scholarly journals A Comparative Performance Analysis of Zero Voltage Switching Class E and Selected Enhanced Class E Inverters

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2226
Author(s):  
Ratil H. Ashique ◽  
Md Hasan Maruf ◽  
Kazi Md Shahnawaz Habib Sourov ◽  
Md Mahadul Islam ◽  
Aminul Islam ◽  
...  
Keyword(s):  
Power Output ◽  
Performance Standard ◽  
Optimum Operating ◽  
Duty Ratio ◽  
Switching Frequency ◽  
Optimum Operating Condition ◽  
In Series ◽  
Load Network ◽  
Switch Voltage ◽  
Class E

This paper presents a comparative analysis of the class E and selected enhanced class E inverters, namely, the second and third harmonic group of class EFn, E/Fn and the class E Flat Top inverter. The inverters are designed under identical specifications and evaluated against the variation of switching frequency (f), duty ratio (D), capacitance ratio (k), and the load resistance (RL). To offer a comparative understanding, the performance parameters, namely, the power output capability, efficiency, peak switch voltage and current, peak resonant capacitor voltages, and the peak current in the lumped network, are determined quantitatively. It is found that the class EF2 and E/F3 inverters, in general, have higher efficiency and comparable power output capability with respect to the class E inverter. More specifically, the class EF2 (parallel LC and in series to the load network) and E/F3 (parallel LC and in series to the load network) maintain 90% efficiency compared to 80% for class E inverter at the optimum operating condition. Furthermore, the peak switch voltage and current in these inverters are on average 20–30% lower than the class E and other versions for k > 1. The analysis also shows that the class EF2 and E/F3 inverters should be operated in the stretch of 1 < k < 5 and D = 0.3–0.6 at the optimum load to sustain the high-performance standard.

scholarly journals Single-Switch LED Post-Regulator Based on a Modified Class-E Resonant Converter with Voltage Clamp

Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 798 ◽  
Author(s):  
Ribas ◽  
Quintana ◽  
Cardesin ◽  
Calleja ◽  
Lopez-Corominas
Keyword(s):  
Low Frequency ◽  
Resonant Converter ◽  
Second Stage ◽  
Resonant Inverter ◽  
Switching Losses ◽  
Measured Efficiency ◽  
In Series ◽  
Converter Topology ◽  
Switch Voltage ◽  
Class E

The strict restrictions imposed both by mandatory regulations and by the recommendations contained in current standards have led to the fact that most commercially available LED ballasts nowadays use two-stage topologies. The first stage is intended to comply with the harmonics standards and the second stage is used to control the LED current and reduce the low frequency ripple. In this work, a new DC–DC resonant converter topology is presented. This topology is derived from a modified Class-E resonant inverter by adding a clamping diode. This diode achieves a double goal: it limits the maximum switch voltage and works as a power recirculating path. This way, the proposed topology behaves as a loss-less impedance placed in series with the LED thus allowing to control the output power. This converter maintains the extremely small switching losses inherent to the Class-E inverter while reducing the voltage stress across the switch. This work presents a simplified design methodology based on the fundamental approach. This methodology was used to design and build a DC–DC post-regulator for a 40 W LED lamp. The results obtained with the laboratory prototype show that this circuit can be used to stabilize and dim the LED current while maintaining very small losses. The measured efficiency was 95.7% at nominal power and above 90% when dimmed down to 25%.

scholarly journals Derivation of Closed-Form Design Equations for Idealized Operation of Inverse Class-E Power Amplifiers at Any Duty Ratio

2015 ◽  
Vol 61 (3) ◽  
pp. 281-287
Author(s):  
Yelin Wang ◽  
Suan-Kien Foo ◽  
Qibing He
Keyword(s):  
Theoretical Analysis ◽  
Closed Form ◽  
Power Amplifiers ◽  
Design Parameters ◽  
Duty Ratio ◽  
Rf Design ◽  
Form Design ◽  
Circuit Components ◽  
Switch Voltage ◽  
Class E

Abstract Complementary to the conventional class-E topology, inverse class-E operation has several advantages over the class-E counterpart, such as lower peak switch voltage and smaller circuit inductance, which are attractive to high power RF design and MMIC implementation. This paper derives the closed-form design equations that can be used to synthesize the idealized operation of inverse class-E power amplifiers at any switch duty ratio. Calculation of the key design parameters, such as the maximum switch voltage and circuit components values, is elaborated and compared with the case of conventional class-E operation. Further, the theoretical analysis is confirmed and verified by numerical simulations performed on a 500 mW, 2.4 GHz idealized inverse class-E power amplifier.

Into Mesh Lubrication of Spur Gears With Arbitrary Offset Oil Jet. Part 1: For Jet Velocity Less Than or Equal to Gear Velocity

1983 ◽  
Vol 105 (4) ◽  
pp. 713-718 ◽  
Author(s):  
L. S. Akin ◽  
D. P. Townsend
Keyword(s):  
Inclination Angle ◽  
Gear Tooth ◽  
Optimum Operating ◽  
Spur Gears ◽  
Optimum Operating Condition ◽  
Operating Condition ◽  
The Common ◽  
Jet Velocity ◽  
Oil Jet

An analysis was conducted for into mesh oil jet lubrication with an arbitrary offset and inclination angle from the pitch point for the case where the oil jet velocity is equal to or less than pitch line velocity. The analysis includes the case for the oil jet offset from the pitch point in the direction of the pinion and where the oil jet is inclined to intersect the common pitch point. Equations were developed for the minimum oil jet velocity required to impinge on the pinion or gear and the optimum oil jet velocity to obtain the maximum impingement depth. The optimum operating condition for best lubrication and cooling is provided when the oil jet velocity is equal to the gear pitch line velocity with both sides of the gear tooth cooled. When the jet velocity is reduced from pitch line velocity the drive side of the pinion and the unloaded side of the gear is cooled. When the jet velocity is much lower than the pitch line velocity the impingement depth is very small and may completely miss the pinion.

Thermoeconomic Approach and Optimization of a Solar Thermal Power Plant

2012 ◽  
Vol 232 ◽  
pp. 609-613
Author(s):  
Ali Baghernejad ◽  
Mahmood Yaghoubi
Keyword(s):  
Power Plant ◽  
Thermal Power Plant ◽  
Thermal Power ◽  
Production Costs ◽  
Solar Thermal ◽  
Optimum Operating ◽  
Production Plant ◽  
Optimum Operating Condition ◽  
Solar Thermal Power

In the present study, a specific and simple second law based exergoeconomic model with instant access to the production costs is introduced. The model is generalized for a case study of Shiraz solar thermal power plant with parabolic collectors for nominal power supply of 500 kW. Its applications include the evaluation of utility costs such as products or supplies of production plant, the energy costs between process operations of an energy converter such as production of an industry. Also attempt is made to minimize objective function including investment cost of the equipments and cost of exergy destruction for finding optimum operating condition for such plant.

Optimization of Fermentable Sugar Production from Pineapple Leaf Waste (Ananas comosus [L.] Merr) by Enzymatic Hydrolysis

2021 ◽  
Vol 18 (1) ◽  
pp. 73-80
Author(s):  
Yohanita Restu Widihastuty ◽  
Sutini Sutini ◽  
Aida Nur Ramadhani
Keyword(s):  
Enzymatic Hydrolysis ◽  
Complex Structure ◽  
Reducing Sugar ◽  
Sugar Yield ◽  
Ananas Comosus ◽  
Optimum Operating ◽  
Cellulose Content ◽  
Optimum Operating Condition ◽  
Operating Condition ◽  
Cellulase Enzyme

Pineapple leaf waste is one agricultural waste that has high cellulose content. Pineapple leaf waste's complex structure contains a bundle of packed fiber that makes it hard to remove lignin and hemicellulose structure, so challenging to produce reducing sugar. Dried pineapple leaf waste pretreated with a grinder to break its complex structure. Delignification process using 2% w/v NaOH solution at 87oC for 60 minutes has been carried out to remove lignin and hemicellulose structure so reducing sugar could be produced. Delignified pineapple leaf waste has been enzymatic hydrolyzed using cellulase enzyme (6 mL, 7 mL, and 8 mL) to produce reducing sugar. The sample was incubated in an incubator shaker at 155 rpm at 45, 55, and 60oC for 72 hours. Determination of reducing sugar yield had been carried out using the Dubois method and HPLC. The model indicated that the optimum operating condition of enzymatic hydrolysis is 7 mL of cellulase enzyme at 55oC to produce 96,673 mg/L reducing sugar. This result indicated that the enzymatic hydrolysis operating condition improved the reducing sugar yield from pineapple leaf waste. The optimum reducing sugar yield can produce biofuel by the saccharification process.

Magnetostrictive Methods of Detecting Torque from Case-Hardened Steel Shafts

1994 ◽  
Vol 360 ◽  
Author(s):  
Ichiro Sasada
Keyword(s):  
Excitation Frequency ◽  
Total Power ◽  
Optimum Operating ◽  
Torque Sensor ◽  
Excitation Current ◽  
Optimum Operating Condition ◽  
Operating Condition ◽  
Nickel Chromium ◽  
Low Profile ◽  
Molybdenum Steel

AbstractThis paper begins with a review of the current problems associated with the application of conventional magnetic-head-type shaft torque sensors. These sensors were first proposedin 1954. Newly developed low-profile magnetic heads for torque sensors which address the problems of the older type of sensors are then presented. The torque sensor which uses the lowprofile pick-up heads is described in detail. Experimental results showing the basicperformance of the torque sensor with carburized nickel chromium molybdenum steel shafts (SNCM 420 in JIS) are then described. In this combination of the heads and the shaft, thehysteresis of the inputoutput relationship is generally small and shows that the direction of traversal around the hysteresis loop changes as the amplitude of the excitation current changes. It is shown that an optimum operating condition exists for the torque sensorin which the hysteresis achieves a minimum value yet the sensitivity remains high. In a particular combination studied in this paper, the optimum excitation current was 0.3 A at the excitation frequency 60 kHz, where the total power loss at the pick-up heads was 0.37W. Under this operating condition, the hysteresis was extremely small, and the linearity was better than 0.6%.

scholarly journals High-Flexibility MPPT Techniques with Communication Scan Network for PV Micro-Grid System

Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 117
Author(s):  
Yu-Kai Chen ◽  
Hong-Wen Hsu ◽  
Chau-Chung Song ◽  
Yu-Syun Chen
Keyword(s):  
Output Voltage ◽  
High Efficiency ◽  
Maximum Power ◽  
Global Maximum ◽  
Switching Frequency ◽  
Grid System ◽  
Pv System ◽  
In Series ◽  
Micro Grid ◽  
High Flexibility

This paper proposes the design and implementation of inductor-inductor-capacitor (LLC) converters with modules connected in series with the power scan method and communication scan network (CSN) to achieve MPPT and regulate the output voltage for the PV micro-grid system. The Dc/Dc converters includes six isolated LLC modules in series to supply ±380 V output voltage and track the maximum power point of the PV system. The series LLC converters are adopted to achieve high efficiency and high flexibility for the PV micro-grid system. The proposed global maximum power scan technique is implemented to achieve global maximum power tracking by adjusting the switching frequency of the LLC converter. To improve the system flexibility and achieve system redundancy, module failure can be detected in real time with a communication scan network, and then the output voltage of other modules will be changed by adjusting the switching frequency to maintain the same voltage as before the failure. Additionally, the proposed communication scan network includes the RS-485 interface of the MPPT series module and the CAN BUS communication interface with other subsystems’ communication for the PV micro-grid application system. Finally, a 6 kW MPPT prototype with a communication scan network is implemented and the proposed control method is verified for the PV system.

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