Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
  • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
  • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
  • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M7/483—Converters with outputs that each can have more than two voltages levels
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
  • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
  • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
  • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M7/483—Converters with outputs that each can have more than two voltages levels
  • H02M7/487—Neutral point clamped inverters
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/0043—Converters switched with a phase shift, i.e. interleaved
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
  • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
  • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
  • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M7/483—Converters with outputs that each can have more than two voltages levels
  • H02M7/4835—Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
  • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
  • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
  • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M7/493—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode the static converters being arranged for operation in parallel
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M1/00—Details of apparatus for conversion
  • H02M1/0003—Details of control, feedback or regulation circuits
  • H02M1/0025—Arrangements for modifying reference values, feedback values or error values in the control loop of a converter

Definitions

• the subject matter of this disclosure relates generally to multi-phase power converter topologies, including without limitation those converter topologies based on H-bridges, and more particularly to a modulation scheme for such multi-phase converters to provide better utilization of a given dc-link voltage by injection of a suitable common-mode voltage to all voltage reference signals.
• a method of operating a power converter comprises: providing a multi-phase converter comprising a plurality of phase paths, wherein each phase path comprises at least one dc-link that is independent from and isolated from every other phase path dc-link; generating a plurality of output phase voltages via the multi-phase converter in response to a predetermined reference voltage for each phase, wherein each output phase voltage is based on a corresponding dc-link voltage source that can be different from every other phase voltage dc-link voltage source; measuring a total dc-link voltage level associated with each output phase voltage; calculating a first difference voltage based on the positive total dc-link voltage and the predetermined reference voltage level for each phase; calculating a second difference voltage based on the negative total dc- link voltage and the predetermined reference voltage level and for each phase; calculating a maximum second difference voltage for all phases; calculating a minimum first difference voltage for all phases; choosing a common mode injection voltage for all phases in between the maximum second difference voltage and
• the converter comprises H-bridges based on 3 -level phase-legs and dc-links with a positive and a negative half dc-link. Calculating the total dc-link voltage for each phase is accomplished by calculating the difference of the positive half dc-link voltage and the negative half dc-link voltage.
• the converter comprises multiple H- bridges per phase and multiple corresponding dc-links per phase. Calculating the total dc- link voltage for each phase is accomplished by calculating the sum of all dc-link voltages per phase.
• Figure 1 illustrates a multi-phase power converter according to one embodiment
• Figure 2 is a flow chart illustrating a method of operating a multi-phase power converter according to one embodiment
• Figure 3 is a graph illustrating output voltage gain for a multi-phase power converter having an independent dc-link voltage source for each phase and using a common-mode injection voltage for each phase based on dc-link ripple voltage according to one embodiment
• FIG. 1 illustrates a multi-phase power converter 10 according to one embodiment.
• Converter 10 can be seen to employ a plurality of active H-bridge inverters 12.
• Each H-bridge inverter 12 is coupled to a corresponding dc-link 14.
• Each phase output voltage is based on its own dc-link voltage that is distinct and independent from every other dc-link voltage.
• the converter 10 H-bridge inverters 12 are each also coupled to corresponding phase connections of a three-phase load/source 22 with a fundamental operating frequency f 0 .
• converter 10 also employs one or more local controllers 24, and may further employ a central or main controller 26.
• the local controller(s) 24 and/or central controller 26 are configured with algorithmic software and/or firmware that is programmed to derive an optimal common-mode injection voltage for each phase based on actually available voltages in each phase.
• modulation of a multi-phase converter 10 is accomplished by considering the actually available dc-link voltage in each phase individually, and then deriving an optimal common-mode voltage for each phase based on its own dc-link voltage that may be different from every other phase dc-link voltage.
• One suitable method for operating a multi-phase converter is described in further detail herein with reference to Figure 2. The present inventors found that converter output power could be increased by at least 5% using the principles described herein. Further, a reduction in dc-link capacitance may result in some applications where a higher voltage ripple can be tolerated.
• one or more local controllers 16 are generally programmed with a predetermined reference voltage that controls a modulation index for each inverter 12.
• the predetermined reference voltage can be generated via a central controller 18 that communicates with local controllers 16 to control the modulation index for each inverter 12.
• Converter 10 can be seen to include a plurality of phase paths A, B and C, wherein each phase path comprises a dc-link 14 that is independent from and isolated from every other phase path dc-link as stated herein.
• each phase path dc-link voltage typically sees a ripple voltage that is phase shifted 120° from every other phase path and that is generated at a frequency of 2f 0 .
• each inverter 12 is implemented with a 3- level neutral-point clamped (3L-NPC) H-bridge 20.
• Each output phase voltage is then generated by a corresponding H-bridge inverter 20 in response to a predetermined reference voltage that determines how each controller 16 will modulate its corresponding 3L-NPC H-bridge inverter 20.
• a flow chart 30 illustrates a method of operating a multi-phase power converter with isolated dc-links using the principles described herein according to one embodiment.
• the desired modulation index for each phase A, B, C is determined according to one embodiment by first measuring the total dc-link voltage level associated with each output phase voltage as represented by block 32.
• a first difference voltage is then calculated based on the predetermined reference voltage level and the positive dc-link voltage for each phase, and a second difference voltage is also calculated based on the predetermined reference voltage level and the negative dc-link voltage for each phase as represented by block 34.
• a maximum second difference voltage is determined from the calculated second difference voltage for each phase, and a minimum first difference voltage is determined from the calculated first difference voltage for each phase as represented in block 36.
• a common-mode injection voltage is calculated as the average of the maximum second difference voltage and the minimum first difference voltage for each phase as represented in block 38.
• the common-mode injection voltage calculated in block 38 is then added to the predetermined reference voltage for each phase to generate an adjusted reference voltage, such that each generated output phase voltage level is adjusted in response to its corresponding adjusted reference voltage as represented in block 40.
• Figure 3 is a graph 50 illustrating output voltage gain for a multi-phase power converter having an independent dc-link voltage source for each phase and using a common-mode injection voltage for each phase based on dc-link ripple voltage according to one embodiment.
• Each dc-link has a ripple voltage that is phase shifted 120° from every other dc-link ripple voltage.
• the graphs shown in Figure 3 are representative for a dc-link with a 15% peak-to-peak dc-link ripple voltage.
• the upper dotted line 52 represents an average positive DC voltage for each dc-link while the lower dotted line 54 represents an average negative DC voltage for each dc-link.
• Normalized phase output voltages 56, 58 are depicted for a multi-phase power converter that is modulated using a typical common-mode injection scheme and also for a common-mode injection scheme using the principles described herein respectively.
• a comparison between the normalized output voltages 56 and 58 shows a gain of about 7.8% in favor of the common-mode injection scheme using the principles described herein.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Inverter Devices (AREA)
• Dc-Dc Converters (AREA)
• Rectifiers (AREA)

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• 2011
  • 2011-12-09 US US13/315,660 patent/US9071164B2/en active Active
• 2012
  • 2012-12-07 KR KR1020147015261A patent/KR20140099268A/ko not_active Withdrawn
  • 2012-12-07 CN CN201280060638.3A patent/CN103988412B/zh active Active
  • 2012-12-07 BR BR112014013134A patent/BR112014013134A2/pt not_active IP Right Cessation
  • 2012-12-07 EP EP12814039.9A patent/EP2789093B1/en active Active
  • 2012-12-07 WO PCT/US2012/068328 patent/WO2013086247A2/en not_active Ceased
  • 2012-12-07 AU AU2012347712A patent/AU2012347712A1/en not_active Abandoned
  • 2012-12-07 RU RU2014121056A patent/RU2014121056A/ru not_active Application Discontinuation
  • 2012-12-07 JP JP2014546100A patent/JP6134733B2/ja not_active Expired - Fee Related
  • 2012-12-07 CA CA2857732A patent/CA2857732A1/en not_active Abandoned

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