TWI443949B - Single - Phase AC - DC Power Converter with Electrical Isolation - Google Patents

Description

Single-phase AC-DC power converter with electrical isolation

The invention relates to a power converter, in particular to a single-phase AC-DC power converter with electrical isolation.

Generally, the conventional power converter is divided into an AC-DC converter and a DC-DC converter, and a two-stage conversion is usually required for the function of the up-down voltage. The first stage converter is first rectified, that is, the alternating voltage is converted into direct current voltage (AC-DC) and power factor (PF) correction, and the second stage converts the direct current low voltage into a direct current high voltage or The DC high voltage is converted to DC low voltage (DC-DC) for the DC voltage of the boost-buck function, so the conventional converter cannot achieve extremely high conversion efficiency, such as the Republic of China Invention Patent Notice No. 447187 "Single A phase-up/step-down AC-DC converter, which is composed of a conventional power semiconductor switching element, an inductor, a capacitor, a power diode, and a control circuit of a group of converters to achieve a single phase capable of inputting The AC power source is converted into an adjustable or lowered DC voltage output, wherein the single-phase full-bridge rectifier is connected by connecting an inductor to the input end of the power supply and the conventional single-phase full-bridge rectifier. The output ends are connected in parallel by two groups of one work After a series circuit composed of a diode and a power semiconductor switching element, a capacitor is connected in series at two connection points of the two series circuits, and a filter inductor is connected in parallel at both ends of one of the power diodes. A series circuit consisting of a filter and a filter capacitor, and the load resistor is connected to the filter capacitor, and another feature is that a single-stage conversion can be used to obtain a high-efficiency single-phase rise/ The step-down AC to DC converter, especially the effect that the input current is a sine wave and has a unit power factor.

Moreover, in the conventional single-phase AC-DC converter, the power factor is often different depending on whether the load is fully loaded, and the input current harmonic is large and easy to be distorted. However, the conventional disadvantage is that the duty cycle operation range is small, and Without the use of a coupled inductor to achieve a shortened release time, the inventors have focused on research and developed a single-phase AC-DC power converter with electrical isolation.

The invention provides a single-phase AC-DC power converter with electrical isolation, comprising: an input voltage; an input filter electrically connecting the input voltage, and comprising a filter inductor and a filter capacitor, the filter The inductor is connected in series with the filter capacitor; a bridge rectifier is connected to the input filter; a conversion circuit is connected to the bridge rectifier, and includes a first inductor, a second inductor, a first switch, and a second a switch, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, and a seventh pole a first storage capacitor and a first diode, wherein the first inductor and the second inductor are connected to the first switch and the first diode, and the first inductor is connected to the first switch and the first inductor One end is connected to the second switch, the second diode, the fifth diode and the storage capacitor, and one end of the second inductor is connected to the second diode and the bridge rectifier, and the other end of the second inductor is connected Connecting the third diode And the fourth diode, and the first connection in the first inductor The transformer is connected to the connection node of the diode and the storage capacitor, and the secondary side of the transformer is connected to the sixth diode and the seventh diode, and the sixth diode is connected in series with the seventh diode An output circuit is connected in parallel with the conversion circuit, and includes an output inductor connected in series with an output capacitor, and a load resistor is connected in parallel at both ends of the output capacitor.

Further, the first inductor and the second inductor are coupled inductors.

Further, the inductance of the first inductor is equal to the inductance of the second inductor.

The advantages of the invention are:

1. The present invention is applicable to an input voltage having an effective value of 90 volts - an effective value of 264 volts, and can be applied to a wider load range.

2. The invention has lower current total harmonic distortion.

3. The invention has a relatively stable DC output voltage.

4. The DC link voltage of the present invention is lower than the peak value of the input voltage and is much smaller than the DC voltage of 450 volts, which is in accordance with practical principles.

(1)‧‧‧ Input voltage

(2)‧‧‧Input filter

(3)‧‧‧Bridge rectifiers

(4)‧‧‧Transition circuit

(5)‧‧‧Output circuit

(S ₁ )‧‧‧First switch

(S ₂ )‧‧‧Second switch

(L ₁ )‧‧‧First inductance

(L ₂₎ ‧‧‧ second inductor

(L _f )‧‧‧Filter inductor

(L _o )‧‧‧Output inductance

(C ₁₎ ‧‧‧ storage capacitor

(C _f) ‧‧‧ filter capacitor

(C _o )‧‧‧output capacitor

(D ₁ )‧‧‧First Diode

(D ₂ )‧‧‧Secondary

(D ₃ )‧‧‧ Third Dipole

(D ₄ )‧‧‧Fourth diode

(D ₅ )‧‧‧ Fifth Diode

(D ₆ )‧‧‧ Sixth diode

(D ₇ )‧‧‧ seventh pole

(R)‧‧‧Load resistor

(T _r )‧‧‧Transformers

The first figure is a schematic system block diagram of the present invention.

The second figure is a detailed physical structure circuit diagram of the present invention.

The third A diagram is the current path diagram of Mode 1 of the present invention.

The third B diagram is the current path diagram of the mode 1 of the present invention, illustrating that the first switching switch S ₁ and the second switching switch S _{2 are} turned on, and the input voltage is a positive half wave and the primary winding and the secondary side of the coupled inductor The current path of the winding for energy storage in series.

The fourth A diagram is the current path diagram of mode 2 of the present invention.

The fourth B diagram is the current path diagram of the mode 2 of the present invention, illustrating that the first switching switch S ₁ and the second switching switch S _{2 are} turned off, and the input voltage is a positive half wave and the primary winding and the secondary side of the coupled inductor discharging windings are parallel to the current path ₁ of the storage capacitor C.

The fifth A diagram is a current path diagram of mode 3 of the present invention.

The fifth B diagram is the current path diagram of the mode 3 of the present invention, indicating that the first switch S ₁ and the second switch S ₂ are still off, and the input voltage is a positive half wave and the output inductor L _{o is} released to the output. The current path of capacitor C _o and load resistor R.

Figure 6A is a current path diagram of mode 4 of the present invention.

Figure 6B is a current path diagram of mode 4 of the present invention, illustrating that the first switch S ₁ and the second switch S _{2 are} turned on, and the input voltage is a negative half wave and the primary winding and the secondary side of the coupled inductor The current path of the winding for energy storage in series.

The seventh figure is a waveform diagram of the input voltage e _s of the present invention, the trigger signals of the first switching switch S ₁ and the second switching switch S ₂ , the unfiltered input current, and the coupled inductor current.

The eighth figure is a waveform diagram of the input voltage e _s and the input current i _s of the input voltage 90V _rms , the output voltage 24V _dc and the full load output power 200W of the present invention.

The ninth figure is a waveform diagram of the DC link voltage V _c1 and the output voltage V _o of the input voltage 90V _rms , the output voltage 24V _dc and the full load output power 200W of the present invention.

The tenth figure is a waveform diagram of the input voltage e _s and the input current i _s of the input voltage 264V _rms , the output voltage 24V _dc and the light load output power 20W of the present invention.

The eleventh figure is a waveform diagram of the DC link voltage V _c1 and the output voltage V _o of the input voltage of 264V _rms , the output voltage of 24V _dc and the light load output of 20W.

Figure 12 is a circuit diagram of another embodiment of the present invention.

With regard to the technical features and the enhancement of the present invention, the preferred embodiments of the following drawings can be clearly presented. Referring to the first and second figures, the present invention is a single-phase AC-DC with electrical isolation. The power converter comprises: an input voltage (1) and an input filter (2), and the input filter (2) is electrically connected to the input voltage (1), and the input filter (2) a filter inductor (L _f ) and a filter capacitor (C _f ), wherein the input voltage (1) is connected in series with the filter inductor (L _f ), and then the filter capacitor (C _f ) is connected in parallel, and the input filter (2) electrically connected to a bridge rectifier (3), the bridge rectifier (3) is connected in parallel with the input filter (2), and the bridge rectifier (3) is electrically connected to a conversion circuit (4), The conversion circuit (4) includes a first inductor (L ₁ ), a second inductor (L ₂ ), a first switch (S ₁ ), a second switch (S ₂ ), and a first diode. (D ₁ ), a second diode (D ₂ ), a third diode (D ₃ ), a fourth diode (D ₄ ), a fifth diode (D ₅ ), and a Sixth diode (D ₆ ), one seventh a diode (D ₇ ), a storage capacitor (C ₁ ), and a transformer (T _r ). In this embodiment, the first inductor (L ₁ ) and the second inductor (L ₂ ) are coupled inductors. And the primary side winding [first inductance (L ₁ )] and the secondary side winding [second inductance (L ₂ )] of the coupled inductor are the same number of turns, and the drain of the first switching switch (S ₁ ) (Drain) The end is electrically connected to the bridge rectifier (3), one end of the first inductor (L ₁ ) is connected to the source end of the first switch (S ₁ ) and the first diode (D ₁ ) The other end of the first inductor (L ₁ ) is connected to the drain terminal of the second switch (S ₂ ), the cathode terminal of the second diode (D ₂ ), and the fifth diode (D). ₅ ) a cathode end and a storage capacitor (C ₁ ), and a second inductor (L ₂ ) is connected at one end to the anode end of the second diode (D ₂ ) and the bridge rectifier (3), and the second The other end of the inductor (L ₂ ) is connected to the cathode end of the third diode (D ₃ ) and the cathode end of the fourth diode (D ₄ ), and is in the anode of the first diode (D ₁ ) connecting the transformer (T _r) and the terminal of the storage capacitor (C ₁₎ of the connection node, and the secondary side of the transformer (T _r) of the sixth connection An anode body (D ₆₎ connected in series and the terminal of the seventh diode (D ₇₎ of the cathode terminal, and (D ₇₎ and then is electrically connected to the seventh diode an output circuit (5), and the output The circuit (5) is connected in parallel with the conversion circuit (4), and the output circuit (5) includes an output inductor (L _o ) connected in series with an output capacitor (C _o ), and is located at both ends of the output capacitor (C _o ) Then parallel a load resistor (R).

Further, please refer to the second figure, the present invention further includes a front half power converter and a second half power converter, wherein the front half power converter is a single phase correction type AC-DC (AC-DC) drop. - buck-boost power converter, and the latter half of the power converter is a DC-DC forward power converter, initially using a wide-band modulation technique (PWM) Driving the first switch (S ₁ ) and the second switch (S ₂ ) synchronously, so that the current of the first half of the power converter, that is, the coupled inductor in the conversion circuit (4) is operated in a discontinuous conduction mode, When the power supply voltage is positive half-wave, the currents i _L1 and i _{L2 of the} coupled inductor are as shown in the seventh figure, and when the first switch (S ₁ ) and the second switch (S ₂ ) are turned on, The primary side winding [first inductance (L ₁ )] and the secondary side winding [second inductance (L ₂ )] of the coupled inductor are connected in series and start energy storage, and when the first switching switch (S ₁ ) and the second When the switch (S ₂ ) is turned off, the primary winding of the coupled inductor [first inductance (L ₁ )] and the secondary winding [second inductance] (L ₂ )] is parallel and begins to release energy, input the current i _S ' of the bridge rectifier (3), the waveform of which is shown in the seventh figure, the input filter (2) can be input to the bridge rectifier ( 3) The current i _S 'the harmonic filtering, so the input current can get a nearly sinusoidal waveform, and the input current is in phase with the input voltage, the power factor is almost equal to 1, and the bridge rectifier (3) will be The input AC voltage is rectified into a DC voltage, that is, AC-DC, and the parallel discharge energy characteristic of the coupled inductor in the conversion circuit (4) can shorten the time of energy release, thereby making the duty cycle (Duty) -Cycle) has a larger operating range.

The operating principle of the power converter of the present invention has the following six modes, please refer to the second figure, the third A picture, the third B picture, the fourth A picture, the fourth B picture, the fifth A picture, the fifth B. The figure, the sixth A picture and the sixth B picture are shown as follows:

Mode 1: In this mode, the first switching switch (S ₁ ) and the second switching switch (S ₂ ) are turned on, and when the input voltage is a positive half wave, the primary side winding of the coupled inductor [the first inductance ( L ₁ )] and the secondary winding [second inductance (L ₂ )] are connected in series and stored, and the energy stored by the storage capacitor (C ₁ ) is discharged to the output via the transformer (T _r ) Inductor (L _o ), output capacitor (C _o ) and load resistor (R), the current path is shown in Figure 3A and Figure 3B.

Mode 2: In this mode, the first switch (S ₁ ) and the second switch (S ₂ ) are turned off, and when the input voltage is a positive half wave, the primary winding of the coupled inductor [first inductor (L ₁ )] and the secondary winding [second inductance (L ₂ )] are connected in parallel and discharged to the storage capacitor (C ₁ ), and the output inductor (L _o ) is discharged to the output capacitor (C _o ) and load resistance (R), the current path is shown in Figure 4A and Figure 4B.

Mode 3: In this mode, the first switching switch (S ₁ ) and the second switching switch (S ₂ ) are still turned off, and when the input voltage is a positive half wave, the primary winding of the coupled inductor [first The inductance (L ₁ )] and the secondary winding [second inductor (L ₂ )] are released, and the output inductor (L _o ) is continuously discharged to the output capacitor (C _o ) and the load resistor (R). Please refer to the fifth A and fifth B diagrams for the current path.

Mode 4: In this mode, the first switch (S ₁ ) and the second switch (S ₂ ) are turned on, and when the input voltage is a negative half wave, the primary winding of the coupled inductor is [ An inductor (L ₁ )] and a secondary winding [second inductor (L ₂ )] are connected in series and stored, and energy stored in the storage capacitor (C ₁ ) is discharged via the transformer (T _r ) to The output inductor (L _o ), the output capacitor (C _o ), and the load resistor (R), the current path is shown in Figure 6A and Figure 6B.

Mode 5: In this mode, the input voltage is a negative half wave, the first switching switch (S ₁ ) and the second switching switch (S ₂ ) are turned off, and the primary side winding of the coupled inductor [first inductance (L ₁ )] and the secondary winding [second inductance (L ₂ )] are connected in parallel and discharged to the storage capacitor (C ₁ ), and the output inductor (L _o ) is discharged to the output capacitor (C _o ) and load resistor (R), the current path is the same as mode 2, please refer to the fourth A and fourth B.

Mode 6: In this mode, the input voltage is a negative half wave, the first switching switch (S ₁ ) and the second switching switch (S ₂ ) are still turned off, and the primary winding of the coupled inductor [first The inductance (L ₁ )] and the secondary winding [second inductor (L ₂ )] are released, and the output inductor (L _o ) is continuously discharged to the output capacitor (C _o ) and the load resistor (R). And its current path is the same as mode 3, please refer to Figure 5A and Figure 5B.

Furthermore, as shown in the seventh figure, the input voltage e _s , the trigger signal of the first switching switch (S ₁ ) and the second switching switch (S ₂ ), the unfiltered input current, and the waveform of the coupled inductor current are shown. .

Furthermore, please refer to the eighth and ninth diagrams. The eighth diagram is the input voltage e _s and the input current i when the operating state is 90V _rms , the output voltage is 24V _dc, and the full-load output power is 200W. waveform diagram of _s, and the ninth line of FIG operating state when the input voltage of 90V _rms, 24V _dc output voltage and full load output power of 200W waveform diagram when a DC link voltage V _c1 and V _o of the output voltage.

Furthermore, please refer to the tenth and eleventh figures. The tenth figure is the input voltage e _s and input when the operating state is 264V _rms , the output voltage is 24V _dc, and the light load output power is 20W. The waveform of the current i _s , and the eleventh figure is the waveform of the DC link voltage V _c1 and the output voltage V _o when the operating state is the input voltage is 264V _rms , the output voltage is 24V _dc, and the light load output power is 20W. Figure

Moreover, referring to FIG. 12, a circuit diagram of another embodiment of the present invention is such that the inductance value of the first inductor is equal to the inductance of the second inductor (ie, L ₁ = L ₂ ). In place of the coupled inductor, and its mode of operation is like the above six modes, not to mention here.

As described above, the embodiments and drawings of the present invention are set forth in the preferred embodiments of the present invention and are not intended to limit the invention.

In view of the foregoing description of the embodiments, the operation and the use of the present invention and the effects of the present invention are fully understood, but the above described embodiments are merely preferred embodiments of the present invention, and the invention may not be limited thereto. Included within the scope of the present invention are the scope of the present invention.

(1)‧‧‧ Input voltage

(2)‧‧‧Input filter

(3)‧‧‧Bridge rectifiers

(4)‧‧‧Transition circuit

(5)‧‧‧Output circuit

(S ₁ )‧‧‧First switch

(S ₂ )‧‧‧Second switch

(L ₁ )‧‧‧First inductance

(L ₂ )‧‧‧second inductance

(L _f )‧‧‧Filter inductor

(L _o )‧‧‧Output inductance

(C ₁ )‧‧‧ Storage Capacitors

(C _f )‧‧‧Filter capacitor

(C _o )‧‧‧output capacitor

(D ₁ )‧‧‧First Diode

(D ₂ )‧‧‧Secondary

(D ₃ )‧‧‧ Third Dipole

(D ₄ )‧‧‧Fourth diode

(D ₅ )‧‧‧ Fifth Diode

(D ₆ )‧‧‧ Sixth diode

(D ₇ )‧‧‧ seventh pole

(R)‧‧‧Load resistor

(T _r )‧‧‧Transformers

Claims (3)

A single-phase AC-DC power converter with electrical isolation includes: an input voltage; an input filter electrically connected to the input voltage, and includes a filter inductor and a filter capacitor, the filter inductor is connected in series The filter capacitor; a bridge rectifier connected to the input filter; a conversion circuit connected to the bridge rectifier, and comprising a first inductor, a second inductor, a first switch, a second switch, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a seventh diode, and a first diode a storage capacitor and a transformer, wherein the windings of the first inductor and the second inductor are the same number of turns, the first inductor is connected to the first switch and the first diode at one end, and the other end of the first inductor is connected to the first inductor a second switching switch, a second diode, a fifth diode, and a storage capacitor, wherein one end of the second inductor is connected to the second diode and the bridge rectifier, and the other end of the second inductor is connected to the second Triode and fourth pole And connecting the transformer to the connection node of the first diode and the storage capacitor connected to the first inductor, and the secondary side of the transformer is connected to the sixth diode and the seventh diode, and The sixth diode is connected in series with the seventh diode; an output circuit is connected in parallel with the conversion circuit, and includes an output inductor connected in series with an output capacitor, and a load resistor is connected in parallel at both ends of the output capacitor. The single-phase AC-DC power converter with electrical isolation, as described in claim 1, wherein the first inductor and the second inductor are coupled inductors. The single-phase AC-DC power converter with electrical isolation as described in claim 1 is characterized in that the inductance of the first inductor is equal to the inductance of the second inductor.