Switching power converter power electronics integration technology

The manufacturing characteristics of power electronic power equipment are: many non-standard parts, long design cycle, high cost, low reliability, and heavy workload, while users require the power electronic products produced by manufacturers to be practical, highly reliable, small in size and weight, and low in cost. This puts great pressure on manufacturers, and there is an urgent need to carry out research and development of integrated power electronic modules to achieve the goals of standardization, modularization, manufacturability, large-scale production, and cost reduction of power electronic products.

In fact, in the development process of power electronic integration technology, it has gone through the development stages of modularization of power semiconductor devices, integration of power and control circuits, and integration of passive components (including magnetic integration technology).

1) Power electronic device module

Power electronic circuits are often composed of multiple power electronic devices. For example, a bidirectional switch requires at least two three-terminal devices and two diodes. Considering that series/parallel, single-phase, three-phase half-bridge or full-bridge switch circuits require several or even dozens of switch devices and some auxiliary devices (such as fast diodes). The power electronic converter has many interconnection wires and large parasitic inductance between the power electronic devices. In order to make it compact, small, and easy to process, and to shorten the interconnection wires between the switch devices and reduce the inductance, the power electronic devices must be modularized and integrated. Combining several power switch devices and fast diodes into a standard power electronic device module (Power Module) is the most primitive and simple integration and modularization in the development process of integrated power electronic technology. The emergence of reverse blocking (RB) IGBT has eliminated two diodes from the bidirectional IGBT switch, which is conducive to the formation of a matrix converter module.

However, the power electronic device module is only an integration of several power electronic devices and has not yet been integrated with drive, control, protection, detection, communication and other functions, and needs further development.

2) Intelligent Power Module

In the 1980s, the intelligent power electronic module (IPM) was developed to integrate power electronic devices with drive, intelligent control, protection, logic circuits, etc. IPM is also called smart power electronic integrated circuit (Smart Power IC).

The development direction in recent years is to integrate low-power systems on a chip (Systemn Chip), which can make power electronic products more compact and smaller, and also reduce the length of the lead, thereby reducing parasitic parameters. On this basis, integration (A11 in ONe) can be achieved, integrating all components together with control protection in one module. It is reported that researchers in the United States have integrated the motion control system of a low-power asynchronous motor (including inverter, microprocessor, control protection circuit) into the motor, forming an integration of the transmission control system and the motor.

3) Integrated power electronics system

In the 1990s, with the development of large-scale distributed power systems, the design concept of IPM was extended to integrated power electronic circuits with larger capacity and higher voltage, and the integration level was improved, which was called Integrated Power Electronics Module (IPEM). Power electronic devices are integrated with circuits, control, detection, execution and other components to obtain standard and manufacturable IPEM modules, which can be used for both standard design and special design. The advantage is that products can be provided to users quickly and efficiently, significantly reducing costs and improving reliability.

The multi-layer integrated packaging technology of embedded power electronic semiconductor power devices is applied to package together heat sinks, substrates, insulating heat transfer materials, power busbars, power semiconductor power devices, copper layers, ceramics, integrated passive components, metal layers, surface mount chips (driving, detection and protection components), etc.

The design of IPEM modules must take into account both circuit connection and heat flow path and heat dissipation. In the past, the traditional method of interconnecting chips in power semiconductor devices was aluminum wire bonding, which had poor performance and reliability. Circuits were connected by wires, which increased parasitic inductance. Now, IPEM modules use planar metallization technologies such as sprayed metal layers and surface mount metal layers to connect circuits, which can minimize parasitic parameters.