Abstract: Uses the single quadrant electric circuit in the traditional entire bridge electric circuit’s foundation to study the new electric circuit, achieves expands the existing electric circuit analysis situs application domain the goal. Introduced the voltage double quadrant Buck, Boost, Buck/Boost electric circuit as well as to their switch component shutdown and the clear analysis.
Key word: Converter; Analysis situs; Double quadrant; Voltage control
Introduction
Does not have the electrical energy changing pattern in the direct-current transformation, only has the direct-current electrical parameter change. The DC/DC converter has the cost to be low, the weight is light, the reliability is high, structure simple and so on characteristics, therefore, obtained the widespread application in the industrial field and the laboratory. The single quadrant DC voltage converter electric circuit’s characteristic is output voltage mean value Uo the followed dutyfactor D value changes, no matter but D is what value, the Uo polarity is invariable throughout, this is can satisfy the request regarding a direct-current switch voltage-stabilized source kind of application place. But regarding the direct-current velocity modulation power source, the load for the direct-current electrically operated machine-hour, the above performance then cannot satisfy the request, thus has developed the multi-quadrant DC voltage transfer network.
The reflection image limits power consumption the road to divide into the output current mean value Io polarity invariable electric circuit and the output voltage mean value Uo polarity invariable electric circuit two kinds, usually the preceding kind of electric circuit is called the electric current reflection image to limit power consumption the road, the latter kind of electric circuit is called the voltage reflection image to limit power consumption the road. The electric current reflection image limits power consumption the road is refers to output current mean value Io the peak-to-peak value and the polarity changes along with control signal us, but output voltage mean value Uo polarity actually throughout for positive, namely the electric circuit may move in first and the second quadrant. The voltage reflection image limits power consumption the road is refers to output voltage mean value Uo the peak-to-peak value and the polarity changes along with control signal us, but output current mean value Io actually throughout for positive, namely the electric circuit may move in first and the fourth quadrant. This article electric circuit will carry on the analysis to voltage double quadrant Buck 睟 the oost.
1 Buck electric circuit
1.1 circuit structures
Main circuit as shown in Figure 1. With the inductance, the interface resistance and the equivalent voltage series circuit expresses the active load, bridge’s direct-current input end parallel filter electric capacity. This is an entire bridge circuit structure, bridge’s each arm with all controls the component (S1, S2) and does not control the component (D1, D2) to compose. S1 and the S2 control uses the PWM control, like this may adjust the D value, and examines the load promptly the movement condition, from this controlling switch’s shutdown and clear. This electric circuit’s primary device, power source, load supposition for ideal. The output filter inductance is big enough, may guarantee that the load current is continual, and linear fluctuation.
1.2 principles of work
1.2.1 movements in the first quadrant
This is refers to the output terminal voltage mean value and the average current is the active status.
(0≤t≤DT) S1 and S2 even breakover, equivalent circuit like
Shown in Figure 2(a), output voltage Uo is Ud, the input current is equal to the output current, the output current linearity grows, load from power source absorption energy.
(DT≤t≤T) the S1 breakover, the S2 separation, the D1 copper bias after flow, equivalent circuit as shown in Figure 2(b), as a result of S1 and the D1 breakover, the Uo value is zero.
The output voltage mean value is Uo=DUd
1.2.2 movements in the fourth quadrant
This is refers to the output terminal voltage mean value for negative, but average current for active status. When electric circuit load for electric motor, and actuation potential energy load, if hoist’s raising mechanism, when lays down the heavy item, the electrical machinery reverses under the heavy item function, the armature inductance electric potential is reverse, the electromagnetism torque becomes the brake torque, to assure the security, must change the control signal the polarity and the peak-to-peak value, causes the electric circuit work in the fourth quadrant, feeds back the potential energy after the transfer network to the direct-current power supply. The concrete work process is as follows.
(DT≤t≤T)S1 and S2 separates, the inductance terminal voltage is reverse, the D1, D2 copper bias breakover, equivalent circuit as shown in Figure 3(a), output voltage Uo is - Ud, the load feedback energy.
(0≤t≤DT) the S1 separation, the S2 breakover, the load current trades in S2 from D2. Equivalent circuit as shown in Figure 3(b), the Uo value is zero.
The output voltage mean value is Uo=-DUd
As shown in the above analysis this electric circuit and the control policy may realize the double quadrant Buck electric circuit function.
2 Boost electric circuits
2.1 circuit structures
Main circuit as shown in Figure 4. In the chart S1, S2, S3 is all controls the component, D1 and D2 does not control the component. The load is still the active load, directs current the input end series inductance. The S1, S2, S3 control uses the PWM control, this electric circuit’s primary device, power source, load similar supposition for ideal. The output filter inductance is big enough, may guarantee that the load current is continual, and linear fluctuation. May see, this electric circuit’s design concept is also uses the entire bridge to realize the double quadrant movement, its advantage lies in is simple, is reliable.
2.2 principles of work
2.2.1 movements in the first quadrant
(DT≤t≤T)S1 the separation, S2 and the S3 even breakover, equivalent circuit as shown in Figure 5(a), inductance voltage UL=Ud-Uo.
0≤t≤DT) the S1, S2, S3 even breakover, equivalent circuit as shown in Figure 5(b), inductance voltage UL=Ud.
The output voltage mean value is Uo=Ud/(1-D)
2.2.2 movements in the fourth quadrant
(DT≤t≤T) S1, S2, S3 separates, the inductance terminal voltage is reverse, D1 and the D2 copper bias breakover, equivalent circuit as shown in Figure 6(a), inductance voltage UL=Ud Uo.
(0≤t≤DT) the S1 breakover, S2 and S3 separate, equivalent circuit as shown in Figure 6(b), inductance voltage UL=Ud.
The output voltage mean value is Uo=-Ud/(1-D)
3 Buck-Boost electric circuits
3.1 circuit structures
Main circuit as shown in Figure 7. In the chart S0, S1, S2, S3, S4 is all controls the component. The load is still the active load, directs current input end shunt inductance Lo. All switches use the PWM control, this electric circuit’s primary device, power source, load similar supposition for ideal. The output filter inductance is big enough, may guarantee that the load current is continual, and linear fluctuation. This electric circuit is the main switch and the inductance exchanges the position mutually with the double quadrant Boost electric circuit difference. Is also uses single quadrant Buck 睟 the oost electric circuit’s main circuit to grow, and all controls the electric circuit using the entire bridge to realize the double quadrant function. Change dutyfactor D may realize pressure-rise or the voltage dropping function.
3.2 principles of work
3.2.1 movements in the first quadrant
(0≤t≤DT) the S0, S1, S2 even breakover, S3 and the S4 separation, equivalent circuit as shown in Figure 8(a), inductance voltage UL=Ud.
(DT≤t≤T) S0, S1 and the S3 separation, S2 and the S4 breakover, equivalent circuit as shown in Figure 8(b), inductance voltage UL=-Uo.
3.2.2 movements in the fourth quadrant
(DT≤t≤T) the S0, S2, S4 separation, S1 and the S3 breakover, the inductance terminal voltage is reverse, equivalent circuit as shown in Figure 9(a), inductance voltage UL=Uo.
(0≤t≤DT) the S0, S3, S4 breakover, S1 and the S2 separation, equivalent circuit as shown in Figure 9(b), inductance voltage UL=Ud.
The output voltage mean value is Uo=-DUd/(1-D)
4 conclusions
This article in traditional single quadrant Buck, Boost, the Buck-Boost electric circuit basically grew double quadrant Buck, Boost, the Buck-Boost electric circuit, and has analyzed its concrete work process. This article analysis limited power consumption Lu Ji for the reflection image to direct current transfer network’s research to provide the new mentality.
