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Brief Analysis of PWM Controller

Brief Analysis of PWM Controller

(Summary description)The biggest difference between a voltage source and a current source is that one is the load that determines the current, and the other that the load determines the voltage.

Brief Analysis of PWM Controller

(Summary description)The biggest difference between a voltage source and a current source is that one is the load that determines the current, and the other that the load determines the voltage.

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The biggest difference between a voltage source and a current source is that one is the load that determines the current, and the other that the load determines the voltage.

Cheap pwm controller

The pwm controller is effective for both voltage source and current source control, and can change the average voltage or average current. The same method used to analyze voltage pwm control can also be used to analyze current pwm control (exchanging capacitance and inductance).
Taking ac-dc-ac as an example, the voltage-type DC side has a large capacitor, and the voltage ripple is small, which can be approximated to a constant voltage source, and the voltage cannot be reversed. The current-type DC side series has a large inductance, and the current ripple is small, which can be approximated as a constant current source, and the current cannot be reversed.
From the point of view of the inverter circuit, since the current of the current type cannot be reversed, but the voltage can be reversed, the anti-parallel reactive feedback diode used in the voltage type is not required. When the motor is driven, the current type is easier to achieve regenerative braking.
In terms of inverter loads, the voltage type is suitable for loads that exhibit high impedance to harmonic currents, such as inductors. The current type is suitable for loads with low harmonic impedance, such as capacitors. Therefore, when controlling the motor, the current type needs to be connected in parallel with a capacitor. When a similar voltage type is connected to a capacitive load, an inductor needs to be connected in series.
The current type may be inductive because the load is mostly inductive, and the DC side inductance is often large and bulky, and there are few applications, so there are too few contacts.

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