Simulink simulation circuit model of open loop buck buck buck chopper circuit based on MATLAB

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BUCK How the circuit works

Buck The working principle of the converter in the inductive current continuous mode is as follows ： The on and off of the switch are controlled by the driving pulse output by the control circuit . When the control circuit pulse output is high , The switch tube is on , The freewheeling diode D The anode voltage is zero , Cathode voltage is voltage Us, Reverse cut-off , Current flows through the switch is Flow through the inductor L Directional load R Power supply ; here L The current in the increases gradually , stay L The self induced potential at both ends, which is positive at the left end and negative at the right end, prevents the current from rising ,L Convert electrical energy into magnetic energy for storage . After time ton after , The control circuit pulse is low , Switch off , but L The current in the must not jump , Inductance at this time L Both ends generate a positive self induced potential at the right end and a negative self induced potential at the left end, preventing the current from falling , So that D Forward bias conduction , therefore L The current in passes through D Make up the loop , Current value Gradual decline ,L The magnetic energy stored in is converted into electrical energy and released to supply the load R. After time toff after , The control circuit pulse turns on the switch tube , Repeat the process . filter Wave capacitance C Its function is to reduce the output voltage Uo The pulse of . The freewheeling diode D Is an essential component , Without this diode , Not only does the circuit not work properly , And when the switch tube changes from on to off ,L High self induced potential will be generated at both ends, which will damage the switch tube .

（ The picture comes from the Internet ）

One 、 About buck Open loop simulation circuit construction

be based on Matlab Of Simulink Simulation circuit construction .

Two 、 Parameters given

1. Pulse signal setting

The pulse signal here is given as frequency 40kHz、 Duty cycle 37.52%、 The peak value is 1.

2. Parameters of other components are given

DC supply voltage 15v、 inductance 5mH、 capacitance 10uF、 Load resistance 2.5 o ;
The buck A circuit is an input 15v Output voltage 5v, electric current 2a、 The ripple size cannot exceed 1%.

3、 ... and 、 Data processing

1. Waveform ripple measurement

It can be seen from the figure that the current ripple error is 0.9%=（2.054-2.036）/2;

It can be seen from the figure that the voltage ripple error is 0.06%=（5.116-5.113）/5;

2. Overall waveform observation

It can be clearly seen from the figure that the time for the system to reach stability is short , Meet the target task requirements .

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summary

That's what we're going to talk about today , This article only briefly introduces based on Matlab Of Simulink Simulation buck Construction of step-down chopper circuit , So that we can quickly and conveniently buck Circuit simulation and data processing .