Controllable resonant type converter development for capacitor charging loads

The paper investigates various controlling options for the selected resonant converter topology, which is optimized for capacitor charging systems. Several of the controlling algorithms were studied in depth, and one of them was practically verified. There are two major advantages about the system:...

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Datum:	2017
Hauptverfasser:	Volkov, I.V., Podolnyi, S.V.
Format:	Artikel
Sprache:	English
Veröffentlicht:	Інститут електродинаміки НАН України 2017
Schriftenreihe:	Технічна електродинаміка
Schlagworte:	Перетворення параметрів електричної енергії
Online Zugang:	http://dspace.nbuv.gov.ua/handle/123456789/158971
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Zitieren:	Controllable resonant type converter development for capacitor charging loads / I.V. Volkov, S.V. Podolnyi // Технічна електродинаміка. — 2017. — № 6. — С. 11–17. — Бібліогр.: 6 назв. — англ.

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spelling	irk-123456789-1589712019-09-20T01:26:00Z Controllable resonant type converter development for capacitor charging loads Volkov, I.V. Podolnyi, S.V. Перетворення параметрів електричної енергії The paper investigates various controlling options for the selected resonant converter topology, which is optimized for capacitor charging systems. Several of the controlling algorithms were studied in depth, and one of them was practically verified. There are two major advantages about the system: full/partial soft-switching mode what allows to use higher switching without the system efficiency drop; controllable energy flow from the input to the output, without any additional sophisticated parts. Розроблено декілька способів керування вибраною структурою резонансного перетворювача, що працює на ємнісне електроразрядне навантаження. Деякі методи розглянуто детально, один із них – з практичною перевіркою. Така система має дві основні переваги: повний/частковий режим софт-світчінгу, який дозволяє використовувати її на більш високих частотах без суттєвого зниження ККД; керована передача енергії без суттєвих ускладнень силової частини/системи керування. Разработан ряд способов управления выбранной структурой резонансного преобразователя, работающего на емкостную электроразрядную нагрузку. Некоторые методы рассмотрены детально, один из них – с практической проверкой. Данная система обладает двумя основными преимуществами: полный/частичный режим софт-свитчинга, что позволяет использовать её на более высоких частотах без существенного снижения КПД; управляемая передача энергии без существенных усложнений силовой части/системы управления. 2017 Article Controllable resonant type converter development for capacitor charging loads / I.V. Volkov, S.V. Podolnyi // Технічна електродинаміка. — 2017. — № 6. — С. 11–17. — Бібліогр.: 6 назв. — англ. 1607-7970 DOI: https://doi.org/10.15407/techned2017.06.0011 http://dspace.nbuv.gov.ua/handle/123456789/158971 621.314 en Технічна електродинаміка Інститут електродинаміки НАН України
institution	Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection	DSpace DC
language	English
topic	Перетворення параметрів електричної енергії Перетворення параметрів електричної енергії
spellingShingle	Перетворення параметрів електричної енергії Перетворення параметрів електричної енергії Volkov, I.V. Podolnyi, S.V. Controllable resonant type converter development for capacitor charging loads Технічна електродинаміка
description	The paper investigates various controlling options for the selected resonant converter topology, which is optimized for capacitor charging systems. Several of the controlling algorithms were studied in depth, and one of them was practically verified. There are two major advantages about the system: full/partial soft-switching mode what allows to use higher switching without the system efficiency drop; controllable energy flow from the input to the output, without any additional sophisticated parts.
format	Article
author	Volkov, I.V. Podolnyi, S.V.
author_facet	Volkov, I.V. Podolnyi, S.V.
author_sort	Volkov, I.V.
title	Controllable resonant type converter development for capacitor charging loads
title_short	Controllable resonant type converter development for capacitor charging loads
title_full	Controllable resonant type converter development for capacitor charging loads
title_fullStr	Controllable resonant type converter development for capacitor charging loads
title_full_unstemmed	Controllable resonant type converter development for capacitor charging loads
title_sort	controllable resonant type converter development for capacitor charging loads
publisher	Інститут електродинаміки НАН України
publishDate	2017
topic_facet	Перетворення параметрів електричної енергії
url	http://dspace.nbuv.gov.ua/handle/123456789/158971
citation_txt	Controllable resonant type converter development for capacitor charging loads / I.V. Volkov, S.V. Podolnyi // Технічна електродинаміка. — 2017. — № 6. — С. 11–17. — Бібліогр.: 6 назв. — англ.
series	Технічна електродинаміка
work_keys_str_mv	AT volkoviv controllableresonanttypeconverterdevelopmentforcapacitorchargingloads AT podolnyisv controllableresonanttypeconverterdevelopmentforcapacitorchargingloads
first_indexed	2025-07-14T11:30:37Z
last_indexed	2025-07-14T11:30:37Z
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fulltext	ISSN 1607-7970. Техн. електродинаміка. 2017. № 6 11 ПЕРЕТВОРЕННЯ ПАРАМЕТРІВ ЕЛЕКТРИЧНОЇ ЕНЕРГІЇ CONTROLLABLE RESONANT TYPE CONVERTER DEVELOPMENT FOR CAPACITOR CHARGING LOADS I.V. Volkov, S.V. Podolnyi Institute of Electrodynamics National Academy of Sciences of Ukraine, pr. Peremohy, 56, Kyiv, 03057, Ukraine. E-mail: dgp@ukr.net The paper investigates various controlling options for the selected resonant converter topology, which is optimized for capacitor charging systems. Several of the controlling algorithms were studied in depth, and one of them was practically verified. There are two major advantages about the system: full/partial soft-switching mode what allows to use higher switching without the system efficiency drop; controllable energy flow from the input to the output, without any additional sophisticated parts. References 6, figures 9. Key words: resonant converter, capacitor charging systems, soft-switching. Introduction. Capacitor charging systems are widely used for various industrial, special, domestic, science experiments electrical and power electronic applications, like pulse welding, laser technic, magneto- impulse processing of metals, volume electro-erosion processing, etc. [3]. The major operational condition for such system types is an economic charge of the storage capacitor according to some specific time-domain law, and optimal interrelations between processes in the charging circuit and the power source (especially if it’s autonomous one) [2, 3]. There are three main methods known for the storage capacitor charging: from constant voltage type source, from constant current type source and from constant power type source [4, 6]. The first one has low efficiency – below 50% due to the restricting input current requirement with a resistor. In the case of using a current limiting inductor, its energy capacity (sizes and price accordingly) is relatively big, and contributes to more than quarter to the device energy capacity [3]. The main drawback of the second type – the maximum power of the power source two times exceeds the average power per cycle, required for the capacitor full charging. The constant power case has the disadvantage of increased dynamical energy losses in its semiconductor devices, which create such a mode at the first place. There are numerous schematic methods exist for overcoming those disadvantages in each particular case, and in this article we use quasi-separated schematic of two separate resonant tanks (Fig. 1) to facilitate hard-switching energy losses and EMI-effects of conventional power converter equipment and improve switching conditions for the semiconductors switches. For these purposes we utilize in the converter a transitional “small” capacitor C0, that during the charging cycle of the “big” output capacitor Cout >> C0 repeatedly transfers small portions of energy (“quants”) until the system is fully charged. In this article, we propose and compare possible algorithms for the converter switches, which would provide optimal energy transfer with minimal dynamical losses in the transistors switches. All the switches here are one directional. Several theoretical algorithms can be used for obtaining different types of the converter behaviours. For this particular reason the Fig. 1 schematic includes K21 as a controllable element, though in some cases this one can be substituted with a diode. We don’t consider static losses at the beginning (Fig. 1 doesn’t contain resistive elements in order to simplify functional possibilities of the device analytically). The first resonant tank. This circuit works during the switch K1 conductive state, and closed K2 respectively. It has three elements {Uin, L0, C0} with two possible initial states on the C0. The transient processes are described by well known equations [1] © Volkov I.V., Podolnyi S.V., 2017 ORCID ID:http://orcid.org/0000-0002-0696-0382 Fig. 1 12 ISSN 1607-7970. Техн. електродинаміка. 2017. № 6    t L U tii Cdt idL in   sin01 00 2 2 0  , (1) where 00 CLZ  is the wave impedance; 001 CL is the circular frequency. The voltage C0              .cos1\|cossin11 0 000 tUtutUdtt L U C dtti C tu in t in in     (2) In the case of considering the transient half-cycle, i.e. t= /, UC0 =2 Uin. The doubled voltage require two additional conditions: the active resistance is negligible; zero initial condition U(C0) = 0. Let’s consider the case   00 ~ CUCU  , then (1) transforms to the following    t Z UU ti Cin sin0  , (3) and the voltage C0         tUUUdtti C Utu CinCC cos1~~1~ 00 0 0   . (4) As can be seen from (4), at the moment t = /   0000 ~2~2~ CinCinCC UUUUUU  . (5) That means the initial condition can both increase or decrease the transferring energy of the converter per working cycle. The second resonant tank. The circuit include three basic elements with its initial conditions. Fig. 2 bellow shows the above mentioned in Laplace domain. The operational circuit components are: the “large” output capacitor Cout>>C0, the dosing “small” capacitor C0 with initial condition V0=UC0 and Vout – variable part of the output capacitor voltage аt nth step of charging. Normally, Lout initial current ILout(0)=0. The operational current I(p)       outout out outout out LpCC VV pLpCpC pVpV pM pNpI 2 0 0 0 0 1111       . (6) Inverse Laplace-transformation for I(p) according to the decomposition theorem       , 22 00 2 1 tj out outtj out out k k k e Lj VV e Lj VV p dp dM pN ti          where pk is the roots of the M(p) polynomial. Since  tjee tjtj  sin2 ,      t Z VV t L VV ti out out out   sinsin 00     . (7) Cout voltage           t out out out out outout dtt Z VV C Vdtti C Vtu 0 0 sin11      t ZC VV Vtu out out outout   cos10    . (8) Note   CCCLCLCC outoutoutoutout 1 ,  outout CCCCC  00 , hence       tVV C CVtu out out outout cos10   . Let outC CC / , then       tVVVtu outCoutout  cos10  . (9) Since 10  CCC  . Fig. 2 ISSN 1607-7970. Техн. електродинаміка. 2017. № 6 13 Similarly capacitor C0 voltage     t C VV CVdti C Vtu out C cos11 0 0 0 0 00     . Let 0/ CCC  , then       tVVVtu outcC  cos1000  . (10) Due to 10  CCC  . At the moment  t , or the full half-cycle, the residual voltage of the dosing capacitor  outcres VVVu  00 2 . (11) The dosing capacitor is fully discharged 0resu only in one case outut C C VV V   2 00 0 , (12) or if 0CCout  , then 05.0 VVout  . For all other cases, it will have positive or negative residual voltage. Generally speaking, in some real cases we could encounter not zero initial condition for the inductor current   000 II Lout  . By rewriting (6) implying this additional condition   outout outout outout outout LpCC IpLVV pLpCpC ILpVpV pI 2 0 00 0 00 1111       . (13) The inverse Laplace-transformation for the I(p)                   tIeeI L VVjti m tjtj out out sin 22 00 , (14) where   Z U Z VVZI Z VV II moutout m ~~ 2 0 22 0 2 02 0           ,                    2 0 22 0 0 0 0 arcsin 22 out out VVZI IZ IZ VV arctg   . Respectively Cout voltage            tZIVtI C Vtu mCL t m out Lout coscos~sin1 0 . (15) And C0 voltage            tZIVtI C Vtu mC t m out C coscos~sin1 0 0 00 . (16) The equation (9) shows that there are two variables for uout(t): V0 and t which can be controlled dynamically. Both the tanks can be adjusted to influence these parameters to a certain degree. Consequently, the full spectra of possible controlling algorithms, for the “large” capacitor charging, are predetermined by these two variables. Controlling algorithms. Let’s consider some of them in more details. 1.1: V0, t are not regulated. In this case, both the input and the output resonant tanks work under pure soft-switching conditions, so dynamic losses are zero. The residual voltage ures of the dosing capacitor rapidly increases on each charging cycle, and the magnitude of the input current respectively, until the following condition Vout = Uin takes place. After that knee point Vout > Uin, and the input current Iin decreases by the same rate, i.e. it’s symmetrical respectively to the knee. Theoretical charging limit for the case approaches doubled input voltage, or inout UV  2 . The case has a significant drawback, namely very high growing rate of the input current, which for the practical schemes should almost always be limited to an upper maximum value. 14 ISSN 1607-7970. Техн. електродинаміка. 2017. № 6 Let’s consider the example Uin = 310 V, Z = 50 Ohm, C = 5e-3. Then the charging dynamic is illustrated bellow (Fig. 3). The voltage Uout here is shown on a scale 10:1. The output voltage grows until the residual voltage on the dosing capacitor 0resu (Fig. 3, a). If 0resu then the output does not get any new energy portion due to the circuit conducts only in one direction, otherwise it would discharge backwardly, CLC UU 0 (Fig. 3, b). 1.2: V0 is regulated in the first link. It can be shown that that the input link equations for its current and the dosing capacitor voltage, under all non-zero initial conditions, are similar to (14), (15)              ,coscos ,sin)( 00   tZIVtu tIti mC m (17)   Z VVZI I out m 2 0 22 0   ,         0 0 2 IZ VV arctg out  . According to (17) V0 can be regulated with the getting away from the full soft-switching concept and introducing beforehand commutation of the input switch timing ton or the input angle on, i.e. ton < /. Here we make a deal with the trade-off of somewhat decreased scheme overall efficiency for the ability to limit the input current. Taking into account the aforesaid condition for ton/on, let’s rewrite (17) as follow                                  ZI VU II UtZIV ItI m on mon m m 0max max max0 max cosarccos arcsin coscos sin , (18) where Umax is the dosing capacitor maximum voltage; Imax is the maximum magnitude of the input current for all charging cycles. The second equation of (18) adds limitation to the maximum residual voltage   1cos max max    ZI uU res . (19) Let’s consider the example, where Umax=2Uin, besides there’s a complyance to all other restrictions. It should be noted, that for this type of regulation we have to include additional energy return circuit for the inductor energy not to be wasted while the switch commutation occurs, otherwise the input circuit will have low efficiency with high EMC-noise radiation. By assuming the foresaid true, our system is simplified and before each new cycle I0 = 0, hence   Z VU Z VVZI I inout m 0 2 0 22 0     . (20) Let’s consider the second controlling algorithm to the same parameters that we mentioned in the previous case. The corresponding model output capacitor theoretical limit, under selected Umax=2Uin condition, approaches Uout  1.2Uin. The output resonant tank works in the soft-switching mode all the time. Total amount of charging cycles – 45, what’s notably longer than the previous case (Fig. 4, a). The result is obvious, since the system pumps less energy per cycle on average. The upper limit Umax defines the maximum residual voltage of C0, which in its turn sets the input current magnitude for the next charging a b Fig. 4 a b Fig. 3 ISSN 1607-7970. Техн. електродинаміка. 2017. № 6 15 cycle. Fig. 4, b illustrates ton / on behaviour, as was mentioned before if on  then additional switching losses exist; they have the decreasing tendency over time. As can be seen after 32 cycles the systems works in full soft-switching mode, what corresponds to the following condition Uout= Uin. 1.3: I0 is regulated in the first link. In the previous case we took Umax as the main limitation from (18). Alternatively,   maxsin ItIm  can be selected for the same purpose. Similary to the case 1.2 an additional energy return circuit for the inductor is needed. Expression (20) gives us the following limitation on the peak current    min0 1 inininm UUVU Z I  . (21) Expression (21) shows that Im & Umax & ures eventually are the same thing from the selected limitation point of view, linearly dependant on each other; i.e. we could select any limitation here suitable to a specific task. The overall process does not change. 2.1: uout limitation in the second tank. As shown on Fig. 1, by introducing K21 switching element, the output circuit gains the ability to limit the residual voltage/input current by way of isolating C0 from the superfluous recharging current at an appropriate moment of time. The controlling algorithm for the case works in three stages: 1) C0 charging from the input; 2) C0 discharging with the residual voltage limiting; 3) waiting until the Lout magnetic energy will be fully transferred to the output capacitor. For such a scenario the total charging-discharging cumulative time TC = t1 + t2 + t3 varies, due to Lout initial condition isn’t constant, besides the residual magnetic energy transferring isn’t fast process, 0,, CLoutCoutLout ff  , and at the beginning the situation when t3 > t1 + t2 rather possible. Consequently, the input impulses duty-cycle is not uniform, changing from some maximum to its minimum – 50%. Even though the charging process takes 28 cycles (Fig. 5), the value 27 CT is bigger than for the previous case with almost 50 cycles. The output voltage approaches Uout  1.2Uin. The output switch works in both modes, namely it has hard- switching closing for the first seventeen cycles, and the full soft- switching mode afterwards. The peak of residual magnetic energy Ires is defined by both I0 / Umax / ures value and the system parameters. Fig. 6 shows the same process for the input/output currents dosing in time domain. The simplest practical implementation for the case is using a diode as the K21 switch. An ideal diode will be automatically turned on when the dosing capacitor voltage reaches zero, therefore the residual voltage also stay zero and the system works in full soft-switching mode for the whole time. Besides the approach simplifies the controlling system implementation. If the full charging time is a critical parameter – this will a drawback, because of the limitation on the maximum transferred energy per cycle. The diode switching time is volatile, can be found as follow       0cos1000 tVVVU LCC  a b Fig. 5 Fig. 6 16 ISSN 1607-7970. Техн. електродинаміка. 2017. № 6         LC VV V t 0 01arccos   . (22) Fig. 7 shows the dynamic for the case of using a diode. After the 50th cycle the dosing capacitor has residual positive voltage which respectively decrease input current until the final point. The process last about two times longer in comparing to the controllable K21. There is a possibility to simplify further the controlling algorithm by making the duty cycle constant, however for the price – the current at the beginning will have higher magnitude (Fig. 8). The average pumping energy her is higher, hence the charging process is a bit faster. Special precautions should be taken for the diode selection, otherwise its life-cycle could be tangibly shortened. This variant was investigated experimentally. On estimation level, we confirmed dynamical characteristics of the system, what is shown on the following pictures Fig. 9). UC0(t) UCout Iout Fig. 9 Conclusion. The proposed converter schematic with the intermediate dosing capacitor has notable advantages as compared with the classical approaches, namely – low dynamical energy losses and algorithmic flexibility. If the charging time isn’t the major parameter than the physical implementation of the converter, e.g. with an additional diode, does not require complex feed-backs and tracking systems. The system doesn’t tend to malefaction from external electromagnetic interferences due to its inbuilt properties, which induce overvoltages and overcurrents. After more detailed analysis of the system energy efficiency behavior, first of all with considering the reactors quality factor, we’ll cover the system possible practical applications. a b Fig. 7 Fig. 8 ISSN 1607-7970. Техн. електродинаміка. 2017. № 6 17 1. Demirchyan K., Neyman L. Theoretical Foundations of Electrical Engineering. Vol. 2. – SPb.: Piter, 2006. – 576 p. (Rus) 2. Milyakh A.N., Volkov I.V. Stabilized current systems based on inductive-capacitive converters. − Kiev: Naukova Dumka, 1974. – 216 p. (Rus) 3. Pentegov I.V. Fundamentals of the charging circuits theory for capacitive energy storage devices. − Kiev: Naukova Dumka, 1982. – 420 p. (Rus) 4. Polishchuk Yu.A. To the study of charging systems of capacitive storage devices from a source of limited power / Ustroistva preobrazovatelnoi tekhniki, vypusk 1. − Kiev: Naukova Dumka, 1969. − Pp. 10-16. (Rus) 5. Rashid M.H. Power Electronics Handbook. − N.-Y.: Academic Press, 2002. − 895 p. 6. Shcherba A.A., Suprunovska N.I. Electric energy loss at energy exchange between capacitors as function of their initial voltages and capacitances ratio // Tekhnichna Elektrodynamika. – 2016. – No 3. – Pp. 9-11. УДК 621.314 КЕРОВАНИЙ ПЕРЕТВОРЮВАЧ РЕЗОНАНСНОГО ТИПУ ДЛЯ ЄМНІСНИХ ЕЛЕКТРОРОЗРЯДНИХ НАВАНТАЖЕНЬ І.В. Волков, чл.-кор. НАН України, С.В. Подольний, канд.техн.наук Інститут електродинаміки НАН України, пр. Перемоги, 56, Київ, 03057, Україна, e-mail: dgp@ukr.net Розроблено декілька способів керування вибраною структурою резонансного перетворювача, що працює на ємнісне електроразрядне навантаження. Деякі методи розглянуто детально, один із них − з практичною пере- віркою. Така система має дві основні переваги: повний/частковий режим софт-світчінгу, який дозволяє вико- ристовувати її на більш високих частотах без суттєвого зниження ККД; керована передача енергії без суттєвих ускладнень силової частини/системи керування. Бібл. 6, рис. 9. Ключові слова: резонансний перетворювач, ємнісне електророзрядне навантаження, софт-світчінг. 1. Демирчян К., Нейман Л. Теоретические основы электротехники. T.2. – СПб.: Питер, 2006. – 576 c. 2. Милях А.Н., Волков И.В. Системы стабилизированного тока на основе индуктивно-емкостных преоб- разователей. − Киев: Наукова думка, 1974. – 216 с. 3. Пентегов И.В. Основы теории зарядных цепей емкостных накопителей энергии. − Киев: Наукова думка, 1982. – 420 с. 4. Полищук Ю.А. К исследованию систем заряда емкостных накопителей от источника ограниченной мощ- ности / Устройства преобразовательной техники, вып. 1. − Киев: Наукова думка, 1969. − С. 10-16. 5. Rashid M.H. Power Electronics Handbook. − N.-Y.: Academic Press, 2002. − 895 p. 6. Shcherba A.A., Suprunovska N.I. Electric energy loss at energy exchange between capacitors as function of their initial voltages and capacitances ratio // Технічна електродинаміка. – 2016. – № 3. – С. 9-11. УДК 621.314 УПРАВЛЯЕМЫЙ ПРЕОБРАЗОВАТЕЛЬ РЕЗОНАНСНОГО ТИПА ДЛЯ ЕМКОСТНЫХ ЭЛЕКТРОРАЗРЯДНЫХ НАГРУЗОК И.В. Волков. чл.-корр. НАН Украины, С.В. Подольный, канд.техн.наук Институт электродинамики НАН Украины, пр. Победы, 56, Киев, 03057, Украина, e-mail: dgp@ukr.net Разработан ряд способов управления выбранной структурой резонансного преобразователя, работающего на емкостную электроразрядную нагрузку. Некоторые методы рассмотрены детально, один из них − с прак- тической проверкой. Данная система обладает двумя основными преимуществами: полный/частичный режим софт-свитчинга, что позволяет использовать её на более высоких частотах без существенного снижения КПД; управляемая передача энергии без существенных усложнений силовой части/системы управления. Библ. 6, рис. 9. Ключевые слова: резонансный преобразователь, емкостная электроразрядная нагрузка, софт-свитчинг. Надійшла 24.05.2017 Остаточний варіант 03.08.2017

Controllable resonant type converter development for capacitor charging loads

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