In-depth Analysis: High-Voltage Motors — The Powerful Heart of Industrial Power
Time:
2022-01-10
In the modern industrial system, electric motors serve as key devices that efficiently convert electrical energy into mechanical energy, providing indispensable power support for various production activities.
In the modern industrial system, electric motors serve as key devices that efficiently convert electrical energy into mechanical energy, providing indispensable power support for various production activities. Among them, high-voltage motors, with their unique advantages, play an important role as the "power heart" in many large industrial equipment and complex working conditions. Recently, with the acceleration of industrial automation and the increasing demand for energy efficiency improvement, the technology and application of high-voltage motors have once again become the focus of the industry.
High-voltage motors, as the name suggests, refer to electric motors with a rated voltage above 1000V. In practical applications, voltage levels of 6000V and 10000V are more common. However, due to differences in power grid standards across countries and regions, high-voltage motors with voltage levels such as 3300V and 6600V also exist. The emergence of high-voltage motors mainly stems from the increasing power demand of motors. If low-voltage power supply is still used, such as a 300KW/380V motor, the current will be limited by the wire's carrying capacity, making it difficult to achieve high power output and significantly increasing costs. By increasing the voltage, the current can be effectively reduced, thereby achieving efficient transmission and utilization of high power electrical energy. This is the key reason why high-voltage motors are widely used.
Taking the high-voltage asynchronous motor as an example, its working principle is based on the law of electromagnetic induction. When symmetrical three-phase alternating current is applied to the three-phase winding, a rotating magnetic field is generated inside the motor. This rotating magnetic field rotates at high speed and cuts through the rotor conductors, inducing an electromotive force in the rotor conductors. Since the ends of the rotor conductors are short-circuited by a metal short-circuit ring forming a closed loop, an induced current is generated in the conductors. The interaction between the rotating magnetic field and the induced current produces electromagnetic force, which forms an electromagnetic torque on the shaft in the same direction as the rotating magnetic field. Driven by this torque, the rotor continuously rotates in the direction of the rotating magnetic field. According to Lenz's law, the magnetic flux generated by the rotor current always tries to oppose the change of the stator's rotating magnetic flux. Even when the motor runs without load, a certain amount of energy is consumed to compensate for friction, ventilation, copper loss, iron loss, and so on.
High-voltage motors are widely used across various industries and serve as the core power source driving various large mechanical equipment. In the mining field, high-voltage motors can drive large crushers, ball mills, hoists, and other equipment, providing strong power for ore crushing, grinding, and transportation, ensuring efficient mining operations. In the petrochemical industry, high-voltage motors power key equipment such as compressors, centrifugal pumps, and fans, ensuring stable operation of raw material transportation, gas compression, and ventilation and cooling during reaction processes. In the power industry, high-voltage motors drive equipment such as coal pulverizers, feedwater pumps, and blowers, providing reliable power support for fuel grinding, boiler water supply, and combustion assistance in thermal power plants. Additionally, in industries such as metallurgy, cement, and papermaking, high-voltage motors also play a crucial role, driving large equipment like rolling mills, rotary kilns, and paper machines, promoting the smooth operation of the entire industrial production process.
Due to the large current impact during the start-up of high-voltage motors, different starting methods are required for motors of different capacities. Generally, motors below 1000KW with sufficient power supply capacity can be started directly, with the inrush current reaching 3 to 6 times the rated value. However, for large-capacity motors, to reduce the impact of starting current on the power grid and the motor itself, various starting methods such as series reactor starting, variable frequency starting, and hydraulic coupling starting are commonly used. Each of these starting methods has its advantages and disadvantages. For example, variable frequency starting offers smooth start and wide speed regulation range but has relatively high equipment costs; hydraulic coupling starting has a simple structure and low cost but involves certain energy losses during speed regulation.
In terms of speed regulation technology, significant progress has been made in recent years for high-voltage motor speed control. Common speed regulation methods include hydraulic coupling speed control, high-low-high type variable frequency drive, high-low type variable frequency drive, cascade speed regulation variable frequency drive, current source type direct high-voltage variable frequency drive, voltage source type three-level variable frequency drive, and power module series multi-level variable frequency drive. Among them, the power module series multi-level variable frequency drive technology has become one of the mainstream technologies in the field of high-voltage motor speed regulation due to its advantages such as low input-side harmonics, high power factor, low output-side dv/dt, and meeting the requirements of ordinary asynchronous motors. However, different speed regulation technologies are suitable for different application scenarios and working conditions, and users need to make reasonable choices based on actual situations.
With the proposal of the "carbon peak and carbon neutrality" goals, high efficiency and energy saving have become important directions for the development of high-voltage motor technology. In response to national energy-saving policies, many motor manufacturing enterprises have increased R&D investment, striving to improve the energy efficiency level of high-voltage motors. For example, Harbin Electric Group Jiamusi Motor Co., Ltd. took the lead in obtaining the new Level 1 energy efficiency certification for high-voltage motor series under the new national standard GB 30254 - 2024 "Energy Efficiency Limits and Energy Efficiency Grades for High-Voltage Three-Phase Cage Asynchronous Motors," becoming the first domestic company capable of selling and supplying 505 specifications of 4 main series of new Level 1 energy efficiency high-voltage motors. This achievement not only demonstrates the company's leading position in the field of high-efficiency energy-saving motor R&D and manufacturing but also sets an example for promoting energy efficiency upgrades across the entire industry.
In the field of new energy vehicles, the supply voltage of drive motors also shows a trend toward high voltage, with common voltage platforms including 400V, 800V, 900V, and 1000V. Taking the 800V architecture as an example, its application significantly shortens electric vehicle charging time, reduces system heat generation, decreases the quality and volume of power electronics integration, and increases load capacity by 25% to 50%. Many well-known automotive brands such as Porsche Taycan, IM LS6, and BYD have adopted this architecture. However, the increase in voltage imposes higher requirements on the motor's withstand voltage level, the insulation capability of in-vehicle electrical equipment, and the insulation level of windings, which need to be addressed through continuous technological innovation.
As an important power device in the industrial field, the continuous innovation and development of high-voltage motor technology are of great significance for improving industrial production efficiency, reducing energy consumption, and promoting industrial upgrading. With ongoing technological progress and changing market demands, high-voltage motors are expected to achieve more breakthroughs in efficiency improvement, performance optimization, and intelligent control, injecting new momentum into the sustainable development of global industry.
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