Power devices are developing toward highly integrated intelligent power modules

The review of the development of power devices, from the diode and the triode, realized the leap to noncontrollable controllable; birth controlled thyristor open controllable devices to power from the gate controlled thyristor ruled high power device market. But thyristor can only control the turn-on and cannot control the turn off, which limits its development in many fields. Especially in the high frequency field, it is necessary to control the power conversion with high frequency, so as to improve the efficiency of the power conversion device and reduce the volume. Bipolar power transistors (GTR) first stand out, and as saturation voltage drops and frequency increases, GTR has found its place in many fields. However, due to its large control power (low power amplification), the protection design is complex, and the device has two breakdown problems, so the application can not be quickly promoted. With the birth and development of power metal oxide semiconductor field effect transistors (MOSFET), MOSFET has been rapidly changing the field of small and medium power conversion by means of micro power voltage control characteristics and high frequency. But its on state resistance and voltage limit its application to high voltage development. At the same time, the invention of the insulated gate bipolar transistor (IGBT) combines the voltage control characteristic of MOSFET and the saturation voltage characteristic of GTR, and breaks through the restriction of the two kinds of devices and starts to enter the field of high power.
On the other hand, with the continuous progress of power devices, power conversion applications continue to expand, the application circuit is more complex, from single to control the chopper to two tube half bridge circuit, from four to six H pipe bridge circuit three-phase inverter circuit and multi circuit switch. While the main inverter circuit power device increases, the control circuit and drive technology requirements are getting higher and higher. Although the efficiency of single power devices is becoming higher and higher, the control is simplified, but the complexity of the circuit raises new requirements for users. Power modules come into being for the convenience of customers to use power devices. Its design aims to solve the problem of power unit configuration, heat dissipation, and even drive problems in the module to provide users with easy to use and reliable power devices.
The drive technology of power devices has also gone through the stage of development from current drive to voltage drive, photoelectric conversion to high voltage integrated circuit (HVIC). In the current drive era of bipolar transistors, due to the great loss, the driver and protection circuits are omitted to be distributed by the clients in order to make the module volume as small as possible. However, the volume of power module is very large, and the influence of stray inductance also limits its development to high frequency. These defects limit the popularization and development of power module. IGBT replaces bipolar transistors, enabling power modules to develop rapidly: first, because voltage drives are used, device drivers are easier to implement, and second, efficiency increases to make miniaturization possible. The application of HVIC technology is to make the drive technology have a great leap, the main features of HVIC are: single power supply (4 optocoupler supply), low temperature drift, time delay, high frequency and small volume. The continuous decrease of driving power, the large decrease of the driving circuit space and the increase of frequency can help to drive the integrated circuit and the power device in one module.
In recent years, the intelligent power module (IPM) with drive and protection circuit has been put on the market, such as MITSUBISHI's IPM module, users do not have to consider the specific operation of the device, only the design of the system control part and the optimal structure. The new IPM module even switches the power supply in the module, which is more convenient for users. This was also the main reason why people liked the IPM module at first. At the same time, the device manufacturers to improve the technical level of devices at the same time, is also trying to launch a more systematic module, such as rectifier, inverter, drive, protection and control system, and filtering, switching power supply module. Users only need to understand the interface circuit and definition, and can quickly form a running system.
Chinese household electrical appliances, especially the OEM of frequency conversion air conditioning industry, started from scratch. Now, they have been able to design their own products independently, and have experienced the process of high integration of IPM modules to discrete devices in the application of power conversion module. This shows that our power conversion, especially in power conversion applications in home appliances has been initially mastered. This is the only way to mature technology, so as to improve our ability to develop products as a whole.
On the other hand, we are paying a high price for mastering technology. If the development costs will be added to the product, will lose the price advantage, so the industry and the emergence of labor trends: professional power devices manufacturing company in cooperation with air conditioning OEM, the joint development of high performance and low cost inverter air conditioner. In fact, the United States and Japan appliance OEM has been using this market mechanism, with the ability to provide advanced technology and minimum cost supplier cooperation, and create a win-win situation. Although OEM prices were slightly higher in initial small volume purchases, the cost was substantially reduced relative to independent development, and most of the development costs and risks were shifted to device manufacturing.