The Research Of Soft Switching Technology Based On Memory Elements

As the working frequency of modern power electronic devices is higher, the switching losses are also increased and electromagnetic interference are also more serious. Soft-switching technology is an effective method to solve problems above. However, soft-switching technology is susceptible by the resonant frequency, the load size and the switching frequency, which lead to some inherent disadvantages of soft-switching technology, such as cannot adapt to the changed load; power device are forced to withstand excessive voltage or current which caused the device could be easily damaged; additional inductor and capacitor also add up to the volume and weight of the devices, which would decrease the power density. It is an urgent need to find a new way to improve all above-mentioned disadvantages of the soft switching technology.Memristor, Memcapacitor and Meminductor are important invention in the field of circuits and systems. Memory elements have some merits such as nanoscale dimensions, low power dissipation and high integration density, which can effectively reduce the size and improve the integration density of the soft-switching converter. The special nonlinear characteristic of the memory elements is expected to further improve the performance of the soft switching technology. Firstly, the paper studies the related nonlinear characteristics of resonant circuit based on memory elements. Then, explore the applications of memory elements in soft switching technology. The main contents of the paper are as follows:(1) Build the mathematical model and circuit simulation models of memristor, meminductor and memcapacitor. Lay a foundation for the application of memory elements.(2) Research the nonlinear characteristics of the resonant circuits composed by memristor, memcapacitor and meminductor and compare with traditional resonant circuits. Established the resistance, inductance, capacitance adjustment circuit to achieve frequency adjustable resonant circuit. Lay the foundation for achieving the resonant frequency adjustable soft-switching converters.(3) Complete the design of Buck ZCS QRC converter which composed by memcapacitor. Analyze the dynamics characteristic of the circuit. Compare with the traditional converter to verify that it can achieve ZCS function and can better adapt to the changing load. The resonant frequency of Buck ZCS QRC based on memcapacitor can be adjusted by the capacitance adjusting circuit, which can reduce the current and voltage stress.(4) Simulate to verify that Buck ZCS PWM converter based on memcapacitor can achieve ZCS function, and has a higher output power, a faster stable speed, less current and voltage stress, and fewer oscillation, which can further reduce the switching noise. The most important is that Buck ZCS PWM converter based on memcapacitor has less high-frequency harmonic, which can reduce the harmonic interference.Using the characteristic of memory elements to explore the application in soft switching techniques, which provides a new way to solve the problems of soft-switching technology. The method proposed in this paper could extend the application area of memory elements.