Some performance comparisons between diode rectification and PWM rectification?

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Some performance comparisons between diode rectification and PWM rectification? [Copy link]

The inverter uses diode rectification and PWM rectification. Compare several important parameters. How big is the difference between the power factor, voltage harmonics, and current harmonics on the grid side under different loads? Take a 500KW380V rectifier unit as an example?

Moreover, for PWM rectification with feedback function, how to judge and calculate the power fed back at different times and the amount of energy fed back over a period of time?

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There are significant differences in performance between diode rectification and PWM rectification. The following are some of the main performance comparisons between the two:

1. Diode Rectification

1. working principle :
   • The unidirectional conductivity of the diode is used to convert alternating current into direct current.
   • Current can only flow into the positive terminal of the diode and out of the negative terminal.
2. Performance characteristics :
   • Advantages : simple structure and low cost.
   • shortcoming :
     • Uncontrollability: Electric energy can only be transmitted from the AC side to the DC side, and the output voltage is uncontrolled.
     • Both the output voltage and input current contain large ripple and harmonic components.
     • Due to the unidirectional conductivity of the diode, bidirectional flow of energy is not possible.
3. Common parameters :
   • Maximum average rectified current IF: refers to the maximum average forward current allowed to pass through the diode when it works for a long time.
   • Maximum reverse operating voltage VR: refers to the maximum reverse voltage allowed to be applied across the diode.

2. PWM Rectification

1. working principle :
   • It uses fully controlled power electronic devices and realizes rectification through PWM control technology.
   • It can not only work in rectification and inversion state, but also in power factor controllable state.
2. Performance characteristics :
   • advantage :
     • Strong controllability: The output voltage is controllable, and the DC power can be fed back to the AC power grid.
     • The harmonic components in the input current are greatly reduced, improving the power quality.
     • Energy can flow in both directions, which is suitable for situations where energy feedback is required.
   • Disadvantages : relatively complex structure and high cost.
3. special function :
   • It is suitable for applications that require high-precision control, high-efficiency conversion, and low harmonic pollution.
   • It is widely used in electric vehicles, UPS power supplies, wind turbines and solar power generation systems.

Summarize:

Diode rectification and PWM rectification each have their own advantages and disadvantages. Diode rectification has a simple structure and low cost, but the output voltage is uncontrollable and has a large harmonic content; although PWM rectification has a complex structure and high cost, it has excellent controllability and power quality, and is suitable for occasions with high requirements for power quality. When choosing a rectification method, you should weigh it according to the specific application scenario and needs.