I. Basic Parameters 1. Rated Voltage · Description: The voltage required for the controller to operate normally must match the voltage of the battery pack. · Common values: 24V, 36V, 48V, 60V, 72V. Currently, 48V is the mainstream choice. 2. Current Limit/Rated Current · Description: The maximum operating current that the controller is allowed to output. This parameter is critical in determining the electric vehicle’s power (torque) and acceleration capability. The higher the current, the greater the instantaneous power delivered to the motor, resulting in stronger acceleration and hill-climbing ability—but also faster battery consumption. · Common values: 15A, 20A, 25A, 30A, 35A, etc. Typical commuter bikes operate around 15A–25A, while high-performance or electric motorcycle models can reach over 30A. 3. Rated Power · Description: The continuous power output capability of the controller, roughly equal to Voltage × Current. It needs to match the motor’s rated power. · Common values: 180W, 250W, 350W, 400W, 500W, 800W, 1000W, 1500W, etc. Different countries and regions have legal regulations on the maximum power allowed for electric bicycles to be road-legal (e.g., 250W in the EU, 400W under China’s new national standard). 4. Phase Angle · Description: A matching parameter between the controller and the internal magnetic poles of the motor. If the phase angle doesn’t match, the motor won’t rotate properly, leading to jitter, abnormal noises, or even complete failure to turn. · Common values: 60° and 120°. When replacing the controller, it’s essential to ensure that the phase angle matches the original motor. 5. Motor Type Compatibility · Description: The controller must match the type of motor being used. · Main types: · Brushed motors: Use carbon brushes for commutation; the controller design is simple but they are now less commonly used. · Brushless motors: Use electronic commutation, offering high efficiency and long lifespan—currently the absolute mainstream. Brushless controllers are further divided into: · Sine-wave controllers: Output a smooth, sine-wave-like current waveform, providing extremely stable and quiet operation, high torque, and high efficiency—this is the current trend. · Square-wave controllers: Output a square-wave current waveform; the technology is mature and cost-effective, but they produce more noise and vibration during operation and have slightly poorer torque stability. 6. Throttle Signal Type · Description: The method by which the controller recognizes the throttle signal. · Main types: · Analog voltage signal: The most common type, typically outputting a linearly varying voltage from 1.0V to 4.2V. · PWM signal: Uses pulse-width modulation to transmit signals, offering stronger anti-interference capability. · Digital signal: Used in some high-end smart models. · Note: When replacing the controller, make sure the throttle signal type is compatible. 7. Other Interfaces and Features · Description: Whether the controller supports the following features depends on its design and interfaces: · Pedal-assist sensor · Cruise control · Reverse gear · Anti-theft alarm lock for the motor · E-ABS (electronic braking/energy recovery) · Three-speed switch (low, medium, high speed) · LCD instrument panel communication II. Description of Core Features 1. Speed Regulation Function · This is the most basic function. The controller receives signals from the throttle and precisely controls the motor speed by adjusting the voltage and current supplied to the motor (i.e., the PWM duty cycle), thereby enabling the vehicle to accelerate and decelerate smoothly. 2. Brushless Motor Commutation · For brushless motors, the controller needs to sequentially switch the currents supplied to the motor’s three-phase windings based on the rotor position signals fed back by Hall sensors, allowing the motor to keep rotating continuously. If no Hall signals are available (known as “Hall-less mode”), some advanced controllers can estimate the rotor position through back electromotive force to achieve startup and operation. 3. Brake Power Cut-off · When the brake lever is squeezed, a switch inside the lever sends a signal to the controller. Upon receiving this signal, the controller immediately cuts off the power supply to the motor, ensuring riding safety and also conserving energy. 4. Undervoltage Protection · This is a critically important protective function. When the battery voltage drops below a preset threshold (e.g., about 42V for a 48V battery pack), the controller will stop working and cut off the output, preventing over-discharge of the battery and effectively extending its lifespan. After undervoltage protection is triggered, the battery usually needs to be recharged before the controller can resume operation. 5. Overcurrent Protection · When the vehicle’s load suddenly becomes excessive (such as severe overload