EJEEE
https://doi.org/10.62909/ejeee.2024.005 Edison Journal for Electrical and Electronics Engineering
Article
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Employing the Cascode Methods, A Transformer-Less High
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Voltage Gain Step-Up DC-DC Converter
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Basim Khalid Mohammed Ali 1, *, , Wisam Hasan Ali 2,3, and Noor Hameed Jalil 4,
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1 Peter the Great St. Petersburg Polytechnic University (SPbPU), Saint Petersburg, Russia;
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basim.KM@spbpu.edu.ru
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2 School of Electrical and Electronic Engineering, Engineering campus, Universiti Sains Malaysia (USM),
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Penang, Malaysia; wisam@student.usm.my
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3 Electronic and Communication Engineering, Çankaya University, Ankara, Turkey
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4 Department of Computer Engineering Information Technology, Çankaya University, Ankara, Turkey; noor-
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@ceit.cankaya.edu.tr
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* Correspondence; Tel.: +7-9312449642
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Abstract: The goal of this research is to use the cascade approach to buck boost converters in order
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to produce high step-up voltage gain with a suitable duty ratio for an electric energy conversion
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system. Electronic equipment that demand electricity must convert AC voltage sources into DC
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power since they cannot be powered directly by the current electrical AC voltage. Significant volt-
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age increases cannot be achieved by traditional boost converters because of the influence of power
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switches, parasitic resistive parts, and the diodes' reverse-recovery issue. The high voltage gains
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step-up (HVGSU) DC-DC converter, which combines two integrated buck-boost converters with a
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single switch, is proposed in this study. With the cascode technique, high voltage gain can be ob-
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tained without an extreme duty ratio; in this case, the switch's duty ratio is regulated by PWM tech-
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nology. There is a thorough discussion of the suggested converter's equipment and modeling.
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Keywords: Amplifier converter; cascode method; dc to dc converter; high voltage gain step-up
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1. Introduction
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Worldwide, alternative power supplies are favored because they provide a clean,
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pollution-free, and environmentally friendly atmosphere [1-3]. Electric cars powered by
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renewable energy sources (RESs) will be crucial for transportation in the future. High
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step-up voltage gain is typically the result of lower voltage achieved from photovoltaic
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cells. To achieve the required voltage levels, DC-DC converters are advised [4]. For in-
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stance, high-intensity discharge lights used in automotive applications require a higher
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working voltage than the battery voltage [5]. Applications for HVGSU DC-DC Converters
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include UPS, conversion of energy from renewable sources, and industry testing [6]. A
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high ac input voltage is additionally necessary in boost PFC circuits to achieve low THD
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and high-power factor [7, 8].
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Generally speaking, reverse recovery issues with the diodes and parasitic compo-
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nents make smooth high voltage gain impossible. Fly back converters can enable HVGSU,
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but the transformer's leakage capacitance restricts the voltage stress on the switches [9-
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11]. Efficiency is increased by the HSUVG in addition to voltage levels. Numerous ap-
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proaches are used in the literature to achieve HV with fewer switches and increase econ-
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omy; these are explained as follows: In order to improve the conversion rate and lessen
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the voltage stress on the switches, a novel DC-DC converter topology is presented [10, 12,
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13]. A single-switch DC to DC converter is suggested, which lowers the loss of switching
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and issues with reverse recovery [14]. It is suggested to use the cascode approach in
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Citation: To be added by editorial
staff during production.
Academic Editor: Dr. Oladimeji Ibra-
him
Received: 27/5/2024
Revised: 2/6/2024
Accepted: 8/6/2024
Published: 14/6/2024
Copyright: © 2024 by the authors.
Submitted for possible open access
publication under the terms and
conditions of the Creative Commons
Attribution (CC BY) license
(https://creativecommons.org/license
s/by/4.0/).
EJEEE 2024, Vol.2 28 of 34
conjunction with a transformer-less DC-DC converter to lessen the voltage and current
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pressures on the switches [10, 15]. It is suggested to use a voltage multiplier with an inter-
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laced conversion for power control uses, like electric cars [1]. To obtain high voltage, a
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DC-DC converter with a connected inductor is suggested [5]. For superior converting en-
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ergy with greater power factor, a soft switching technique is suggested in conjunction
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with a PWM and PFC controller [16]. Transformers, linked inductors, and switching ca-
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pacitors are avoided with a bidirectional H-bridge DC-DC converter with DC link [2].
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When using a bidirectional DC-DC converter that is constructed using SVM technique
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instead of a traditional DC-DC converter with PWM technique, large capacitor stacks can
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be removed. For HVDC applications, a DC-DC converter with MPPT is suggested for con-
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verting a 10–40v PV cell to 300v [17]. To increase the effectiveness of conversion, a low-
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cost single-ended converter with isolation and non-isolation configuration is suggested
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[4].
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This study suggests an HVGSU DC-DC converter that uses PWM technology in-
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stead of a transformer. This setup works quite well with RESs that have links to the net-
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work [18-20].
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2. Materials and Methods
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2.1 High- Voltage Output Amplifier Converter for Cascode
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A transformer-less high step-up DC to DC converter using the cascode method is pro-
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posed in this paper. Figure 1 shows the suggested converter's circuit layout
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Table 2: Voltage Gain of traditional and Cascode Converter
for Diverse Load Rate
Load Cy-
cle
Cascode amp. Con-
verter
0.1
0.19
0.2
0.48
0.3
0.98
0.4
1.69
0.5
2.99
0.6
4.98
0.7
9.09
0.8
23.98
0.9
98.96
Table 1: Imaginary designs of High-Voltage
Increase step up DC-DC Converter
Vi
(V)
Ii
(A)
Pi
(W)
V0
(V)
Io
(A)
Po
(W)
RL(Ω)
η%
24
1.19
30
200
0.2
21
2020
68
23.9
2.48
62
200
0.3
41
1030
66
24
3.48
85
200
0.4
61
670
71
23.9
4.58
112
200
0.5
81
550
72
24
5.76
138
200
0.6
99
460
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Table 1 describes the theoretical results under different load circumstances. Under full
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load, the conversion efficiency is 73.9%. 99.9 watts is the output power and 136.99 watts
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is the source of power under full load circumstances.
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EJEEE 2024, Vol.2 29 of 34
Figure 1. Circuit diagram of the planned cas-
code converter
Figure 2. Inductor transient streams for open loop cascode converter
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Figure 3. Diode currents of a closed loop cascode
converter
Figure 4. Inductor currents of a closed loop cascode converter
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2.2 Strict Cascode Amplifier Converter Design
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The suggested converter's operational structure is shown in Figure 4. There are two
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phases in this block illustration: the power phase and the control phase. The power phase
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comprises a high voltage gain boost converter built on the cascode technology and a DC
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input supply that ranges from 23.9 to 39.9 volts. 200 volts DC, the power phase's results,
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is fed back into the voltage feedback. The image connector, pulse width modulation con-
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troller, and voltage feedback make up the control phase. Here, TL493 IC is utilized as a
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pulse width modulated controller, TLP249 IC is used as a photo coupler, and CA3139 IC
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is used as voltage feedback.
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A high voltage gains improvement converter based on the cascode method receives
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an input voltage of 23.9 volts. Its output, 199 volts, is sent to voltage feedback, and the
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resistor combo is used to lower the 199 volts to 4.99 volts. The CA3139 compensation,
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which serves as a feedback IC, receives this 4.99V. The +4.99V reference is then sent to the
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IC TL493 pulse generator, which produces a pulse with a magnitude of +4.99V, but not
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EJEEE 2024, Vol.2 30 of 34
enough to activate the MOSFET switch. In addition to serving as an isolation device, the
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TLP249 photo coupler is utilized to boost the pulse's magnitude from +4.99 Volts to, say,
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+14.99 Volts. The IRFP459 MOSFET receives a pulse with a magnitude of +14.99 V. The
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cascode converter circuit schematic for hardware execution is shown in Figure 4. The in-
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put capacitance (Ids), which is linked across the MOSFET, is drained in this system by the
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MOSFET operating as a switch. Table 3 provides the cascode converter's characteristics.
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3. Results
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3.1 Discussion
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Equations (1) and (2) provide the final benefits of the standard and cascode convert-
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ers as a result of work rate.
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

(1)
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
 
(2)
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Table 2 makes it evident that if the load ration is greater than 0.41, the voltage win of
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the suggested converter is greater than the voltage increases of the amplifier converter.
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Therefore, by taking into account an efficiency period higher than 0.389, a cascode ar-
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rangement can yield a significant step-up voltage increase. The cascode converter with
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both open and closed loop execution, as well as the traditional boost conversion, are all
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simulated. Table 3 provides the suggested converter's characteristics.
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Table 3. Specifications of the Cascode
converter
Restriction
Value
Vin
24 V
Vo
199V
Po
99 W
fos
49 kHz
Co1
679µF
Co2
679µF
L1
52.5µH
L2
64 µH
Kp
0.0002
Ki
0.099
Table 4. Evaluation of inductor passing currents
Open Loop Current
Closed Loop Current
Peak Amplitude: 161 Amps
23 Amps
Transient Period: 0.3 S
0.099 sec
Settling Period: 0.2 S
0.059 sec
The waveform shapes of a typical amplifier converter are shown in Figures 2. It
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shows the gate's signal of an amplifier converter and shows the input the voltage, results
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voltage, current, and current of an amplifier converter. Figure 3 display the diode cur-
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rents, inductor currents, input voltage, current, output voltage, current, and inductor tran-
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sient currents of an open- and closed loop cascode converter.
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The task is to take a specific input energy of 23.9V and turn it into a final voltage of
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200V. The voltage that came out of the closed-loop cascode converter quickly surpassed
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that of each of the dual converters, reaching 49.9V. (See Figures 2 and 3) This is acquired
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from the DC supply and the rear semi stage input. On the other hand, the output voltages
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of the two semi-stages added together via cascade form the ultimate output voltage of the
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suggested converter. Figures 2 and 3 show an analysis of the inductor electrical currents
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for cascode converters with open and closed loops. While the inductor currents in an open
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loop cascode converter settle more slowly, the highest intensity of 159.81 A is significantly
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higher than that of a closed cascode converter, which is approximately 22.8 A. Table 4
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provides a comparison of standard, open loop, and closed cascode converters.
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EJEEE 2024, Vol.2 31 of 34
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3.2 Trial Findings
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The control phase and power phase comprise both sections of the work's hardware
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execution. These are described in brief in the parts that proceed.
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3.2.1 Control Phase
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The TL493 (PWM Generator), TLP249 (Isolator), CA3139 (Compensator), and 7813 &
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7814 Governors were the parts utilized in the control phase. As illustrated in Figure 5, the
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cutting teeth waveform and reference voltages are compared to produce the gate pulses
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for a MOSFET using the pulse width modulation (PWM) approach. The 4.9-volt gate pulse
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produced by the TL493 PWM Inverter in this instance (Figure 6) is insufficient to turn on
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an IRFP459 MOSFET. Therefore, the 4.9-volt gate pulsing is multiplied to the 14.9-volt
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pulse seen in Figure 6 using a TLP249 optical isolator. It functions as an absorber as well.
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When the TL493 is coupled to the electrical circuit, it generates impulses in the system
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with a frequency for switching of 49.9 KHz and load rates of 0.959, 0.679, 0.249, and 0.899,
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accordingly, as shown in Figure 6.
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Figure 5. PWM Comparison (Vref & Vcarrier)
Figure 6. Gate Pulse from TL493 with Load rate
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3.2.2 Phase of Energy
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The IRFP459 MOSFET, two inductors, two capacitors, and four diodes are the parts
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of the electrical power phase that are seen in Figure 7. The resulting voltage, which is a
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constant DC value of 199 volts, is displayed in Figure 8. The current that is output for
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RL=679.9 Ohms, or continuous DC current, is shown in Figure 8, and the input current
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and gate pulses are delivered to MOSFET IRFP459 in Figure 9. Inductor Current (IL1) and
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Inductor Current (IL2) are shown in Figures 9, respectively. Inductor L1 current (IL1) is
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also found to be greater than inductor L2 current (IL2).
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A contrast of the simulated and experimental data is presented in Table 5. Table 6
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shows that in both modeling and experiments, the resultant voltage produced is 199 volts
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for an identical starting voltage of 23.9 volts. In the modeling and experimentation, the
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resultant effectiveness is 69.96% and 69.12%, correspondingly. There is substantial agree-
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ment regarding the outcomes of the model and the results of the experiment. Tables 6 and
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7 provide the design specifications and the electric layout for the suggested converter,
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accordingly.
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EJEEE 2024, Vol.2 32 of 34
Figure 7. Mechanisms employed in energy phase of a planned con-
verter in hardware execution
Figure 8. Production voltage from the casode converter
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154
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Table 6. Proposal Obligation
V in
24 – 39.9 v
V Out
199 V
I Out
0.49 A
Fsw
49.1 kHz
Pout
99.8 W
Table 7. Proposal Scheming
L1
52 µH / 9 A
L2
635 µH / 4A
C1 and C2
679 µF / 449 v
D1 – D4
14.9 A
S1
29 A, 449 v
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157
Restrictions
Closed Loop Cascode amp.
Converter
Since
Imitation
Since
Trial
Vi (V)
23.9
23.9
RL(Ω)
679
679
II (A)
3.39
3.49
D
0.669
0.679
PI (W)
82.39
83
VO (V)
199
199
IO(A)
0.291
0.29
PO (W)
58.19
57
ŋ (%)
70.59
69.39
Table 5. Contrast of Replication and Hard-
ware outcomes
Figure 9. Input production & Gate Pulse specified to the MOSFET
EJEEE 2024, Vol.2 33 of 34
5. Conclusions
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This study presents the hardware components and simulations of a high step-up DC-
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DC converter. The findings of the simulated circuit and the real-world circuit are observed
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to be quite similar. The architecture makes use of the cascode approach to get a suitable
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duty ratio along with a high voltage gain. A prototype in the lab is shown to confirm the
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results. The outcomes of the simulation and experiment are obtained and analyzed. Con-
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sidering the switching loss of the cascoded buck-boost converter with different expenses,
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the switching lost will worsen at high switching frequencies. Reducing switching losses is
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necessary in order to increase effectiveness and frequently switching. The Zero-Voltage-
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Switching method is a useful way to tackle this issue. In this approach, the electrical power
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converter's frequency of switching can be significantly increased without lowering the
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converter's effectiveness.
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Acknowledgments: “This project would not have been possible without the generous financial sup-
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port of the Peter the Great St. Petersburg Polytechnic University (SPbPU), Saint Petersburg, Russia.
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Lastly, I would like to acknowledge the study participants who generously shared their time and
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insights”.
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Conflicts of Interest: Declare conflicts of interest or state “The authors declare no conflict of inter-
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est.”
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EJEEE 2024, Vol.2 34 of 34
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