GB2584217A - Apparatus and methods for use in a resonant converter - Google Patents

Apparatus and methods for use in a resonant converter Download PDF

Info

Publication number
GB2584217A
GB2584217A GB2011204.1A GB202011204A GB2584217A GB 2584217 A GB2584217 A GB 2584217A GB 202011204 A GB202011204 A GB 202011204A GB 2584217 A GB2584217 A GB 2584217A
Authority
GB
United Kingdom
Prior art keywords
value
resonant
signal
control signals
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB2011204.1A
Other versions
GB202011204D0 (en
GB2584217B (en
Inventor
Toyos Bada Carlos
Skinner Andrew
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TDK Lambda UK Ltd
Original Assignee
TDK Lambda UK Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB1800642.9A external-priority patent/GB2565861B/en
Application filed by TDK Lambda UK Ltd filed Critical TDK Lambda UK Ltd
Priority claimed from PCT/GB2019/050094 external-priority patent/WO2019138251A1/en
Publication of GB202011204D0 publication Critical patent/GB202011204D0/en
Publication of GB2584217A publication Critical patent/GB2584217A/en
Application granted granted Critical
Publication of GB2584217B publication Critical patent/GB2584217B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4241—Arrangements for improving power factor of AC input using a resonant converter
    • 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
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
    • 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
    • H02M3/01—Resonant DC/DC converters
    • 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
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33573—Full-bridge at primary side of an isolation transformer
    • 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
    • H02M7/505—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 using devices of a thyratron or thyristor type requiring extinguishing means
    • H02M7/515—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 using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
    • H02M7/523—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 using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only with LC-resonance circuit in the main circuit
    • 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
    • H02M1/0012—Control circuits using digital or numerical techniques
    • 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
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H02M1/0058—Transistor switching losses by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero
    • 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
    • H02M7/4815—Resonant converters
    • 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
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

An apparatus (21) is described for facilitating emulated current-mode control of a resonant converter (1). The apparatus (21) comprises: an input (21) a for a first signal suitable for use in determining a phase of a resonant current, wherein the resonant current corresponds to a current in a resonant network (3) of the converter (1); an input (21b) for a second signal suitable for use in determining a target phase difference between the resonant current and a driving voltage, wherein the driving voltage corresponds to a voltage provided by a switch network (2) of the converter (1) to the resonant network (3); one or more outputs (21c, 21d) for one or more control signals for controlling operation of the switch network (2); and circuitry (21e-i). The circuitry (21e-i) is configured to: use the first signal in determining a first value, wherein the first value is related to a phase difference between the resonant current and the driving voltage; use the second signal in determining a second value, wherein the second value is related to the target phase difference; and set the one or more control signals based at least in part on a comparison of the first and second values, wherein the one or more control signals are for causing the phase difference to track the target phase difference.

Claims (30)

Claims
1. Apparatus for facilitating emulated current-mode control of a resonant converter, the apparatus comprising: an input for a first signal suitable for use in determining a phase of a resonant current, wherein the resonant current corresponds to a current in a resonant network of the converter; an input for a second signal suitable for use in determining a target phase difference between the resonant current and a driving voltage, wherein the driving voltage corresponds to a voltage provided by a switch network of the converter to the resonant network; one or more outputs for one or more control signals for controlling operation of the switch network; and circuitry configured to: use the first signal in determining a first value, wherein the first value is related to a phase difference between the resonant current and the driving voltage; use the second signal in determining a second value, wherein the second value is related to the target phase difference; and set the one or more control signals based at least in part on a comparison of the first and second values, wherein the one or more control signals are for causing the phase difference to track the target phase difference.
2. Apparatus according to claim 1 wherein the first signal is indicative of the timing of zero-crossings of the resonant current.
3. Apparatus according to claim 1 or 2 wherein the circuitry is configured to determine the first value using the first signal and at least one of the one or more control signals.
4. Apparatus according to claim 1 or 2 comprising: an input for a third signal suitable for use in determining a phase of the driving voltage; wherein the circuitry is configured to determine the first value using the first signal and the third signal.
5. Apparatus according to any preceding claim wherein the circuitry is configured to determine the first value based on: a value indicative of a time difference between a zero-crossing of the resonant current and a zero-crossing of the driving voltage; and a value indicative of the period of the resonant current and the driving voltage.
6. Apparatus according to claim 5 wherein the circuitry is configured to determine the value indicative of the period in accordance with a frequency of operation of the switch network set by the circuitry.
7. Apparatus according to claim 5 or 6 wherein the circuitry is configured to adjust the value indicative of the time difference so as to overestimate a time lag of the resonant current with respect to the driving voltage, and further configured to determine the first value based on the adjusted value indicative of the time difference.
8. Apparatus according to any preceding claim wherein the circuitry is configured to constrain the second value to a particular range, the range corresponding to a phase lag of the resonant current with respect to the driving voltage being greater than zero.
9. Apparatus according to any preceding claim wherein the second signal is indicative of a target output current of the converter and wherein the circuitry is configured to determine the second value in accordance with a known relationship between the output current and the phase difference between the resonant current and the driving voltage.
10. Apparatus according to any preceding claim wherein the one or more control signals are suitable for changing an operating frequency and/or a duty cycle of the switch network.
11. Apparatus according to any preceding claim wherein the circuitry comprises a microcontroller.
12. Apparatus according to any preceding claim wherein the circuitry comprises at least one processor and non-transitory memory storing computer programme code, wherein the computer programme code, when executed by the at least one processor, causes the circuitry to set the one or more control signals.
13. A resonant converter with control circuitry comprising: an inner loop comprising apparatus according to any preceding claim; and an outer loop configured to sense an output level of the converter and to produce a signal corresponding to the second signal, wherein the inner and outer loops cause an output level of the converter to tend towards a target output level.
14. A method suitable for use in a resonant converter, the method comprising: obtaining a first signal or value suitable for use in determining timing of a resonant current, wherein the resonant current corresponds to a current in a resonant network of the converter; obtaining a second signal or value suitable for use in determining timing of a driving voltage, wherein the driving voltage corresponds to a voltage provided by a switch network of the converter to the resonant network; using the first signal or value and the second signal or value in determining at least one third value related to a time difference between the resonant current and the driving voltage; and, in response to the at least one third value meeting one or more criteria, at least partly overriding one or more control signals, wherein the one or more control signals are for controlling operation of the switch network and are otherwise determined so as to set an output of the resonant converter.
15. A method according to claim 14 wherein the one or more criteria include: the at least one third value indicating that the time difference is less than a minimum time difference.
16. A method according to claim 14 or 15 wherein the one or more criteria include: the at least one third value indicating that the time difference has decreased by at least a particular amount in a particular period of time.
17 A method according to claim 15 or 16 wherein overriding the one or more control signals comprises: changing the one or more control signals so as to increase the time difference and/or reduce the output of the resonant converter.
18. A method according to claim 17 wherein overriding the one or more control signals comprises: changing the one or more control signals so as to incrementally increase a switching frequency of the switch network.
19. A method according to claim 17 or 18 wherein overriding the one or more control signals comprises: changing the one or more control signals so as to set a switching frequency of the switch network to a particular frequency.
20. A method according to any one of claims 14 to 19 comprising: in response to the at least one third value meeting a further criterion, stopping overriding the one or more control signals, wherein the further criterion corresponds to the at least one third value indicating that the time difference has increased by a particular amount in a particular period of time.
21. A method according to claim 20 wherein stopping overriding the one or more control signals comprises: changing the one or more control signals so as to incrementally decrease a switching frequency of the switch network.
22. A method according to claim 16 or 20, wherein the particular period of time corresponds to a switching period of the switch network.
23. A method according to any one of claims 14 to 22 wherein: the first signal or value is indicative of timing of zero-crossings of the resonant current; and/or the second signal or value is indicative of timing of falling or rising edges of the driving voltage.
24. A method according to any one of claims 14 to 23 comprising: obtaining a fourth value related to a target phase difference between the resonant current and the driving voltage; using the first signal or value and the second signal or value in determining a fifth value related to a phase difference between the resonant current and the driving voltage; and setting the one or more control signals based at least in part on a comparison of the fourth and fifth values.
25. A method according to claim 24 comprising: obtaining a sixth signal or value indicative of a target output current of the converter; and determining the fourth value in accordance with a known relationship between the output current and the phase difference between the resonant current and the driving voltage.
26. Apparatus configured to perform a method according to any one of claims 14 to 25.
27. Apparatus according to claim 26 comprising: an input for each of the first and second signals; an output for each of the one or more control signals; and circuitry configured to perform the method.
28. A resonant converter comprising: an inner loop and an outer loop; wherein the outer loop is configured to sense an output level of the resonant converter and to provide a demand signal to the inner loop, and the inner loop is configured to use the demand signal in determining the one or more control signals; and apparatus according to claim 26 or 27, wherein the apparatus is at least partly comprised in the inner loop.
29. A method for use by apparatus for facilitating emulated current-mode control of a resonant converter, the apparatus comprising an input for a first signal suitable for use in determining a phase of a resonant current, wherein the resonant current corresponds to a current in a resonant network of the converter, an input for a second signal suitable for use in determining a target phase difference between the resonant current and a driving voltage, wherein the driving voltage corresponds to a voltage provided by a switch network of the converter to the resonant network, and one or more outputs for one or more control signals for controlling operation of the switch network, the method comprising: using the first signal in determining a first value, wherein the first value is related to a phase difference between the resonant current and the driving voltage; using the second signal in determining a second value, wherein the second value is related to the target phase difference; and setting the one or more control signals based at least in part on a comparison of the first and second values, wherein the one or more control signals are for causing the phase difference to track the target phase difference.
30. A non-transitory computer-readable storage medium storing a computer programme comprising instructions that, when executed by one or more processors, cause the one or more processors to perform a method according to any one of claims 14 to 25 and 29.
GB2011204.1A 2018-01-15 2019-01-14 Apparatus and methods for use in a resonant converter Active GB2584217B (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB1800642.9A GB2565861B (en) 2018-01-15 2018-01-15 Apparatus for use in a resonant converter
GBGB1817720.4A GB201817720D0 (en) 2018-10-30 2018-10-30 Methods for use in a resonant converter
PCT/GB2019/050094 WO2019138251A1 (en) 2018-01-15 2019-01-14 Apparatus and methods for use in a resonant converter

Publications (3)

Publication Number Publication Date
GB202011204D0 GB202011204D0 (en) 2020-09-02
GB2584217A true GB2584217A (en) 2020-11-25
GB2584217B GB2584217B (en) 2022-09-14

Family

ID=64655502

Family Applications (2)

Application Number Title Priority Date Filing Date
GBGB1817720.4A Ceased GB201817720D0 (en) 2018-01-15 2018-10-30 Methods for use in a resonant converter
GB2011204.1A Active GB2584217B (en) 2018-01-15 2019-01-14 Apparatus and methods for use in a resonant converter

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GBGB1817720.4A Ceased GB201817720D0 (en) 2018-01-15 2018-10-30 Methods for use in a resonant converter

Country Status (1)

Country Link
GB (2) GB201817720D0 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0430358A1 (en) * 1989-11-29 1991-06-05 Koninklijke Philips Electronics N.V. Circuit arrangement
US6326740B1 (en) * 1998-12-22 2001-12-04 Philips Electronics North America Corporation High frequency electronic ballast for multiple lamp independent operation
EP2458723A1 (en) * 2010-11-24 2012-05-30 Nxp B.V. A circuit for a resonant converter
US20150003117A1 (en) * 2013-06-26 2015-01-01 Stmicroelectronics S.R.L. Method of controlling a switching converter in burst mode and related controller for a switching converter

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0430358A1 (en) * 1989-11-29 1991-06-05 Koninklijke Philips Electronics N.V. Circuit arrangement
US6326740B1 (en) * 1998-12-22 2001-12-04 Philips Electronics North America Corporation High frequency electronic ballast for multiple lamp independent operation
EP2458723A1 (en) * 2010-11-24 2012-05-30 Nxp B.V. A circuit for a resonant converter
US20150003117A1 (en) * 2013-06-26 2015-01-01 Stmicroelectronics S.R.L. Method of controlling a switching converter in burst mode and related controller for a switching converter

Also Published As

Publication number Publication date
GB201817720D0 (en) 2018-12-19
GB202011204D0 (en) 2020-09-02
GB2584217B (en) 2022-09-14

Similar Documents

Publication Publication Date Title
US10804801B2 (en) Hysteretic current mode buck-boost control architecture having sequential switching states
US10355596B2 (en) Buck-boost converter
US9124180B2 (en) Multiple resonant converter apparatus and control method
GB2589477A (en) Removal of near DC errors in a peak-controlled boost converter using a low bandwidth secondary control loop
US7944715B2 (en) Controller for use in a resonant direct current/direct current converter
TW201613243A (en) Resonant converter, control circuit and associated control method with adaptive dead time adjustment
EP2458723B1 (en) A circuit for a resonant converter
US9584035B2 (en) Dual-edge tracking synchronous rectifier control techniques for a resonant converter
JP2017533692A5 (en)
US20120133348A1 (en) Audio-skipping of a constant on-time power converter
US20230246538A1 (en) Zero-voltage-switching control circuit, control method and switching power supply
WO2011047110A2 (en) Dimmer decoder with improved efficiency for use with led drivers
CN109995231A (en) The digital control method of Boost AC-DC constant voltage source
CN103746552B (en) Control system and control method for stepless current limiting of switch power supply
GB2578379A (en) A DC-DC converter
US9985539B1 (en) Power controller with turn-on time configured according to number of current limit operations
GB2584217A (en) Apparatus and methods for use in a resonant converter
JP2023053372A5 (en)
RU2010140813A (en) METHOD OF CONTROL OF THE SWITCHING DEVICE OF THE RESONANT POWER CONVERTER, IN PARTICULAR FOR PROVIDING THE REQUIRED POWER, IN PARTICULAR FOR THE X-RAY GENERATOR
CN110943605A (en) Control method and device of totem-pole power factor correction circuit
CN110365243B (en) Inverter voltage adjusting method and device, inverter and computer readable medium
US11264913B2 (en) Apparatus and methods for use in a resonant converter
CN103856088A (en) Hysteresis current control method for changing timing period
KR102028066B1 (en) Electric range of induction heating type radiating low elctromagnetic wave
US20130093348A1 (en) Method, apparatus and system for controlling light source