School Papers

Suppose your boss asks you to take a

Suppose that you work in ABB (multinational corporation in Switzerland, but that’s immaterial now) and your boss asks you to take a look at solar energy system installed in Switzerland. A simplified schematic diagram is shown below. Fortunately, because everything is connected in a modular way, you can look at each part of the circuit separately and ignore the interaction among them. To further simplify analysis, assume there are no losses unless stated otherwise.DC-DC Converter:First, let’s focus on the dc-dc converter, which is connected between the solar panel and a 60 V battery. As the output voltage of the solar panel can change depending on factors such as lighting condition and temperature, we need the dc-dc converter to maintain the terminal voltage at the battery at 60 V. Upon checking their circuit, you realize that they are using a type of dc-dc converter that you’ve never seen before. The schematic diagram of this converter, which is nicknamed Buck2, is shown below.a. 4 Analyze this circuit and calculate the transfer relation (voltage conversion ratio). Both switches are in position 1 for 0 < t < DTs and in position 2 for the reset of switching period.b. 1 How much average current is delivered from the dc-dc converter into the battery when it is operating at its peak power of 180W?c. 3 You persuade the owner to abandon the Buck2 and use a boost instead (mainly because you are more comfortable with a boost, but you have technical reasons too). The schematic diagram of your new boost converter is shown below. Assume you also change the solar panels to a less expensive model that generates, depending on conditions, a voltage between 30 V to 50 V. If you were the designer, what inductance L would you use to ensure the ripple in input current (i.e., inductor current) was less than 100 mA in the worst voltage conditions? The boost is operating at 100 kHz. (First determine what worst condition means.)d. 1 In an attempt to save costs, the owner asks you to remove the diode in the boost converter. What goes wrong in the circuit if you comply?EE 4303 - Power Electronics Page 3 of 7e. 1 You open the case of the dc-dc converter to look inside. You see it is equipped with lots of heat sinks, while the circuit diagram does not show any resistors. Then what is causing heat in the converter?f. 3 Even the boost converter might not be the best type of converter to use in this application. For example, the owner may want to invest more in the future and buy another solar panel and connect it in series with the previous one. Now the voltage that you get is twice the original voltage; that is, between 60V to 100 V. What type of converter do you need to accommodate both current and future scenarios? Draw a schematic diagram of this converter.