High Voltage Capacitor DC Photovoltaic Capacitors Svg Capacitors Inverter Capacitor

• Type: Polypropylene Capacitor
• Application: General Purpose, AC / Motor, Power, Air Conditioner, High Voltage, Automobile
• Packaging Type: Surface Mount
• Shipping Cost: Estimated freight per unit.: about shipping cost and estimated delivery time.
• Currency: US$
• Return&refunds: You can apply for a refund up to 30 days after receipt of the products.
• Model NO.: DC Link
• Capacitance: 25~4500UF
• Structure: Fixed Capacitor
• Manufacturing Material: Polypropylene
• Transport Package: Carton
• Specification: DC Link
• Trademark: SMILER
• Origin: Guangdong, China (Mainland)
• Production Capacity: 50, 000 PCS Per Day

Product Description

 
  

• Compensate for the difference between the power required by the inverter and the output power of the rectifier bridge that changes by two or six times the power frequency;

 

• Provide input current of switching frequency of inverter or freight frequency converter;

 

• Reduce the current harmonic of switching frequency into the power grid;

 

• Absorb the demagnetization energy of the motor when all power switching devices are turned off in the emergency stop state;

 

• Provide instantaneous peak power;

 

• Protect the inverter or frequency converter from the impact of the instantaneous peak value of the power grid.

 

  

As the core component of dc/ac converter, DC bus capacitor mainly plays the role of bus voltage support and ripple suppression. As the buffer unit of DC and AC converter, the capacity of DC bus capacitor not only directly determines the fluctuation amplitude of DC bus voltage, but also affects the output waveform of the converter; Moreover, its capacity is directly related to its own cost and volume.Therefore, how to select and determine the DC bus capacitance of dc/ac converter is very important.

In engineering applications, the DC bus capacitance of three-phase dc/ac converter is mostly obtained through engineering experience and combined with actual test and adjustment. However, this method not only consumes a lot of manpower and material resources, but also has low efficiency. In addition, in the prior art, there are also some schemes for DC capacitor type selection design from the calculation method, such as determining the effective value of ripple current of DC capacitor by calculating the ripple factor of DC capacitor, and then carrying out the type selection design of bus capacitor, or calculating and determining the capacitor capacity through the charge accumulation at the midpoint of the capacitor in the PWM modulation wave period; However, the calculation methods in the existing technology only give the design scheme of the DC bus capacitance of the three-level dc/ac converter from a single point of view, and do not comprehensively consider the synchronous requirements of the DC bus capacitance and withstand ripple current, which is not conducive to the selection in practical application.

The role of DC bus capacitance in frequency converter or inverter

When the frequency converter has inductive load, the reactive energy can only be buffered by the energy storage element of the filter in the DC link. Voltage type inverter uses capacitance to store energy, while current type inverter uses inductance to store energy. There are the following types:;

• Compensate for the difference between the power required by the inverter and the output power of the rectifier bridge that changes by two or six times the power frequency;
• Provide input current of switching frequency of inverter or freight frequency converter;
• Reduce the current harmonic of switching frequency into the power grid;
• Absorb the demagnetization energy of the motor when all power switching devices are turned off in the emergency stop state;
• Provide instantaneous peak power;
• Protect the inverter or frequency converter from the impact of the instantaneous peak value of the power grid.

Parameters and selection of DC bus capacitance

Calculate the following parameters for DC bus capacitance; Therefore, the main factors to be considered in model selection are:

DC bus voltage: its voltage shall be considered first in the selection process; Select the withstand voltage of the capacitor according to the actual voltage.

Capacity of capacitor: This is mainly judged according to the power of capacitor.

Ripple current of capacitor: select a capacitor that can withstand higher ripple current.

Temperature rise and heat dissipation of capacitor: generally, the capacitance is 105 degrees.

Service life of capacitor: its service life is not only related to the problems of the capacitor itself, but also related to the above parameters. Improper selection will affect its service life.

These parameters are very important to the performance of frequency converter and inverter.