The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper presents small signal ac analysis of LLC current resonant converter. Equivalent source model that represents a switching element as an equivalent source having averaged current and voltage is employed and described in detail. From analysis, the transfer function of the switching frequency to the output voltage of the converter becomes a quadratic system. Resonant capacitor and inductor...
This paper proposes a novel PFM controller for LLC converter. The proposed controller employs a hysteretic comparator and has phase lead characteristic, which improves system stability and the transient performance. Steady state and frequency characteristics of the proposed circuit are analyzed and confirmed by experiments. Since the proposed method does not need to use high GBW O.P.Amp., it becomes...
This paper presents a simple and low cost PV simulator using diode characteristics for development of PV system. In order to reproduce characteristics of PV module, instead of huge digital data of I-V characteristics of PV module considering temperature dependence, a real diode is used in the proposed system. A low cost microcontroller that has a little amount of data memory is used to control the...
This paper presents small signal analysis of dc-dc converters with ripple-based control. A simple and adaptable method for the analysis of ripple-based converter is introduced. A buck converter with ripple-based control is analyzed as an example. A prototype converter is implemented and the presented experimental results confirm the validity of theoretical analysis. From the results, it is clarified...
This paper presents analysis and design method of hysteretic PWM controller. Analysis based on averaged model was performed. Results of analysis show the controller has the characteristics of type 2 and clarify characteristics given by the circuit elements. The circuit design is performed by using the analysis results. It shows the procedure for giving the parameters of the control circuit. Design...
This paper proposes fast response, accurate and low cost maximum power point tracking (MPPT) controller for photovoltaic (PV) system. The proposed method is based on linearized I–V characteristics at MPP of PV array in order to obtain fast and accurate response. The linear combination of voltage and current of solar cell is used as the control variable that is controlled to be a constant value with...
A new method to suppress voltage stress of switches and transformers is proposed for phase shift controlled dc-dc converter. In the proposed method, two transformers are used and secondary windings are connected in series, which allows zero voltage switching of the switches. Since switching nodes are coupled together by transformer, the locations of them do not matter, so series connection of power...
This paper presents a new high efficiency DC-DC converter for electric double layer capacitor (EDLC). The bi-directional two-stage converter combined with a coupling capacitor and a coupled inductor (CCCI) is used in order to obtain high power efficiency at large voltage conversion ratio. Static characteristics of the proposed converter are analyzed and confirmed by experiments. As a result it is...
This paper presents a new LLC converter combined with switched capacitor for high voltage applications. In the proposed converter, the flying capacitor of the switched capacitor is divided into two parts, and they are used as resonance capacitors of an LLC converter. The proposed method reduces the switch voltage stress to a half of the input voltage, and the current in switches are a half of that...
A hysteretic PWM controller is one of attractive control methods to realize the fast transient response for the rapid change of the load current and input voltage of switching power converters. The performance of this control method depends on the time constant of the RC network which generates a ripple voltage for the PWM circuit in the feedback path and has a feature of trade off between the higher...
This paper presents a novel digital control method that improves both phase margin and jitter of a dc-to-dc switching converter. The proposed method has two controlled pulse, one is generated by digital control and the other by analog control. The resulted switching frequency is twice of analog control and digital control frequency, which results in smaller ripple currents in the converter. From the...
This paper proposes a novel hysteretic PWM controller that consists of two comparators with hysteretic characteristics and OR gates for a buck converter. The proposed controller operates in double switching frequency of the clock signal input for synchronization with keeping excellent dynamic performances of hysteretic PWM method. It was confirmed that the proposed method provides not only excellent...
This paper proposes a new two-stage converter with a coupling capacitor and a coupled inductor. In order to downsize the two-stage converter, two inductors are tightly coupled together. Circuit operation is described in detail. Steady state analysis is performed and confirmed by experiments. It is clarified that the proposed converter has advantages of larger voltage conversion ratio and higher power...
Vehicles employing idle reduction system need a step up DC-DC converter which operates stably for a voltage drop of a battery during engine restart. This paper proposes a power supply for idle reduction system employing a ripple regulator having an excellent transient performance and stability without using electrolytic capacitors which results in long life. The feedforward circuit is employed in...
Vehicles employing idle reduction system need a step up DC-DC converter which operates stably for a voltage drop of a battery during engine restart. This paper proposes a power supply for idle reduction employing a ripple regulator having an excellent transient performance and stability without using electrolytic capacitors, which results in long life. The feedforward circuit is employed in order...
This paper presents a constant frequency ripple regulator free from sub-harmonic oscillation. In order to obtain good transient responses for input voltage and load current changes, a new PWM control method with inherent derivative characteristics is proposed. The ripple regulator presented in this paper consists of a comparator, a simple RC network and an error amplifier, and it can be synchronized...
This paper proposed a new control method employing a hysteretic PWM controller with an input voltage feedforward for the boost and buck boost converters without using a current mode control. A triangular and hysteretic window voltages to generate the switching pulse signal are obtained in the comparator circuit by adding two resistors and an RC integral network. The feedforward signal from the input...
The capacitor coupled 2-stage converter (CC2SC) has large voltage conversion ratio and high power efficiency. However, when the conventional drive circuit is used for the CC2SC, there is a problem that the magnitude of gate drive voltage for the high side switch in the first stage becomes lower and the high side switch cannot be switched on properly. Without modification, a floating power supply is...
This paper proposes a high efficiency high power density AC/DC converter with holdup time extension capability. The proposed AC/DC converter is composed of a proposed two-phase PFC circuit and a ZVS/ZCS current fed isolated converter. During brief interruption of input power, the proposed PFC circuit operates as a boost regulator in order to keep a constant output voltage. Bulk storage capacitors...
One of the important functions of AC/DC converters is to supply a stable output DC voltage to electronic equipment even if momentary power outages occur. During the momentary power outage, the power is supplied from the storage capacitor of a PFC circuit to load through an isolated converter. Therefore very large capacitors should be necessary to compensate during interruption of AC power. Furthermore,...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.