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Semiconductor technology is high end? Electricity in a low carbon society

high-end technology

Is semiconductor technology a high-end technology? It plays an important role in a low-carbon society. Power electronics is a technology that utilizes semiconductor devices to convert and control electricity, which is very friendly for a low-carbon society. The current wave of electrification of automobiles is also thanks to this. In order to improve the efficiency of energy utilization, we need to focus on how to improve the efficiency of control.

Power electronics originated in the late 1950s, starting with silicon rectifier devices. The term power electronics first appeared in 1973.semiconductor system Prior to this, there were technologies related to power generation and control, such as electric motors and thyristors. However, it can be said that this was the moment when the concept of integrated processing of power, electronics and control was born. Power engineers did not understand electronics and electronics engineers did not understand power control. Therefore, it became important to fill this gap.

After the birth of the power electronics concept, the control efficiency of electric power began to receive attention, and now it has become a keyword to support a decarbonized society.

First of all, let us introduce the electric motor, which is used in various electronic devices.semiconductor test system Whether it is an air conditioner or a refrigerator that uses a compressor, motors are used in these household appliances. The vibration function of cell phones is also based on motors, and even in factories, equipment that runs on electricity uses some kind of motor. In other words, motors can be said to account for a large portion of electricity consumption. In addition, most electric power (e.g., thermal power generation, nuclear power generation, wind power generation, hydro power generation) is generated by motors (generators). Advances in electric motors will lead to advances in power electronics and will also contribute significantly to saving electricity.

Electric motors can be broadly categorized into direct current (DC) motors and alternating current (AC) motors. In addition, they can be categorized into several types such as permanent magnet motors, brushless motors, servo motors, and stepper motors based on their structure and control methods.

The basic structure of a motor is that the rotor rotates between the stators. At this point, the part that provides the power is called brushes. However, the presence of brushes causes friction between the brushes and the commutator, which leads to inefficiency. In addition, the brushes wear out and therefore need to be replaced periodically.

As a result, brushless motors, which eliminate the brushes, have emerged. In particular, brushless motors using three-phase alternating current are also used as motors for electric vehicles.

Motors that use permanent magnets for the rotor are called "permanent magnet motors".semiconductor solutions As shown in the figure, those that use permanent magnets on the surface of the rotor are called "surface permanent magnet synchronous motors (SPM)", and those that are embedded inside are called "internal permanent magnet synchronous motors (IPM)".

Some brushless motors use a ferromagnetic core instead of permanent magnets in the rotor. Such motors are called "reluctance motors". Although simple in construction because they do not use permanent magnets, these motors have been avoided because of noise, vibration, and large torque fluctuations. However, with advances in power electronics and computer control technology, their use has expanded.

So far, servo motors have been the mainstay for controlling rotor speed. By employing a servo mechanism, it has the advantage of automatically controlling position and speed and being able to withstand sudden fluctuations in load, but the disadvantage of needing to be driven by a high voltage source.

In contrast, stepper motors operate synchronously by means of pulse signals and therefore have the advantages of low voltage and small size. On the other hand, the smoothness of rotation is not as good as that of servo motors. The previously mentioned reluctance motors are also a type of stepper motor, so these disadvantages have now been eliminated.