TW200541193A - High-efficiency DC/DC converter with high voltage gain - Google Patents

Abstract

This invention develops a high-efficiency DC/DC converter with high voltage gain to solve the voltage spike across the clamped switch as the switch is turned off. A conventional boost converter including a single inductor is the common usual. However, the main switch in this circuit has to possess the power capability of high voltage and large current, and it has the problem of reverse-recovery within the output diode. As a result, the conversion efficiency is degraded, and the voltage gain is limited. For the boost converter scheme with a transformer, the step-up range is also limited by the turn ratio, and the conversion efficiency is difficult to improve without handling the leakage energy efficiently. In the proposed converter topology, a high magnetizing current charges the primary winding of the coupled inductor and the clamped capacitor is discharged to the auxiliary capacitor when the switch is turned on. On the contrary, the magnetizing current flows continuously to boost the voltage in the secondary winding of the coupled inductor, and the voltages across the secondary winding of the coupled inductor, the clamped capacitor and the auxiliary capacitor are connected in series to charge the filter circuit. Thus, the related voltage gain is higher than conventional converter circuits. Moreover, this scheme has the voltage-clamped property, i.e., the switch is turned on under zero-current-switching (ZCS) and its sustainable voltage is comparatively lower than the output voltage, so that it can select low-voltage low-conduction-loss devices and there are no reverse-recovery currents within the diodes in this circuit. Consequently, this circuit strategy adopts lower-conduction-loss devices in the low-voltage side with large currents, and the high-voltage side is suppressed in a low current form. From the theoretical derivation and experimental results, the proposed converter topology has favorable voltage-clamped effect, superior voltage gain and conversion efficiency. The proposed high-efficiency converter in this invention can be used for transforming low-voltage sources to high-voltage applications, such as conventional batteries, fuel cells, photovoltaic and wind energy, to further increase the energy utility rate.

Description

200541193 发明 Description of the invention: [Technical field to which the invention belongs] Many power applications, such as gas-discharge headlamps, high-voltage DC busbars of inverters in uninterruptible power systems, and wideband traveling wave tube amplifiers, all require high-voltage DC Power supply generally uses batteries as the source of power; on the other hand, clean source power systems such as solar, wind and fuel cells are usually low-voltage DC power sources, so high-efficiency DC / DC converters with high boost ratios Guarana is another necessary energy conversion mechanism. The high efficiency and high boost ratio DC / DC converter of the present invention can convert: 将 traditional pools and clean energy power generation systems into high-voltage DC power supply systems, greatly improving energy utilization and increasing power supply stability; ⑺ After the mains f source is rectified into a money power supply, this creation can be used to boost the voltage to a volt-level DC power system, or adjust the DC voltage to provide a back-end power circuit and improve the quality of the power. The technical field covered by the present invention includes power electronics, DC / DC technology, and energy technology. Although the technical field covered by the present invention is wide, it is mainly based on the use of a surface-coupled inductor architecture and voltage clamping technology to improve the high-speed custom. The components used in the voltage converter must withstand the stress of the f voltage and the current on both sides, so that its capacity can not be fully used and the lack of conversion efficiency is lacking. [Previous technology] The general conventional boost converter circuit is shown in Figure 2⑻, # Duty Cycle to increase the input voltage level = Power semiconductor of the Bacon converter at the time of cut-off ㈣cross voltage: ^ voltage value, so you must choose a withstand voltage greater than or equal to the output side electric + conductor switch. If you use M0SFET elements, its characteristics include a large on-resistance 200541193 impedance (soil ^), naturally derived higher commutation cry The middle wheel 屮 ^ ν notification is lost. In addition, the traditional boost type: two and the diode has a reverse recovery 1 Surge current flow = the body switch is turned on at the moment 'the output diode of the wheel must be almost severely switched ^ What is the bias current? This current flows through the power semiconductor switch, causing a single and low cost.], ^ Because of this, the conversion efficiency is not good. However, due to the simple structure of the structure, the lack of power; In the case of high and not demanding efficiency, it is widely used in the second industry. For example, the power factor regulator (power factor C_ct-) has the advantage of using dust-free wood structures, that is, the use of transformers. The maximum DC of this circuit is two: two. , Voltage side circuit. Generally, the most commonly used deleted DC / The 甬 and 甬 f 2 instead reduce the repetitive converter. Its advantage is that when it is used on the low reciprocal side and the high-voltage side switch is turned off, it will not be transmitted to the healthy side due to the open connection, resulting in low-voltage side circuit components. Mo ° Ran: However, the balance control of the excitation current and the leakage inductance energy processing both overcome the problems. In addition, 'there is also a point when the transformer is used in a boost architecture', such as the maximum voltage is increased to the ratio, and the output rectification is extremely low. The stress of double the output voltage, so that the cushioning circuit is not possible. For the boost circuit, what is the meaning of isolation? If the circuit is actively controlled on the low voltage side, in other words, controlling the f circuit can control the system, and control the After using the voltage clamping technology to open the relationship, use the lower voltage rated power half-off. 'Do you still need to isolate it? So various circles have researched and developed non-isolated architectures and used coupled inductive boost circuits, as shown in Figure 2 (b). It has the same characteristics as the flyback south boost ratio. Because the coupling inductor is a non-isolated 200541193 lift-off structure, the secondary circuit can assist the booster. The lift-up example and the power output are better than the flyback.式 电路。 Type circuit. However, when the circuit in Figure 2 (b) turns off, the surge voltage generated by the leakage inductance must be equipped with a damping circuit to consume its energy and avoid damage caused by the overvoltage of the switch, so its conversion efficiency is not good. ≫ Therefore many Experts and scholars propose high-efficiency step-up converter technology (such as the paper listed in the following remarks) to improve the disadvantages of the traditional step-up converter mentioned above. There are roughly four categories: First type: Flexible switching technology reference Π] Use the leakage of coupled inductors Inductive and switching parasitic capacitance (general tS) (Parasitic Capacitance or Output Capacitance) resonance characteristics, the switch is turned on at the lowest point of the resonance voltage, to solve the problem of reverse recovery current of the diode, so the switching loss is greatly reduced, and it is a single switch architecture The light-load efficiency can reach more than 97%. The switching voltage of Figure 9⑷ and Figure u 本 of the present invention also has a flexible switching function similar to this. References ⑴ Many shortcomings · (1) The switch must still bear the voltage and current of the high and low voltage sides; (2) The switch capacity utilization rate is low, and the TO-247 switch is used to pack the capacity, but only 20 (^^ output, obviously The high efficiency characteristics of this architecture cannot be performed under higher loads; (3) inductor current ripple and switching losses are high; (4) only 50% increase in input voltage, low boost ratio, (5) ' Cross-frequency control will result in complicated driving circuit and limited flexible switching effect of heavy load. Generally resonant circuits are susceptible to changes in load and inductance-capacitance parameters. At the same time, large switching current ripples will increase additional conduction losses. Reference [2] Output The power conversion efficiency of i.6kW is higher than that of the previous literature, but the control circuit of this circuit needs to be equipped with an auxiliary switch. The voltage difference between the output V and the input 300V is not high, and the on-current is low. This flexible switching of Q will be achieved. 200541193 The key technology of high efficiency conversion. Generally speaking, the problem of σ recovery current, high input electricity house: liter; = effective treatment of diode reverse broadcast, Liu crying, and t liter. Isolation architecture change … The short on-time of the switch means that the energy of the differential pressure is provided by the open _. When the switch is on, the short-circuit current of the parasitic capacitance of the switch: === the reverse recovery current of the processing body, and the TA part of the switch: the loss Can] 'where / (. Is the switching frequency, v' Switching voltage: Capacitance ') If the switch is turned on before the two ends of the circuit are “lower than: Hours of switching: Switching loss 2 = The proportion is greatly reduced, so the flexible switching characteristics = The voltage depends on the operation, and the benefit for improving the conversion efficiency is limited. The second type: transformer boost = literature [3] using transformers with flexible switching technology, up to 97. But the boost ratio is less than three times, and far It is lower than the resistance ratio. The switch bears the same voltage as the output voltage, so the transformer :: Γ is fully utilized to apply the power of low conduction loss on the low side = third type: coupled inductor architecture. [4 ] The effect of the leakage inductance energy system has been successfully processed. In the article, the clamping capacitor is used to absorb the low-voltage leakage. == Modal = It helps to increase the voltage gain. On the other hand, under the system of plus flying, the voltage that the switch withstands is lower than the output voltage. , For the previous few wooden structures, 'the boost ratio is the highest, even at the rated power output, it still shows a good conversion efficiency of 10 200541193', which is a big step for high efficiency and high boost ratio converter. References published later [ 5] Describe the reference [4]. When the switch is on, the reverse bias voltage of the voltage-side diode is the output electric dust and the turns ratio. It must be used in conjunction with a shock-absorbing circuit to eliminate the leakage caused by the leakage inductance. This kind of situation is more obvious in high output voltage and high turns ratio architecture. Reference [5] adjusts the former output capacitor to the secondary side high voltage circuit, which effectively reduces the reverse bias voltage of the diode, but it is undeniable that The shock-absorbing circuit still can't be dropped. The fourth type: the secondary side multi-group series boost reference [6] uses a two-stage or single-stage architecture, flexible switching and transformer boost to obtain high voltage gain. After the secondary side of the transformer is rectified, multiple sets of windings are connected in series to obtain a high voltage output of 3e2kV, which is mainly a power supply for communication satellites. There is a similar circuit connection method in reference [5]. Because the flexible switching characteristics are used to effectively deal with the reverse recovery current of the high-voltage side diode, the conversion efficiency is very high. The input voltage is 26V-44V. When the rated load is 150, the minimum efficiency is 94 · 10 / 〇 In the category of high boost ratio technology, it is a classic. Further analysis, in fact, 3 2kv is the secondary side multi-winding voltage series connection can be increased to this range, if the maximum output voltage of a single winding is only 75 volts. The main architecture uses four switches, three inductors, and a transformer. The actual maximum voltage of the auxiliary switch is 150V, and the withstand voltage of 250V-23A is actually selected. The actual maximum voltage of the main switch is 120V, and the withstand voltage of 200V · 100A is selected. All four TO-247 switches are used, but the output power is only 150W, and the capacity of the components is not fully used. However, the architecture is used for communication satellites, and efficiency is the primary consideration. Comprehensively observe the references listed in the prior art and other coupled inductor structures, and the voltage waveforms across the switches, such as reference [. Zhixin 15 and reference 200541193 Fig. 19 [Fig. 19] of the measured switching MOSFET voltage waveform, there is a surge voltage at the moment of cut-off, and its voltage exceeds half of the normal cross-over voltage. The switching voltage specification must be increased, or even higher than the output. Voltage. With MOSFET manufacturing characteristics,

The increase will be much higher than the voltage rise. Generally speaking, the MOSFET's conduction loss is proportional to the square of the current. The heavy-load conduction loss of the high-voltage MOSFET will be limited to the IGBT power semiconductor switch. Therefore, some high-efficiency circuits can only be light. The ability to load has some performance. This is the general researcher's strengths to avoid their weaknesses. The switching surge voltages presented in References [1] and [5] are caused by the current flowing through the inductors inside the line and components when the primary side of the coupled inductor is turned off, and the instantaneous current changes. The solution must be in parallel with the damping circuit on both sides of the switch. The flow-through circuit must be as short as possible. This path must have both a low skin effect and a mutual inductance value.咼 幵 Voltage ratio device, voltage clamping technology is far more important than flexible switching mechanism. < I will summarize the lack of previous high boost ratio converter technology: (1) resonance, = the field of play should be in the high-wheeler voltage architecture; (2) the switching capacity is not fully driven, (, 3) All components on the high and low voltage sides achieve voltage clamping; ⑷ not knocked = = characteristics of the exciting current and induced current of the device; (5) conversion ㈣ 7 The existing architecture can achieve high efficiency and high boost ratio at the same time. The purpose of η i is to reduce the voltage to the ratio of the step-up converter device with the above-listed losses. Under the premise that the same turn _ = duty cycle 1 is turned on, the voltage gain ratio is higher than the aforementioned structure. = The later performance also reveals that this creation still features high-efficiency conversion: 200541193 Note: References 1. DC Lu, DKW Cheng, and YS Lee, UA single-switch continuous-conduction-mode boost converter with reduced reverse -recovery and switching losses / 5 IEEE Transactions on Industrial vol · 50, pp · 767-776, 2003 · 2. CMC Duarte, and I. Barbi, “An improved family of ZVS-PWM active-clamping DC-to-DC converters / 5 IEEE Transactions on Power Electronics, vol. 17? Pp. L-7? 2002. 3. ES da Silva, L. dos Reis Barbosa, JB Vieira, Jr ”LC de Freitas, and VJ Farias, uAn improved boost PWM soft -single-switched converter with low voltage and current stresses / 9 IEEE Transactions on Industrial Electronics, vol. 48? pp. 1174-1179, 2001. 4. Q. Zhao, and F. C. Lee, “High-efficiency, high step_up DC_DC converters / 9 IEEE Transactions on Power Electronics, vol. 18? pp. 65-73, 2003. 5. KC Tseng, and TJ Liang, "Novel high-efficiency step-up converter / 9 IEE Proceedi ngs Electric Power Applications, vol. 151, pp. 182-190, 2004. 6. I. Barbi, and R. Gules, " Isolated DC-DC converters with high-output voltage for TWTA telecommunication satellite applications / 5 IEEE on Power Electronics, vol. 18? Pp. 975-984, 2003. In the following, the high-efficiency boost converter technology of the aforementioned reference is summarized and compared to further highlight the "high efficiency and high boost ratio DC / DC converter of the present invention. '' Technical reference indicators for technological breakthroughs. 200541193

References Input Voltage Output Voltage Output Capacity Maximum Conversion Efficiency Voltage Gain and Multiple Switch Use Specifications or Waveforms Highest Cross-Voltage Advantages and Disadvantages [1] 100V 150V 200W 97.4% 1.5 500V / 14A Advantages: Flexible switching Disadvantages: Low boost ratio and Large inductance capacity [2] 300V 400V 1.6kW 98.3% 1.3 500V / 20A Advantages: Flexible switching Disadvantages: Too low boost ratio and high clamping voltage [3] 80V 200V 400W 97.5% 2.5 400V / 10A Advantages: Disadvantage of flexible switching : Up to four times the step-up ratio [4] 48V 1 75V 380V lkW 92.3% (75V-lkW) ^ _ \ + nD Cli / — 1-D 8.0 250V / 14A Parallel 4 advantages: simple structure and low conduction loss Disadvantages of the parts: Diodes need to be equipped with damping circuits [5] 12V 42V 35W 93% G — 1 + W 30V Advantages: Diodes with lower voltage specifications Disadvantages: Diodes still need to be equipped with damping circuits y 1 -D 3.5 [6] 26V 1 44V single group up to 750V 150W 94.7% 28.8 200V- 100A * 2 250V- 23A * 2 Advantages: Flexible switching High efficiency High boost ratio Disadvantages Costs Complex South architecture Original creation 24V 1 40V 200V 800W 97 % 400W ^ \ + D + nD Oy — v 1-Z) Step-up ratio 8 times 75V-209A-TO-247 Switch maximum voltage 65V [Abstract] The block diagram of the "high efficiency and high step-up ratio DC / DC converter" disclosed in the present invention is shown in Figure 1. The DC voltage of the DC input circuit 101 is that when the power semiconductor switch 2 of the primary circuit 102 is turned on, the current stores energy in the primary winding a of the coupled inductor, and at the same time clamps the clamping capacitance of the circuit 103 (^ through 200541193 overpower semiconductor switch). The path provided by 2 is conductive, and charges the auxiliary capacitor 03 and the auxiliary inductor Z3 of the auxiliary booster circuit 104. When the power semiconductor switch e is turned off, the current of the primary circuit 102 leaves the power semiconductor 2 switch and passes through the box circuit. The clamped diode a of 103 flows into the clamped capacitor of the circuit ^, at this time, the auxiliary capacitor 6 starts to discharge, and the current of the two capacitors provides a freewheeling path of the primary winding & leaky energy, but this leakage inductance The current also forces the high-voltage capacitor 02 of the secondary circuit 105 to discharge, and then passes through the path provided by the rectifier diode% of the filter circuit 105 to flow into the filter capacitor and the DC output circuit 107, which completes the DC low-voltage power supply. The important sequence for converting into DC high voltage power supply. At the end of the entire switching period, the secondary winding of the coupled inductor & The exciting current transmits energy to the secondary winding $ through the core, and its current Z_, 2 will charge the high-voltage capacitor C2 to provide the required discharge energy for the next cycle. And before the power semiconductor switch 2 is turned on, the auxiliary inductor & In addition to charging the auxiliary capacitor q with a very low proportion of current, at the same time passing through the non-polar point of the primary winding & to transmit energy through the core to the secondary circuit ι05, which is the opposite of _ person-side winding current, _ / ", Due to the leakage inductance component of the winding, the switch is switched on / off and the current is switched (Zer0_Current Switching (zCS). "Circuit" sequence and working mode are shown in Figure 3 and Figure 4, respectively. The following will use Figure 3 and the principle of J1 in this book to make the description simple and easy to understand. , The following content to the control function section, the circuit attribution (such as the circuit 101) is omitted, and the corresponding drawings can be directly compared to the description of the month: ^ formula 1: time [,.-Switch ρ on for a period of time 200541193 order time When, = /., Open Off 2 has been conducting for a period of time, and the current / λ1 of the primary winding A of the light side + inductor ρ flows through the leakage inductance and magnetic inductance of the primary winding and flows back to the negative pole of the DC input circuit through switch 2. Since 2 Inductor 7; the polarity point of the secondary winding ζ2 induces a positive voltage, and the 4th person is the south voltage of the circuit ^ _ pole body A shows reverse deflection, so the inductor 7 is light during the on time of switch 0; In the power state, no induced current is provided to the secondary circuit. The energy of the capacitor c, uses the current path provided by switch 2 to charge the auxiliary capacitor C3 with the auxiliary inductor Z3 of the auxiliary circuit, which provides clamping. The path of electrical energy release, at the same time the voltage of the auxiliary capacitor q and the clamping circuit string can further reduce the voltage that the switch 2 needs to withstand. Mode 1 · time h-/ 2], switch ρ triggers the signal cut-off moment Switch 2 triggers the signal cut-off moment 〇 = / ι), the current of the coupled inductor primary winding & ^^ The parasitic capacitance at both ends is charged. Mode 3: Time is wide, 3]; clamping diode 0 and rectifier diode% are on. In the previous mode, the clamping capacitor C | voltage drops for discharge, and charging starts after the switch is stopped in mode 2. The third mode starts with ^, the voltage of the switch ^ is higher than the voltage v of the clamping capacitor ς, and at this time, μ, the electric field ν (ι 蚪, the orange diode ZV, the member is turned on, and the primary winding ζ is guided.雷 洁 · 哭石 # Soil ... 1 motor, 丨 / ;, L to orange capacitor C 丨 Charge. At the same time 〇, the voltage at both ends of switch 2 rises. According to Kirchhoff ’s voltage law, the rectifier diode The reverse bias voltage, 0, and 择, which are zero, gradually decrease, and the reverse direction is turned on. Therefore, the voltage Vn of the capacitor C is clamped, and the maximum voltage of the switch 2 is limited. However, clamping diodes in series, and clamping lightning in series ^ 0a a The circuits of each C1 in the east of the city must be short and tightly connected in parallel to the two ends of switch 2, otherwise the line stray inductance is still generated and the switch two 200541193 Surge voltage at the terminal. When the clamping diode a and the rectifying diode are turned on, the current l of the primary winding 4 is divided into two paths of the current ′ to charge the clamping capacitor q and force the auxiliary capacitor ^ to discharge due to the principle of the capacitance current balance. Due to the leakage current limited by the primary winding a, the current continues to flow, and the exciting current has not been led to the secondary winding z2, so the total current of the auxiliary inductor 4 and the auxiliary capacitor ^ 3 + L), Follow the path of the high-voltage capacitor C2 of the secondary circuit and the rectifying diode β. Charge the filter capacitor C. ° ^ Mode 4: Time [/ factory, 4]; the high-voltage diode A turns on the primary winding A The leakage inductance and current energy are continuously released, and the voltage v (: 2 of the high-voltage capacitor C2 decreases due to discharge. 'The positive voltage generated by the secondary winding core at a non-polar point' will cause the high-voltage diode to be turned on and excited. The electric power ^ is transmitted to the two under-side windings z2 through the iron core, and the electric power U starts to rise. However, because the electric power on the human side continues to decrease, the capacitance C | The cutoff is due to the wave capacitor. The output voltage F. rises, and the auxiliary capacitor c sounds high. Dust: Valley: The voltages vC3 and Vc2 decrease due to discharge. The rectified diode capsule and the intercept voltage are the same as the clamped diode β, so Required for two diodes = low voltage, low voltage diodes can be used In the subsequent electricity, the high-capacitance capacitor c # 雷 ， Π η 士 & 1, / 2 6 2 charges the current L called the auxiliary inductor 4, and the source to the clamp passes through the auxiliary capacitor q and the secondary winding to identify the DC power supply and path. The non-polar point current of the underside winding ^ will be charged in a transformer manner to the high-side capacitor C2 by the secondary winding A '. Current // 3 200541193 The part passing through the DC power supply G is a circulating component, but because The auxiliary inductor, especially the current l, is much smaller than the current of switch 2, and the DC power supply is low voltage. In addition, the time is short, so the circulating energy is much lower than the overall energy conversion, which has a limited impact on the conversion efficiency. 'Mode 6: Time [, 5 -,.]; Switch 2 is turned on. Because the non-polar point current 3 flowing into the primary winding A is limited by the leakage inductance 4 of the primary side A, the freewheeling characteristic. When the switch 2 is turned on, it cannot draw any current from the auxiliary capacitor diameter. It has zero current switching characteristics (zcs) when it is turned on. 3 When the leakage current A flows through the primary side, it turns into a DC power supply. After the supply, the current / Λ2 of the secondary winding A gradually decreases. When biased, the current k drops to Zero, complete a switching cycle (Switching Cyc) le, and then the working mode returns to the case of mode 1. [Formula derivation] Let the coupling inductance 7; the resistance of the primary winding A and the secondary winding & The ratio is, and the coupling coefficient 々 is defined as:: the magnetic inductance (also known as mutual inductance h is the leakage inductance of the primary winding A J + ¥ when the body switch 2 is turned on), the primary excitation inductance is equivalent to the voltage im ⑺ The meter shows that the house is a theory of equilibrium. 'When the discussion is over, the excitation electric voltage V / ni " DkVs / (\-D) above formula Z) > &, ancient u > (3)' ,, Behring cycle. However clamp the capacitor. Clamping voltage v. It is related to the leakage inductance voltage of the primary side 200541193, group A. When calculating this voltage, the time required for the current to cut off must be calculated. As shown in Figure 5, the charge and discharge current based on the high-voltage capacitor q ::: balance principle. And the initial value of the current is-half of the exciting current, then the duty cycle occupied by the switch until the leakage inductance L drops to zero can be summarized as Di = 4 [Ar + (lZ)) 7: s〇 / [(^ + 4) rv] (4)

:: Kaguan switching cycle, 々 is the switch cut-off to the leakage inductance current. The time required to decrease to zero, the time for charging the high-voltage capacitor C2 at a constant current, the time for the high-voltage capacitor ^ to change from zero current to the constant current, and the time to trigger the switch ρ to turn on. Since & is much smaller than (丨 ,, equation (4) can be simplified as follows:

Dl = ^ / 7 ^ = 4 (lD) / («+ 4) (5) Therefore, the leakage inductance 4 of the primary winding a can be obtained according to the voltage balance formula. )) s (6) Substituting the voltage formula obtained by the leakage inductance A and the exciting inductance 4 of the positive secondary winding A, the voltage of the clamping capacitor port can be obtained as

vn = vas. = Fv + vu + V / m = τ ^ [1 + τ (1, ⑺, according to the private formula (7), the relationship between the voltage required to switch ρ and other parameters can be obtained. Return to switch 2 During the conduction period, the auxiliary capacitor q passes through the auxiliary inductor core, and comes from the clamping capacitor. The energy of 1 forms a step-down system, which decreases to the auxiliary voltage h. The relationship is VC3 = ^ Vri ⑻ 19 200541193 Therefore, the higher the leakage inductance ratio Box report 丨 Lei ^ The voltage of the circuit and the output circuit, = Vil is still higher, relatively increase the auxiliary switch to withstand the voltage v can be = ^ to feedback the circuit will adjust down # any cycle ... So this creation It can reduce the leakage inductance to the electric earth shirt. When the switch ^ is off, the voltage at the non-polar point of the coupling inductor 12 is positive, and its ㈣… VL2 = vC2 ^ nvIm = DknVs / (1-〇) (9) Two: ^: wide and ~ three 'pair filter capacitor ^ and load & release energy, the output DC voltage is (10) (11) = vn + vC3 + v / 2 = i ± ^ ± ^ Therefore, the converter voltage gain can be expressed as G, = ^ L = +: ^ 0 ^) (1 + D)

Vs l — DT ^ D ~~~ Define the handle coupling coefficient as moxibustion = 098 and substitute it into the equation. The ratio of the number of “bubble area” is 3 ~ 1, 5 and 7, respectively, the gain of the converter cycle of the duty cycle ~ _ "Nothing" is a bluff line, and the solid line is the electrical waste gain of the conventional coupled inductor architecture. As the responsibility period D increases, the gap gradually increases. This is the boost of the auxiliary boost circuit of this creation. The proportion has gradually increased, which is the main reason for higher than the conventional boost ratio. Then increase the data selection-fixed M ratio in the above figure to "= 5, and increase the coefficient 0.9 to 0.95, please! The curve 6 of the voltage gain of the duty cycle converter is shown in Fig. 6 (b). According to the two graphs, the coupling coefficient is affected by the voltage gain% within about 3%. Therefore, the light coupling coefficient can be left as a value for analysis of the converter characteristics. When the turning coefficient moxibustion is equal to], the second term of equation (11) is zero, and the converter voltage gain can be simplified as q = K) = ^ + D + Dn y a vs— ~ T ^ F ~ (12) 20 200541193 Substituting equation (12) into equation (7) The relationship between the highest voltage the switch can bear and the output thickness is vds = '0 + D + Dn) (1 3)

In addition, from the equation (12), the duty cycle d is D- ~ X

Gy ^ r \ Λ-η (14) The present invention aims to improve the principle and control efficiency of the prior art based on domestic and foreign literature and custom circuits as follows: '1. The clamp circuit can absorb the inductance energy of the line, make wiring easy, and benefit industrial availability. The snubber circuit currently used in the literature is one of the commonly used voltage clamping techniques, and is roughly divided into passive (composed of capacitors, resistors, and diodes), and active (additional auxiliary switches, capacitors) And diode) and regenerative passive (capacitive and polar) three kinds of 'mainly absorb the energy that affects the voltage clamping inductance and the diode's normal recovery current. The capacitive energy of a passive damping circuit is full ::: xiao consumption ’and therefore has the worst efficiency. The active damping circuit requires additional switching and control circuits, and the internal circulation is also another-it is necessary to overcome the voltage clamping technology of this creation by adopting regenerative passive and absorbing the impact of voltage clamping. The output end, so the circuit reads less' only adds a little _ switching loss to another Shengli auxiliary circuit, which has the highest efficiency. The instantaneous high current change rate is the cut surge voltage. Because the power u is usually caused by the product of the lead, the ancient thunder, the input and the current, so the output current of the low-voltage mutton direct power supply is extremely low. Surges are frequent. Miscellaneous, ^ ";, some final stray inductance, stray discharge sensation mainly comes from improper wiring between each other, 200541193 inductance, the inductance in the wire and the equivalent inductance inside the component. The surge voltage will be directly reflected on both sides of the switch and burned. In order to protect the switch, the voltage clamping effect can be obtained by connecting high-capacitance capacitors in parallel at the nearest two ends, so even the line inductance will not affect the clamping effect. Generally speaking, it is a practically challenging subject to achieve high current and low mutual inductance wiring. However, this creative circuit can effectively reduce the influence of line mutual inductance. 2. The energy absorbed by the clamping capacitor of the clamping circuit can be reused for boosting, there is no circulating current problem, and the purpose of voltage clamping is further achieved. This creation not only sends the energy of the clamping circuit out of the output, but also loops into the voltage clamping in the process, which further reduces the voltage required by the switch. 3. High conversion efficiency. In this non-isolated architecture, a strict distinction is made between low-voltage high-current and high-voltage low-current characteristics. Therefore, the component ratings can be selected with lower withstand voltage and low on-voltage specifications to achieve low-cost, high-conversion converter devices. [Embodiment] The general specifications of all the embodiments of the present invention are described below. Main components-Power Semiconductor switch 2 uses MOSFET, numbered as IRFP2907, on-resistance, _ = 4 · 5 ^ ω, withstand voltage 75V and rated current 209A, package type TO-220. Set the rated output voltage to 200V and the maximum clamping voltage of the switch to 60V. In order to keep a sufficient duty cycle D, the discharge ratio, and the effective value of generating a smaller switching current, so the switching duty cycle β is defined to be about 0.5, and a higher conversion efficiency can be obtained. Finally, it is considered that the power supply of the embodiment can be a 24V battery, and the boost ratio is 8.33. Substituting the above data into equation (14), calculate the turns ratio η to 5.33, take 22 200541193, and the integer is set to π = 5. Due to the ratio of the clamping voltage of the switch to the wheel ^ ^, the conditions of the highest input voltage must be considered. The% voltage involved is approximately positive. The no-load power generation output voltage is about 40V. When using the fuel cell for the equation, to obtain the input voltage. 40V switch duty cycle: 〇 2) 3 and equation (13) can be pressed "",. Is about 63V, about ^% from the voltage withstand voltage of 75V. 36 'Electricity at both ends of the switch. If calculated from battery power, the voltage margin from 24V to 2 ° 〇 = ^ 上 ^ voltage margin is 0.51, and the voltage across the switch is about 50V, which is still 30%. The duty cycle can be used. The above-mentioned design point of view is analyzed and plotted, and the relationship between the residual voltage and voltage G is shown in FIG. 7 (a), and the switching voltage v spot is input to the electric soil W and the input voltage p is shown in FIG. 7 (b). In this way, it should be clearer that the switching frequency of the converter for each creation of this creation is set to g100kHz, which is-general industry = ancient, according to data. Frequency ’remaining detailed specifications are as follows

v (): 200VDC

Tr. A = ll.6 / ^ /; z2 = 290 / ^ /; ^: ^ v2 = 3: i5; ^: = 〇.98; core: EE-55 L3: 25μΗ Q · IRFP2907? 75V / 209A? i? / AV (ON) = 4.5mn? TO-247

cm: 3300 // F / 50F * 10 C ,: 10 // F / 100F c2: 20uF / 250V

C3: ΙΟμΡ / ΙΟΟν C (): 47wF / 250F

dx, d〇: STPS20H100CT, 100V / 2 * 10A (schottky) 9TO-220AB

A: SFA1606G, 400V / 16A, TO-220AB In order to further understand the content of this creation, the experimental wave of the following example 23 200541193 shape, the voltage and current code of the component, please refer to the circuit disclosed in Figure 4. In order to verify the "high efficiency and high boost ratio DC / DC converter" disclosed in the present invention, it has the function of voltage fluctuation clamping function and high capacity and high conversion efficiency. Figure 8 shows the components used in fuel cell boosting to 200V. Voltage and current waveforms. The DC power source of the DC input circuit 101 in this embodiment is a fuel cell produced by Ballard Corporation in the United States, and the output voltage range is about 38v (no load). The test conditions of this embodiment are 200V-700W output specifications. Under the load conditions, the fuel cell provides a voltage of about 30v. Observing Figure 8 (a) _ (h), the voltage across the MOSFET is clamped at 60V, and the primary circuit winding & current _ L is about 60A at the highest. For the inductance value of η · 6, the core The required capacity is not large. The switch on duty cycle β is 0.45, and there is still a considerable margin adjustment to correspond to input voltage fluctuations, load effects, and increase output voltage. The current on the high-voltage side winding is much smaller than the current on the low-voltage side, which indicates that the purpose of the voltage and current division of the high-voltage and low-voltage sides has been completely achieved in this creation. Check the voltage waveform of the low-voltage Schottky diode (%). Without a damping circuit, there is no surge voltage at the two ends of the diode, and it is lower than 100V, so the two diodes mentioned above have been reached. Voltage clamping effect. Figure 8 (i) shows the output voltage and current response of 200V, 70W to 780W instantaneous loading and unloading. According to the waveform display, the voltage ripple is less than 2%, and the energy regulation is fast due to the small excitation inductance. Therefore, under severe load changes, the voltage change rate is very low. Another embodiment of the fuel cell power generation system is disclosed in FIG. 9. The test condition is that the load is gradually increased from 70W to 710W, and the voltage and current waveforms of the switch 2 are measured. When the output power increases, the fuel cell voltage decreases, and the duty cycle needs to be increased to maintain a fixed output voltage. At this time, the voltage across switch 2 is still clamped. 24 200541193 is about 60V. Figure 10 is one of the embodiments of the "high-efficiency high-rising-ratio DC / DC converter i" disclosed in the present invention, which is applied to the conversion efficiency of fuel cell boosting to 200v. This embodiment is to verify the feasibility of the theory The calculation basis of performance and efficiency does not include the power consumed by the driving signal circuit. The output power of this creation is operated in 2 lectures: Hours, with reference Π] The leakage inductance A of the shaft inductor factory and the switch 2 Capacitance c ”vibration phenomenon, as shown in the waveform shown in Figure 9⑷, when switch Q is turned on: the voltage Viw is lower than the clamping voltage. In addition, in low-voltage operation, the proportion of switch switching loss and conduction loss is small, so the device outputs at 40w power. At this time, the efficiency has exceeded 92.5%. The highest efficiency exceeds 97%. This part can also be proved by the commonly used board circuit software. When the output power is higher, the output voltage of the fuel cell is also reduced. ^ Figure 1 1 This is one of the embodiments of the "high efficiency and high step-up ratio DC / DC converter behavior", which is applied to a 24V battery boosted to 200V, a load range is 70W to 800W, and the voltage and current waveforms of the switch. The effect of voltage clamping by waveform observation is close to the theoretical analysis. Figure 12 shows the operation conditions; a conversion rate chart. Under this test condition, the highest efficiency exceeds M ″%, and the overall efficiency is slightly lower than that in FIG. 10, because the boost ratio of this embodiment exceeds Us, but its conversion efficiency still exceeds most of the references listed in the prior art. Although the present invention has been disclosed in the foregoing preferred embodiments, it is not intended to limit = hair: 'Any person skilled in the art will not depart from the spirit and scope of the present invention, and can make various changes and modifications. Therefore, the present invention The scope of the patent application attached to the protection scope shall prevail. Tian 25 200541193 [Brief description of the diagram] FIG. 1 shows a block diagram of a “high efficiency and high boost ratio DC / DC converter” disclosed by the present invention. ㈤Commonly used 幵 Pressure converter: ⑷Traditional boost converter; 升压. Boost converter with coupled inductor. The diagram does not show the "high efficiency and high boost ratio DC / DC converter" disclosed by the present invention, and the circuit timing.

Fig. 4 shows the "high efficiency and high boost ratio DC / DC converter" disclosed by the present invention, and the circuit operating mode. FIG. 5 shows an equivalent area diagram of the charging and discharging current iV: 2 of the “high efficiency and high boost ratio DC / DC converter” disclosed in the present invention. Figure 6 Table I The voltage gain curve of the "high efficiency and high boost ratio DC / DC converter" and the conventional coupling inductor circuit disclosed in the present invention: (a) Coupling coefficient moxibustion-0.098, when the turns ratio is different, the duty cycle It is compared with the inverter voltage gain curve, (b) the turns ratio is equal to 5, the coupling coefficient changes from to, the duty cycle /) and the inverter voltage gain curve.

Figure? Represents the "high efficiency and high boost ratio DC / DC converter behavior" disclosed in the present invention, the output voltage is L = 2⑽ ^ and the coupling coefficient, and the relationship curve between the input voltage and various parameters: (a) input voltage & 2. Relation curve diagram of switching duty cycle D and duty cycle A; (b) Graph of input voltage fs and switching voltage ~. Fig. 8 shows one embodiment of the "high efficiency and high boost ratio DC / DC converter" disclosed in the present invention, applied to a fuel cell boosted to 200V, and the voltage and current waveforms of each element. 26 200541193 FIG. 9 shows one of the embodiments of the “high efficiency and high boost ratio DC / DC converter” disclosed in the present invention, which is applied to boost the fuel cell to 200V, the load measurement range is 70W to 710W, and the voltage and current waveforms of the switch . FIG. 10 shows one embodiment of the “high efficiency and high boost ratio DC / DC converter” disclosed in the present invention, which is applied to a fuel cell boosting to 200V conversion efficiency. FIG. 11 shows one embodiment of the “high efficiency and high boost ratio DC / DC converter” disclosed in the present invention, which is applied to a 24V battery boosted to 200V, the load measurement range is 70W to 800W, and the voltage and current waveforms of the switch. FIG. 12 shows one of the embodiments of the “high efficiency and high boost ratio DC / DC converter” disclosed in the present invention, which is applied to the conversion efficiency of boosting a 24V battery to 200V. The numbers of the main parts in the figure represent the following meanings: 101: DC input circuit 102:-Secondary circuit 103: Clamping circuit 104: Auxiliary boost circuit φ 105: Secondary side circuit 106: Filter circuit 107: DC output circuit%: DC voltage of DC input circuit 7: Transformer with high field current (coupling inductor for short) ρ: —MOSFET switch of secondary circuit A: Primary winding of coupling inductor (including field inductance and leakage inductance) 27 200541193 z2 Inductor secondary winding (including leakage inductance) a: auxiliary inductor of auxiliary boost circuit c / yv: filter capacitor C of DC input circuit ,: clamp capacitor of clamp circuit c2: high voltage capacitor of secondary circuit c3: auxiliary Auxiliary capacitor C of the boost circuit. : Filter capacitor of the filter circuit A: Clamp diode of the clamp circuit D2 • South voltage diode of the secondary circuit Team: Rectifier diode of the filter circuit 仏: Load of DC output circuit

28

Claims (1)

200541193 The scope of patents for patent application and application ... 1. A high-efficiency, high-ratio DC / DC converter, the first of which includes a primary circuit ... including a power semiconductor switch and a primary winding with a surface inductor ; Road:-a clamping diode and-a clamping capacitor; _ Af road.-㈣I auxiliary inductor and 彳 _ auxiliary capacitor, a road: including ― high capacity, ― high M Diode and 'a secondary-side winding of a coupled inductor; Circuit: composed of a filter capacitor and a rectifying diode; When the power semiconductor switch of the primary circuit is turned on, the over-power semiconductor is turned on to provide r The auxiliary capacitor and auxiliary inductor of the voltage circuit are charged; when the power semiconductor = 2_, the current of the -secondary circuit leaves the power semiconductor switch, and the =: Γ: pole body flows into the registered capacitor of the circuit. At this time, the auxiliary electric second: =: 'The current of the two capacitors is provided-the secondary winding leakage inductance = guest: = but this current also forces the path provided by the rectifier diode of the high-voltage circuit of the secondary circuit to conduct, according to = = at the end of r During the second period Winding, pass to the secondary winding, and its current will charge the high-voltage capacitor in order to :; 'discharge energy required for the cycle; at the power semiconductor_low __: =: = over auxiliary: the non-polar point of the group' It is transmitted to the secondary-side circuit through the iron core. This ^ 29 200541193 will hold 3 winding currents, which will cause zero-current switching when the switch is turned on due to the leakage inductance component of the winding. The characteristics of this device are: the first point, the ancient number The main external voltage ratio of the ”fish”, “”, and the external pressure ratio “only the low-inductance inductor is required, and the two or two Yubei cycle control” can output a high voltage gain; the second profitable circuit can absorb the line inductance energy It makes wiring easy. There is 1 ± 'second point' clamping energy absorbed by the clamping capacitor of the clamping circuit: Retransmission: boosting to further achieve the purpose of voltage clamping; the fourth point is that the device is in a non-isolated architecture. Strictly distinguish the low-voltage side sophomore: low-current characteristics of the same voltage-side winding, optional low-voltage, high-frequency components suitable for the voltage range. Fifth, during the voltage boosting process of this device, the DC voltage source and the power semiconductor switch are turned off , Supply current to the output end. This part increases the conversion efficiency without switching and through magnetic circuit conversion during boosting & high efficiency and high boost ratio DC / DC conversion as described in item 1 of the application scope. U, 'The power semiconductor switch of the primary side circuit has a low conduction loss characteristic of low voltage and high current. 3 · ^ Li application scope! The high-efficiency and high-boost ratio DC / DC converter described in the item # wherein the coupling inductance of the primary circuit and the secondary circuit is a double-winding transformer with a magnetizing current of a nip gap; using the transformer turns ratio of 2 is the same, Separate the respective voltage and current ranges, with low turns on the low side and high current, and vice versa on the high voltage side. 4. = High efficiency and high boost ratio DC / DC converter benefits as described in item 1 of the scope of patent applications, in which the clamping circuit can not only absorb the stray inductance energy of the line, but also accommodate the leakage inductance energy of the primary winding of the coupled inductor. And its absorbed energy 30 200541193 can be reused for ㈣, and further-reduce the maximum voltage to which the power semiconductor switch is subjected; the lighter inductance-the higher the secondary winding leakage inductance will reduce the secondary winding induced voltage, but when the leakage inductance ratio The higher the voltage of the auxiliary booster circuit will be increased, so the influence of leakage inductance on the boost ratio and voltage clamping can be reduced; the consumption inductor used in this device can accept high leakage inductance transformers. Sandwich winding method with high coupling coefficient can be completed by using the conventional two-winding method. 5. The high-efficiency and high-boost-rate DC / DC converter according to item 1 of the scope of the patent application. The two ends of the clamping diode used in the clamping circuit are respectively connected to a power semiconductor switch and a clamping capacitor. Power semiconductor switches are the same, so Schottky diodes with low voltage and low conduction loss can be used. Khan 6. The high-efficiency and high-boost-rate DC / DC converter described in item 1 of the scope of the patent application. The rectifier diode used in the filter circuit is opposite to the conduction sequence of the power semiconductor switch. The required voltage and power semiconductor are required. The switches are the same, so Schottky diodes with low voltage and low conduction loss can be used.