Reliability allocation methods: A systematic literature review

A reliability allocation method of mechanism considering system performance reliability

The invention relates to a high power wideband ultrasonic power supply based on silicon carbide device and a control method thereof. The power supply comprises a PWM rectifying circuit, a DC chopping power adjusting circuit, a full bridge inversion circuit, a main transformer, a matching network, a matching network driving circuit, a digital control circuit, a phase locking circuit, a voltage sampling circuit, a current sampling circuit, a power adjusting control circuit, a protection circuit, a driving circuit, a DDS (direct digital frequency circuit), a piezoelectric transducer and the like. Power switch devices used by the PWM rectifying circuit, the DC chopping power adjusting circuit and the full bridge inversion circuit are all large energy gap silicon carbide devices. The switch frequency, the transformation frequency, the power density and the reliability of the power supply are remarkably improved, the output power is 1kw-10kw, the frequency search range is 18-100 kHz, and the power supply adopts a variable step frequency tracking digital method based on resonant frequency automatic identification.

High power wideband ultrasonic power supply based on silicon carbide device and control method thereof

The invention discloses a frequency tracking device of a wireless energy transmitting system, wherein the frequency tracking device is based on single-chip microcomputer control. The frequency tracking device of the wireless energy transmitting system comprises a full-bridge inverter circuit drive circuit, a DDS chip, a single-chip microcomputer, a phase difference detecting circuit, a primary winding loop, a voltage sampling circuit, a current sampling circuit and an amplifying and shaping circuit. The invention further discloses a frequency tracking method of the frequency tracking device applied to the wireless energy transmitting system. The frequency tracking method comprises the following steps that firstly, the single-chip microcomputer reflects a frequency tracking result with frequency data and transmits the frequency data into the DDS chip; secondly, the controlled quantity output by a phase detecting circuit is kept constant only in the detuned state or in the resonance state; thirdly, the frequency control word of the DDS chip is updated in time by the single-chip microcomputer so that a new working frequency can be generated to drive an inverter circuit, and meanwhile the phase detecting circuit conducts circle detection and judgment until the resonance of system recovers. The frequency tracking device of the wireless energy transmitting system and the frequency tracking method of the frequency tracking device have the advantages that the structure is simple, and the problem of frequency detuning of the wireless energy transmitting system is effectively solved.

Frequency tracking device of wireless energy transmitting system and frequency tracking method thereof

The invention relates to an ultrasonic power source for transducer cascading. The ultrasonic power source comprises a rectifier bridge, a filter circuit, a direct-current chopper circuit, a full-bridge inverter circuit, a first impedance stepless matching network, a second impedance stepless matching network, a first transducer, a second transducer, a matching network control circuit, a voltage current sampling circuit, a frequency tracking circuit, and a constant power circuit. The matching network control circuit controls magnitude of matching inductors of the first and second impedance stepless matching networks, accessing an inverter output circuit. Output voltage and current of the full-bridge inverter circuit are connected to the frequency tracking circuit and the constant power circuit through the sampling circuit; the frequency tracking circuit controls full-bridge inversion frequency; the constant power circuit controls magnitude of the output voltage of the direct-current chopper circuit. The ultrasonic power source has the advantages that coaction of the first and second matching network control circuits ensures normal operation of transducer cascading and the traditional single-inverter single-transducer operating mode is changed.

Ultrasonic power source for transducer cascading

The resonance characteristics of ultrasonic transducer are analyzed based on the equivalent circuit of transducer and the quantitative calculation of admittance circle, and a control method of frequency tracking based on variable step length is proposed, and the limits of step switching are deduced, and the control parameters of the control method based on variable step length is designed in this paper. The results of simulation and experiment show that the system based on the control method can control output frequency in high precision. And while ultrasonic power supply ensure steady-state error minimum, holding a good dynamic performance, which meets the requirements of the technology of ultrasonic power supply.

http://ieeexplore.ieee.org/iel7/7027308/7037809/07037889.pdf

The research on phase lock method of ultrasonic power supply with variable step length control

Due to the topology particularity of power converter, AGREE reliability allocation method, which is widely used in engineering, is not completely suitable for power converter. Based on the principles of AGREE reliability allocation and allowing for the characteristics of power converter, a modified AGREE reliability allocation method is proposed. In this method, the component complexity is measured by technical maturity, and the component importance is measured by the role of component plays in circuit circulation and the importance of adjacent components, system reliability index can finally be allocated to the components. The method is verified to be effective.

A modified AGREE reliability allocation method research in power converter

Component importance is the key parameter of reliability analysis in power converter. Because of the particularity of topology, the traditional importance evaluation methods are not completely suitable for power converter. Based on complex network theories, the topology of power converter can be transformed to a complex network, and a method to evaluate component importance is proposed by using importance evaluation matrix, in which we synthesize node closeness, node degree and importance contributions of adjacent node. And the time complexity of this method is lower than O(n3). Finally, the experience of Buck converter verified this method is effective and feasible, and results are in conformity with actual fact.

The component importance evaluation of power converter based on complex network

The utility model relates to an ultrasonic power supply for transducer cascade. The ultrasonic power supply comprises a rectifier bridge, a filter circuit, a DC chopper circuit, a full bridge inverter circuit, a first impedance stepless matching network, a second impedance stepless matching network, a first transducer, a second transducer, a matching network control circuit, a voltage and current sampling circuit, a frequency tracking circuit, and a power constant circuit. The matching network control circuit controls the size of the matching inductance of the first impedance stepless matching network and the second impedance stepless matching network connected to an inverter output circuit. According to the ultrasonic power supply, through the common action of the frequency tracking circuit and the first and second impedance stepless matching networks, the normal working of the transducer cascade can be ensured, and the operation mode of the previous single inverter single transducer is changed.

Guiping Du

Papers

The research on phase lock method of ultrasonic power supply with variable step length control

Ultrasonic power source for transducer cascading

A modified AGREE reliability allocation method research in power converter

The component importance evaluation of power converter based on complex network

Ultrasonic power supply for transducer cascade