Application Support

Introducing Ceramic Capacitors for Use in Factory Automation (FA)

Factory Automation
In the area of factory automation (FA*1), the smart factory trend has led to a heightened need for smaller devices, improved reliability and higher heat resistance. While in the area of ceramic capacitors, the commercialization of products that are compatible with a wider capacitance range and that support higher withstanding voltage specifications is being promoted. 
Here, we introduce examples of circuits, for power supplies and inverters that are actually used in FA applications, and examples of electrolytic capacitors and film capacitors being replaced with multilayer ceramic capacitors and the main points concerning this replacement. 

 

*1 FA:Factory Automation




Factory Automation
Factory Automation
Factory Automation
Factory Automation

Murata Icon X Factory Automation Block Diagram

Factory Automation

Fig.1 Factory Automation Block Diagram


The above figure shows a general block diagram illustrating factory automation.
FA is made up of PLCs, inverter drivers, AC servomotors, various power supplies, and other devices.

Here, we introduce an example of a circuit that uses AC/DC and DC/DC converters and a circuit that uses an inverter.

Murata Icon X Example of Applied Circuit (AC/DC converter, DC/DC converter)

Factory Automation

Fig.2 AC/DC DC/DC Converter Block Diagram


The above is an example of a general circuit for an AC/DC converter and 
a DC/DC converter.


(1) Safety Certified capacitors are required for AC line filters (C1, C2) and coupling capacitors (C3) in primary and secondary coupling.

Type Class
SMD X1/X2/Y2
GA3 Series, Safety Standard Certified Chip Multilayer Ceramic Capacitors for General Purpose 
Lead X1/Y1
DE1 Series, Safety Standard Certified (X1,Y1) Lead Type Ceramic Capacitors for General Purpose
X1/Y2
DE2 Series, Safety Standard Certified (X1,Y2) Lead Type Ceramic Capacitors for General Purpose

(2) Low-loss capacitors are required for snubber capacitors (C5, C6), since high-frequency switching is applied. 

Accordingly, temperature compensation-type (Class 1) capacitors are recommended.  
On the other hand, for C7, high capacity is required since high frequency noise components must be removed. For this, high dielectric constant (Class 2) capacitors are recommended.

Factory Automation

Fig.3 Example of DC Bias by Temperature Characteristics

Type
SMD
GRM Series, Chip Multilayer Ceramic Capacitors for General Purpose 
GR3 Series, High Effective Capacitance & High Ripple Current Chip Multilayer Ceramic Capacitors for General Purpose
Lead RDE Series, Lead Type Multilayer Ceramic Capacitors for General Purpose 

(3) Relatively large-capacity capacitors are required for smoothing capacitors (C4, C8) to remove low-frequency noise.

Type
SMD
KRM Series, Metal Terminal Type Multilayer Ceramic Capacitors for General Purpose
KR3 Series, High Effective Capacitance & High Ripple Current Metal Terminal Type Multilayer Ceramic Capacitors for General Purpose
Lead RDE Series, Lead Type Multilayer Ceramic Capacitors for General Purpose


Murata Icon X Example of Applied Circuit (inverter circuit)

Factory Automation

Fig.4 Inverter Circuit


The above is an example of a general circuit for an inverter.


Removal of the high-frequency noise component is required for snubber capacitors (C1).
Type
SMD
KRM Series, Metal Terminal Type Multilayer Ceramic Capacitors for General Purpose
KR3 Series, High Effective Capacitance & High Ripple Current Metal Terminal Type Multilayer Ceramic Capacitors for General Purpose 
Lead RDE Series, Lead Type Multilayer Ceramic Capacitors for General Purpose

Murata Icon X Replacing Film Capacitors and Electrolytic Capacitors

Reason behind replacement with Monolithi Ceramic Capacitors
In recent years, switching elements, and in particular, power converters, have become able to support higher frequencies and to be driven at higher temperatures. For reasons such as these, practical applications for increasing efficiency have been promoted, which has led to a higher demand for smaller components that are compatible with high temperatures. monolithi ceramic capacitors have good impedance characteristics at high frequencies and are compatible with high temperatures. Because of these advantages, replacement with monolithi ceramic capacitors is being promoted even in areas where electrolytic capacitors and film capacitors have been traditionally used.  
The following introduces the main points and advantages of replacement and an actual example.

Fig. 5 Rated Voltage and Capacitance Range


Factory Automation

Fig. 6 Impedance Frequency Characteristics 10μF

When replacing a film or electrolytic capacitor with a monolithi ceramic capacitor, the capacity does not necessarily have to match. Because MLCCs have extremely outstanding impedance characteristics at high frequencies, they can be used even at capacities lower than that of film or electrolytic capacitors if they are on the high frequency side at around 100 kHz.



Factory Automation


The maximum allowable working temperature of monolithi ceramic capacitors is 125°C, which makes them ideal for use in hot environments.
In applications, particularly those such as power converters, where higher efficiency is required, components have been developed to support higher frequencies and are being driven at higher temperatures. monolithi ceramic capacitors support the downsizing of circuit boards and provide greater freedom in design because of their resistance to high temperatures, which makes them suitable for use in hot environments, and their ability to be mounted closer to heat generating sources. Also, in recent years, attention has been focused on the shift over to monolithi ceramic capacitors because of the trend of using entirely SMD components to reduce mounting costs.
For example, as shown in Fig. 7, when there is a high-temperature, heat-generating source, film capacitors had to be mounted away from the heat-generating source in order to withstand the hot environment. However, by replacing traditional capacitors with monolithi ceramic capacitors, SMD components can now be mounted closer to heat-generating sources.


Factory Automation

Fig.7 How Replacement with Monolithi Ceramic Capacitors Works 



Main points in replacement with monolithi ceramic capacitors

Case 1: Replacement of a snubber capacitor film capacitor with a monolithi ceramic capacitor 
The number of cases where replacement is being promoted in power converters is on the increase.

Case1


Case 2: Replacement of a smoothing capacitor electrolytic capacitor with a monolithi ceramic capacitor

Although it is highly difficult to replace because of the capacitance required, replacement in some applications has begun.

Case2


Lineup of ceramic capacitors


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