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









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.

This page provides circuit examples for AC/DC and DC/DC converters, examples of inverter circuits, and examples of power supplies for circuit breakers.

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.

Our new products rated at AC 400 V and AC 500 V are suitable for AC 400-V and AC 690-V AC/DC converters.

Type Safety standard subclass
Rated voltage

SMD X1/X2/Y2
AC250V
GA3 Series, Safety Standard Certified Chip Multilayer Ceramic Capacitors for General Purpose 
Lead X1/Y1
AC500V
DE1 Series General use Safety standard certified (X1, Y1) Lead-type ceramic capacitor Type RA
X1/Y1 AC500V
(X1 760V)
DE1 Series General use Safety standard certified (X1, Y1) Lead-type ceramic capacitor Type RB
X1/Y2
AC400V
DE2 Series General use Safety standard certified (X1, Y2) Lead-type ceramic capacitor Type SA

(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)

Murata Icon X Circuit example (power supply for circuit breaker)

Fig. 5 Power supply for circuit breaker

The above example shows a power supply used in a circuit breaker.

(1) Smoothing capacitors (C1) must be relatively large capacitors to eliminate low frequency noise.

Type
SMD
GR3 Series General use chip multilayer ceramic capacitor with highly effective capacitance and high ripple-current resistance
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

(2) Primary and secondary coupling capacitors (C2) must be capacitors that have obtained safety standard certification.
AC 500-V and AC 400-V rated products are suitable for supplying power to breakers through high impulse resistance.

Type Safety standard subclass
Rated voltage

Lead X1/Y1
AC500V DE1 Series General use Safety standard certified (X1, Y1) Lead-type ceramic capacitor Type RA
X1/Y1
AC500V
(X1 760V)
DE1 Series General use Safety standard certified (X1, Y1) Lead-type ceramic capacitor Type RB
X1/Y2
AC400V DE2 Series General use Safety standard certified (X1, Y2) Lead-type ceramic capacitor Type SA

Murata Icon X Replacing Film Capacitors and Electrolytic Capacitors

Reason behind replacement with Multilayer 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. Multilayer ceramic capacitors have good impedance characteristics at high frequencies and are compatible with high temperatures. Because of these advantages, replacement with multilayer 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. 6 Rated Voltage and Capacitance Range


Factory Automation

Fig. 7 Impedance Frequency Characteristics 10μF

When replacing a film or electrolytic capacitor with a multilayer 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 multilayer 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. Multilayer 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 multilayer 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 multilayer ceramic capacitors, SMD components can now be mounted closer to heat-generating sources.


Factory Automation

Fig.8 How Replacement with Multilayer Ceramic Capacitors Works 



Main points in replacement with multilayer ceramic capacitors

Case 1: Replacement of a snubber capacitor film capacitor with a multilayer 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 multilayer 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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