RU2490776C1 - Resonance commutator switch (versions) - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: device contains the first key (1) with back-to-back connected diode, the second key (2), capacitor (3) and inductor (4) connected in-series with the first key (1); output of the anode of back-to-back connected diode forms a negative power lead of the resonance commutator switch while output of the inductor (4) connected to one output of the second key forms a positive power lead of the resonance commutator; it is assumed that the capacitor (3) is connected in parallel to the second key (2) which second output is connected to the negative power lead of the resonance commutator switch.

EFFECT: reducing dynamic losses in power commutator switches of pulse-type regulators, inverters and active front ends.

4 cl, 10 dwg

Description

The invention relates to power electronics, in particular to converters with reduced dynamic losses in power semiconductor switches, and can be used in circuits of switching DC voltage regulators.

A known converter circuit in which, using elements of a resonant LC circuit, provides soft switching of transistors at zero current (see US patent No. 4720667, publ. 19.01.1988).

The disadvantage of this solution is that the conduction interval in the circuit is fixed. In this case, the regulation of the output voltage and power in the circuit can be done only by the frequency method.

The closest in technical essence is the resonant switch (see Barbi I., Bolacell J., Martins D., Libano F. “Buck Quasi-Resonant Converter Operating at Constant Frequency: Analysis, Design and Experimentation”, IEEE, 1989, pp873 -880), which includes the first key with an anti-parallel diode, the second key, a capacitor and a choke connected in series with the first key, the output of the anode of the anti-parallel diode forms a negative power terminal of the resonant switch, and the output of the choke connected to one terminal of the second key, forms a positive power terminal of the resonant switch pa

This solution provides soft switching of the keys at zero current, and locking the second key allows you to adjust the conduction interval by temporarily interrupting the resonance process by disconnecting the capacitor from the resonance circuit. In this case, pulse-width regulation of the output voltage and power is possible in the circuit. However, during the entire conduction interval, the switched off capacitor has an accumulated charge, which gradually decreases due to leakage currents. Therefore, at relatively large conduction intervals, soft switching conditions may be violated. Another drawback of this circuit is the mandatory presence of an anti-parallel diode on the second switch, since the current in the serial circuit of the second switch and capacitor changes direction during the switching process. Moreover, due to the inertial properties of the counter-parallel diode, the second key is locked at a conditionally zero current, and spurious high-frequency oscillations occur in the circuit.

The technical result of the device of the present invention is as follows:

1. Regulation of the conduction interval in the circuit is ensured when the state of the second switch is on, and the charge on the capacitor is equal to zero.

2. There is no need for a counter-parallel diode for the second switch, and the second switch is switched at zero voltage.

The indicated technical result is achieved in a resonant switch containing a first key with an anti-parallel diode, a second key, a capacitor and a choke connected in series with the first key, the anode output of the anti-parallel diode forms a negative power terminal of the resonant switch, and the output of the choke connected to one the output of the second key, forms a positive power output of the resonant switch, due to the fact that in accordance with the first object of the present invention, the capacitor is connected parallel to the second switch, the other terminal of which is connected to the negative power terminal of the resonant switch.

In this case, the cathode of the first counter-parallel diode can be connected to an additional power terminal of the resonant switch.

The same technical result is achieved in a resonant switch containing a first key with an anti-parallel diode, a second key, a capacitor and a choke connected in series with the first key, the output of the anode of the anti-parallel diode forms a negative power terminal of the resonant switch, and the output of the choke connected to one output of the second key forms a positive power output of the resonant switch, due to the fact that in accordance with the second object of the present invention, one output of the capacitor with It is one with the positive power terminal of the resonant switch, and the other terminal of the capacitor forms an additional power terminal of the resonant switch.

In this case, the cathode of the first counter-parallel diode can be connected to an additional power terminal of the resonant switch.

The invention is illustrated by the attached drawings, in which the same elements are denoted by the same reference numerals.

Figure 1 presents the resonant switch according to the first embodiment.

Figure 2 presents the resonant switch of figure 1 with an additional power output.

Figure 3 presents the resonant switch according to the second variant implementation.

Figure 4 presents the resonant switch of figure 2 with an additional power output.

Figure 5 presents a diagram of the closest analogue.

In Fig.6 presents the resonant switch of Fig.1, connected to a DC voltage Converter (switching regulator step-up type).

In Fig.7 presents the resonant switch of Fig.1 with an additional power output connected to a DC voltage Converter (pulse regulator step-up type).

On Fig presents the resonant switch of figure 2, connected to a DC voltage Converter (switching regulator step-up type).

Figure 9 presents the resonant switch of Figure 2 with an additional power output connected to a DC / DC converter (step-up regulating pulse regulator).

Figure 10 presents the waveforms of the full switching cycle in the resonant switch in accordance with the present invention.

The resonant switch (Fig. 1) contains: a first key 1 with an anti-parallel diode and a second key 2, elements of the resonant circuit: a capacitor 3 and a choke 4. In addition, the drawings show a positive power terminal 5 and a negative power terminal 6.

The inductor 4 and the first key 1 are connected in series. In this case, the output of the serial circuit connected to the anode of the counter-parallel diode forms a negative power terminal 6. Another terminal of the serial circuit forms a positive power terminal 5. The second switch 2 and the capacitor 3 are connected in parallel and are connected in parallel to the serial circuit of the inductor 4 and the first switch 1. At the same time, the negative terminal of the second key 2 is connected to the positive power terminal 5 of the resonant switch.

As shown in FIG. 2, the counter-parallel diode cathode can be connected to an additional power terminal 7 of the resonant switch.

As shown in FIG. 3, one terminal of the capacitor 3 is connected to the positive power terminal 5 of the resonant switch, and the other terminal of the capacitor 3 forms an additional power terminal 8 of the resonant switch.

As shown in FIG. 4, the cathode of the counter-parallel diode can be connected to an additional power terminal 7 of the resonant switch, with one terminal of the capacitor 3 connected to the positive power terminal 5 of the resonant switch, and the other terminal of the capacitor 3 forms an additional power terminal 8 of the resonant switch .

Consider the operation of the resonant switch with switching at zero current in the DC-DC Converter circuit in accordance with Fig.6.

Let the first key 1 and second key 2 be open at the initial instant of time. Then, the inductor current Lf of the input filter, designated as the load current I _N , flows through the open diode circuit D to the capacitor circuit Cf of the output filter, charged to a constant voltage U _OUT and load N. The voltage across the capacitor 3, connected in parallel with the switch 2, at this is equal to voltage U _OUT . At the beginning of the switching cycle, the first key 1 is unlocked.

1. The interval of the ramp current ramp 4.

When a control signal is supplied to the first key 1 through an open diode D, a voltage U _{OUT is} connected in parallel with the inductor 4, causing a linear increase in the current in it and, accordingly, in the first key 1, thereby unlocking the first key 1 at zero current:

$$I_{\mathrm{four}}(t)=I_{\mathrm{one}}(t)=\frac{U_{\mathrm{AT}SX}}{L_{\mathrm{four}}}t;(\mathrm{one})$$

where L ₄ is the inductance of the inductor 4; I ₄ - throttle current 4; I ₁ - current of the first key 1.

After a time interval Δt ₁ , the inductor current 4 reaches the load current I _N , and the diode D is locked:

$$\Delta t_{\mathrm{one}}=\frac{I_N{L}_{\mathrm{four}}}{U_{\mathrm{AT}SX}}.(2)$$

1. The initial resonance interval.

After locking the diode D in the circuit, the resonance process begins. At the same time, at the beginning of the resonance period, the current in the inductor 4 will increase, and the voltage across the capacitor 3 will decrease:

$$\begin{array}{l}{I}_{\mathrm{four}}(t)=I_N+\frac{U_{\mathrm{AT}SX}}{{\rho }_k}\sin {\omega }_{R}t\\ U_3(t)=U_{\mathrm{AT}SX}\cos {\omega }_{R}t\end{array}\};(3)$$

- волновое сопротивление резонансного контура; ω_р - круговая частота резонанса; U₃ - напряжение на конденсаторе 3; С₃ - емкость конденсатора 3.Where $${\rho }_k=\sqrt{L_{\mathrm{four}}/C_3}$$

- wave impedance of the resonant circuit; ω _p is the circular resonance frequency; U ₃ is the voltage across the capacitor 3; C ₃ - capacitor 3.

When the voltage across the capacitor 3 drops to zero after a time interval Δt ₂ , the second switch 2 is turned on, and the resonance process is automatically interrupted:

$$\mathrm{<figure-callout\; id="2"\; label="\Delta \; t"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{t}_{}{}_2=\frac{\pi }{2}\sqrt{L_k{C}_k}.(\mathrm{four})$$

It should be noted that the negative terminal of the second switch 2 must be connected to the positive power terminal 5 of the resonant switch, since it is in this direction that the switch 2 in the on state will be able to perceive the difference between the currents of the inductor 4 and the load when the diode D. is off.

3. The conductivity interval.

When the first and second switches 1 and 2 are turned on, the required interval of conduction of the load current is provided in the circuit.

4. The final resonance interval.

After locking the second key 2 at a given point in time in accordance with the applied method of pulse-width regulation, the resonance process resumes. In this case, in accordance with the system of equations (3), the current of the inductor 4 begins to decrease, and the voltage across the capacitor 3 changes its polarity. When the resonant current of the inductor 4 decreases to zero, the oscillation process will continue, since the counter-parallel diode of the first key 1 will come into effect. After the time interval Δt ₃ from the moment of locking the second key 2, the current of the inductor 4 again becomes zero. In this case, the counter-parallel diode of the first key 1 is locked, and the resonant process ends:

$$\mathrm{<figure-callout\; id="3"\; label="\Delta \; t"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{t}_{}{}_3=\sqrt{L_{\mathrm{four}}{C}_3}(\arcsin (\frac{I_N{\rho }_k}{U_{\mathrm{AT}SX}})+\pi ).(5)$$

5. The interval of the ramp voltage across the capacitor 3.

After locking the counter-parallel diode of the first key 1, the inductor current Lph of the input filter starts to close through the capacitor 3, since the diode D is still in the off state. In this case, the voltage across the capacitor 3 begins to linearly change:

$$U_3(t)U_{\mathrm{AT}SX}\cos \left[{\omega }_R(\mathrm{<figure-callout\; id="2"\; label="\Delta \; t"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{t}_{}{}_2+\Delta t_3)\right]+\frac{{\mathrm{<figure-callout\; id="3"\; label="I\; N\; C"\; filenames="00000010.png,00000011.png"\; state="\{\{state\}\}">I\; </figure-callout>}}_N}{C_{}}.(6)$$

To lock the first switch 1 at zero current, it is necessary to remove the control pulse from it before the voltage across the capacitor 3 again changes its polarity.

After increasing the voltage across the capacitor 3 to the value of U _{OUT, the} diode D is unlocked, and the complete switching cycle is completed. Note that in this cycle, soft switching of the first (main) key 1 at zero current and soft switching of the second (auxiliary) key 2 at zero voltage were provided.

The principle of operation of the resonant switch does not change if, using the additional power output 7, the inductor 4 of the resonant circuit is removed from the serial connection circuit with the first key 1 and connected in series to the diode D circuit (Fig. 7). This statement follows from the fact that the system of equations describing the electrical processes in the circuit remains unchanged, and the current of the first key 1 when moving the inductor 4 into the circuit of the diode D remains an independent variable, which is now determined by the algebraic sum of the load current and the current of the inductor 4.

The principle of operation of the resonant switch does not change if, in accordance with the second object of the present invention, the output of the resonator circuit capacitor 3, previously connected to the negative power terminal, forms an additional power terminal 8 and is connected to any of the fixed potentials of the circuit, for example, to an output voltage source (Fig. 8). This statement follows from the fact that the system of equations describing the electrical processes in the circuit remains unchanged, and the voltage on the first key 1, when the capacitor 3 is connected to any of the fixed potentials of the circuit, remains an independent variable, which is now determined by the algebraic sum of the value of the fixed potential and capacitor voltage 3.

The principle of operation of the resonant switch does not change if, with the help of an additional power output 7, the inductor 4 of the resonant circuit is removed from the serial connection circuit with the first key 1 and connected in series to the circuit of diode D, and the output of the resonator circuit capacitor 3, previously connected to the negative power output, forms another additional power output 8 and is connected to any of the fixed potentials of the circuit (Fig.9).

The principle of operation of the resonant switch does not change when applying different types of keys: bipolar and field effect transistors, thyristors, bipolar transistors with an insulated gate (IGBT), etc.

The presented resonant switch can be used in any other pulse converter by replacing the controlled power switch of the converter with the inventive resonant switch with the positive and negative power terminals of the resonant switch connected to those converter nodes where the corresponding positive and negative terminals of the controlled power switch were previously connected. In this case, using an additional power output 7, the resonant circuit inductor can be connected in series with the antiphase key element of the converter, and using another additional power output 8, the output of the resonator circuit capacitor 3, previously connected to the negative power output, can be connected to any fixed potential of the circuit transducer.

Consider an example of a specific implementation of the device of the present invention.

The proposed device was designed for a DC-voltage converter (Figure 4), the switching processes in which are calculated using the circuit simulation program PSpice.

The output voltage across the filter capacitor Cf: U _OUT = 300 V.

The average value of the continuous load current through the inductor Lf filter:

J = 100 A.

The first and second switches 1 and 2 are PT-IGBT transistors, voltage class 600 V, average collector current 100 A, saturation voltage 1.6 V, output capacitance 0.3 nF.

Pulse type diode D, voltage class 600 V, average current 100 A, open voltage 1.2 V, reverse recovery time 40 ns.

Choke 4 - inductance 0.8 μH.

Capacitor 3 - capacitance 0.2 μF, voltage 1000 V.

Figure 10 presents the waveforms of the full switching cycle in the resonant switch in accordance with the present invention.

Vertical Scale:

Channel 1: voltage on the first key 1; 200 B / div

Channel 2: current of the first key 1 and inductor 4; 200 A / div

Channel 3: voltage on the second key 2 and capacitor 3; 200 B / div

Channel 4: current of the second key 2; 200 A / div

Horizontal Scale:

Time - 2 μs / div.

The first (main) key 1 is switched at zero current, and the second (auxiliary) key 2 is switched at zero voltage.

Claims (4)

1. The resonant switch containing the first key with an anti-parallel diode, the second key, a capacitor and a choke connected in series with the first key, the output of the anode of the anti-parallel diode forms a negative power terminal of the resonant switch, and the output of the choke connected to one terminal of the second key , forms a positive power terminal of the resonant switch, characterized in that the capacitor is connected in parallel with the second switch, the other terminal of which is connected to the negative power terminal of the resonance th switch. 2. The resonant switch according to claim 1, characterized in that the cathode of the on-parallel diode is connected to an additional power terminal of the resonant switch. 3. The resonant switch containing the first key with an anti-parallel diode, the second key, a capacitor and a choke connected in series with the first key, the output of the anode of the anti-parallel diode forms a negative power terminal of the resonant switch, and the output of the choke connected to one terminal of the second key , forms a positive power terminal of the resonant switch, characterized in that one terminal of the capacitor is connected to the positive power terminal of the resonant switch, and the other terminal of the capacitor It provides an additional power output to the resonant switch. 4. The resonant switch according to claim 3, characterized in that the cathode of the on-parallel diode is connected to an additional power terminal of the resonant switch.

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