Installation and heat dissipation of Bonfiglioli Vectron cold plate frequency converter

Installation and heat dissipation of Bonfiglioli Vectron cold plate frequency converter

Introduction: The Engineering Value of Cold Plate Inverter

In industrial drive applications, the heat dissipation problem of frequency converters has always been a key factor restricting power density and reliability. Traditional air-cooled frequency converters rely on built-in fans and heat sinks for convective heat dissipation, but in high protection level cabinets, high temperature or dusty environments, fans are prone to aging, heat dissipation efficiency decreases, and occupy a large installation space. The ACT/ACU series "Cold Plate" frequency converter launched by Bonfiglioli Vectron conducts the heat of power devices (rectifier bridge, IGBT) directly to an external cold plate, and then uses a user designed heat dissipation base, liquid cooled plate or rack structure for secondary heat dissipation, thereby eliminating the dependence on built-in fans and achieving higher protection levels and more compact system integration.

The difference between this cold plate variant (model suffix with "C", such as ACT xxx xxx C) and the standard version is only the radiator design, electrical performance, control functions, and software are completely consistent. This article is based on the official cold plate installation manual of Bangfeili, systematically sorting out its technical parameters, thermal resistance calculation, mechanical installation, and temperature monitoring points, providing on-site engineers with a complete technical guide for engineering practice.

Product variants and supply scope

Cold plate frequency converters are divided into three major structural sizes according to power levels, and the corresponding supply contents may vary slightly:

Low power (ACT/ACU 201 0.55~3.0kW; 401 0.55~4.0kW): includes the inverter body, main circuit plug-in terminals (X1 for power/DC bus, X2 for braking resistor/motor), relay output terminal X10, control terminal X210A/B, as well as paper installation instructions and a CD ROM with a complete manual. This type of model does not come with standard heat sinks, and users need to prepare their own installation base.

Medium power (ACT/ACU 201 4.0~9.2kW; 401 5.5~15.0kW): The inverter body, X10 terminals, control terminals, and documentation are also provided, but the main circuit terminals are fixed (non plug and play) and do not have independent power/motor terminal blocks. They need to be directly connected to the internal screw terminals of the inverter.

High power (ACT/ACU 401 18.5-30.0kW): The supply range is similar to medium power, but the size is larger, weighing up to 8.0kg, and the installation holes are correspondingly expanded.

All cold plate models are not equipped with built-in cooling fans and rely entirely on external cooling media. After receiving the goods, it is necessary to inspect the appearance and quantity within 7 days. If there is any damage, the carrier must be notified immediately to maintain insurance rights.

Key technical parameters and power levels

The rated data of the cold plate frequency converter is indicated by the recommended motor shaft power (kW), while providing thermal design key values such as energy dissipation (Pv) and thermal resistance (Rth). Classified by voltage level and power range:

3.1 230V level (ACT/ACU 201)

Model suffix Motor power (kW) Heat dissipation Pv (W) @ 2kHz Internal dissipation Pint (W) Thermal resistance Rth (K/W) Appearance (H × W × D) mm

05~15 0.55~3.0 43~170 12~31 0.93~0.24 190×82×140 / 250×85×140

18~22 4.0~9.2 200~420 35~68 0.20~0.10 250×125×144 / 250×150×144

3.2 400V level (ACT/ACU 401)

Model suffix Motor power (kW) Heat dissipation Pv (W) @ 2kHz Internal dissipation Pint (W) Thermal resistance Rth (K/W) Appearance (H × W × D) mm

05~18 0.55~4.0 40~115 12~31 1.00~0.35 190×82×140 / 250×85×140

19~25 5.5~15.0 145~310 48~107 0.24~0.11 250×125×144 / 250×150×144

27~31 18.5~30.0 420~750 160~265 0.08~0.05 250×225×171

All data is based on a switching frequency of 2kHz. If the switching frequency is increased, the output current needs to be reduced (refer to the standard manual for details). The thermal resistance value is measured under the condition of no forced airflow and sufficient space reserved in all directions (up/down ≥ 300mm, left/right ≥ 100mm).

Principles of Thermal Management and Thermal Resistance Calculation

The heat dissipation path of the cold plate frequency converter is: power chip → internal thermal conductive medium → cold plate (i.e. the metal plate at the bottom of the frequency converter) → external installation base (user provided heat sink or liquid cooling plate) → environment. Thermal resistance Rth is a key parameter for measuring heat dissipation capability, defined as:

Rth=Tk  max−TuPv

R th= P vT kmax−T u

among which 

Tkmax The maximum allowable temperature for the cold plate is 75 ° C for low power (≤ 3kW) and 70 ° C for medium/high power (≥ 4kW) (note: the manual states that 4~18.5kW is 70 ° C, and 30kW is not separately specified but recommended for reference);

Tu The ambient temperature around the cold plate (typically designed at 35 ° C, but can also be adjusted according to actual operating conditions);