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
  • H02M1/00—Details of apparatus for conversion
  • H02M1/14—Arrangements for reducing ripples from DC input or output
• • 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
  • H02M3/00—Conversion of DC power input into DC power output
  • H02M3/02—Conversion of DC power input into DC power output without intermediate conversion into AC
  • H02M3/04—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters
  • H02M3/10—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M3/145—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
  • H02M3/155—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
  • H02M3/156—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
  • H02M3/158—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
  • H02M3/1582—Buck-boost converters

Definitions

• the invention relates generally to power converters and, more particularly, to power converters using a bridge topology.
• FIG. 1 An example of a bridge 100, which can operate in boost and buck modes can be seen.
• This bridge 100 is generally an H-bridge, using switches SI to S4, and an inductor L, which is coupled between the switching nodes of the H-bridge.
• switches S4 and S3 are closed and open, respectively, while pulse width modulation (PWM) signals are provided to switches SI and S2.
• PWM pulse width modulation
• switches SI and S2 are closed and open, respectively, while PWM signals are provided to switches S3 and S4.
• the most inefficient mode of operation is a bridge mode or buck-boost mode, where two of the switches SI to S4 are closed to generate an inductor voltage VL.
• Some reasons for the inefficiency are that switching losses are incurred in all four of switches SI to S4 and that this mode results in a high average inductor current II.
• Also contributing to the inefficiency is the rippled current (or variations in the inductor current II).
• switches SI and S3 are, for example, closed at the same time, and the inductor current II varies between the periods in which both switches SI and S3 are close or open, namely between times tl to t2 and times t3 to t4.
• An example embodiment of the invention accordingly, provides an apparatus.
• the apparatus comprises a buck-boost switching regulator having buck switches, boost switches, an input terminal, and an output terminal, wherein the buck-boost switching regulator is adapted to operate in a buck mode, boost mode, and bridge mode; and control circuitry that is coupled to at least one of the output terminal and the input terminal and that controls the buck-boost switching regulator with control signals, and wherein the control circuitry adjusts phase relationships between corresponding boost switches and buck switching in bridge mode to reduce ripple current in the buck-boost switching regulator.
• the buck-boost switching regulator further comprises: a first switch that is coupled between the input terminal and a first switching node; a second switching that is coupled between the first switching node and ground; an inductor that is coupled between the first switching node and a second switching node; a third switch that is coupled between the second switching node and ground; and a fourth switching that is coupled between the second switching node and the output terminal.
• control circuitry provides a first, second, third, and fourth control signals for the first, second, third, and fourth switches, respectively.
• control circuitry adjusts the third control signal to have an on-time for the third switch that is centered to an off- time for the first switch.
• control circuitry adjusts the second control signal to have an on-time for the second switch that is centered to an off-time for the fourth switch.
• control circuitry further comprises: a voltage divider that is coupled to the output terminal; and an error amplifier that receives a reference voltage and that is coupled to the voltage divider and the processor.
• the processor is a digital signal processor (DSP).
• DSP digital signal processor
• a method comprises detecting at least one of an input voltage, an output voltage, an input current, and an output current of a buck-boost switching regulator having buck switches, boost switches, an input terminal, and an output terminal, wherein the buck-boost switching regulator is adapted to operate in a buck mode, boost mode, and bridge mode; and operating the buck-boost switching regulator in a bridge mode, wherein phase relationships between corresponding boost switches and buck switching are adjusted to reduce ripple current in the buck-boost switching regulator.
• the buck-boost switching regulator further comprises: a first switch that is coupled between the input terminal and a first switching node, wherein the first switch receives a first control signal; a second switching that is coupled between the first switching node and ground, wherein the second switch receives a second control signal; an inductor that is coupled between the first switching node and a second switching node; a third switch that is coupled between the second switching node and ground, wherein the third switch receives a third control signal; and a fourth switching that is coupled between the second switching node and the output terminal, wherein the fourth switch receives a fourth control signal.
• the step of operating further comprises adjusting the third control signal to have an on-time for the third switch that is centered to an off-time for the first switch.
• the step of operating further comprises adjusting the second control signal to have an on-time for the second switch that is centered to an off-time for the fourth switch.
• an apparatus comprising a solar cell; a buck-boost switching regulator having buck switches, boost switches, an input terminal, and an output terminal, wherein the buck-boost switching regulator is adapted to operate in a buck mode, boost mode, and bridge mode, wherein the input terminal is coupled to the solar cell; and control circuitry that is coupled to at least one of the output terminal and the input terminal and that controls the buck-boost switching regulator with control signals, and wherein the control circuitry adjusts phase relationships between corresponding boost switches and buck switching in bridge mode to reduce ripple current in the buck-boost switching regulator.
• the solar cell further comprises a plurality of solar cells.
• FIG. 1 is a circuit diagram of a conventional bridge
• FIG. 2 is a timing diagram illustrating the relationship between bridge control signals and inductor ripple current for FIG. 1;
• FIG. 3 is an example of a system in accordance with an example embodiment of the invention.
• FIG. 4 is a timing diagram illustrating the relationship between bridge control signals and inductor ripple current for FIG. 3.
• FIG. 3 illustrates a system 300 in accordance with an example embodiment of the invention can be seen.
• System 100 generally comprises a bridge 100, solar cell 302, capacitor CI, voltage divider (resistors Rl and R2), error amplifier 308, processor 304, and storage medium 306.
• the voltage divider, error amplifier 308, processor 304, and storage medium 306 generally operate as a control circuitry, while bridge 100 and capacitor CI generally operate as a buck-boost switching regulator.
• an input voltage V I and input current I IN are provide to the input terminal of the switching regulator from, for example, a solar cell 302 (which may include multiple solar cells coupled in series or parallel to the input terminal) so as to generate an output voltage V OUT and an output current ⁇ at the output terminal.
• the control circuitry measures the output voltage V OUT and the input voltage V I and generates the appropriate pulse width modulation (PWM) or control signals for switches SI through S4.
• PWM pulse width modulation
• the error amplifier 308 compares an output from the voltage divider to a reference voltage REF so that the processor 304 can perform correction of the PWM signals.
• the error amplifier 308 and voltage divider can be removed, with the functionality being provided by the processor 304.
• input current L N , output current ⁇ , or input voltage V I may be used instead of the output voltage V OUT for correction of the PWM signals.
• the processor 304 may be a digital signal processor or DSP.

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

Priority Applications (2)

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Publications (2)

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• 2010
  • 2010-08-31 US US12/872,831 patent/US8749215B2/en active Active
• 2011
  • 2011-08-31 WO PCT/US2011/049954 patent/WO2012030952A2/en not_active Ceased
  • 2011-08-31 JP JP2013527263A patent/JP5889307B2/ja active Active
  • 2011-08-31 CN CN201180037739.4A patent/CN103053102B/zh active Active

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