1. Definition and types of agricultural automatic spraying systems

The agricultural automatic spraying system is a modern equipment that integrates electronics, machinery, sensors, and automatic control technology with agricultural irrigation and plant protection principles. It covers irrigation (such as intelligent sprinklers, drip irrigation systems, etc. for precise water supply to farmland) and plant protection (such as automatic pesticide sprayers, fog machines, etc. for pest control). These systems play an important role in the agricultural production process. By accurately controlling the amount, range and time of water or pesticide spraying, they improve the efficiency of agricultural resource utilization, increase crop yield and quality, promote the development of agriculture in the direction of high efficiency, precision and intelligence, and provide strong support for ensuring food security and sustainable agricultural development.

 2. Application of MOSFET

MOSFET Application in Driving Motors for Automatic Agricultural Spraying Systems

This system can choose MOSFET tube VBL1615 as the key device in the drive motor control circuit, and its parameters are:
- Single N
- VDS (V): 60 - VGS
(positive V): 20 - Vth
(V): 1.7
- VGS = 4.5V (m times): 12
- VGS = 10V (m times): 11
- ID (A): 75
- Technology: Trench
Package: TO263

Motor drive and control : In terms of drive motor, its 75A current carrying capacity can provide stable power for 3kW centrifugal pump motor to cope with startup shock. The 60V VDS and appropriate Vth can cooperate with the control circuit to accurately adjust the motor speed and torque through PWM signals according to sensor feedback to achieve precise spraying in different areas, improve the utilization efficiency of water resources and pesticides, and ensure the quality and safety of agricultural products.

Power management and optimization : In the switching power supply circuit, the 48V lithium battery power can be converted into 12V, 5V and other voltages for each module. The low on-resistance reduces power consumption and improves the power conversion efficiency by 5% - 10%. The power consumption can be reduced in standby or low load to extend the battery life. For example, the standby power consumption at night can be reduced to 10% - 20% of the normal level.

System protection and fault detection : It can cooperate with the protection circuit to quickly cut off the circuit in case of abnormalities such as motor overload, short circuit, power supply fluctuation, etc. If the motor fault current increases or the chip overheats (about 150°C), it will automatically stop working. It can also monitor parameters such as on-resistance and send an alarm to the control center in case of abnormalities to facilitate timely maintenance and improve system reliability and stability.

3. Key points for selecting MOSFET

    1.Electrical parameters

Withstand voltage value (VDS) : In view of the complex agricultural environment and power supply fluctuations, the common 24V or 48V DC powered spraying system should choose a 60V - 100V withstand voltage MOSFET tube to prevent power surges and motor back electromotive force from causing breakdown, ensuring stable system operation.

Current carrying capacity (ID) : Because a large current is required to drive the motor to start and run, especially for large sprinkler irrigation or plant protection equipment, for 1kW - 5kW motors, MOSFET tubes with a rated current of 50A - 100A or above are recommended to ensure reliable motor driving and avoid starting or running problems caused by insufficient current.

On-resistance (RDS (on)) : In agricultural spraying systems, reducing power consumption is critical to energy utilization and battery life. In high-power motor drive scenarios, try to choose MOSFET tubes with an on-resistance of less than 10mΩ to reduce conduction power loss and improve system efficiency and economy.

Threshold voltage (Vth) : System control circuits often use low-voltage power supply (such as 5V or 3.3V), and the MOSFET threshold voltage should match it. Generally, 1V - 3V is selected to ensure reliable conduction and cutoff under control signals, reducing circuit design complexity and cost.

2. Performance characteristics

Switching speed : In motor drive and power conversion circuits, MOSFET tubes need to switch frequently. For PWM speed regulation commonly used in agricultural spraying systems, a higher switching frequency (20kHz - 100kHz) is required to achieve precise control of motor speed, reduce noise and vibration, and enhance system stability and reliability.

Shock resistance : The agricultural operating environment is harsh. Voltage spikes, current surges and mechanical vibrations may damage MOSFET tubes. MOSFETs with avalanche energy levels and anti-static capabilities should be selected to ensure long-term stable operation in complex environments.

Temperature stability : The ambient temperature of the spraying system working outdoors varies greatly. The MOSFET tube needs to work in a wide temperature range (-40℃ to 125℃) and have small electrical parameter drift under high temperature. Use TO263 packaging and combine heat dissipation measures (heat sink or fan) to prevent performance degradation and damage caused by high temperature and ensure system reliability.

3. Reliability and security

Reliability testing and certification : To ensure the long-term reliability of MOSFET tubes in agricultural spraying systems, they need to undergo high temperature aging, temperature cycling, humidity, vibration, salt spray and other tests to simulate harsh conditions to test performance stability. Products that have passed industrial-grade electronic product certification and other related standards are selected to ensure stable operation of the system.

Protection and isolation measures : In system design, protection and isolation measures should be taken. The MOSFET tube should be sealed or placed in a protective casing, and a waterproof, dustproof and corrosion-resistant design should be adopted to improve durability. Electrical isolation should be done for high-voltage and high-current circuits to prevent leakage and short circuits, ensure the safety of operators and equipment, and ensure the safe operation of the agricultural automatic spraying system.

VBsemi's MOSFET products have outstanding electrical, performance, reliability and safety advantages, and a rich product line that can be matched on demand, helping agricultural automatic spraying systems operate efficiently and safely, promoting agricultural modernization and improving production efficiency.