A thermoelectric cooler (TEC) module is a solid state device which can control heat flux using current. It is very useful in small scale temperature control, providing fast temperature response and ultra-high temperature stability. TEC temperature control equipment can also be very compact and green. No mechanical moving or hot/cold material consumption is needed.
Chroma’s Advanced TEC Controllers have an excellent temperature monitoring engine, which allows 2 T-type thermocouple inputs. The cold junction of the engine is internally stabilized up to 0.001℃, for that 0.01℃ temperature resolution and control stability can be achieved. The TEC driver uses a filtered PWM architecture, which obtains high driving power efficiency as ordinary PWM drivers have, but smoothens the current modulation to a DC-like output. It’s very important for electro-magnetic sensitive measurements.
Another important feature of Chroma’s Advanced TEC Controllers is the true TEC PID auto tune function. Chroma’s Advanced TEC Controllers have unique auto tune algorithm to guarantee the best control and temperature response. Stability down to the temperature resolution, which is 0.01℃, is regularly achieved regardless the size and geometry of thermal platforms.
High TEC driving capability is another merit of Chroma’s Advanced TEC Controllers. Chroma’s Advanced TEC Controllers deliver 300W and 800W for high power TEC driving. More TEC driving power means wider temperature range, faster temperature response, and larger platform applications. For comparable accuracy and stability, Chroma offers one of the best TEC driving power to price ratio in the market.
Excellent Thermal Response, Temperature Precision, and Control Stability
TEC module is a bi-directional heat pump controlled by current. So a temperature control system with TEC modules can reach temperatures higher or lower than ambient. Compared with traditional temperature control methods, this is compact, fast responding, and using only one controller.
Though there are many special features for TEC modules, users still need good TEC controllers to get all the benefit. Chroma’s Advanced TEC Controller is specially designed for optimal performance of TEC temperature cont rol. Changing temperature from one to another can be very fast. There is no overshoot or minimal overshoot approaching the target temperature. When thermal perturbation happens, even for a 100W on/off perturbation, Chroma’s Advanced TEC Controllers can often reduce the temperature variation to less than 1℃ within few seconds. As temperature stability is concerned, Chroma’s Advanced TEC Controllers offer 0.01℃ stability in most cases.
Using Chroma’s TEC method, rising and falling of temperature is about 5~60℃ per minute.
High Driving Capability
There were many small output power TEC controllers in the market mainly for small devices and small scale lab tests. As technologies grow, higher TEC driving power than before is demanded in many new applications. For example, testing solar cells larger than 4 inch squares from -20℃ to 85℃ requires more than 100W TEC driving power, not to mention the thermal load of sunlight can be 30W or more. High power-LEDs for lighting have great concerns about their thermal property. 30 W-LED module testing from -20℃ to 150℃ also demands high TEC driving power.
Chroma’s Advanced TEC Controllers can deliver 300W/800W TEC driving power, satisfying needs from small to large platforms. In typical applications, many pieces of high power TEC modules can be driven by a controller output. For the cost of every driving power, Chroma offers very competitive solutions.
High Temperature Accuracy and Resolution
TEC controllers using thermocouple in market usually have accuracy about 1℃ and resolution 0.1℃. This is not good enough for many applications. For example, rating solar cell power efficiency needs temperature accuracy much less than 1℃. Phase change of some material can happen within 0.1℃ or less. Some biochemical process can be ver y sensitive to a critical temperature. Thermal resistance measurement of heat pipes often results in a temperature deviation much less than 1℃. Some high resolution TEC controllers are using different types of temperature sensors, such as RTD, temperature IC, or thermistors. Unfortunately, these temperature sensors can have trouble for metal contact, or too bulky to measure the point of interest.
Chroma’s Advanced TEC Controllers are thermocouple based and with temperature accuracy* 0.3℃ and resolution down to 0.01℃. Users can take advantage of thermocouple for easy measurement setup, while maintain high accuracy and resolution. This means users can achieve test results with high repeatability, high accuracy, and therefore high confidence.
True Large-Signal PID / Auto Tune for TEC Control
PID control is an important feature for a good controller. The PID parameters basically describe the dynamic response of a system and can be very different from one to another. It does not guarantee a successful control unless proper PID parameters are set. It is very painful and time consuming to search for PID parameters manually. So an advanced controller should feature PID auto tune function.
Many other TEC controllers use a small signal and one-directional temperature transient to find PID parameters. This auto tune method is OK for heater only temperature control, but not always successful for TEC control. In order to truly match the thermal response of a TEC control system, Chroma’s Advanced TEC Controllers use a large signal and bi-directional driving method for PID auto tune. This proprietary method results in the superb temperature control behavior, which is fast, precise, and very stable. While some other TEC controllers require a set of PID parameters for every 20℃ interval, Chroma’s Advanced TEC Controllers need only a set of optimal PID parameters (usually auto tuned at 40~50℃) to cover all operation from -70 to 250℃.
Available for Chroma’s Advanced TEC Controller are graphical softpanels which allow for intuitive control and measurements. Viewing TEC current and temperature vs. time curves, recording data to a file, and running temperature cycling, ramping sub-programs, etc., are all provided. PID parameters, current limit, and other important settings can also be read and set from a pop-up setup windows.