# A High Gain Modified Quadratic Boost DC-DC Converter with Voltage Stress Half of Output Voltage
## 1 Introduction  
The global warming problem is becoming more severe nowadays, due to which, research across all disciplines to reduce greenhouse gases is ongoing. Generally, the burning of fossil fuels is the largest source of greenhouse gas production [1]. To make our environment cleaner, renewable energy is the most effective solution currently available. Although nuclear energy has the potential to provide sustainable green energy, its post-process (i.e., containing the nuclear waste) is very dangerous to our environment, and its harmful effect will continue for many years because of the exponential decay process [2]. Renewable energy, mainly solar power-based energy, is the only viable source for enormous amounts of energy, which very soon could fully substitute fossil fuel-based energy systems [3]. However, due to certain limitations, each solar photovoltaic cell generates a very low output voltage in terms of DC bias, whereas many appliances which utilize electricity have until now required a much higher voltage level, both in terms of AC and DC. In order to boost the output voltage and power level, a series and parallel connection of solar cells were performed, but that is still not sufficient enough [4]. On the other hand, the output voltage of the solar module can provide a maximum of 48 V, so to provide the required voltage level for the electronics, a converter is required that offers the necessary solution by working in the form of energy conversion, i.e., a boost converter. Additionally, appliances that requirea voltage level in the range of the available bias that a solar module can provide are still in need of a buck-boost converter [5; 6; 7] to maintain the voltage regulation. Moreover, as transportation systems are shifting from fossil fuel-based power to electric vehicles [8], in order to drive the vehicles the power converter needs to be capable enough to provide a sufficient voltage level for the inverter to drive the main drive system, i.e., high rated induction motor including the other application parts of the electric vehicle [9]. In addition, the application of high voltage gain DC-DC converters for industrial application has been seen for a long time [10], and in the future, they need to become more compact and sophisticated to maintain the sustainability for an application in industry 4.0 [11; 12; 13; 14]. As a result, the research on boost DC-DC converters is drawing more and more attention as their potential application is increasing substantially. In Figure 1 the general application of DC-DC converter is presented. In general, theoretically, the well-known traditional simple boost converter can achieve a high gain (i.e., 10 times) at a duty ratio near 90-95%, but practically, it is impossible to achieve due to the presence of parasitic resistance in passive components, as it limits the charging current in the inductor loop [15]. Additionally, operating at a very high duty cycle may create a reverse recovery problem for the power diode, so it reduces the system performance by increasing the conduction loss of the converter, which further limits the system efficiency [10]. To overcome all these challenges, the operation of the boost converter is preferable at a lower duty ratio [16]. The reported quadratic boost topology has the potential to boost the voltage level by following the quadratic equation, which, interestingly, can provide much higher voltage gain at a lower duty ratio [17]. In addition, several other techniques have been extensively employed to boost the voltage gain, and the Voltage Multiplier Cell (VMC)-based configuration is one of them [18]. A switched capacitor-based DC-DC converter has already been reported by various research groups [19; 20]. Though it has a very simple structure and is an effective technique that provides a high voltage gain by reserving a very low space for the converter, a high inrush current is one of the major problems for this switched capacitor VMC-based boost converter.