Many DC motor controllers on the market are designed with significant functional limitations to reduce costs. One critical shortcoming is the lack of active current measurement and regulation.

1. Why Current Limitation is Crucial

   • DC motors can draw 3 to 10 times their rated load current during startup or sudden acceleration.
   • These short but intense overload conditions are especially dangerous for the internal power electronics stage.
   • Without active current limitation, the power stage can immediately burn out, resulting in irreversible damage to the controller.

2. The Solution: Ultra-Fast Current Limitation

   • The only effective solution is selecting a motor controller equipped with proper and ultra-fast current limitation.
   • Our motor controllers are supervised by a highly efficient ARM Cortex microprocessor, which performs more than 100,000 measurements per second.
   • If overload conditions occur, the processor instantly intervenes to keep the output within the safe operating range.

3. Advantages of Current Limitation

   • This current limitation function not only serves as a protective feature but also enables the motor to deliver precise and controllable output torque across the entire range of operation.

By choosing a motor controller with advanced current regulation capabilities, you can ensure both the safety of your system and optimal motor performance.

When designing motor controllers, there are several important criteria to ensure durability and reliable operation. Below, we highlight some critical design aspects.

1. Adequate Buffer Capacitance

   • A key element in motor controller design is integrating sufficient buffer capacitance.

   • PWM motor controllers (Pulse Width Modulation) achieve near-lossless regulation by rapidly switching the output between 0 and the supply voltage.

   • DC motors, due to their mechanical inertia, respond very slowly to these rapid fluctuations, making the switching imperceptible in terms of output speed variation.

   • However, the sudden pulse-like load demands cannot always be served by the power source (e.g., a battery located several meters away).

   • Instead, onboard capacitors act as a temporary buffer, supplying the necessary energy during these high-current pulses.

2. Importance of Sufficient Capacitance for High Performance

   • The power transistors can only efficiently handle rapid switching if the buffer capacitors provide the required current surge without significant voltage drop.
   • For this reason, the onboard capacitors must:
     • Be capable of sustaining high current flow.
     • Operate without excessive heating, which could lead to component failure.

3. Risks of Insufficient Capacitance

   • Many motor controllers on the market, to reduce costs, include either too few capacitors or capacitors with low current ratings.
   • Insufficient capacitance can result in:
     • Dangerous overvoltage spikes within the circuit.
     • Long-term issues like overheating, which accelerates capacitor drying and reduces their lifespan.

4. Optimal Solution: High-Quality Capacitors with Low ESR

   • The best way to mitigate these issues is by designing motor controllers with:
     • Sufficient capacitors for energy storage.
     • Low ESR (Equivalent Series Resistance) capacitors to handle high currents efficiently.
   • Proper electrical and thermal design ensures optimal performance and durability under continuous operation.

For more details on capacitor selection and design principles, see our article on Buck Converter Design, which you can read here:

In many applications, it’s necessary not only to control the speed of a motor but also to reverse its direction. Below, we describe traditional and modern approaches to achieving motor direction reversal.

1. Reversing Motor Polarity with Relays

   • A traditional yet reliable method for reversing the direction of a DC motor involves using a double-circuit relay or contactor.
   • This setup allows for a straightforward change in the polarity of the voltage applied to the motor.

2. Drawbacks of Mechanical Switches

   • While this method is simple and widely used, it comes with some challenges:
     • Contact reliability issues can arise over time.
     • The copper and bronze contacts of relays may carbonize due to arcing, leading to poor conductivity.
     • Over time, the switching reliability may degrade, resulting in inconsistent operation.

3. Modern Solution: H-Bridge Controllers

   • A more effective and reliable alternative is using a motor controller with an H-bridge configuration for the output power stage.
   • Benefits of H-bridge-based controllers include:
     • No mechanical wear, ensuring long-term reliability.
     • Fast and efficient switching using semiconductor components.
     • The ability to handle high-speed direction changes without introducing significant delays.

By transitioning to H-bridge motor controllers, you can achieve precise, efficient, and durable direction control, avoiding the common problems associated with mechanical relays.

4Q (Four-Quadrant) or Full H-Bridge motor controllers are advanced systems designed for complete electronic control of the motor’s output polarity. This eliminates the need for mechanical relays. These controllers support four operational modes:

1. Forward drive
2. Reverse drive
3. Forward braking
4. Reverse braking

Below are the key advantages of this approach compared to relay-based direction control:

1. No Relays Required

   • Simpler Design: There’s no need for relays, complex wiring, or additional relay control circuits.
   • Integrated Functionality: The motor controller itself electronically handles the polarity reversal to control motor direction.

2. Increased Reliability

   • Relay-based systems are prone to contact wear and issues such as carbonization of contacts, leading to degraded performance over time.
   • Electronic switching in H-bridge controllers eliminates these mechanical failure points, providing longer-lasting and more reliable operation.

3. Regenerative Braking

   • A significant advantage of 4Q controllers is their ability to support regenerative braking.
   • This feature allows the motor to act as a generator during braking, converting mechanical energy into electrical energy and feeding it back to the battery.
   • Regenerative braking is useful when actively slowing down a spinning motor, improving energy efficiency and reducing wear on mechanical braking systems.

4. Smooth and Precise Control

   • The fully electronic design enables seamless switching between directions and braking modes, resulting in smoother operation.
   • The controller can handle high-speed transitions without the delays or wear associated with mechanical relays.

By choosing a 4Q full-bridge motor controller, you gain a compact, reliable, and energy-efficient solution for controlling motor direction and braking, far superior to traditional relay-based methods.

In our webshop, you can find both one-way controllers and reversible (H-bridge) controllers. The choice between these depends entirely on the application and the specific requirements.

1. One-Way Controllers

   • These controllers are designed for applications where the motor or device operates in only one direction.
   • Suitable for:
     • Fans
     • Pumps
     • Heating elements
     • LEDs
   • Advantages:
     • Simpler design.
     • More cost-effective.
     • Ideal for systems where reversing the output polarity is unnecessary.

2. Two-Way (H-Bridge) Controllers

   • These controllers are capable of reversing the output polarity, allowing the motor to operate in both forward and reverse directions.
   • Suitable for:
     • Applications requiring motor direction control (e.g., robotics, vehicles, or conveyor systems).
     • Use cases that benefit from regenerative braking.
   • Advantages:
     • Full control of direction and braking.
     • Can handle more complex motion profiles.

Choosing the Right Controller

If your application involves simple, one-directional operation (like fans or LEDs), a one-way controller is sufficient. However, for systems requiring reversible motor control or advanced braking features, a two-way (H-bridge) controller is the better choice.

DC motor controllers can be powered by a wide range of power sources, but there are some considerations based on the type of supply being used.

1. Battery-Powered Operation

   • Motor controllers can operate directly from battery power without any special settings or adjustments.
   • Batteries are ideal for applications requiring high current surges, such as motor startups or regenerative braking, as they can absorb and supply current efficiently.

2. DC Power Supply Operation

   • When using a DC power supply, certain precautions may be necessary, depending on the application:
     • Regenerative Braking Considerations:
       • If the motor is used in applications with active braking and regenerative energy recovery, the power supply may not handle the returned energy effectively.
       • Most DC power supplies have limited or no capacity to absorb reverse current.
       • To address this, our motor controllers allow the regenerative feedback to be disabled or adjusted to a low value.
     • This adjustment ensures safe operation and prevents potential damage to the power supply.

3. Overvoltage Protection

   • Our motor controllers are equipped with overvoltage protection to safeguard against voltage spikes.
   • Each controller has a default maximum voltage limit, which can be adjusted:
     • Either by the user.
     • Or by us upon request, pre-programmed to meet specific needs.

Summary

For battery-powered systems, no special adjustments are needed. However, for DC power supplies, it’s important to configure regenerative braking properly to prevent overloads. Additionally, overvoltage protection settings can be fine-tuned to ensure reliable and safe operation in all scenarios.

When operating DC motor controllers from batteries, it’s crucial to implement protections to prevent damage to the battery. One key aspect is ensuring that the voltage of the battery cells never drops below a safe minimum value.

1. Low Voltage Protection

   • Discharging a battery below its safe voltage limit can cause irreversible damage to the cells and drastically reduce its lifespan.
   • While standalone low-voltage protection circuits are available, an integrated solution is much simpler and more effective.
   • Our DC motor controllers include a programmable low-voltage cutoff feature:
     • This automatically disconnects the motor when the battery voltage falls below the set threshold.
     • Prevents deep discharge and protects the battery from damage.

2. Pre-Configured and Adjustable Settings

   • Each of our controllers has a default pre-programmed minimum voltage limit.
   • This limit can be adjusted as needed:
     • By the user through configuration options.
     • By us, upon request, to match specific battery requirements.

Benefits of Integrated Low Voltage Protection

Using a controller with built-in low-voltage cutoff eliminates the need for additional external circuitry, offering a compact and efficient solution for battery-powered systems. This feature ensures the longevity and reliability of your batteries while maintaining seamless operation.

No, a DC motor controller cannot be directly connected to an AC power supply. However, it can be adapted for use with an AC source by following specific steps.

1. Rectification Required

   • To use an AC power supply, you need to install a rectifier bridge (diode bridge) to convert the AC voltage to DC.

2. Voltage Consideration

   • When rectifying AC voltage, the resulting DC voltage will be approximately 1.42 times higher than the AC input.
     • For example, an AC voltage of 230V will produce a DC voltage of around 325V.
   • Ensure the DC motor controller is rated for this higher voltage.

3. Important Precautions

   • Always check the motor controller’s maximum voltage rating before connecting a rectified AC supply.
   • Use additional filtering components (e.g., capacitors) to smooth out the rectified voltage for stable operation.

Summary

While a DC motor controller cannot directly operate from AC power, a rectifier bridge allows you to convert AC to DC. Just ensure the resulting DC voltage is within the controller’s operating range to prevent damage.

A common question is whether motor controllers can handle the inductive spikes generated by DC motors and whether they include adequate freewheeling diode protection. Our motor controllers are specifically designed to handle these challenges with advanced solutions.

1. Inductive Current Management

   • DC motors, being inductive loads, generate voltage spikes during operation, especially when switching or decelerating.
   • These spikes must be effectively managed to prevent damage to the controller and motor.

2. Active Half-Bridge or H-Bridge Design

   • Instead of relying on simple freewheeling diodes, our controllers use an active half-bridge or, depending on the model, a full H-bridge design:
     • This actively manages the inductive current, providing a more efficient and reliable solution.
     • These designs are capable of symmetrically conducting inductive load currents across the full operating range.

3. Problems with Simple Controllers

   • Some basic controllers, particularly those with one-way control or integrated relay-based direction switching, rely solely on undersized diodes for inductive current management.
   • These solutions are prone to failure:
     • At low speeds and high load currents, the diodes can quickly overheat or fail entirely, leading to immediate breakdowns.

4. Our Solution

   • By utilizing active bridge designs, our controllers eliminate the need for large, external diodes while providing robust protection against inductive currents.
   • This approach ensures long-term reliability and efficient operation across a wide range of speeds and loads.

Summary

The use of active half-bridge or H-bridge technology in our motor controllers guarantees effective management of inductive currents, surpassing the limitations of simple diode-based solutions. This ensures optimal performance and reliability, even under demanding conditions.

For our HLXH, FRXH, and DXH series controllers, the ultra-low energy loss design eliminates the need for additional cooling or heatsinks in most scenarios.

1. No Extra Cooling Required

   • These controllers are highly efficient, meaning that heat generation is minimal during operation.
   • In typical environments, they can operate reliably without any additional cooling measures.

2. Optional Ventilation

   • While not strictly necessary, active ventilation (e.g., a fan) can still be beneficial in certain conditions:
     • High ambient temperatures: When the surrounding environment is very warm.
     • Extended operation under heavy load: For added thermal stability and prolonged lifespan.

3. Built-In Reliability

   • The controllers are designed to handle standard operating conditions without overheating, ensuring durability and consistent performance.

Summary

Extra cooling is generally unnecessary for our controllers, thanks to their efficient design. However, in hot or demanding environments, adding a fan can provide additional peace of mind and enhance performance longevity.

Reversing the rotation direction of series-wound DC motors, which use a field winding, requires a different approach compared to permanent magnet motors. The only way to reverse the rotation is by swapping the polarity of the field winding (S1-S2). Below are some solutions for this task:

Solution 1: Using a High-Current Contactor

A high-current contactor with a dual switching circuit can reverse the field winding polarity.

1. Setup:

   • The field winding is connected in series with the motor armature.
   • The contactor switches the polarity of the S1-S2 terminals.

2. Operation:

   • The entire motor load current flows through the field winding.
   • Reversing the field polarity reverses the magnetic field, which changes the motor’s rotation direction.

Solution 2: Using a Separate Controller for the Field Winding

This solution uses a controller to manage the field winding’s polarity and current independently.

1. Setup:

   • The armature (A1-A2) is connected to one controller for speed regulation.
   • The field winding (S1-S2) is connected to a separate H-bridge controller that:
     • Supplies constant current.
     • Allows polarity reversal for directional control.

2. Advantages:

   • The armature and field can be controlled independently for optimal performance.
   • The field controller handles only the field winding current, reducing overall current demand.

Solution 3: Using an Integrated Controller

An integrated motor controller can simultaneously manage both the armature and field winding.

1. Features:

   • Simplifies the setup by combining control functions for both windings into one device.
   • Handles speed regulation, field current control, and directional changes seamlessly.

2. Application:

   • Ideal for applications requiring precise and compact control.

Summary

• For simpler setups, use a high-current contactor to reverse field winding polarity.
• For advanced control, use an independent controller for the field winding or an integrated controller for both the armature and field.
• Our motor controllers are compatible with these configurations, enabling easy and reliable implementation.

Yes, a precharge resistor is a simple yet vital addition to the power input of electronic controllers. Its purpose is to reduce the peak inrush current during startup, preventing dangerous voltage spikes at the controller’s power input.

Why Is a Precharge Resistor Needed?

When DC motor controllers are powered on, their internal capacitors—typically large in capacity—are in a discharged state. If connected directly to the power supply:

• The capacitors immediately draw a high inrush current.
• Low internal resistance of batteries (around 10 mΩ) combined with low resistance in thick power wires can lead to:
  • Sparks at the connection terminals.
  • kA-scale current spikes, causing:
    • Voltage overshoots due to inductance in power wires.
    • Potential damage to the controller’s input circuitry.

When to Pay Special Attention

1. Low-Resistance Batteries:
   High-capacity, low-resistance batteries are more likely to cause inrush issues.

2. Long Power Cables:
   Longer cables increase inductance, amplifying voltage spikes.

3. High Input Voltage Scenarios:
   If the controller’s maximum voltage rating is close to the supply voltage, the risk of damage increases.

How to Mitigate the Issue?

1. Shorten and Twist Wires:

   • Minimize cable length.
   • Twist positive and negative wires together to reduce inductance.

2. Use a Precharge Resistor:

   • Install a precharge resistor in parallel with the main power switch.
   • The resistor charges the controller’s capacitors gradually before the main switch closes.

Example Circuit with Precharge Resistor

In higher voltage applications (e.g., electric vehicles):

1. Connect a resistor parallel to the main power switch.
2. Upon initial connection, the resistor charges the capacitors.
3. After a delay, the main switch closes, bypassing the resistor and providing full power.

This arrangement prevents damaging current spikes while ensuring smooth operation.

Summary

While not always necessary, a precharge resistor is highly recommended in systems with:

• High-capacity or low-resistance batteries.
• Long power wires.
• High voltage close to the controller’s maximum rating.

If you’re unsure, feel free to contact us for guidance or detailed implementation advice!

All DC motors generate high-frequency noise due to the sparking between the brushes and commutator plates. These electromagnetic interferences (EMI) can disrupt:

• Nearby electronic circuits.
• Motor controller electronics (in rare cases).

Types of Noise

1. Radiated Noise:

   • High-frequency electromagnetic waves emitted directly by the motor.
   • Requires shielding for mitigation, which is often impractical and complex.

2. Conducted Noise:

   • High-frequency noise travels through power lines back to other connected electronics.
   • Easier to address compared to radiated noise.

How to Reduce Motor Noise

1. Using Ceramic Capacitors:

   • Install ceramic capacitors across the motor terminals to suppress conducted noise.

   • Recommended Values:

     • 10–100 nF (1 kV): General suppression in the mid-frequency range.
     • 1 nF (1 kV, Y5V type): Effective in high-frequency ranges.

   • These capacitors provide near-zero impedance at high frequencies, absorbing noise spikes.

2. Ferrite Beads on Motor Wires:

   • Place ferrite rings or beads around the motor wires.
   • Ferrite materials present high impedance to high-frequency noise, blocking interference.
   • Do not impede motor current flow.

Example Noise Suppression Circuit

A suggested arrangement includes:

• A ceramic capacitor connected directly across the motor terminals.
• Additional capacitors connected between each terminal and the motor casing (if metallic).
• Ferrite beads placed on motor wires near the motor terminals.

Summary

Effective suppression of DC motor noise involves:

1. Installing ceramic capacitors for conducted noise.
2. Using ferrite beads to block high-frequency signals on wires.
3. For critical applications, combining these measures can significantly reduce interference.

For detailed guidance or assistance in selecting the right components, feel free to reach out!

No, DC motor controllers are not suitable for driving BLDC motors.

Why Aren’t They Compatible?

1. Motor Type:

   • BLDC (Brushless DC) motors operate with three-phase windings.
   • They require a variable AC drive that provides specific phase sequences to function properly.

2. Difference in Drive Method:

   • DC motors use a simpler, direct current control approach.
   • BLDC motors need a controller that can generate the correct commutation signals for the three-phase coils.

We are currently developing specialized controllers for BLDC motors to meet these requirements.

For the DC motor controllers we develop, you can use any standard 1-10kOhm potentiometer for speed control. Additionally, standard 5V Hall effect pedals and levers can also be used, which provide an output voltage ranging from 0.8V to 4.2V.

You can also connect any other 0-5V analog signal from another source for speed regulation.

Yes, any development board can be used, whether it’s a PWM modulation signal or direct serial communication commands to control all functions. Detailed information about serial communication can be found in the datasheets.

Yes. Limit switches can be connected in various configurations. Most DC motor controllers have an Enable (EN) pin, which can be used to easily disable the output power stage. If necessary, we can program the electronics to automatically detect the limit switches and respond accordingly.

Our DC motor controllers can be controlled with direct serial communication commands for all functions. Detailed information about serial communication is available in the datasheets. Additionally, Arduino libraries and C example functions are available for easy integration.

Yes, if needed, we can program the controllers to use the Modbus RTU protocol.

Currently, two types of remote control modules are available to adjust motor speed and direction. These modules can be found here:

Yes. Each motor controller can receive PWM signals from an RC receiver.

No, the motor controller inputs are not electrically isolated. In certain applications, where the controller signal source operates at different potentials, an optical isolator may be necessary. This can be easily implemented using optocouplers, as detailed in the diagram below, or by using an available optical isolation circuit, which can be used for isolating serial communication or logic and PWM inputs.