Parallel Resonant Push-pull Inverter Research Articles

The Characteristics of Five Ceramics and Two Granites as Solid Dielectrics for An Ozone Generator

The utilization of ozone is commonly applied in various fields, for instance, it is used as a disinfectant for water treatment, disinfecting, sterilizing medical devices and preserving foodstuffs. Ozone is a nearly colorless gas with a characteristic odor that can be detected by humans up to 0.01 ppm. It can be produced by the dielectric barrier discharge method,which is generally used as a method of generating ozone supplied by high voltage or also called high voltage plasma generators. High voltage plasma occurs in the dielectric barrier discharge air gap, as a result of the air failed in maintaining its insulator properties. The power supply used in this study is a parallel resonant pushpull inverter using a flyback transformer. Furthermore, this study did not use an additional magnetic loudspeaker and used ceramic dielectrics instead. 5 types of ceramics and 2 different types of granite and combined the range of air gap were used during examination and research. The research indicates that the best plasma was found in ceramics 3, 5, granite 1 and 2 with an air gap of 2mm. The current discharge in ceramic 1 with an air gap of 2 mm was higher than the others. The highest voltage discharge was on granite 2 with an air gap of 2 mm. Ceramics 3, 5, granite 1 and 2 with an air gap of 2mm had better ozone concentrations than ceramics 1, 2 and 4.

Dielectric Barrier Discharge Induced By Permanent Magnet In Attraction And Repulsion Conditions For Ozone Generator

Ozone is used in various area including medicine, drinking water treatment and waste treatment. Ozone can be produced using dielectric barrier discharge which is supplied by high voltage. High voltage occurs in the dielectric barrier discharge such as air gap that it is as a result of the failure of air in maintaining its insulator properties. Power supply used in this study is a parallel resonant push-pull inverter using a fly back transformer. In order to produce good plasma in producing ozone, a magnetic filed is added to dielectric barrier discharge. In this study, a magnet was placed on each anode and cathode electrode with the condition of attraction (model I) and repulsion (model II). The addition of two magnets to each electrode was also carried out under the conditions of attraction (model III) and repulsion (model IV). It is shown that the plasma intensity in the model I and III was higher than model II and IV. The discharge current in the model I and III was higher than model II and IV. The highest ozone concentration was model III and the lowest ozone concentration was in model IV. Model I had a higher ozone concentration than model II.

An Improved Autonomous Current-Fed Push-Pull Parallel-Resonant Inverter for Inductive Power Transfer System

In the inductive power transfer (IPT) system, it is recommended to drive the resonant inverter in zero-voltage switching (ZVS) or zero-current switching (ZCS) operation to reduce switching losses, especially in dynamic applications with variable couplings. This paper proposes an improved autonomous current-fed push-pull parallel-resonant inverter, which not only realizes the ZVS operation by tracking the zero phase angle (ZPA) frequency, but also improves the output power and overall efficiency in a wide range by reducing gate losses and switching losses. The ZPA frequencies characteristic of the parallel-parallel resonant circuit in both bifurcation and bifurcation-free regions is derived and verified by theory and experiments, and the comparative experimental results demonstrate that the improved inverter can significantly increase the output power from 7.68 W to 8.74 W and has an overall efficiency ranging from 63.5% to 72.5% compared with the traditional inverter at a 2 cm coil distance. Furthermore, with a 2-fold input voltage (24 V), the improved inverter can achieve an approximate 4-fold output power of 38.9 W and overall efficiency of 83.6% at a 2 cm coil distance.

Bidirectional Current-Fed Resonant Inverter for Contactless Energy Transfer Systems

This paper presents a bidirectional current-fed parallel resonant push-pull inverter (CFPRPI) for contactless energy conversions. In conventional CFPRPIs, each switch is in series with a blocking diode. Direct zero voltage switching (ZVS) is proposed to remove the series blocking diodes for higher efficiency and boosting ratio. In addition, the modified inverter has bidirectional power flow capability when these blocking diodes are omitted. Resonant tuning of the system is investigated by using a phase-locked loop and a new self-oscillating switching technique (SST). By using the new SST, the inverter has direct ZVS in a wide range of operating frequencies, which is necessary for inductively coupled power transfer systems. Finally, a laboratory prototype with an input voltage of 12 V and a maximum output power of 60 W has been implemented.

Single-Phase Current Source Induction Heater with Improved Efficiency and Package Size

This paper presents a modified Current Source Parallel Resonant Push-pull Inverter (CSPRPI) for single phase induction heating applications. One of the most important problems associated with current source parallel resonant inverters is achieving ZVS in transient intervals. This paper shows that a CSPRPI with the integral cycle control method has dynamic ZVS. According to this method, it is the Phase Locked Loop (PLL) circuit that tracks the switching frequency. The advantages of this technique are a higher efficiency, a smaller package size and a low EMI in comparison with similar topologies. Additionally, the proposed modification results in a low THD of the ac-line current. It has been measured as less than %2. To show the validity of the proposed method, a laboratory prototype is implemented with an operating frequency of 80 kHz and an output power of 400 W. The experimental results confirm the validity of the proposed single phase induction heating system.

A Current-Fed Parallel Resonant Push-Pull Inverter with a New Cascaded Coil Flux Control for Induction Heating Applications

This paper presents a cascaded coil flux control based on a Current Source Parallel Resonant Push-Pull Inverter (CSPRPI) for Induction Heating (IH) applications. The most important problems associated with current source parallel resonant inverters are start-up problems and the variable response of IH systems under load variations. This paper proposes a simple cascaded control method to increase an IH system's robustness to load variations. The proposed IH has been analyzed in both the steady state and the transient state. Based on this method, the resonant frequency is tracked using Phase Locked Loop (PLL) circuits using a Multiplier Phase Detector (MPD) to achieve ZVS under the transient condition. A laboratory prototype was built with an operating frequency of 57-59 kHz and a rated power of 300 W. Simulation and experimental results verify the validity of the proposed power control method and the PLL dynamics.

High-Voltage Closed-Loop Power Supply for Ozone Generators

In this paper the design, implementation and experimental results of a high-voltage power supply for ozone generation are presented. The power stage arrangement is formed by a buck converter plus a current-fed parallel-resonant push-pull inverter. The buck converter is used to both regulate the output power against the line voltage variation, and to control the power delivered to the ozone generator (OG). The push-pull inverter assures safe operation of the OG by working at the parallel resonant frequency given by the high-voltage transformer plus OG characteristic. The closed-loop operation of the proposed converter is analyzed and implemented as a method to compensate variations in the line voltage and in the OG. A low cost commercial UC3872 integrated circuit is used to control both the push-pull inverter and the buck converter, providing OG power control and regulation via buck converter duty cycle. Protections against short circuit and no load operation are also implemented. Experimental results for a 100 W prototype are shown and discussed.

Analysis, Design, and Experimentation of a High-Voltage Power Supply for Ozone Generation Based on Current-Fed Parallel-Resonant Push–Pull Inverter

The use of supply frequencies above 50-60 Hz allows for an increase in the power density applied to the ozonizer electrode surface and an increase in ozone production for a given surface area, while decreasing the necessary peak voltage. Parallel-resonant converters are well suited for supplying the high capacitive load of ozonizers. Therefore, in this paper the current-fed parallel-resonant push-pull inverter is proposed as a good option to implement high-voltage high-frequency power supplies for ozone generators. The proposed converter is analyzed and some important characteristics are obtained. The design and implementation of the complete power supply are also shown. The UC3872 integrated circuit is proposed in order to operate the converter at resonance, allowing us to maintain a good response disregarding the changes in electric parameters of the transformer-ozonizer pair. Experimental results for a 50-W prototype are also provided.