TWI415522B - Power conversion device - Google Patents

Abstract

An electric power conversion device is suitable for driving a High Intensity Discharge (HID) lamp.. The power conversion device includes an input filter unit, a first power factor correction unit, a second power factor correction unit, a full-bridge switch unit, and an output filter unit. The full-bridge switch unit includes a first switch, a second switch, a third switch, and a fourth switch, and produces a conversion voltage presenting as a low-frequency square wave by switching the first to fourth switches between the on and off states. The first and second power factor correction units perform the power factor corrections based on the switching of the first and fourth switches. Furthermore, the power factor correction units can share the switches with the full-bridge switch unit to proceed the circuit operation, so as to reduce the number of electronic components required and simplify the control operation, thereby decreasing the cost and reducing the loss of power transmission.

Description

Power conversion device

The present invention relates to a power conversion device, and more particularly to a power conversion device for driving a high intensity gas discharge lamp.

High intensity discharge lamps (HID lamps) have the advantages of high brightness, power saving and low heat, and are gradually being widely used in the lighting industry. However, HID lamps have problems with acoustic resonance, which can cause various phenomena of the lamp, such as: arc instability, color temperature variations, light output fluctuations, or Arc extinction, even causing a lamp crack. The reason for audio resonance is that when the input power frequency is correlated with the eigen-frequency of the lamp in certain frequency bands, and the energy exceeds a critical value, a standing wave is formed in the lamp.

The principle of solving the problem of audio resonance is to operate the HID lamp at a frequency that does not produce audio resonance, or to reduce the energy that causes the audio resonance to below a critical value. One solution is to operate a frequency window that does not produce audio resonance. However, the frequency at which the audio resonance occurs will vary with the time of use of the different lamps, which will increase the frequency at which no audio resonance occurs for each tube. Difficulty. Another solution is to drive the lamp at a very high frequency (>500 kHz). Although it can avoid the audio resonance frequency, in order to meet the high conversion efficiency, the circuit cost and design of the power conversion device for driving the lamp will be increased. Difficulty.

Another solution is to drive the HID lamp with a low frequency (<1 kHz) square wave current (or voltage) to avoid the high frequency of audio resonance (several kHz to several hundred kHz), as shown in Figure 1, which is a three The stage power conversion device is adapted to output a low-frequency square wave current, and cooperates with the ignition circuit to drive the HID lamp, and includes: a filtering unit 1, a rectifying unit 11, a power factor correcting unit 12 (first stage), and a step-down The conversion unit 13 (second stage), a full bridge switch unit 14 (third stage), a first control unit 15, a second control unit 16, and a third control unit 17. The three-stage power conversion device can effectively avoid the audio resonance phenomenon by driving the HID lamp with the low-frequency square wave current, but the three-stage architecture must perform three power conversions, resulting in increased switching loss and energy conduction loss, and conversion efficiency. Dropping and using three sets of control circuits complicates the circuit structure and increases the cost.

In order to reduce costs and increase conversion efficiency, some studies have integrated three-level circuits into two-stage or single-stage circuits. As shown in Figure 2, the Republic of China Publication No. 200808124 proposes a single-stage power conversion device suitable for communication. The input voltage is converted into an output current of a low frequency sine wave to drive the HID lamp. The power conversion device includes: an input filtering unit 18, a rectifying and power factor correcting unit 181, a full bridge switching unit 182, and an output filtering unit 183. And a control unit 184.

Since the rectification and power factor correcting unit 181 is switched with the full bridge switching unit 182, the function of the operation is like a boost converter, so that the output voltage of the rectifying and power factor correcting unit 181 must be several times the peak value of the input voltage, so as to be higher. The power factor correction effect causes the full bridge switch unit 182 to use a switch with a high withstand voltage specification, resulting in an increase in cost and a large volume, and a high withstand voltage switch having a large parasitic capacitance reduces the switching speed of the component, so that the switching loss is The increase in nonlinearity leads to a decrease in power conversion efficiency.

Further, all of the switches of the full bridge switch unit 182 operate at a high frequency, so that the output filter unit 183 filters out the high frequency components from the switches to provide an output current of a low frequency sine wave to drive the HID lamp. However, since the output voltage of the low frequency is still a sine wave rather than a square wave, the pull-up speed of the voltage is not fast enough, and the HID lamp is difficult to start up and cannot be in a state of stable illumination, and even a case of extinction occurs.

Accordingly, it is an object of the present invention to provide a power conversion apparatus which provides high conversion efficiency and which avoids the above-mentioned conventional drawbacks.

The power conversion device is adapted to drive a high intensity gas discharge lamp and comprises:

An input filtering unit receives an AC input voltage and an input current, and provides an AC filtered voltage and a pulse current;

a first power factor correction unit receives the filtered voltage and the pulse current, and generates a first correction voltage that is always flowing;

a second power factor correcting unit receives the filtered voltage and the pulse current, and generates a second correcting voltage of the current, and adds the second modified voltage and the first modified voltage to a total voltage;

a full bridge switch unit includes a first switch, a second switch, a third switch, and a fourth switch, the full bridge switch unit receives the summed voltage, and the first switch to the fourth switch Switching between the on state and the off state, converting the summed voltage into a low voltage square wave conversion voltage, and each low frequency square wave period includes a plurality of high frequency square waves;

An output filtering unit receives the converted voltage and filters out a high frequency component of the converted voltage to generate an output voltage of a low frequency square wave to drive the high intensity gas discharge lamp;

The first power factor correcting unit adjusts the pulse current during the positive half cycle of the filtered voltage according to the switching of the first switch to correct the input voltage and the power factor of the input current, and the filtering Converting the voltage into the first correction voltage, and the second power factor correcting unit adjusts the pulse current during the negative half cycle of the filtered voltage according to the switching of the fourth switch to correct the input voltage and the input current The power factor converts the filtered voltage into the second modified voltage, and the filtering unit filters out high frequency harmonic components in the pulse current to make the input current substantially sinusoidal.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to FIG. 3, a preferred embodiment of the power conversion device of the present invention is adapted to convert an AC input voltage V _in an external power supply into an output voltage V _{CO in} a low frequency square wave to cooperate with an ignition circuit to drive the HID lamp. (eg, a complex metal lamp), and includes: an input filter unit 2, a first power factor correction unit 21, a second power factor correction unit 22, a full bridge switch unit 31, an output filter unit 41, and a control Unit 51.

The input filtering unit 2 is electrically connected to the external power source, and receives an input voltage V _in and an input current i _in provided by the external power source, and provides an AC filtered voltage and a pulse current i _p , and filters out the The high frequency harmonic component of the pulse current i _p causes the input current i _in from the external power source to exhibit a sine wave, and includes an input inductor L _m and an input capacitor C _m , the input inductor L _m including an electrical connection The external power source receives a first end of the input voltage V _in and the input current i _in , and a second end of the output filter voltage and the pulse current i _p , the input capacitor C _m includes an electrical connection to the input inductor L _m a first end and a second end of the second end.

The first power factor correction unit 21 is electrically connected to the input filter unit 2, and receives the filtered voltage and the pulse current i _p , and generates a first current correction voltage V _dc1 , and includes a first diode D ₁ , a third diode D ₃ , a first winding L ₁ , and a first capacitor C _dc1 .

The first diode D ₁ has an anode and a cathode electrically connected to the second end of the input inductor L _m to receive the filtered voltage and the pulse current i _p . The third diode D ₃ has a cathode electrically connected to the cathode of the first diode D ₁ and an anode. The first winding L ₁ has a first end (polar point end) and a second end (non-polar point end) electrically connected to the cathode of the first diode D ₁ . The first capacitor C _{dc1 is} electrically connected between the polarity end of the first winding L ₁ and the anode of the third diode D ₃ , and the voltage across the first correction voltage V _dc1 .

The second power factor correcting unit 22 is electrically connected to the input filtering unit 2 and the first power factor correcting unit 21, and receives the filtered voltage and the pulse current i _p , and generates a second correcting voltage V _dc2 And adding the second correction voltage V _dc2 and the first correction voltage V _dc1 to a total voltage V _dc , and including a second diode D ₂ , a fourth diode D ₄ , and a second Winding L ₂ and a second capacitor C _dc2 .

The second diode D ₂ has a cathode and an anode electrically connected to the second end of the input inductor L _m to receive the filtered voltage and the pulse current i _p . The fourth diode D ₄ has an anode electrically connected to the anode of the second diode D ₂ and a cathode electrically connected to the anode of the third diode D ₃ . The second winding L ₂ has a first end (polar point end) and a second end (non-polar point end) electrically connected to the anode of the second diode D ₂ . The second capacitor C _{dc2 is} electrically connected between the polarity end of the second winding L ₂ and the cathode of the fourth diode D ₄ , and the voltage across the second correction voltage V _dc2 . Since the second capacitor C _{dc2 is} connected in series with the first capacitor C _dc1 , the second correction voltage V _dc2 and the first correction voltage V _{dc1 are} summed into the total voltage V _dc .

In this embodiment, the first winding L ₁ and the second winding L ₂ may be wound in the same core (not shown), but the first winding L ₁ and the second winding L ₂ may also be It is wound around two different iron cores (not shown). The full bridge switch unit 31 receives the summed voltage and has a first switch S ₁ , a second switch S ₂ , a third switch S ₃ , and a fourth switch S ₄ , and the first switch S ₁ to the fourth switch S ₄ are switched between an on state and an off state, and the summed voltage is converted into a converted voltage which is a low frequency square wave, wherein the second and third switches S ₂ , S ₃ operate at a low frequency, and The first and fourth switches S ₁ , S ₄ operate at a high frequency, so that a plurality of high frequency square waves are included in the period of each low frequency square wave.

The first switch S ₁ is an electrical connector having a first polarity terminal of the first winding L ₁ of the end point, is electrically connected to a second end of the second end of the input capacitance C _m (denoted point A), and a control terminal, the control terminal controlled so that the first switch S ₁ is switched between a conducting state and an off state.

The second switch S ₂ has a first end electrically connected to a polarity end of the first winding L ₁ , a second end (labeled as point B in the figure), and a control end, the control end being controlled to enable The second switch S ₂ is switched between an on state and an off state. The voltage between the second end of the first switch S _{1 and} the second end of the second switch S ₂ (ie, the voltage between points A and B) is the converted voltage.

The third switch S ₃ has a first end electrically connected to the second end of the second switch S ₂ , a second end electrically connected to the polarity end of the second winding L ₂ , and a control end, the control controlled so that the end of the third switch S ₃ is switched between conducting state and an oFF state.

The fourth switch S ₄ has a first end electrically connected to the second end of the first switch S ₁ , a second end electrically connected to the polarity end of the second winding L ₂ , and a control end, the control The terminal is controlled to switch the fourth switch S ₄ between an on state and an off state.

The output filtering unit 41 receives the converted voltage of the full bridge switching unit 31, and filters out the high frequency component of the converted voltage to generate a low frequency square wave output voltage V _CO to drive the high intensity gas discharge lamp, and has a Transformer T ₁ , an output inductor L _O and an output capacitor C _O .

The transformer T ₁ includes two windings wound around a core (not shown), a third winding L ₃ , and a fourth winding L ₄ electrically connected to the ignition circuit. And each winding has a polarity point end and a non-polar point end.

The third winding L ₃ , the output capacitor C _O and the output inductor L _O are connected in series between the second end of the first switch S ₁ (labeled A) and the second end of the second switch S ₂ (labeled B) The HID lamp is connected in parallel with the output capacitor C _O , and the voltage across the output capacitor C _O is the output voltage V _CO .

Should the first power factor correction unit 21 according to the first switch S _1, and during the positive half cycle of the filtered voltage (and the input voltage V _in the positive half cycle), that the first winding L ₁ operates a discontinuous conduction mode, and the current i _L1 exhibits a triangular wave waveform, and the peak value of the current i _L1 is proportional to the AC input voltage V _in , thereby adjusting the pulse current i _p to make the input voltage V _in and The input current i _{in is in} phase, increasing the power factor of the external power supply. The first power factor correcting unit 21 further converts the filtered voltage into the first modified voltage V _dc1 during the positive half cycle of the filtered voltage according to the switching of the first switch S ₁ .

And the second power factor correcting unit 22 operates the second winding L ₂ during the negative half cycle of the filtered voltage (also during the negative half cycle of the input voltage V _in ) according to the switching of the fourth switch S ₄ . a discontinuous conduction mode, and the current i _L2 exhibits a triangular wave waveform, and the peak value of the current i _L2 is proportional to the AC input voltage V _in , thereby adjusting the pulse current i _p to make the input voltage V _in and The input current i _{in is in} phase, increasing the power factor of the external power supply. The second power factor correcting unit 22 further converts the filtered voltage into the second modified voltage V _dc2 during the negative half cycle of the filtered voltage according to the switching of the fourth switch S ₄ . In this embodiment, the first correction voltage V _dc1 is equal to the second correction voltage V _dc2 , but in other embodiments, the two may not be equal.

The control unit 51 is electrically connected to the control terminals of the first to fourth switches S ₁ to S ₄ and generates four control signals for respectively controlling the first to fourth switches S ₁ to S ₄ for switching.

As shown in FIGS. 4 and 5, the parameters V _G1 VV _G4 represent the control signals of the first to fourth switches S ₁ to S ₄ , respectively, wherein V _G2 and V _G3 operate in a complementary square waveform. Low frequency (<1 kHz, which is equal to the frequency of the input voltage in this embodiment, and synchronized to 60 Hz), and its duty cycle is substantially less than 50%, and there is a short dead time between the switches, During the time delay, the voltages of V _G2 and V _G3 are both equal to zero, so as to prevent the second switch S2 and the third switch S3 from being simultaneously turned on to form a short circuit, causing the switch to be burned. V _G1 and V _G4 are switched at a high frequency (20 kHz to 100 kHz, 25 kHz in this embodiment) during a period in which V _G3 and V _{G2 are} at a high potential, respectively, while V _G3 and V _{G2 are} at a low potential, respectively. V _G1 and V _G4 are both at zero potential.

As shown in FIG. 6, wherein the V _G1 parameter represents a control signal of the first switch S ₁ , i _L1 , i _L2 , i _LO represent flow through the first winding L ₁ , the second winding L ₂ , and the output inductor L _{O , respectively.} The current, i _D3 and i _D4 parameters respectively represent the current flowing through the third diode D ₃ and the fourth diode D ₄ , and the parameters i _S1 , i _S2 , i _S3 , and i _S4 respectively represent the flow through the first The current of one switch S ₁ , the second switch S ₂ , the third switch S ₃ , and the fourth switch S ₄ .

For simplification circuit analysis, the input filtering unit 2 is ignored, and the following operation in which the input voltage V _in is a positive half cycle is discussed in four modes.

Mode one (time t0~t1):

Refer to FIG. 3, FIG. 6 and FIG. 7, in what mode, switch S ₁ is the first and the third switch S ₃ is turned on. And in Figure 7, the trend of the current path is shown in this mode. For convenience of description, the turned-on diodes and switches are indicated by solid lines, and the turned-off diodes and switches are indicated by broken lines. In this mode, the turned-on diodes have only the first diode D ₁ .

The external power source supplies an input current i _in to the first winding L ₁ via the first diode D ₁ and the first switch S ₁ to transfer energy from the external power source to the first winding L ₁ and because of the first factor correcting unit 21 with a first switch S ₁ is switched, operate in discontinuous mode (DCM), the _L-1 of the first winding current rises linearly from zero and the rising slope proportional to the input voltage V _in.

On the other hand, the first capacitor C _dc1 and a second capacitor C _dc2 through the first, the third switch S _1, S ₃ output inductor L _O is charged, the voltage of the output inductor L _O is equal to the sum of the subtraction output voltage V _dc The voltage V _{CO of the} capacitor C _O , and the output filtering unit 41 operates in the DCM, causing the current i _{LO of the} output inductor L _O to rise linearly.

Mode 2 (time t1~t2):

Refer to FIG. 3, FIG. 6 and FIG. 8, in the second mode, the first switch S ₁ is switched to non-conducting and the third switch S ₃ is still turned on. Marked out in FIG 8 In this mode two, to the current path, and, in mode two, the nature of diode conduction only the third diode D ₃ and a fourth switch S ₄ of the diode SD _4.

Because the first and second correction voltages V _dc1 and V _{dc2 are} higher than the input voltage peak, the first diode D _{1 is} reversely biased, and the current i _{L1 of the} first winding L ₁ flows through the third diode D ₃ . A capacitor C _{dc1 is} charged, and the voltage across the first winding L ₁ is -V _dc1 , causing the current i _{L1 of the} first winding L _{1 to} begin to decrease linearly.

And the output inductor current i L _O of _{the LO} via a third switch S _3, a fourth switch S ₄ is essentially the SD diode ₄ charging the output capacitor C _O, and the output voltage across inductor L _O is -V _CO, so i _{The LO} begins to decrease linearly. The voltage across the output inductor L _O is converted from mode 1 (V _dc -V _CO ) to mode 2 (-V _CO ). It can be seen that the output inductor L _O and the output capacitor C _O operate like a buck converter. The high frequency component of the conversion voltage is filtered out so that the output voltage V _CO across the output capacitor C _O is a low frequency square wave. When the current i _{L1 of the} first winding drops to zero, it enters mode three.

Mode three (time t2~t3):

Refer to FIG. 3, FIG. 6 and FIG. 9, three mode, a first switch S ₁ is turned on while continuing the third switch S ₃ is maintained turned on. 9 marked out three times in this mode, to the current path, and in mode three, the diode conduction only the fourth switch S ₄ nature diode SD _4.

The output inductor L _O and the output capacitor C _O continue to supply energy to the HID lamp via the third switch S ₃ and the intrinsic diode SD _{4 of the} fourth switch S ₄ until the current i _{LO of the} output inductor L _O drops to zero. Mode four.

Mode four (time t3~t0):

Refer to FIG. 3, FIG. 6 and FIG. 10, the pattern looked, although the third switch control signal S ₃ is maintained so that the high potential and the ground point B just like a short circuit, but no current flows through the third switch S _3, and therefore considered Cutoff, and no diodes are turned on.

The current i _{LO of the} output inductor L _O is already zero, so the energy is supplied from the output capacitor C _O to the HID lamp. When the first switch S _{1 is} turned on again, it returns to mode one.

And _in the negative half cycle portion of the input voltage V _in , the difference from the positive half cycle portion of the input voltage V _in is in the mode one, the control terminals of the second switch S ₂ and the fourth switch S ₄ are pulled to a high potential, and the mode The second to fourth mode are that the control terminal of the second switch S ₂ is maintained at a high potential, and the control terminal of the fourth switch S ₄ is pulled to a low potential, because the working principle and the input voltage V _in the positive half cycle portion of the operation essence It is symmetrical, so it will not be repeated here.

As shown in FIG. 11, the parameter T _s is the switching period of the first and fourth switches S ₁ , S ₄ , assuming that the input voltage of the alternating current provided by the external power source is V _in (t)=V _m sin(2π f _L t) Where f _L and V _m are the frequency and amplitude of the input voltage V _in , respectively. The input current i _in and the input power P _in are as shown in equations (1) and (2), respectively:

Where L _P represents the sense value of the first winding L ₁ , and d _r and f _s represent the duty cycle and switching frequency of the first switch S ₁ .

When the voltage of the first winding of L ₁ integration time is less than zero, the first power factor correction unit 21 operates in discontinuous current mode, the push of formula (3)

When operating in DCM when the first work factor correcting unit 21 can be input to the peak voltage can be ensured in the input voltage V _in every point can work in DCM, design conditions of formula (4) is the sum of the voltage V _dc.

Since the second power factor correcting unit 22 and the first power factor correcting unit 21 are symmetric structures, the sense values of the first winding L ₁ and the second winding L ₂ are equal and the duty cycle and the switching frequency of the fourth switch S ₄ are the same as the first A switch S ₁ , so the design conditions of the first correction voltage V _dc1 and the second correction voltage V _dc2 are the same, both are V _dc /2.

Experimental results:

Figure 12 shows the waveform of the input voltage V _in and the input current i _in . It can be seen that the input current i _in is a sine wave and is _in phase with the input voltage V _in , thus increasing the power factor and reducing the total current distortion.

Fig. 13 shows currents i _L1 and i _{L2 of} the first and second windings L ₁ and L ₂ . The two-factor correction unit 21, 22 operates in the discontinuous conduction mode for the entire period of the input voltage V _in .

14 corresponds to FIG. Showing the entire cycle of the input voltage V _in, the current flowing through the HID lamp i _lamp, and a waveform of the voltage across the V _CO.

Fig. 15 shows the waveform of the current i _LO of the output inductor L _O corresponding to the period of the entire input voltage V _in .

Fig. 16 shows the waveform of the current i _LO of the output inductor L _O and the current i _L1 of the first winding L ₁ when the input voltage V _in is between positive half cycles.

Fig. 17 shows the waveform of the current i _LO of the output inductor L _O and the current i _L2 of the first winding L ₂ when the input voltage V _in is between negative half cycles.

In summary, the power conversion device of this embodiment has the following advantages:

(1) By sharing the switches by the two power factor correcting units 21, 22 and the full bridge switching unit 31, the number of electronic components can be effectively reduced and the control mode can be simplified.

(2) It can be seen from equation (4) that the first and second correction voltages V _dc1 and V _{dc2 of the} present invention do not need to be much larger than the input voltage to obtain a good power factor, so that a switch with low withstand voltage can be used to reduce the component volume. And to avoid switching speed drops.

(3) Driving the high-intensity gas discharge lamp with a low-frequency square wave voltage to avoid audio resonance of the lamp.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

2. . . Input filter unit

twenty one. . . First power factor correction unit

twenty two. . . Second power factor correction unit

31. . . Full bridge switch unit

41. . . Output filter unit

51. . . control unit

L _m . . . Input inductance

C _m . . . Input capacitance

L ₁ . . . First winding

L ₂ . . . Second winding

D ₁ . . . First diode

D ₂ . . . Second diode

D ₃ . . . Third diode

D ₄ . . . Fourth diode

S ₁ . . . First switch

S ₂ . . . Second switch

S ₃ . . . Third switch

S ₄ . . . Fourth switch

SD ₁ . . . The first diode of the first switch

SD ₂ . . . The essence of the second switch

SD ₃ . . . The essence of the third switch

SD ₄ . . . The essence of the fourth switch

C _dc1 . . . First capacitor

C _dc2 . . . Second capacitor

L _O . . . Output inductance

C _O . . . Output capacitor

T ₁ . . . transformer

L ₃ . . . Third winding

L ₄ . . . Fourth winding

1 is a circuit diagram of a conventional three-stage power conversion device;

2 is a circuit diagram of a conventional single-stage power conversion device;

Figure 3 is a circuit diagram of a preferred embodiment of the present invention;

Figure 4 is a timing diagram of each switch of the present invention;

Figure 5 is a partial exploded waveform of each switch;

Figure 6 is a timing diagram of the preferred embodiment of the present invention at the positive half cycle of the input voltage;

Figure 7 is a circuit diagram of the preferred embodiment of the present invention illustrating the operation in a mode;

Figure 8 is a circuit diagram of the preferred embodiment of the present invention illustrating the operation in mode two;

Figure 9 is a circuit diagram of the preferred embodiment of the present invention illustrating the operation in mode three;

Figure 10 is a circuit diagram of the preferred embodiment of the present invention illustrating the operation in mode four;

Figure 11 is a current diagram of the preferred embodiment of the present invention, illustrating the current waveform input to the two-factor correction unit;

Figure 12 is an experimental measurement diagram of the preferred embodiment of the present invention, illustrating that the input voltage and input current waveform from an external power source are in phase;

Figure 13 is an experimental measurement diagram of the preferred embodiment of the present invention, illustrating current waveforms of the first winding and the second winding;

Figure 14 is an experimental measurement diagram of the preferred embodiment of the present invention, illustrating the current flowing through the HID lamp and the waveform of the voltage across it;

Figure 15 is an experimental measurement diagram of the preferred embodiment of the present invention, illustrating the waveform of the current of the output inductor;

Figure 16 is an experimental measurement diagram of the preferred embodiment of the present invention, illustrating the waveform of the current of the output inductor and the first winding when the input voltage is between positive half cycles;

Figure 17 is an experimental measurement diagram of the preferred embodiment of the present invention, illustrating the waveform of the current of the output inductor and the second winding when the input voltage is between negative half cycles.

2. . . Input filter unit

twenty one. . . First power factor correction unit

twenty two. . . Second power factor correction unit

31. . . Full bridge switch unit

41. . . Output filter unit

51. . . control unit

L _m . . . Input inductance

C _m . . . Input capacitance

L ₁ . . . First winding

L ₂ . . . Second winding

D ₁ . . . First diode

D ₂ . . . Second diode

D ₃ . . . Third diode

D ₄ . . . Fourth diode

S ₁ . . . First switch

S ₂ . . . Second switch

S ₃ . . . Third switch

S4. . . Fourth switch

SD ₁ . . . The first diode of the first switch

SD ₂ . . . The essence of the second switch

SD ₃ . . . The essence of the third switch

SD ₄ . . . The essence of the fourth switch

C _dc1 . . . First capacitor

C _dc2 . . . Second capacitor

L _O . . . Output inductance

C _O . . . Output capacitor

T ₁ . . . transformer

L ₃ . . . Third winding

L ₄ . . . Fourth winding

Claims (14)

A power conversion device for driving a high-intensity discharge lamp, comprising: an input filter unit, receiving an AC input voltage and an input current, and providing an AC filter voltage and a pulse current; The power factor correcting unit receives the filtered voltage and the pulse current, and generates a first correcting voltage of the current; a second power factor correcting unit receives the filtered voltage and the pulse current, and generates a second current Correcting the voltage, and summing the second correction voltage and the first correction voltage into a total voltage; a full bridge switch unit, including a first switch, a second switch, a third switch, and a fourth switch, The full bridge switch unit receives the summed voltage, and switches between the on state and the off state by the first switch to the fourth switch, and converts the total voltage into a converted voltage of a low frequency square wave, and each The low frequency square wave period includes a plurality of high frequency square waves; and an output filtering unit receives the converted voltage and filters out high frequency components of the converted voltage to generate a low frequency square wave Outputting a voltage to drive the high-intensity discharge lamp; wherein the first power factor correcting unit adjusts the pulse current during a positive half cycle of the filtered voltage according to the switching of the first switch to correct the input voltage And a power factor of the input current, and the filtered voltage is converted into the first modified voltage, and the second power factor correcting unit adjusts the pulse wave during a negative half cycle of the filtered voltage according to the switching of the fourth switch a current to correct a power factor of the input voltage and the input current, and converting the filtered voltage to the second modified voltage, the filtering unit filtering out high frequency harmonic components in the pulse current to make the input current It is essentially a sine wave. The power conversion device according to claim 1, further comprising a control unit, wherein the control unit outputs four control signals to the full bridge switch unit to respectively control the first switch to the fourth switch, The control signals of the second switch and the third switch operate at a low frequency with complementary square waves, and there is a delay time between switching. The power conversion device of claim 2, wherein the control signals of the first switch and the fourth switch operate in a time when the control signals of the second switch and the third switch are high. The high frequency is maintained at a low potential for a period of time when the control signals of the second switch and the third switch are low. The power conversion device of claim 1, wherein the second switch and the third switch are switched at a frequency of less than 1 kHz, and a duty cycle thereof is substantially less than 50%. The power conversion device of claim 1, wherein the second switch and the third switch are switched at a frequency of 60 Hz, and a duty cycle thereof is substantially less than 50%. The power conversion device of claim 1, wherein the switching frequency of the second switch and the third switch is substantially equal to the frequency of the input voltage. The power conversion device of claim 1, wherein the first switch and the fourth switch are switched at a frequency greater than 20 kHz. The power conversion device of claim 1, wherein the first switch and the fourth switch are switched at a frequency of 25 kHz. The power conversion device of claim 1, wherein the first power factor correction unit comprises a first diode, a third diode, a first capacitor, and a first winding. The first diode has an anode electrically connected to the input filtering unit to receive the filtered voltage and the pulse current, and a cathode having a cathode electrically connected to the cathode of the first diode a cathode and an anode, the first winding has a first end electrically connected to the first switch, and a second end electrically connected to the cathode of the first diode, the first capacitor is electrically connected to the first Between the first end of a winding and the anode of the third diode, and the voltage at both ends thereof is the first correction voltage; the second power correction unit includes a second diode and a fourth diode a second capacitor, and a second winding, the second diode has a cathode electrically connected to the input filtering unit to receive the filtered voltage and the pulse current, and an anode, the fourth diode Having an anode electrically connected to an anode of the second diode and a cathode, The second winding has a first end electrically connected to the fourth transistor, and a second end electrically connected to the anode of the second diode, the second capacitor being electrically connected to the first of the second winding The voltage between the terminal and the cathode of the fourth diode is at the second correction voltage. The power conversion device of claim 9, wherein the first switch has a first end, a second end, and a control end electrically connected to the first end of the first winding, the control The end is controlled to switch the first switch between an on state and an off state; the second switch has a first end, a second end, and a control end electrically connected to the first end of the first winding, The control terminal is controlled to switch the second switch between an on state and an off state, wherein a voltage between the second end of the first switch and the second end of the second switch is the conversion voltage; The third switch has a first end electrically connected to the second end of the second switch, a second end electrically connected to the first end of the second winding, and a control end, the control end being controlled to enable the The third switch is switched between an on state and a off state; the fourth switch has a first end electrically connected to the second end of the first switch, a second end electrically connected to the first end of the second winding, and a control end, the control end is controlled to cause the fourth switch to be guided Switch between the on state and the off state. The power conversion device of claim 9, wherein the first winding and the second winding are wound in the same core. The power conversion device of claim 9, wherein the first winding and the second winding are respectively wound in two different cores. The power conversion device of claim 9, wherein the first end of the first winding is a polarity point end, and the second end of the first winding is a non-polar point end, and the second The first end of the winding is a polarity point end, and the second end of the second winding is a non-polar point end. The power conversion device of claim 10, wherein the output filtering unit comprises an output inductor and an output capacitor, the output inductor and the output capacitor being at the second end of the first switch and the second switch The second ends of the series are connected in series, and the voltage across the output capacitor is the output voltage.