The secret of variable frequency motor energy saving and long life

What is frequency conversion?

When it comes to frequency conversion, we should first introduce the concepts of my country's mains frequency and fixed frequency. The standard of my country's mains is industrial frequency AC, with a frequency of 50Hz; fixed frequency works on the basis of the mains frequency. Since the frequency of its power supply cannot be changed, the motor speed of the fixed frequency equipment is basically unchanged, and the start and stop of the motor can only be adjusted by on/off control. Its advantages are low cost and mature technology, and its disadvantages are also imaginable, which is the loss of the motor and the consumption of electric energy. Frequency conversion is to add a frequency conversion circuit on the basis of fixed frequency, which will change the power supply frequency of the motor to achieve the adjustment of the motor speed. Thereby reducing power consumption, reducing motor loss, and extending the service life of the motor.

Inverter equipment is widely used in daily life, such as inverter air conditioners, inverter refrigerators, inverter washing machines, etc. So what is the internal structure of the inverter?

The internal circuit structure of the frequency conversion equipment is roughly divided into AC power input, PFC power factor correction circuit, DC-DC converter, motor drive circuit, digital signal transmission, analog signal transmission and interface protection circuit, etc. In order to help customers quickly advance the R&D process and support customers to quickly bring products to market, Toshiba provides complete circuit solutions in power conversion, motor drive and interface protection for users' reference and use.

Figure 1 Internal structure of frequency conversion equipment

In terms of power input, PFC power factor correction circuit and DC-DC converter, Toshiba is very careful in the use of devices. Among them, the MOSFET involved in the DC-DC conversion in the circuit is recommended to use Toshiba's self-developed U-MOS series MOSFET. The advantages of this MOSFET are that it can achieve high speed, low noise, and low switching loss. It also has direct plug-in, surface mount packaging and 3.3mm×3.3mm TSON small packaging, which is convenient for users to be compatible with previous products and can also miniaturize the product to the extreme.

For the MCU communication and control involved in the circuit, Toshiba recommends the use of the TMPM37X series MCU. The MCU package ranges from VQFN32 5mm/5mm to LQFP100 14mm/14mm, the Flash ROM ranges from 64KB to 512KB, and the RAM ranges from 4K to 32K, making it easy for users to choose the MCU that suits them.

Figure 2 PFC power factor correction structure

In terms of motor control, Toshiba recommends that users use DTMOS series MOSFETs based on the power of the motor. This series of MOSFETs has a super junction and can be used in high-output power applications, and provides D-MOS (double diffused) MOSFET series products for low-output power applications. At the same time, the DTMOS series MOSFETs have two packages, the direct-insert TO-220SIS and the surface-mount TOLL, which allow users to replace previous MOS solutions with very small changes to the circuit board.

Figure 3 Motor drive circuit using MOSFET

In terms of digital signal and analog signal transmission interaction and interface circuits, Toshiba is committed to designing circuit protection to the extreme. Users can use Toshiba's optocouplers, electronic fuses, TVS and Schottky diodes and other components to achieve overall circuit safety protection, reducing the risk of damage to the user's circuit.

Figure 4 MCU and external device communication circuit using digital optocoupler

Figure 5 MCU and external device communication circuit using analog optocoupler

Figure 6 Interface protection circuit

Toshiba has extensive and professional technologies and products in the research and development and design of semiconductor circuits, especially in the fields of power supply, MOSFET driver and interface protection. We hope to provide customers with more valuable solutions and product information for product selection. If you want to know more complete solution information, you can also click "Read the original text"! .

About Toshiba Electronic Devices & Storage Corporation

Toshiba Electronic Devices & Storage Corporation is a leading supplier of advanced semiconductor and storage solutions, with more than half a century of experience and innovation, providing customers and partners with outstanding solutions in discrete semiconductors, system LSI and HDD.

With 23,100 employees around the world dedicated to maximizing the value of their products, Toshiba Electronic Devices & Storage Corporation places great emphasis on close collaboration with customers to promote co-creation of value and jointly develop new markets. The company, now with annual sales exceeding 711.0 billion yen (US$6.2 billion), looks forward to contributing to building a better future for people everywhere.