Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
  • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
  • H03K17/78—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled
  • H03K17/785—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled controlling field-effect transistor switches
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
  • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
  • G05F1/10—Regulating voltage or current 
  • G05F1/12—Regulating voltage or current  wherein the variable actually regulated by the final control device is AC
  • G05F1/40—Regulating voltage or current  wherein the variable actually regulated by the final control device is AC using discharge tubes or semiconductor devices as final control devices
  • G05F1/44—Regulating voltage or current  wherein the variable actually regulated by the final control device is AC using discharge tubes or semiconductor devices as final control devices semiconductor devices only
  • G05F1/45—Regulating voltage or current  wherein the variable actually regulated by the final control device is AC using discharge tubes or semiconductor devices as final control devices semiconductor devices only being controlled rectifiers in series with the 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
  • H02M5/00—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases
  • H02M5/02—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC
  • H02M5/04—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC by static converters
  • H02M5/22—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
  • H02M5/275—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC 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
  • H02M5/293—Conversion of AC power input into AC power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into DC 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
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/10—Controlling the intensity of the light
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
  • H05B45/30—Driver circuits
  • H05B45/37—Converter circuits
  • H05B45/3725—Switched mode power supply [SMPS]
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
  • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
  • H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
  • H03K2217/0009—AC switches, i.e. delivering AC power to a load
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
  • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Definitions

• the invention relates to a power management system and methods to provide an electronic switch and dimming control.
• AC alternating current
• Traditional access to alternating current (AC) electrical power in home and business environments is provided by mechanical outlets that are wired into the facility electrical system. These outlets are protected from excessive electrical loads or potentially dangerous ground faults using electromechanical devices such as fuses and circuit breakers.
• electromechanical devices such as fuses and circuit breakers.
• the control of conventional electrical room appliances such as lighting and ceiling fans occurs using electromechanical switches.
• electromechanical switches These fundamentally mechanical control devices provide simple on-off control and inevitably wear out and, over time, can cause short circuits or potentially dangerous arcing.
• More nuanced control of common electrical appliances is typically provided by electronic devices such as triacs which allow the AC mains waveform to be interrupted on a cycle- by-cycle basis, so-called phase control.
• the present invention relates to a novel approach for the control of AC power throughout a facility electrical system ranging from simple outlet on-off switching to continuous variation of the applied AC power for, for example, the dimming of electrical lights. More particularly the invention relates to a combination of functions that provides in one embodiment both on-off and phase-control of the AC mains waveform.
• MOSFETs power MOS field-effect transistors
• AC AC
• a novel floating control circuit uses rectifying diodes connected at the drains to precharge the gate-source bias voltage thereby turning both devices "on”, and an optically coupled phototransistor that shorts the gate terminals to the common source terminal to force the devices into their "off state when illuminated by an isolated optical source.
• the power MOSFET switches are normally "on” unless forced “off by the optical control signal.
• the optical control signal can be applied continuously for nominal on-off control of the power delivered to the load, or it can be synchronized with the AC mains waveform to provide phase control.
• Integrated control circuitry for the optical control signal can provide either leading edge phase control preferred for switching reactive loads or trailing edge phase control preferred for nonlinear loads such as LEDs.
• Figure 1 is a schematic diagram of the basic power MOSFET bidirectional switch unit.
• Figure 2 is a schematic diagram of a prior art bidirectional switch using optoelectronic bias generation.
• Figure 3 is a schematic diagram of the basic elements of the improved bidirectional switch.
• Figure 4 is a schematic diagram of an embodiment of the improved bidirectional switch.
• Figure 5 is a schematic diagram of the embodiment of Figure 3 using two switching elements to reduce total switch “on” resistance and increase total switch “off resistance.
• Figure 6 is a schematic diagram of an embodiment similar to that of Figure 3, but with the switching elements in both arms of the AC power supply.
• Figure 7 is a schematic diagram of the embodiment of Figure 5 using four switching elements to further reduce total switch "on" resistance and further increase total switch
• FIG. 1 is a schematic diagram showing the basic power MOSFET bidirectional switch controlling the power delivered from AC source 101 to load 108.
• Power MOSFETs 102 and 103 include body diodes 104 and 105, respectively.
• Switch 106 controls the gate-to- source bias voltage applied to power MOSFETs 102 and 103.
• bias voltage 107 is applied to the gate terminals of the power MOSFETs.
• Voltage 107 is a voltage greater than the threshold voltage of the power MOSFETs (typically 5 to 10 volts) causing an inversion layer to form thereby creating a conducting channel extending from the drain to the source of each device.
• each power MOSFET In this "on" state, the drain-to-source behavior of each power MOSFET can be modeled as a low value resistor, R dS . As long as the voltage drop between drain and source remains below about 0.6 volt, the body diodes remain nonconductive and can be neglected.
• the circuit of Figure 1 is equivalently the load 108 connected to AC source 101 through a series resistor having value 2Rd S .
• a more detailed analysis of the power MOSFET structure shows that the body diode is effectively the base-collector junction of a bipolar transistor connected in parallel with the MOSFET channel. Additional parasitic elements include the capacitance of the base- collector junction and a parasitic resistance between the base and the emitter.
• This AC- coupled circuit places a constraint on the rate of change of the drain-to-source voltage, dV ds /dt, to avoid forward biasing the base-emitter junction, thereby causing the bipolar transistor to conduct while the MOSFET channel is "off. While the resulting leakage current may not be sufficient to energize the load 108, it may be large enough to cause additional efficiency or safety concerns.
• the circuit of Figure 1 shows that the conceptual bias switching circuit comprising switch 106 and voltage source 107 floats electrically with the common source terminals of the back-to-back power MOSFETs 102 and 103 which vary across the entire peak-to- peak range of source 101. Although simple in concept, this circuit can be difficult to realize in practice at low cost.
• Figure 2 shows a schematic diagram of a prior art approach to the control circuit.
• Voltage source 106 in Figure 1 is replaced with a photovoltaic diode stack 201 that provides the needed gate-to-source bias voltage when illuminated by a light emitting diode (LED) 206 which is powered by a separate low voltage source 203 and controlled by switch 204 through current limiting resistor 205.
• LED light emitting diode
• Elements 203-206 are assumed to be within optical proximity of diode stack 201.
• LED 206 is switched off, the voltage across diode stack 201 is drained through resistor 202 and the power MOSFETs enter the "off state.
• FIG 3 is a schematic diagram showing the basic elements of the improved switch circuit.
• power MOSFETs are the preferred embodiment switching devices discussed in the following description, it will be apparent to one skilled in the art that other types of field-effect transistors can be advantageously employed in the improved circuit.
• voltage 107 is used to bias power MOSFETs 102 and 103 into their "on” state.
• the power MOSFETs are "on” only as long as switch 106 remains open.
• switch 106 is closed the power MOSFETs are forced to enter their "off state since their gates and sources are shorted together and voltage 107 is dropped across resistor 300.
• Figure 4 is a schematic diagram showing an embodiment of the inventive circuit.
• Voltage source 106 in Figure 1 is replaced in switching unit 400 with a Zener diode 402 having a Zener voltage greater than the threshold voltage of the power MOSFETs.
• Zener diode 402 is biased through rectifier diodes 404 and 406 connected at the drain terminals of the power MOSFETs and protected by current limiting resistors 403 and 405, respectively.
• current limiting resistors 403 and 405, respectively are biased in the absence of illumination resistor-diode branches 403-404 and 405-406 provide bias for Zener diode 402 when either of the drain terminals exceeds the Zener voltage, placing power MOSFETs 102 and 103 in the "on" state.
• LED 206 phototransistor 401 shunts the bias current from branches 403- 404 and 405-406 to the source terminals of the power MOSFETS placing them in the
• FIG 5 is a schematic diagram of the embodiment of Figure 4 using two switch units 400 to improve the performance of the circuit.
• the power MOSFETs are selected to have half the breakdown voltage of the units used in Figure 4.
• the on resistance of the individual switch units can be expected to be reduced by a factor of 5.7, as described above, and the total on resistance of the two switch units connected in series is reduced by a factor of 2.8 relative to the circuit in Figure 4.
• the voltage drop across each of the switch units in the "off state is halved, thereby reducing the dV dS /dt experienced by each unit by a factor of two and consequently reducing the "off state leakage current.
• Figure 5 also includes an electronic switch circuit to control the illumination of LED 206.
• the current through LED 206 from voltage source 203 is limited by resistor 205 and is controlled by transistor 500.
• Transistor 500 is controlled by an external control voltage applied to control terminals 501. This allows for the rapid switching of the LED in synchronism with the AC mains waveform through external control circuitry (not shown) to provide phase control of the applied AC waveform, as is used in dimmer applications.
• the control signal is a train of pulses synchronized with the AC mains waveform and having adjustable pulse widths to effectively control the average current/power delivered to the load, thereby providing a dimming effect for a light source load and a speed control for an AC motor load.
• control signal is a train of pulses having a fixed or variable frequency independent of the AC mains waveform thereby generating a radio-frequency (RF) power waveform at the load terminals for use as a wireless charger/generator.
• control signal is a variable DC voltage allowing variable illumination of the LED thereby allowing the MOSFETs to operate in a linear mode.
• Figure 6 is a schematic diagram of an embodiment similar to that of Figure 5, but with an individual switch unit 400 placed in each arm of the AC power supply. The inventor has found that this circuit configuration further improves the turn-off characteristics of the switch devices, further reducing leakage currents.
• FIG 7 is a schematic diagram of the embodiment of Figure 6 using two switch units 400 in each arm of the AC supply to further improve the performance of the circuit.
• the power MOSFETs are selected to have one-fourth the breakdown voltage of the units used in Figure 3.
• the on resistance of the individual switch units can be expected to be reduced by a factor of 32, as described above, and the total on resistance of the two switch units connected in series is reduced by a factor of 8 relative to the circuit in Figure 4.
• the voltage drop across each of the switch units in the "off state is quartered, thereby reducing the dV dS /dt experienced by each unit by a factor of four and consequently further reducing the "off state leakage current relative to the circuit in Figure 4.
• this circuit configuration further improves the turn-off characteristics of the switch devices, further reducing leakage currents.
• a novel approach for the control of AC power throughout a facility electrical system uses power MOSFETs in a bidirectional switch subcircuit configuration having an optically coupled, electrically floating control circuit that self- biases the switches into the "on” state and uses an optically coupled control element to force the switches into the "off state.
• the time constant of the control circuit is fast enough to allow phase control as well as on-off control.
• a plurality of subcircuits can be easily cascaded to provide improved performance.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• General Physics & Mathematics (AREA)
• Radar, Positioning & Navigation (AREA)
• Automation & Control Theory (AREA)
• Circuit Arrangement For Electric Light Sources In General (AREA)
• Rectifiers (AREA)
• Electronic Switches (AREA)

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Cited By (21)

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• 2017
  • 2017-05-01 JP JP2018558747A patent/JP6997105B2/ja active Active
  • 2017-05-01 WO PCT/US2017/030415 patent/WO2017196572A1/en not_active Ceased
  • 2017-05-01 CN CN201780027382.9A patent/CN109314511B/zh active Active
  • 2017-05-01 EP EP17796572.0A patent/EP3455938B1/en active Active
  • 2017-05-01 US US16/092,839 patent/US10469077B2/en active Active - Reinstated
• 2019
  • 2019-09-12 US US16/568,571 patent/US10812072B2/en active Active

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