with no average DC current, through said reactance; and   a plurality of output switch arrays, each connected to extract energy from said reactance;   said arrays having no more than two switches driving or extracting energy from said reactance at any given time;   wherein said input switch arrays individually drive said reactance with a nonsinusoidal voltage waveform.   
     
     
         55 . The converter of  claim 54 , wherein said bridge arrays are full-bridge arrays. 
     
     
         56 . The converter of  claim 54 , wherein said switch arrays each selectably connect said reactance to a low-impedance voltage source/sink. 
     
     
         57 . The converter of  claim 54 , wherein said inductor is implemented as a transformer. 
     
     
         58 . The converter of  claim 54 , wherein said inductance is paralleled by a capacitor. 
     
     
         59 . A power conversion circuit, comprising:
 an input stage which repeatedly, at various times, drives current into the parallel combination of an inductor and a capacitor, and immediately thereafter temporarily disconnects said parallel combination from external connections, to thereby transfer some energy from said inductor to said capacitor;   wherein said action of driving current is performed in opposite senses and various times, and wherein said disconnecting operation is performed substantially identically for both directions of said step of driving current; and   an output stage which extracts energy from said parallel combination, to thereby perform power conversion.   
     
     
         60 . The converter of  claim 59 , wherein said input stage comprises a full-bridge array of switches. 
     
     
         61 . The converter of  claim 59 , wherein said wherein said input and output stages each comprise a full-bridge array of switches, and are symmetrically connected to said energy-transfer reactance. 
     
     
         62 . The converter of  claim 59 , wherein said stages each selectable connect said reactance to a low-impedance voltage source/sink. 
     
     
         63 . The converter of  claim 59 , wherein said reactance comprises a transformer. 
     
     
         64 . A power conversion circuit, comprising:
 an input stage which repeatedly drives current into the parallel combination of an inductor and a capacitor, and immediately thereafter temporarily disconnects said parallel combination from external connections, to thereby transfer some energy from said inductor to said capacitor; wherein said input stage drives current in different senses at different times; and   an output stage which repeatedly couples power out of said parallel combination, and immediately thereafter temporarily disconnects said parallel combination from external connections, to thereby transfer some energy from said inductor to said capacitor; wherein said output stage couples power out of said combination during two opposite directions of current therein;   wherein said input and output stages both disconnect said parallel combination substantially identically for both directions of current in said combination.   
     
     
         65 . The circuit of  claim 64 , wherein each said driving action is performed using multiple different drive pulses from different legs of a polyphase power line. 
     
     
         66 . A Soft Switched Universal Full-Bridge Buck-Boost Converter, comprising:
 an inductor with a first and second port;   a capacitor attached in parallel with said inductor;   connections to a plurality of voltage sources or sinks (portals) of electric power each with a plurality of ports;   a first set of electronic bi-directional switches that comprise said connections between said first port of the inductor and each said port of each said portal, with one said switch between the first port of the inductor and each port of each portal;   a second set of electronic hi-directional switches that comprise said connections between said second port of the inductor and each port of each portal, with one switch between the second port of the inductor and each port of each portal;   capacitive filtering means connected between each said port within each said portal;   control means to coordinate said switches to connect said inductor to port pairs on each portal, with no more than two switches enabled at any given time; said control means further coordinating said switches to first store electrical energy in the inductor by enabling two switches on a given input portal to connect the inductor to said input portal, then disabling the switches after the proper amount of energy has been stored in the inductor;   and said control means may enable further pairs of switches on the same or other input portals so as to further energize the inductor, and disable said switches after the appropriate inductor energizing is complete;   said control means further enables another pair of switches on another, output, portal to transfer some or all of the inductor energy into said output portal, and then disables said switches after the desired amount of charge has been transferred to said portal;   said control means may enable further pairs of switches on the same or other output portals so as to further send charge into said output portals, and disable said switches after the desired amount of charge has been transferred to said portal;   and if the inductor has excess energy after discharging into the last output portal, said control means then enables an appropriate switch pair to direct said excess energy back into the input portal;   wherein said control means may modify the above sequence so as to achieve any required energy transfer among the ports and portals;   said inductor magnetically storing electrical energy in the form of electric current, using said switches;   energy transfer from one or more input portals to said inductor occurring via current flow through two or more said ports of one or more said portals, with only one pair of ports; and   cyclically repeating said energy and charge transfers.   
     
     
         67 . The converter of  claim 66 , in which after energy transfer and capacitor charging if any, switches complementary to said first switches are enabled, to again transfer electric energy into the inductor, but with the inductor current in the opposite direction; and thereafter the energy is again subsequently transferred to one or more other portals, also by means of enabling switches complementary to said second switches, to thereby complete a Full-cycle operation, which is repeated as required. 
     
     
         68 . The converter of  claim 66 , wherein said inductor is implemented by a transformer with equivalent inductive capacity, which provides galvanic isolation, and optionally current/voltage transforming. between input and output. 
     
     
         69 . The converter of  claim 66 , where one or more of the portals is DC and power flow is unidirectional at all times, and switches connected to said DC and unidirectional power portal may be uni-directional in the direction to support said Unidirectional power flow. 
     
     
         70 . A half-bridge embodiment of the converter of  claim 66 , in which only said first set of bi-directional switches are used with said first port of said inductor, with said second port of the inductor connected to an actual or virtual converter ground, with a virtual ground composed of capacitive connections to the ports of said portals. 
     
     
         71 . A composite of n converters according to  claim 66 , connected at least partially in parallel, and operating at inductor phase angles separated by 180/n degrees; whereby the amount of input/output filtering can be reduced. 
     
     
         72 . A Soft-switched Ralf-Bridge Buck-Boost Converter, comprising:
 first and second power portals, each with two or more ports by which electrical power is input from or output to said portals,   first and second half-bridge switch arrays, each comprising one bidirectional switching device for each said port of each said power portal,   an energy-transfer link reactance with one port connected to both said switch arrays, and with the other port connected to an actual or virtual ground, such that said actual or virtual ground maintains at a relatively constant voltage,   each of said switch arrays being connected to a power portal with said portal possessing capacitive reactance between the legs of said portals configured so as to approximate a voltage source,   with power transfer occurring between said portals via said energy-transfer reactance,   said link energy-transfer reactance consisting of an link inductor and capacitance in parallel,   said power transfer being accomplished in a first power cycle as one or more pairs of input portal legs are singularly or sequentially connected to said energy-transfer reactance to store energy via increased current flow and inductance into said link inductor, followed by one or more pairs of output portal legs singularly or sequentially connected to said energy-transfer reactance to remove energy via decreased current flow and inductance from said link inductor, with any excess energy in said link inductor subsequently returned back to one or more said input portal leg pairs, followed by a reversal of current within said link inductor and a repeat of the heretofore described energy transfer, to constitute a second power cycle, from input to output portal leg pairs, but with opposite but equal current flow in said link inductor and utilizing switches of said switch arrays which are complimentary to said switches used for said first cycle of said power transfer;   said first and second power cycles comprising a single voltage cycle of the energy-transfer link reactance;   said capacitance, in conjunction with said current reversal, producing soft-switching of said switches with low-voltage turn-off, zero voltage turn-on, and low reverse recovery losses;   said bidirectional switching devices being capable of blocking voltage in either direction and conducting current in either direction;   wherein said power transfer cycles are continuously repeated by said control means to produce said power transfer on a continuing basis;   and wherein control means coordinate said switching actions to produce current and power transfer via said power cycles as required to produce desired output voltage and current, as may be used to drive single or polyphase motors at variable speed and voltage, or to drive any other electrical DC, single phase AC, polyphase AC, and/or multiple DC loads;   said capacitance, in conjunction with said current reversal, producing soft-off-switching of said switches with low-voltage turn-off, as current is shunted from each turning-off switch into said substantially parallel capacitance,   said switches having soft turn-on as diodes as the link reactance voltage causes control means enabled switches to transition from reverse to forward bias,   said switches having soft reverse blocking turn-off as the link inductor current linearly decreases to zero after discharging into an output port.   
     
     
         73 . A Soft-switched Full-Bridge Buck-Boost Converter, comprising:
 first and second power portals, each with two or more ports by which electrical power is input from or output to said portals, first and second full-bridge switch arrays, each comprising two bidirectional switching devices for each said port of each said power portal,   a energy-transfer link reactance symmetrically connected to both said switch arrays,   each of said switch arrays being connected to a power portal with said portal possessing capacitive reactance between the legs of said portals configured so as to approximate a voltage source,   with power transfer between said portals via said energy-transfer reactance,   Said link energy-transfer reactance consisting of an link inductor and capacitance in parallel,   said power transfer being accomplished in a first power cycle as one or more pairs of input portal legs are singularly or sequentially connected to said energy-transfer reactance to store energy via increased current flow and inductance into said link inductor, followed by one or more pairs of output portal legs singularly or sequentially connected to said energy-transfer reactance to remove energy via decreased current flow and inductance from said link inductor, with any excess energy in said link inductor subsequently returned back to one or more said input portal leg pairs, followed by a reversal of current within said link inductor and a repeat of the heretofore described energy transfer, to constitute a second power cycle, from input to output portal leg pairs, but with opposite but equal current flow in said link inductor and utilizing switches of said switch arrays which are complimentary to said switches used for said first cycle of said power transfer;   said tryst and second power cycles comprise a single voltage cycle of the energy-transfer link reactance;   said bidirectional switching devices being capable of blocking voltage in either direction and conducting current in either direction;   said power transfer cycles being continuously repeated by said control means to produce said power transfer on a continuing basis;   said control means coordinating said switching actions to produce current and power transfer via said power cycles as required to produce desired output voltage and current, as may be used to drive single or polyphase motors at variable speed and voltage, or to drive any other electrical DC, single phase AC, polyphase AC, and/or multiple DC loads;   said capacitance, in conjunction with said current reversal, producing soft-off-switching of said switches with low-voltage turn-off, as current is shunted from each turning-off switch into said substantially parallel capacitance;   said switches having soft turn-on as diodes as the link reactance voltage causes control means enabled switches to transition from reverse to forward bias;   said switches having soft reverse blocking turn-off as the link inductor current linearly decreases to zero after discharging into an output port.   
     
     
         74 . The converter of  claim 73 , further comprising an isolation transformer. 
     
     
         75 . A multiple power module soft-switched converter, comprising multiple converters according to  claim 73  connected in parallel between an input portal and an output portal, and commonly controlled to minimize harmonics in the current drawn from and delivered to said input and output portals. 
     
     
         76 . An electric vehicle, comprising at least one motor, at least one electrical energy storage device, and a power converter according to  claim 1 ,  9 ,  19 ,  27 ,  34 ,  40 ,  43 ,  46 ,  51 ,  54 ,  59 , or  64 . 
     
     
         77 . A solar energy system comprising at least one photovoltaic array, at least one electrical energy storage device, and a power converter according to  claim 1 ,  9 ,  19 ,  27 ,  34 ,  40 ,  43 ,  46 ,  51 ,  54 ,  59 , or  64 . 
     
     
         78 . A motor system comprising a polyphase power line connection, a polyphase motor, and a power converter according to  claim 1 ,  9 ,  19 ,  27 ,  34 ,  40 ,  43 ,  46 ,  51 ,  54 ,  59 , or  64  connected therebetween as a variable-frequency drive. 
     
     
         79 . A multiple power module soft-switched converter, comprising multiple converters according to  claim 1 ,  9 ,  19 ,  27 ,  34 ,  40 ,  43 ,  46 ,  51 ,  54 ,  59 , or  64  connected in parallel between an input portal and an output portal, and commonly controlled to minimize harmonics in the current drawn from and delivered to said input and output portals. 
     
     
         80 . A composite of n converters according to  claim 1 ,  9 ,  19 ,  27 ,  34 ,  40 ,  43 ,  46 ,  51 ,  54 ,  59 , or  64 , connected at least partially in parallel, and operating at inductor phase angles separated by 180/n degrees; whereby the amount of input/output filtering can be reduced.