TW201031101A - Three-phase AC/DC driver circuit - Google Patents

Abstract

A driver circuit receives a three-phase AC voltage through three input terminals. The driver circuit has a bridge type three-phase switching circuit having three upper and three lower switching elements. The upper switching elements are connected to one of two DC output terminals, and the lower switching elements are connected to the other one of the two DC output terminals. A diode is connected between the output terminals. Sequentially, one of the upper switching elements in a predetermined phase is conducting current while the two lower switching elements of other phases alternately conduct current, and one of the lower switching elements in a predetermined phase is conducting current while the two upper switching elements of the other phases alternately conduct current.

Description

201031101 VI. Description of the Invention: [Technical Field] The present invention relates to the field of power conversion, and more particularly to AC-DC conversion of electric power, such as from an AC power source to a DC load (for example, an LED ( Light-emitting diode) light-emitting load). [Prior Art] Solid-state lighting (SSL) is advantageously used in residential areas, automobiles, and professional applications such as public area lighting, street lighting, transportation systems, gardening, architectural lighting, stadium lighting, and stage lighting. It is expected that solid state lighting will become particularly important for high power lighting systems that are used to illuminate buildings, stadiums and streets, or to be used in greenhouses. In such applications, the power exceeds 1 kW and is required to be obtained from a single-phase or three-phase AC supply voltage source. U.S. Patent No. 4,298,869 teaches the direct supply of single or three phase AC supply voltages to LED strings. In an LED string, a plurality of LEDs in series with one or more resistors adapts the load to the AC voltage and is used to limit the current. By the anti-parallel connection of the LED strings, one of the positive polarity flows through a first LED string, and one of the negative polarity flows through another LED string that is connected in anti-parallel to the first LED string. Although this method is simple and inexpensive, it shows some serious shortcomings. Any current flowing through a string of LEDs requires a particular value of the supply voltage determined by one of the series LEDs. This can result in pulsating currents and low frequency harmonics in the power circuit. In addition, fluctuations in the voltage of the power supply 143719.doc 201031101 will immediately affect the LED current and thus also the intensity of the light produced by the (4). These ballast resistors also cause a large amount of (light) loss, which reduces the overall efficiency of the lighting application. Since it is not possible to directly supply solid-state lamps (such as LEDs) directly from the battery or from the source of the power supply voltage, several electrons are required to drive the stomach. For reasons of efficiency, in high power applications, electronic drives are typically operated in a switching mode. The electronic drivers convert the available enthalpy (or ac voltage to a DC current for use in the solid state lamps. Furthermore, such electronic devices must control and stabilize the current in the solid state lamps, Solid-state lamps are generally connected in series to form a string. The average LED current needs to be stabilized or controlled between a nominal value and zero, and is based on a transistor-based switch and energy storage. One of the inductive and capacitive components of the power electronics circuit to implement the electronic driver. This has been the subject of many publications in the power semiconductor industry. For a high power (eg 1 kW or higher), the LED driver circuit φ not only needs Stabilizing the current in the LED load, and also preventing power supply interaction due to low frequency harmonics. This is generally solved by a two-stage driver topology. In this topology, the first level is a A pre-controller or PFC rectifier that 'takes a sinusoidal current from the power supply. The second power stage is a DC to DC converter that stabilizes the current in a string of LEDs. The second power stage can be based on a simple buck converter. In the DC chain, since the DC power is continuously fed to the LED load, the power flow from the AC line is coordinated. The dual power frequency pulse 143719.doc 201031101 is moving, so it is necessary to store a large amount of electric power to cry., Gandian is fast. The difference is repeatedly fed into the storage (buffer) capacitor or from the storage (buffer) capacitor. Since the A capacitors required in such applications can only be achieved by high temperature sensitive electrolytic capacitors, the life of the driver circuit is particularly limited at high ambient temperatures. For high power applications, the load is evenly distributed. It is also important to have all phases of the three-phase power supply. Applications such as many balanced single-phase LED load driver circuits will mean that if a unit fails, the three-phase power supply will be asymmetrically loaded. [Explanation] Ideal Yes, a two-phase AC/DC driver circuit that does not include an electrolytic capacitor in the power supply circuit is provided. It is also desirable to provide an average load with one of the three-phase power supplies. A three-phase AC/DC driver circuit. It is also desirable to provide a three-phase AC/DC driver circuit that does not substantially generate harmonics in a three-phase power supply. It is also desirable to provide one that has one unit of power factor. A three-phase AC/DC driver circuit that draws sinusoidal current from a power supply. To better address one or more of these concerns, in a first aspect of the invention, a driver circuit is provided that includes: - an input terminal, a second input terminal and a third input terminal; two output terminals for supplying DC output power to a load; a three-phase bridge switching circuit for the first, second and third The input terminal is connected to one of the output terminals via the respective first, second and third unidirectional current conduction switching elements, and further the first, second and third input terminals are respectively passed through the individual Fourth, fifth and sixth unidirectional current conduction switching 143719.doc -6 - 201031101 components are connected to one of the output terminals, the first, second and third switching elements are configured to Flow is conducted to the positive output terminal, and the fourth, fifth, and sixth switching elements are configured to conduct current from the negative output terminal; one is coupled to the first, second, and third input terminals for receiving a three-phase filter circuit of three-phase AC input power of a three-phase power supply; a diode having a cathode connected to the positive output terminal, and

An anode is coupled to the negative output terminal; and a control circuit for controlling switching of the switching elements. In an embodiment of the driver circuit, in operation, the controlling electrically controls the switching of the switching elements to sequentially perform the following actions to achieve conduction of current to the first switching element while alternately causing the fifth switching member And the sixth switching element conducts current; causing the sixth switching element to conduct current while alternately causing the first switching element and the second switching element; <the second switching element conducts current while alternately making the fourth Switching element 1 I /, the switching element conducts current; causing the fourth switching element to conduct 1 while the parent alternately causes the second switching element and the third (four) element to pass a current '· to cause the third switching element to conduct current, Simultaneously, the first::changing element and the fifth switching element conduct current; and the fifth switching component conducts current while alternately causing the # element to conduct current. The first switch 70 and the third (four) in the lighting application, the driver circuit provides a -LED string. [Embodiment] The field and other aspects of this month will be apparent by referring to the following detailed description and together with the + 1 θ Pregnancy-Temple additional drawing considerations. H3719.doc 201031101 see. Figure 1 illustrates a three phase power driver circuit. A three-phase power supply is represented by three voltage sources 10 having a common node 〇 and three terminals r, s and t, and the terminals provide three 120. Phase-shifted AC voltage, each voltage having a sinusoidal shape. The power supply is coupled to a driver circuit at its terminals r, s & t. The driver circuit supplies a load 20'. In the illustrated embodiment, the load 2 is an LED string comprising eight LEDs in series. The driver circuit can drive a parallel circuit of other numbers of LEDs or strings of LEDs. Any other load that requires or receives a DC voltage can be provided instead of a Led string. Thus, although this description refers to a string of LEDs, various other loads can be substituted. The driver circuit includes a filter circuit. The filter circuit includes a plurality of inductors Lf, a plurality of capacitors Cf, and an inductor Ld, each having a relatively small inductance and capacitance. The inductor Lf and the capacitor Cf are used for low pass filtering of all high frequency voltages and current harmonics, so that an almost pure sinusoidal current can be drawn from the power supply. The current system is in phase with the phase voltage. If this effect is achieved, the driver circuit only obtains active power and there is no reactive power. The inductor Ld is used to smooth a load current and prevent or reduce the flow. The light produced by the current of the LEDs varies because the light intensity of the LEDs is proportional to the current flowing through the LEDs. In the driver circuit, 'filtered three-phase voltage and current are supplied to nodes, 2, and 3 to a three-phase bridge converter, which includes 143719.doc 201031101 two limbs' at these The limb 10 includes a switching element embodied as an IGBT (Insulated Gate Bipolar Transistor) transistor ΤΙ, T2, T3, T4, T5 and T6 and a freewheeling diode d〇. Each of the transistors τι_T6 is connected in series to one of the diodes D1_D6. Here, the case of the diode Do is cited, but any other type of unidirectional conduction element, such as a (controlled) transistor, may be substituted. Node 1 is connected to one of the collectors of the transistor τι and one of the emitters of the transistor T4. Node 2 is connected to one of the collectors of transistor Τ2 and one of the emitters of transistor Τ5. The node 3 is connected to one of the collectors of the transistor Τ3 and one of the emitters of the transistor Τ6. The emitters of the transistors Τ1-Τ3 are connected to the anodes of the diodes D1_D3, respectively. The collectors of the transistors T4-T6 are connected to the cathodes of the diodes D4_D6, respectively. The cathode of the diode D1-D3 is connected to a node A, and the anode of the diode D4_D6 is connected to a node B ^ (freewheeling) diode D 〇 one anode is connected to the node B, and two One of the poles of the polar body is connected to node A. One of the filter inductor Ld and the LED string 20 is fed in series through nodes eight and B. It should be noted that the order of the transistor Τχ and the corresponding diode Dx (x=i, 2, 3, 4, 5, 6) in the series may be reversed. It should be further noted that other types of switching elements can also be used, such as M〇SFET (Metal Oxide Semiconductor Field Effect Transistor) or bipolar transistor, such as IGBT (Insulated Gate Bipolar Transistor) or have been integrated A component of the rectifying function of the diode in the switching element (eg, in the GT 闸 (gate open) thyristor). Straw is provided by a suitable buffer circuit (not shown) to facilitate switching of the switching elements. ' 143719.doc 201031101 The operation of this driver circuit is as follows. The driver circuit can be considered as a buck converter in which two terminals of the two-phase power supply are repeatedly switched (connected) to the series connection of the inductor Ld and the load 20. In order to set an on state of the driver circuit, one of the transistors _1_τ3 and one of the transistors Τ4-Τ6 are turned on, that is, one of the nodes i_3 is connected to the node A and the node i- The other one of the three is connected to the node B. There are six possible states for forming an on state, wherein a voltage Ud across the diode Do can be formed by U12, U13, U23, U21, U31 or U32, where Uxy indicates terminals X and y (x, 2) And a phase-to-phase voltage between 3). The transistor pair T1 and T4 of the first limb of the converter bridge, the second limb 72 and 75 of the converter bridge, and the third limb of the converter bridge When the T3 and D6 of the object are respectively connected in series, the two transistors in each series connection will never be turned on at the same time. For a continuous power flow, all possible phase-to-phase voltages of the three-phase power supply are sequentially connected to the load 20 through terminals A and B. These individual phase-to-phase voltages should have a positive value (eg Ud(t)&gt; 0) to cause a load current to flow at 1 。. In this case, no current flows through the diode D (ie, id = 〇). In order to set an open state, at least all of the transistors TI-T3 or all of the transistors T4-T6 should be disconnected, such that a load current ι〇 flows through the diode Do (ie, Id=I〇) » By switching the phase-to-phase voltage U12, U13, U23, U21, U31 or U32 by pulse width modulation' and by a freewheeling state (Ud = 0 in this state), the switched voltage Ud can be further pulsed Width modulation. 143719.doc •10· 201031101 Considering the goal of producing a substantially constant voltage Ud(t)2 average during each switching period (with a pair of transistors enabled during that period), the connection of transistors T1-T6 The pass-to-off ratio must be constantly adjusted to the current phase-to-phase voltage. As an embodiment of a control scheme, the following switching order is selected. During one of the supply voltages T = 1 / fM (e.g., fM = 5 〇 or 60 Hz), each of the transistors T1-T6 is during one of the periods 1/6 of the time t(10): φ t〇NT /6_1/(6.fM) or a phase angle of 60. The internal system is continuously in an on state. In the actual example, these transistors are at 60. The phase range is turned on so that the voltage can reach a maximum value at the freewheeling diode D〇. This performance can be achieved, for example, by making each of the transistors. The on state is achieved by synchronizing with a phase voltage (eg, the phase of the three phase power source to the neutral point (9) voltage). In the transistor Τ1-Τ3Φ, go to Φ a Λ·*,...

1437l9.doc 201031101 Figure 2 shows a graph of the normalized three neutral point voltages U10, U20 and U30 as a function of a phase angle α. Its purpose is to clarify: U10(α)=ϋΜ·〇〇8(α) (1) U20(a)=LFM-cos(a-120°) (2) U3 0(a)=t)M.cos( A-240.) (3) where ϋΜ represents one of the neutral point supply voltage peaks. With this three-phase power supply, the switching sequence can be selected as shown in Table 1 below. Table 1 The maximum neutral point voltage of the transistor in the switching operation of the phase range is 30° &lt; α &lt; 90 ° Τ 6 ΤΙ, Τ 2 - U30 (-LJm) -30 ° &lt; α &lt; 30 ° ΤΙ Τ5 ' Τ6 +υι〇(+ϋΜ) 270°&lt;α&lt;330° Τ5 ΤΙ ' Τ3 -U20(-1Jm) 210°&lt;α&lt;270° Τ3 Τ4, Τ5 +U30(+Om) 150°&lt ;α&lt;210° Τ4 Τ2, Τ3 -UIO(-IJm) 90°&lt;α&lt;150° Τ2 Τ4, Τ6 + U20(+tjM) For a more detailed understanding of the operation of the driver circuit of Fig. 1, Consider an example of a phase range of -30 ° $ α &lt; 3 0 °. Within the other phase ranges, the operation of the driver circuit is generally similar for the transistors indicated. In the phase range of -30 ° $ a &lt; 30 °, the transistor T1 is in an on state, and the transistors T5 and T6 are switched at a high switching frequency. The transistors T2, T3 and T4 are inactive. For the range of phases under consideration, Figures 3(a)-3(h) show the voltages of several transistor control signals, transistors and diodes, 143719.doc -12- 201031101, and diodes. And the load current is 1〇. As can be seen from Figure 3(a), the transistor T1 is at -30 Υ α &lt; 30. The phase range is continuously in the on state (indicated by the word r〇n (on)). Figure 3 shows that the transistor 5 is in an on state for a period of time 12 (and in other periods, the word "offj" is indicated by the word "offj", while Figure 3(c) shows the transistor T6. In a follow-up period t3, it is in an on state (and in an off state in other periods). In FIG. 3(a), 3(1&gt;), and 3 (a magical one of φ is switched) In the period FTswdfl/fsw}, both the transistor and the ^^ are in an off state during a period of time (1'^12-13)=^〇. As seen in Figure 3(d), if the transistor When the D5 or the transistor is in the ON state, the corresponding phase-to-phase voltage is connected to the diode D〇: Ud=ui〇_ U20=U12 or Ud=U10-U30=U13. If the transistor T5 and When both of π are in an off state, the current flows through the diode D〇, so Ud=〇. Figures 3(e), 3(f), 3(g), and 3(h) respectively Shown at a time t1 (u=t2+t3) 'the monthly flow, the left constant B body T1 (constant) load current 1 〇 (current〗 1), flowing through the transistor T5 during a time t2 (constant) load current 1 〇 (current 12), which flows through the transistor D during a time t3 (constant The load current (current 13) and the (constant) load current 10 flowing through the diode Do during time t0. The load current 流 flows through the transistor T1 and flows through the transistor butyl 5 or the transistor T6. If the order of the switching control signals is changed, the basic performance of the circuit does not change. For example, according to Figs. 3(1)(4), 3(1)(8) and (6)(4), the transistor T5 is first turned on at time t2 and follows the relay in time. ^ is turned on. According to Figure 3(1)(a), 3(1)(8) and 3(1)(4), the order of the connection of the electric 曰曰曰m 143719.doc -13- 201031101 T6 is changed. Or 'by the two for Τ5 and Τ6 The freewheeling time to is allocated between the on-state switching control signals, and the order of the switching control signals can be modified. In this case, the entire freewheeling time should not be changed: t〇=t01+t02. (k) This situation is illustrated in (a), 3(k)(b) and 3(k)(c). Since the voltage in t2 is 1 during the switching period; (1 is greater than the voltage in 〇

Ud, the selected switching period Tsw is at -3〇. Righteousness &lt; Within the phase range (see Figure 2). In the case where the current needs to be switched from one limb to the other (for example, the self-driving crystal T5 to the transistor T6, and vice versa), it is not necessary to simultaneously break the first transistor and turn on the first Two transistors. Referring to Fig. 3(d)_3(h), the load current is only provided for the relocation based on if more than one electromorphic system in the lower or upper portion of the limbs is in the -on state. The fact that one of the high phase voltages flows in the limbs can also be selected as follows. Accordingly, if the lower portions of the limbs

The phase-to-phase electrical energy of the first one of the transistors in the (or the upper portion) is lower than the second one of the transistors in the same portion of the corresponding limbs Interphase „ ' additionally by turning on the transistors; the second one, current from the first one of the transistors (where the first one of the transistors is in the turn-on State, and conduct the current, commutating to the second one of the transistors. This situation is illustrated in 3(1)(4)? 3(l)(b) and 3(l)(e), wherein the commutation system The corresponding phase voltage of the second one of the electromorphic crystals is lower than the first one of the transistors in the transistor. At the phase voltage, by disconnecting the first one of the transistors, the current will only be from the first of the transistors: • In the on state, and the conduction current is commutated to the second one of the transistors (where the second one of the transistors is in the off state). Therefore, when the electricity is crystal When the first one of the body and the second one of the transistors are simultaneously turned on, only the transistor having the highest corresponding phase-to-phase voltage will conduct current, and by having the highest correspondence The transistor of the phase-to-phase voltage is disconnected, and the second of the transistors in the transistor can be commutated to the second of the transistors. The situation is illustrated in Figure 3(m)(4). , 3(m)(b) and 3(m)(4), wherein the commutation is represented by a series of parallel arrows in Fig. 3(m)(a). See Fig. 2 and the corresponding formula (1) ) _ (3) and table j, for the control scheme that will be used to control the load current 1 ,, two parameters are required: a modulation factor m (0&lt;m£l); and a phase angle a=2 -7E.fM.t(-30°Sa&lt;30.) For these parameters, the total on-time of one of the transistor T5 and the transistor D6 is required to be tl=t2+t3=Tsw.m.COS(a) And this is based on the assumption that the neutral point voltage U1〇(a)=t)M.cos(a) is synchronized. The transistor should be turned on for a period of time t2=-Tsw.m .cos(a-120.), at the same time, the turn-on time of the transistor D6 should last for a period of time ^^丁...^化+丨"Spoon ^ is in each switching cycle tsw, and the current freewheeling period 1 is t0 = Tsw_t 丄. If the above conditions are met, the driver circuit exhibits the following performance. Within each switching cycle r = Tsw, the output or load voltage is set to u 〇 = ud 143719.doc 201031101 (average) = 1.5.m.! QM. The currents flowing in the terminals 1, 2 and 3 at the input terminals are one +/- 120. The phase width shift is performed by pulse width sinusoidal modulation. The currents are equally divided over the entire switching period r=Tsw, and the currents are proportional to the neutral point voltage: U (4)=mi〇.cos(4) I2(a)=m*Io-c〇s(a-120 °) I3(a)=mI〇.c〇s(a-240o) All higher harmonics are effectively attenuated by the filter circuits Lf, Cf (Fig. 1). An LED load current is determined by the set voltage Uo and the voltage versus current characteristic of the LED load. This is shown in 4(a), 4(b) and 4(c). Figure 4(a) represents a led load which, for illustrative purposes, comprises one of four LEDs forming a string, however the string may contain any number of LEDs and other parallel LED strings may also be present. Figure 4(b) represents an equivalent circuit diagram depicting an LED load. By means of the equivalent circuit diagram, the LED load can be roughly described by two parameters: a voltage υτ, and a differential series resistor.

Rd=AuMi ’ is as indicated in Fig. 4(e). Accordingly, in the case of an LED load, the load current of the driver circuit can be determined as follows: 1 〇; = 〜 UT) / Rd. When the value of Rd is relatively low, a small change in the voltage u〇2 causes a large change in the load current 1〇. In addition, the parameters UT and Rd differ between different physical components, and these parameters also depend on the temperature. Accordingly, a current control circuit can be used, an embodiment of which is illustrated in FIG. 143719.doc 16 201031101 In FIG. 5, filter components Lf and Cf, and transistors T1-T6, diodes D1-D6, and diodes Do are considered to be included in block 50 as compared with FIG. And has input terminals r, s, t and output terminals A, B. In the circuit of Fig. 5, the load current 1 is measured by a current sensor S1, which can be embodied as a shunt resistor or other component. In a subtraction comparator 52, the load current measurement l〇in is compared with a reference current value Iref. A difference (i 〇 m_iref) is fed to a current control circuit 54, which sets the modulation factor m and supplies it to a drive control circuit 56. The drive control circuit 56 generates a plurality of switching control signals ' to turn on the transistor Τΐ_τ6 for a predetermined period of time as described above. Further, the three-phase power supply voltage is measured to determine the instantaneous value thereof and the pulse width modulation of the above-described transistor T1-T6 is synchronized with the frequency and phase of the power supply voltage. A power measurement and synchronization circuit 58 performs this function and is functionally coupled to the supply voltage source and the drive control circuit 56. By setting a value of 11 &gt; 6 {, the power supplied to the load can be varied. For an LED load, setting an Iref value will darken the LED load. Make "capacitor c." In parallel with the load, one of the current surges in the load can be reduced. The control functions performed by the comparator 52, the current control circuit, the drive control circuit 56, and the power supply measurement and synchronization circuit 58 can be performed by a single controller. If the skilled person can properly design the filter which is embodied as the inductor Lf and the comparator Cf, the current control circuit, and the power supply measuring and synchronizing circuit 58, the power supply current becomes Sinusoidal and in phase with the 143719.doc -17- 201031101 supply voltage. Figure 6 shows the characteristic voltage and current waveforms of Ud(1) and π(1) during a 1/2 power (supply) cycle, where n(1) is the AC current in the supply voltage υι〇 phase. It can be seen that the driver circuit draws a sinusoidal current from the power supply having a unit power factor. In summary, according to the above, a driver circuit receives a three-phase AC voltage by three input terminals. The driver circuit has a bridge three-phase switching circuit having three upper switching elements and three lower switching elements. The upper switching elements are connected to one of the two Dc output terminals, and the lower switching elements are connected to the other of the two Dc output terminals. A diode is connected between the output terminals. In sequence, one of the upper switching elements in a predetermined phase is turned "on", and the two lower switching elements of the other phases are alternately turned on, and - among the lower switching elements in the predetermined phase The person is switched on while the other upper switching elements of the other phases are switched on alternately. The driver circuit of the present invention does not require a storage element in the form of an (electrolyte) capacitor. The absence of such capacitors extends the life of the driver circuit and is expected to exceed 1000,000 hours. In this specification, the present invention has been disclosed with reference to a three-phase power supply system. A three-phase power source can be replaced with a power source having a larger number of phases and a corresponding adjustment of the circuit and the control of the circuit in accordance with the present invention can be made in accordance with the principles set forth above. The present invention has been described in detail with reference to the preferred embodiments of the invention. Therefore, the structural and functional details of 143719.doc -18· 201031101 disclosed herein are not to be construed as limiting, but only as the basis of the patent application and as a teaching The present invention is used in a structure that is suitable for almost any detail - a representative basis. In addition, the terms and phrases used herein are not intended to be limiting, and are intended to provide an understanding of the invention. The term "-" ("3" "milk") as used herein is defined as one or more. The term "plurality" as used herein is defined as two or more than four. The term "another" as used herein is defined as at least a second or Nth (N greater than 2). The term "including and/or containing" as used herein is defined to include (ie, open language, Other components or steps are not excluded). Any reference signs within the scope of the claims should not be construed as limiting the scope of the invention or the scope of the invention. Some measures are cited in different technical solutions that differ from each other. This alone does not mean that these measures cannot be combined in a favorable manner. A single processor or other unit, such as a programmable logic controller, performs the functions of several items referenced in the scope of the patent application. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a circuit diagram showing an embodiment of a power supply circuit of the present invention, the power supply circuit supplying power to a led string. Figure 2 shows a graph of normalizing the neutral point voltage for one of the three-phase power supplies. FIG. 3(a) illustrates a timing control sequence of one of the switching elements τι of the power supply circuit of FIG. 1. FIG. 3(b) illustrates a control sequence of one of the switching elements T5 of the power supply circuit of FIG. 1 at time 1437l9.doc -19-201031101. Fig. 3(c) shows a switching timing of one of the switching elements of the power supply circuit of Fig. 1. Fig. 3(d) shows a voltage Ud generated by switching the switching elements indicated in Figs. 3(a), 3(b) and 3(c). Fig. 3(e) shows a current flowing in the switching element T1 indicated in Fig. 3(a). Fig. 3(f) shows the current flowing in the switching element T5 indicated in Fig. 3(b). Figure 3(g) shows one of the currents flowing in the switching element Τ6 indicated in Figure 3(c). Figure 3 (h) shows a current flowing in one of the circuit elements of the power supply circuit of Figure 1. 3(i)(a), 3(i)(b), and 3(i)(c) respectively show the switching control signals of the switching elements T6 and D5 in another pulse width modulation scheme and the obtained Voltage Ud. 3(j)(a), 3(j)(b) and 3(j)(c) respectively show the switching control signals of the switching elements T5 and T6 and the obtained voltage in another pulse width modulation scheme Ud. 3(k)(a), 3(k)(b), and 3(k)(c) respectively show the switching control signals of the switching elements T5 and T6 and the obtained voltage in another pulse width modulation scheme Ud. 3(l)(a), 3(l)(b) and 3(l)(c) respectively show the switching control signals of the switching elements T5 and T6 and the obtained voltage in another pulse width modulation scheme 143719.doc -20· 201031101

Ud. 3(m)(a), 3(m)(b), and 3(m)(c) respectively show switching control signals of the switching elements T6 and T5 and the obtained voltage in another pulse width modulation scheme Ud. Figure 4(a) shows a LED string being powered by a current of 1 ,, producing a voltage drop Uo. FIG. 4(b) is a diagram showing an equivalent circuit diagram of the LED string in FIG. 4(a). Fig. 4(c) shows the electrical characteristics of one of the LED strings shown in Fig. 4(a). Figure 5 is a block diagram showing one of several control circuit components of a power supply circuit of the present invention. Figure 6 shows one of the three-phase power supplies as the voltage Ud and current 11' of the 昧pj $ slave π fishing rod function and the neutral point voltage U i 该 of the three-phase power source. [Main component symbol description] 1-3 Node 10 Three-phase power supply 20 Load 52 Subtraction comparator 54 Current control circuit 56 Drive control circuit 58 Power supply measurement and synchronization circuit A Node B node D1-D6 Diode Lf, Cf filter Circuit 143719.doc -21. 201031101 si Current Sensor T1-T6 Transistor

143719.doc -22-

Claims (1)

201031101 VII. Patent Application Range··1· A driver circuit, comprising: a first input terminal, a second input terminal and a third terminal (1, 2, 3); Two output terminals (A, B) for supplying DC output power to a load (20); a two-phase bridge switching circuit that passes the first, second, and third input terminals through individual First, second and third unidirectional current conduction switching elements (T1, D1; T2, D2; T3, D3) are connected to a positive terminal (A)' of the output terminals and further the first And the second and third input terminals are connected to one of the output terminals by the respective fourth, fifth and sixth unidirectional current conduction switching elements (T4, D4; D5, d5; T6, D6) a negative terminal (B), the first, second and third switching elements (T1 'D1; T2, D2; T3, D3) are configured to conduct current to the positive output terminal (A), and the fourth The fifth and sixth switching elements (τ4, D4; Τ5, D5; Τ6, D6) are configured to conduct current from the negative output terminal (Β); a two-phase filter circuit that is summed to the first And second and second input terminals for receiving three-phase Ac input power from a three-phase power source; a diode (Do), one of which is a cathode It is connected to the positive output terminal (A), and an anode is connected to the negative output terminal (B); and a control circuit for controlling the switching of these switching elements. 2. The driver circuit of claim 1, wherein the switching element comprises a transistor 143719.doc 201031101 The body switching switch is connected in series with one of the diodes. 3. The driver circuit of the requester, wherein, in operation, the control circuit switches the switching of the switching elements by means of a financial operation: five-cutting causes the first switching element to conduct current while alternating Causing the first switching element and the sixth switching element to conduct a current; causing the sixth switching element to conduct a current while alternately causing the first switching element and the second switching element to conduct a current; Causing the first switching element to conduct current while alternately causing the fourth switching component 70 and the sixth switching component to conduct current; causing the fourth switching component to conduct current while alternately causing the second switching component and the first The third switching element conducts current; causing the third switching element to conduct current while alternately causing the fourth switching element and the fifth switching element to conduct current; and causing the fifth switching element to conduct current while alternately making the The switching element and the third switching element conduct current. 4. 5. The driver circuit of claim 3, wherein the switching elements that sequentially conduct current are switched at a first frequency, and the switching elements that alternately conduct current are switched at a second frequency. For example, the driving element of the monthly claim 4, wherein the second frequency is higher than the first frequency 6. For example, the driver circuit of any one of the items 3 to 5, wherein switching of the switching elements that alternately conduct current The pulse width modulation is 。. The driver circuit of the long term 3, wherein each of the sequentially conducting currents 143719.doc -2 - 201031101 one of the switching elements is selected to be supplied to the first and second And a maximum amount of the neutral point voltage of the third switching element with respect to the voltage is from -30 to +30. and is selected to be supplied to the fourth, fifth and sixth switching elements. The neutral point voltage - the maximum amount of one of the voltages in the period from -30 to +30. 8. The driver circuit of claim 1, wherein, in operation, the control circuit switches the components The switching control is implemented by sequentially performing the following: turning on the first switching element while alternately turning the fifth switching element and the sixth switching element on; turning on the sixth switching element while alternating Grounding the first switching element and the second The switching element is turned on; the second switching element is turned on while the fourth switching element and the sixth switching element are alternately turned on; the fourth switching element is turned on while the second switching element φ is alternately turned on And the third switching element; turning on the third switching element while alternately turning on the fourth switching element and the fifth switching element; and turning on the fifth switching element while simultaneously turning on the first The switching element and the third switching element of the invention. 9. The driver circuit of claim 1, wherein, in operation, the control of switching the switching elements of the control circuit is performed by sequentially performing the following actions: The first, fifth and sixth switching elements simultaneously and repeatedly disconnect one of the fifth and the sixth switching elements of 143719.doc 201031101; turning on the sixth, first and second switching elements simultaneously Reversibly disconnecting one of the first switching element and the second switching element; turning on the second, fourth, and sixth switching elements while repeatedly turning off the fourth switching element and the sixth switching element One of turning on the fourth, second, and third switching elements while repeatedly turning off one of the second switching element and the third switching element; turning on the third, fourth, and fifth Switching the element while repeatedly reversing one of the fourth switching element and the fifth switching element; and turning on the fifth, first, and third=cutting of the +4A first switching element while alternately breaking The first switching element and the third switching element are turned on. ^ ίο. ❹ The driver 々 々 actuator circuit of claim 1, wherein the control of switching the switching elements is performed by the control The operation is: performing the following actions: (4) turning on the first switching element 'sequentially: turning on the fifth switching element, turning on the sixth switching element; and disconnecting the fifth switching element and the first a switching element. W turns on the sixth switching element while sequentially: turning on the first switching element, turning on the second switching element; and disconnecting the first switching element and the second switching element; (4) Passing the second switching element while sequentially: Turning on the fourth switching element, I43719.doc -4- 201031101 turning on the sixth switching element; and disconnecting the fourth switching element and the sixth switching element; (d) turning on the fourth switching element while Sequentially: turning on the second switching element, turning on the third switching element; and disconnecting the second switching element and the third switching element; 0) turning on the third switching element while sequentially: turning on The fourth switching element turns on the fifth switching element; and turns off the fourth switching element and the fifth switching element; and (f) turns on the fifth switching element while sequentially: turning on the first Switching the component, turning on the third component; and disconnecting the first switching and the third switching component. 11. A method of driving a -Dc electrical load using a driver circuit as claimed, the method comprising: supplying three-phase AC power to input terminals of the driver circuit; connecting the load to outputs of the driver circuit Terminals; and sequentially controlling switching of the switching elements in the following order: causing the first switching element to conduct current while alternately causing the fifth switching element and the sixth switching element to conduct current; Conducting current while alternately causing the first switching element and the second switching element; causing β first switching π pieces to conduct current while alternately changing the fourth slice 143719.doc 201031101 and the sixth switching element Conducting a current; causing the fourth switching element to conduct a current while alternately causing the second switching element and the third switching element to conduct a current; causing the second switching element to conduct a current while alternately causing the fourth switching element and The fifth switching element conducts current; and 12. causes the fifth switching element to conduct current ' while alternately causing the first switching element and the first The three switching elements conduct current. 3 illuminating device&apos; which comprises a driver circuit as claimed; wherein the load comprises at least one LED string. 143719.doc