The control system of the generator set mainly consists of the main controller, sensors, actuators, operation interface, and communication interface, etc.
Ⅰ. What is the role of the main controller?
It is the brain of the generator set control system. The controller receives feedback signals from various sensors, through the processor's comparison and analysis, makes real-time judgments on signals such as speed, oil pressure, water temperature, and the voltage, current, and frequency of the generator, and performs automatic start-stop control, operation parameter monitoring, fault protection, output management, and data recording, etc.
Ⅱ. What are the main sensors and what is their working principle?
1. Oil pressure sensor
1.1 Installation position: The oil pressure sensor is installed on the main oil passage of the engine.
1.1 Working principle: ① Convert the pressure signal into an electrical signal and send it to the processor and the alarm circuit for comparison with the set alarm voltage. When the pressure is higher or lower than the set alarm voltage value, the alarm circuit outputs an alarm signal; ② The pressure signal is connected to the oil pressure gauge, and the dial displays the engine's oil pressure.
2. Water temperature sensor
2.1 Installation position: Generally installed on the water jacket of the engine's cylinder block or cylinder head, in direct contact with the coolant, to measure the temperature of the engine coolant.
2.2 Working principle: Based on the thermistor principle, the temperature change is converted into a voltage signal, and the voltage signal is generated through a voltage divider circuit, controlling the unit (ECU) to control the injection pump's injection time, injection volume, etc., parameters, to ensure the engine operates normally under different conditions.
3. Speed sensor
3.1 Installation position: Generally installed near the flywheel housing, crankshaft, or camshaft, to detect the engine's speed and crankshaft position.
3.2 Working principle: The speed sensor uses a magnetic sensitive resistor as the detection element, converting the rotational speed of the rotating object into an electrical signal device, which is an indirect measurement device. The control system, based on the signal provided by the speed sensor, precisely controls the injection time and ignition timing to ensure the engine runs at a stable speed, and also provides a guarantee for the generator to output stable voltage and frequency.
4. Oil temperature sensor
4.1 Installation position: Installed on the oil passage or oil pan, to measure the oil temperature.
4.2 Working principle: The sensor sends a signal to the engine computer based on the temperature change of the oil, to adjust the engine's working state. Excessive pressure is likely to damage the oil filter and other seals; if the pressure is too low, the engine cannot supply sufficient oil to each friction surface, and cannot perform its normal cleaning, lubrication, and cooling functions, which may lead to abnormal wear, warping, or cylinder wall damage of the engine.
Ⅲ. How does the generator set perform dual power conversion?
The diesel engine ATS is the abbreviation of automatic transfer switch, also known as dual power automatic transfer switch. When the mains power fails, after a delay confirmation, it automatically switches the load circuit to the generator; when the main power is restored, after a delay confirmation, it automatically switches back to the mains power.
Ⅳ. How does the generator maintain stable output voltage?
The automatic voltage regulator, usually called AVR, monitors the output voltage of the generator and keeps it within the set range, installed at the end of the exciter of the generator.
1. AVR monitors the output voltage of the generator in real time through a voltage sensor; next, it compares the monitored voltage with the set value and calculates the error signal. If the actual voltage is higher than the set voltage, the excitation needs to be reduced; if the actual voltage is lower than the set voltage, the excitation needs to be increased.
2. By adjusting the magnitude of the excitation current, the magnetic field strength of the generator is changed to achieve stable output voltage.