IGBT Stack Research Articles

A 3D Thermal Network Model for Monitoring Imbalanced Thermal Distribution of Press-Pack IGBT Modules in MMC-HVDC Applications

In this paper, the impact of a double-sided press-pack insulated-gate-bipolar-transistor (PP IGBT) cooling structure on its thermal impedance distribution is studied and explored. A matrix thermal impedance network model is built by considering the multi-chip thermal coupling effect for the collector side of the PP IGBT. Moreover, a verification has been made by comparing the proposed matrix thermal network model and the conventional lumped RC network model provided by the manufacturer. It is concluded that the collector side has lower thermal resistance and dissipates about 88% of the heat generated by the IGBT chips inside the module. Then, a modular-multilevel-converter high-voltage-direct-current (MMC-HVDC)-based type test setup composed of the press-pack IGBT stacks is established and the junction temperature is calculated with the proposed thermal model and verified by temperature measurements.

Electric Field Analysis of Press-Pack IGBTs

High voltage IGBT module is the ideal option for the VSC-HVDC power transmission application. At present, wire-bonded technology and press-pack technology are available packaging technologies for high voltage IGBT. The press-pack IGBTs have such advantages as low inductance, low thermal impedance and short circuit failure mode than the wire-bonded IGBT module, which especially suit for high voltage power transmission application by series connection. However, the electrical insulation failure modes of press-pack IGBTs are much less known with limited literature published. In this paper, we presented the electric field analysis of a 3D press-pack IGBT model under DC rating voltage test condition. The electric field distribution of the press-pack IGBT stack was solved as an electrostatic problem by employing the finite element method. The results revealed the potential electrical insulation failure modes of the press-pack IGBTs: corona discharge at the edge of silver plate, partial discharge at the micro gap between die and PEEK frame and creeping discharge at the surface of PEEK frame.

Cryogenic power electronics at megawatt-scale using a new type of press-pack IGBT

Electrical characteristics of a press-pack IGBT stack have been investigated experimentally in both static and dynamic tests at room temperature and at 77 K in an effort to identify a megawatt-scale class semiconductor that performs well electrically, thermally, and mechanically. It has been observed that the forward voltage drop and the turn-off time are both noticeably reduced at cryogenic temperatures, suggesting significant improvement in the device operating area. Furthermore, the stack was subjected to repeated thermal cycles between room temperature and 77 K without observing any degradation. A circuit simulation of a 200-kW boost converter based on the characterized press-back IGBT stack exhibited a reduction in switching and conduction losses at 77 K by 60% and 24%, respectively compared to the values at room temperature. It is expected that the type of press-pack IGBT stacks tested will be key elements to build high power dense, megawatt-scale cryogenic converters for future all-electric ships and electric airplanes.

Auxiliary subsystems of a General-Purpose IGBT Stack for high-performance laboratory power converters

A PWM converter is the prime component in many power electronic applications such as static UPS, electric motor drives, power quality conditioners and renewable-energy-based power generation systems. While there are a number of computer simulation tools available today for studying power electronic systems, the value added by the experience of building a power converter and controlling it to function as desired is unparalleled. A student, in the process, not only understands power electronic concepts better, but also gains insights into other essential engineering aspects of auxiliary subsystems such as start-up, sensing, protection, circuit layout design, mechanical arrangement and system integration. Higher levels of protection features are critical for the converters used in a laboratory environment, as advanced protection schemes could prevent unanticipated failures occurring during the course of research. This paper presents a laboratory-built General-Purpose IGBT Stack (GPIS), which facilitates students to practically realize different power converter topologies. Essential subsystems for a complete power converter system is presented covering details of semiconductor device driving, sensing circuit, protection mechanism, system start-up, relaying and critical PCB layout design, followed by a brief comparison to commercially available IGBT stacks. The results show the high performance that can be obtained by the GPIS converter.

Compact and high repetitive pulsed power modulator based on semiconductor switches

This paper describes the design of a compact and highly repetitive pulsed power modulator based on semiconductor switches. Output specifications of the proposed modulator are as follows: variable output pulse voltage, 1-10 kV; width, 1-10 μs; pulse repetition rate (PRR), 1-50,000 pps; and average output power, 10 kW. The proposed solid-state pulsed power modulator has two main parts: an IGBT stack that hasa gate drive circuit for the pulse output with a variable pulse width and repetition rate, and a capacitor charger that has a controllable output voltage. To connect all the storage capacitors in a series for high voltage pulses, a simple and reliable IGBT stack structure was proposed based on the Marx generator. In addition, the gate driver circuit, which supplies power and signals to all the IGBTs simultaneously, was introduced. This providesa superior protection function against the arc and the short. To charge the storage capacitors, a novel 10 kW (10 kV, 1 A) high voltage capacitor charger with the combined advantage of a series-loaded resonant converter and a ZVS (zero-voltage-switching) full-bridge pulse width modulation (PWM) converter was proposed and designed especially for the solid-state pulsed power modulator. Theexperiment results verified that the proposed scheme and structure can be used effectively for a high voltage pulsed power modulator that requires variable voltage, repetition rate, and pulse width, depending on the process of the applications.

Development of 60 kV, 300 A, 3 kHz Pulsed Power Modulator for Wide Applications

In this paper, a novel pulsed power generator based on IGBT stacks is proposed for wide pulsed power applications. Because it can generate high voltage pulsed output without any step-up transformer or pulse forming network, it has advantages of fast rising time, easiness of pulse width variation, high repetition rate and rectangular pulse shapes. Proposed scheme consists of multiple power stages which were charged parallel from series resonant power inverter. Depending on the number of power stages it can increase maximum voltage up to 60 kV or higher with no limits of power stages. To reduce component for gate power supply, a simple and robust gate drive circuit which delivers gate power and gate signal simultaneously by way of one high voltage cable is proposed. For gating signal and power a full bridge inverter and pulse transformer generates on-ofi signals of IGBT gating with gate power simultaneously and it has very good characteristics of protection of IGBT switches over arcing condition. It can be used for various kinds of pulse power application such as plasma source ion implantation, sterilization, water and gas treatment which requires few kHz pulse repetition rate with few to ten of microseconds pulse width.