CN102801340B - Control method and controller for AC-DC converter - Google Patents

Control method and controller for AC-DC converter Download PDF

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CN102801340B
CN102801340B CN 201210295489 CN201210295489A CN102801340B CN 102801340 B CN102801340 B CN 102801340B CN 201210295489 CN201210295489 CN 201210295489 CN 201210295489 A CN201210295489 A CN 201210295489A CN 102801340 B CN102801340 B CN 102801340B
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feedback
vfb
ac
dc converter
amount
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CN102801340A (en
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何乐年
刘侃
邱建平
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浙江大学
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Abstract

本发明公开了一种AC-DC变换器的控制方法,其通过采集AC-DC变换器的辅助绕组电压信号,并采用高精度的原边反馈技术,自动补偿反馈量,以获得精确的反馈量,进而构造出PWM信号以驱动AC-DC变换器中的开关管,最终实现控制调节变换器输出电压的目的;故本发明方法计算得到反馈量的精度,进而保证了AC-DC变换器输出电压的精度。 The present invention discloses a method of controlling the AC-DC converter, which auxiliary winding voltage signal acquired by AC-DC converter, and the primary-side high-precision technology to automatically compensate for the amount of feedback for accurate feedback amount , a PWM signal is further configured to drive the AC-DC converter switch, and ultimately control the inverter output voltage regulation purposes; method of the present invention so that the accuracy of the calculated amount of feedback, thereby ensuring the output voltage of the AC-DC converter accuracy. 本发明还公开了一种AC-DC变换器的控制器,包括原边采样电路和数字补偿器;原边采样电路包括波形实时分析模块、单输入双输出数模转换器和两个比较器;能够得到相对精确的反馈量,其采用数模转换器(而非模数转换器),相比较之下,降低了设计难度,节省了消耗的面积。 The present invention also discloses a controller for a AC-DC converter, comprising a primary circuit and a digital sampling compensator; primary sampling circuit includes a waveform analysis module in real-time, single-input dual-output digital to analog converters and two comparators; It can be obtained relatively precise amount of feedback, which employs digital to analog converter (analog to digital converter instead), comparison, reduces the design effort, saving area consumed.

Description

—种AC-DC变换器的控制方法及其控制器 - kind of AC-DC converter and its control method of the controller

技术领域 FIELD

[0001] 本发明属于电压变换器控制技术领域,具体涉及一种AC-DC (交流-直流)变换器的控制方法及其控制器。 [0001] The present invention belongs to the voltage converter control, and in particular relates to an AC-DC - control method and a controller (AC-DC) converter.

背景技术 Background technique

[0002] 随着电池充电器、LED驱动电路等的发展,AC-DC变换器的设计技术芯片也得到了飞速发展。 [0002] With the battery charger, LED drive circuit, etc., AC-DC converter chip design technology has been rapidly developed. 对AC-DC变换器芯片的集成度要求也在逐渐提高,设计者被要求尽量少地使用片外器件,以减小硬件开销和变换器整体体积。 Integration of the AC-DC converter chip requirements are gradually increased, the designer is required to minimize the use of off-chip devices, to reduce the hardware cost and overall volume of the transformer.

[0003] 图1是传统的基于副边反馈AC-DC变换器。 [0003] FIG. 1 is based on a conventional secondary feedback AC-DC converter. 如图所示该芯片采用光耦隔离反馈方式,负载电阻上的输出电压通过光电耦合器,传递到变压器原边作为反馈电压,并通过控制器去调节输出电压,这种反馈方式不仅需要一个片外光电耦合器,增加了开销,而且光电耦合器的电流传输比受温度的影响较大,随着温度的变化,电流传输比会呈非线性变化,导致对输出电压的采样出现误差,影响输出电压精度,这种影响在负载较重发热较大的电源中最为明显。 The chip isolation optocoupler feedback embodiment shown, the output voltage on the load resistance through the photocoupler, is transmitted to the primary side of the transformer as a feedback voltage, and by a controller to regulate output voltage, this approach not only requires a feedback sheet outer photocoupler, increased overhead, and the current transmission photocoupler greater impact than by temperature, as the temperature changes, the current transmission ratio will change nonlinearly, resulting in the sampling of the output voltage error occurs, it affects the output voltage accuracy, this effect is heavily loaded large heat supply is most evident.

[0004] 如图2所示的基于原边反馈的AC-DC变换器被广泛采用。 [0004] The AC-DC converter based on the PSR is widely used as shown in FIG. 图中反馈电压是从变换器中变压器的辅助绕组上采样得到,其特点是在不用光电耦合器的情况下也实现原边和副边的隔离,但是由于辅助绕组电压Vsense非直流电压,因此在芯片内部设计一个采样保持电路,在一个固定的采样点去采样来得到反馈量Vfb,但是实际情况下,采样保持电路可能并不十分精确,这个固定的采样点无法跟踪拐点电压,二极管压降的影响会导致采样的不精准。 FIG feedback voltage is sampled from the auxiliary winding of the converter transformer, which is characterized by without the use of optocouplers can achieve isolation of the primary and secondary side, but since the auxiliary winding voltage without DC Vsense voltage, so chip design a sample and hold circuit, at a fixed sampling point to sampling feedback Vfb is obtained, but in reality, the sample hold circuit may not be very precise, this fixed sampling point can not track the knee voltage, the diode drop the impact will not lead to a sampling precision.

[0005] 根据上述的情况可知现有的采样反馈技术,其输出的反馈量Vfb对应的反馈电压与变换器输出电压之间存在一定误差。 [0005] In the above case there is some error between the known prior art sampling feedback, the feedback amount Vfb corresponding to the output of the feedback voltage and the converter output voltage according to. 该误差随着系统的负载条件以及片外器件参数变化而变化,无法在片内对该误差进行补偿。 The error condition of the system as the external load device and a sheet change parameters, the error can not be compensated in the sheet. 反馈量的误差直接影响输出电压的精度。 Feedback amount of error directly affects the precision of the output voltage.

发明内容 SUMMARY

[0006] 针对现有技术所存在的上述技术缺陷,本发明提供了一种AC-DC变换器的控制方法及其控制器,能够得到相对精确的反馈量以控制变换器的输出电压。 [0006] In view of the above drawbacks of the prior art technique exists, the present invention provides a control method and controller for a AC-DC converter, it is possible to obtain a relatively precise amount of feedback to control the output voltage of the converter.

[0007] 一种AC-DC变换器的控制方法,包括如下步骤: [0007] A control method of the AC-DC converter, comprising the steps of:

[0008] (I)采集AC-DC变换器的辅助绕组电压信号Vsense,并获取AC-DC变换器上一周期的反馈量VFB[1-l]; [0008] (I) the Vsense signal acquisition auxiliary winding voltage AC-DC converter, and obtaining feedback AC-DC converter a period VFB [1-l];

[0009] (2)对所述的反馈量VFB[i_l]数模转换后得到反馈电压VI,并将反馈电压Vl的幅值抬升一个固定电压值后得到比较电压V2 ; After obtaining the feedback voltage VI [0009] (2) the amount of feedback VFB [i_l] DAC, and the lifting magnitude of a fixed voltage value obtained by comparing the feedback voltage Vl voltage V2;

[0010] (3)将所述的辅助绕组电压信号Vs.分别与反馈电压Vl和比较电压V2进行比较,分别得到两个比较信号Vsi和Vs2 ; [0010] (3) the auxiliary winding voltage signal Vs. were compared with the feedback voltage Vl and the comparison voltage V2, respectively, to obtain two comparison signals and Vs2, Vsi;

[0011] (4)计算出两个比较信号Vsi和Vs2的下降沿时间差At,并将下降沿时间差At与基准时间差AtMf进行比较,根据两者的差值确定调节量Λ Vfb,进而通过反馈补偿算法利用调节量AVfb对反馈量Vfb[1-1]进行调节补偿,以求得AC-DC变换器当前周期的反馈量Vfb [i]; [0011] (4) to calculate the two comparison signals Vsi Vs2 and fall time difference At, and compares the difference between the fall time and the reference time difference At ATMF, Λ Vfb determined adjustment amount according to the difference between the two, and then through the feedback compensation algorithm using the adjustment amount AVfb feedback amount Vfb [1-1] is adjusted to compensate, in order to achieve feedback AC-DC converter current period Vfb [i];

[0012] (5)根据所述的反馈量VFB[i]构造出PWM信号,以控制AC-DC变换器中开关管的通断。 [0012] (5) The amount of feedback VFB [i] a PWM signal configured to control the on-off switch in the AC-DC converter tubes.

[0013] 所述的反馈补偿算法基于如下算式: [0013] The feedback compensation algorithm is based on the formula:

[0014]当 At〉Δ tref Bi:VFB[i] = Vfb [1-1]-AVfb [0014] When At> Δ tref Bi: VFB [i] = Vfb [1-1] -AVfb

[0015]当 At = Atref 时:VFB[i] = Vfb[1-1] [0015] When At = Atref: VFB [i] = Vfb [1-1]

[0016] 当At < Atref时:VFB[i] = Vfb [1-1]+ Λ Vfb其中:基准时间差Atref为预设的给定值;At与Atrtf相差越大,AVfb也越大。 [0016] When At <Atref: VFB [i] = Vfb [1-1] + Λ Vfb wherein: ATREF reference time difference predetermined for a given value; Atrtf At the larger the difference, AVfb greater.

[0017] 一种AC-DC变换器的控制器,包括原边采样电路和数字补偿器; [0017] An AC-DC converter of the controller, and the sampling circuit comprises a primary digital compensator;

[0018] 所述的数字补偿器用于根据原边采样电路输出的AC-DC变换器当前周期的反馈量VFB[i]构造出PWM信号,以控制AC-DC变换器中开关管的通断; Digital compensator [0018] constructed in accordance with the feedback amount for the current cycle of the primary AC-DC converter circuit outputs a sampling VFB [i] a PWM signal to control the AC-DC converter switch-off;

[0019] 所述的原边米样电路包括一波形实时分析模块、一单输入双输出数模转换器和两个比较器; [0019] The rice-like primary side circuit includes a waveform analysis module in real time, a single-input dual-output digital to analog converters and two comparators;

[0020] 所述的单输入双输出数模转换器接收波形实时分析模块输出的AC-DC变换器上一周期的反馈量VFB[1-l],对反馈量VFB[1-l]数模转换后得到反馈电压Vl并输出,将反馈电压Vl的幅值抬升一个固定电压值后得到比较电压V2并输出; [0020] The one input and two output DAC feedback received waveform AC-DC converter of one cycle of the real-time analysis module output VFB [1-l], the amount of feedback VFB [1-l] DAC after the converted feedback voltage Vl, and outputs the amplitude of the feedback voltage Vl lifting obtained after a fixed voltage value and outputs the comparison voltage V2;

[0021] 两个比较器分别将反馈电压Vl和比较电压V2与AC-DC变换器的辅助绕组电压信号Vsmse进行比较,分别得到两个比较信号Vsi和Vs2 ; [0021] The two comparators each comparing the feedback voltage Vl and the voltage V2 is compared with the auxiliary winding voltage signal Vsmse AC-DC converters, respectively, to obtain two comparison signals and Vs2, Vsi;

[0022] 所述的波形实时分析模块用于计算出两个比较信号Vsi和Vs2的下降沿时间差At,并将下降沿时间差At与基准时间差Atref进行比较,根据两者的差值确定调节量AVfb,进而通过反馈补偿算法利用调节量AVfb对反馈量Vfb [1-Ι]进行调节补偿,以求得AC-DC变换器当前周期的反馈量Vfb [i]。 [0022] The real-time waveform analysis module for calculating two comparison signals Vsi Vs2 and fall time difference At, and compares the difference between the fall time and the reference time difference At Atref, the adjustment amount is determined based on the difference between the two AVfb , and thus the feedback amount Vfb by adjusting the amount of compensation using a feedback algorithm AVfb [1-Ι] be adjusted to compensate, in order to achieve feedback AC-DC converter current period Vfb [i].

[0023] 优选地,所述的单输入双输出数模转换器由两个多路选择器和一串分压电阻构建,该数模转换器采用电阻线性分压构成,结构简单,实现容易,并且电阻的匹配精度很高,保证分压具有良好的线性度。 [0023] Preferably, said one input and two output DAC by two multiplexers constructed and dividing resistor string, the DAC using resistance dividing linear configuration, simple in structure, easy to realize, and the matching accuracy of the resistance of the high partial pressure to ensure a good linearity.

[0024] 优选地,所述的波形实时分析模块和数字补偿器均通过FPGA编程实现,FPGA编程具有较强的灵活性,方便对于时钟精度的控制和调节,具有良好的可重复性。 [0024] Preferably, the real-time analysis of the waveform and the digital compensator module are implemented by FPGA programming, FPGA programming with strong flexibility, convenience and control for adjusting the clock accuracy and with good reproducibility.

[0025] 本发明通过采集AC-DC变换器的辅助绕组电压信号,并采用高精度的原边反馈技术,自动补偿反馈量,以获得精确的反馈量,进而构造出PWM信号以驱动AC-DC变换器中的开关管,最终实现控制调节变换器输出电压的目的;故本发明方法计算得到反馈量的精度,进而保证了AC-DC变换器输出电压的精度;同时本发明控制器采用数模转换器(而非模数转换器),相比较之下,降低了设计难度,节省了消耗的面积。 [0025] The present invention side feedback technology to automatically compensate for the amount of feedback through the acquisition of the auxiliary winding voltage signal of the AC-DC converter, and high-precision original, to obtain a precise amount of feedback, the PWM signal is further configured to drive the AC-DC the converter switch, ultimately control the purpose of adjusting the inverter output voltage; method of the present invention so that the accuracy of the calculated feedback amount, thus ensuring the accuracy of the AC-DC converter output voltage; while the present invention uses a digital to analog controller converter (instead of analog to digital converter), comparison, reduces the design effort, saving area consumed.

附图说明 BRIEF DESCRIPTION

[0026] 图1为AC-DC变换器及其基于副边反馈的控制器的结构示意图。 [0026] FIG. 1 is a AC-DC converter and its secondary structural diagram of the controller based on the feedback.

[0027] 图2为AC-DC变换器及其基于原边反馈的控制器的结构示意图。 [0027] FIG. 2 is a AC-DC converter based on its structural diagram of a primary-side controller.

[0028] 图3为本发明AC-DC变换器及其控制结构示意图。 [0028] Figure 3 is a schematic view of a control structure of converter and its AC-DC invention.

[0029] 图4为AC-DC变换器中信号Is、Vsense和PWM的工作波形示意图。 [0029] FIG. 4 is an AC-DC converter signal Is, a schematic view of the operation waveform Vsense and PWM. [0030] 图5为本发明控制器的结构示意图。 [0030] FIG. 5 is a schematic configuration of the controller of the present invention.

[0031] 图6为单输入双输出数模转换器的结构示意图。 [0031] FIG. 6 is a schematic structural diagram of a single input two-output digital to analog converter.

[0032] 图7(a)为反馈量对应拐点电压时各信号的波形示意图。 A schematic view of waveforms of signals [0032] FIG. 7 (a) corresponds to the inflection point voltage feedback.

[0033] 图7(b)为反馈量相对拐点电压过大时各信号的波形示意图。 [0033] FIG. 7 (b) is a schematic view of waveforms of signals when the knee voltage is too large relative to the amount of feedback.

[0034] 图7(c)为反馈量相对拐点电压过小时各信号的波形示意图。 [0034] FIG. 7 (c) relative to the amount of feedback through the knee voltage waveform diagram showing respective signals h.

[0035] 图8为本发明反馈补偿算法的流程示意图。 [0035] Figure 8 a schematic flow diagram of the feedback compensation algorithm of the present invention.

具体实施方式 Detailed ways

[0036] 为了更为具体地描述本发明,下面结合附图及具体实施方式对本发明控制方法及其控制器进行详细说明。 [0036] To more particularly describe the present invention, the following control method and a controller according to the present invention is described in detail in conjunction with accompanying drawings and specific embodiments.

[0037] 图3所示了本发明AC-DC变换器及其控制器的结构,AC-DC变换器由半波整流器BR、变压器T、开关管Q、二极管D和电容C组成;其中,半波整流器BR的正负输入端接交流电压AC,正输出端与变压器T原边绕组Np的同名端相连,负输出端接地;变压器T原边绕组Np的非同名端与开关管Q的漏极相连,开关管Q的源极接地,开关管Q的栅极接收控制器提供的PWM信号,变压器T副边绕组Ns的非同名端与二极管D的阳极相连,二极管D的阴极与电容C的一端相连,电容C的另一端与变压器T副边绕组Ns的同名端相连并接地,变压器T辅助绕组Naux的非同名端连接有电阻R1,变压器T辅助绕组Naux的同名端接地,电阻R1通过与电阻R2串联后接地; 电容C的两端为AC-DC变换器的输出端口,AC-DC变换器的输出端口接负载R,负载R两端的电压为AC-DC变换器的输出电压Vo。 [0037] FIG. 3 shows the structure of the AC-DC converter and its controller according to the present invention, AC-DC converter by a half-wave rectifier BR, transformer T, switch Q, a diode D and a capacitor C; wherein half wave rectifier BR positive and negative input terminal of the AC voltage AC, is connected to the positive output terminal of the dot end of the primary winding Np of the transformer T, the negative output terminal is grounded; the drain of the primary winding Np of the transformer T and the non-dotted terminal of the switch Q is connected, the PWM signal source of the switching transistor Q is grounded, a gate receiving the Q switch controller provides, an anode connected to the diode D and the non-dot end of the secondary winding Ns of the transformer T, the end of the cathode of the diode D and the capacitor C connected to the same name at the other end of the transformer T secondary winding Ns of the capacitor C is connected and grounded, the non-dot end of the transformer T secondary winding Naux is connected to the resistor R1, the transformer T secondary winding Naux same name grounded, the resistor R1 through a resistor grounded with R2; across capacitor C to the output port of the AC-DC converter, AC-DC converter output port connected to the load R, R across the load voltage is the output voltage Vo of the AC-DC converter.

[0038] 控制器包括原边采样电路和数字补偿器;原边采样电路采集AC-DC变换器的辅助绕组电压信号Vsmse,并根据该信号输出AC-DC变换器当前周期的反馈量VFB[i];数字补偿器根据原边采样电路输出的反馈量VFB[i]构造出PWM信号,以控制AC-DC变换器中开关管Q的通断。 [0038] The controller includes a primary circuit and a digital sampling compensator; primary auxiliary winding voltage sampling circuit signal acquisition Vsmse AC-DC converter, and the feedback amount according to the current cycle of the AC-DC converter output signal VFB [i ]; digital compensator according to the primary side feedback sampling circuit outputted VFB [i] a PWM signal configured to control on and off AC-DC converter of the switching transistor Q.

[0039] 图4所示了AC-DC变换器工作时各信号的基本波形,其中Is为输出绕组电流;当PWM为I时,开关管Q开通,原边绕组电流Ip逐渐上升,变压器T在原边绕组Np上存储能 [0039] Figure 4 shows basic waveforms of signals when working AC-DC converter, wherein the output winding current Is; when PWM is I, Q switch opened, the primary winding current Ip gradually increases, the primary of the transformer T It can be stored on the winding Np

N N

量,辅助绕组电圧V Yn为负值(Naux和Np分别为辅助绕组和原边绕组的线圈匝 Amount, the auxiliary winding is electrically negative-pressure V Yn (NAUX and Np are the number of turns of the coil primary winding and the secondary winding

JNp JNp

数),输出绕组(即副边绕组Ns)两端电压Vs也为负电压,此时二极管D关断,输出绕组上的电流Is为0,负载R由输出电容C供电。 Number), output winding (i.e., a secondary winding Ns) voltage across voltage Vs is also negative, then the diode D is turned off, the output winding current Is is 0, the load capacitance C R outputted from the power supply.

[0040] 当PWM为O时,开关管Q关断,二极管D导通,存储在原边绕组Np上的能量被转移到输出绕组,输出绕组电流Is迅速上升到峰值Isp后开始逐渐下降,下降斜率跟输出绕组两端 After [0040] When PWM is O, switch Q is turned off, the energy diode D is turned on, is stored in the primary winding Np is transferred to the output winding, output winding current Is rapidly increased to a peak Isp gradually decreased, falling slope with both ends of the output winding

N N

电压Vs相关。 Voltage Vs relevant. 当Is未降到零之前,其中:VD是二极管D的 Before Is is not reduced to zero, where: VD is the diode D

N N

压降,Rp是导线和二极管D的寄生电阻。 Drop, Rp is a parasitic resistance of the diode D and the wire. 当电流Is等于零的时刻,Vd = 0,则 When the time of the current Is is equal to zero, Vd = 0, then

丄NS Shang NS

该时刻点电压记为拐点电压(knee voltage) 0当Is电流降到O之后,由于开关管Q未导通,原边绕组Np和开关管Q的寄生电容之间会发生串联谐振,谐振周期由原边绕组Np电感和开关管Q的寄生电容大小所决定,在这一阶段 The point in time referred to as knee voltage voltage (knee voltage) 0 When current Is drops after O, Q since the switch is not turned on, series resonance occurs between the primary winding Np and a parasitic capacitance of the switch Q, by the resonance period Np primary winding inductance and parasitic capacitance of the switch Q size determined at this stage

Figure CN102801340BD00061

,其中:1^是原边绕组电感。 Wherein: 1 ^ is the primary winding inductance.

[0041] 由 [0041] by the

Figure CN102801340BD00062

可知,在拐点处即当输出绕组电流Is降到O的时刻,Vsense跟输出电 It found, i.e. at the inflection point in time when the output O of the winding current Is drops, the Vsense with the output

压\是成正比例关系,因此根据该点处的Vsense计算得到的反馈量是最精确的。 Pressure \ is directly proportional relationship, and thus the feedback amount calculation Vsense is obtained at this point is the most accurate.

[0042] 当Q关断,输出绕组电流Is降到O之后,即Vsense在拐点之后会进入谐振状态,在拐点出现的时刻前后,Vsmse的斜率变化是很大的,针对这个特点,本发明提出了一种AC-DC变换器输出电压的控制方法,包括如下步骤: [0042] When Q is off, the output winding current Is drops O, i.e., after the inflection point Vsense will enter the resonant state, the time before and after the inflection point appears, Vsmse slope change is large, for this feature, the present invention provides one kind of AC-DC converter output voltage control method, including the steps of:

[0043] (1)采集AC-DC变换器的辅助绕组电压信号Vsense,并获取AC-DC变换器上一周期的反馈量VFB[1-l];本实施方式通过电阻R1和R2对变压器T辅助绕组Naux两端的电压进行分压,故采集到的辅助绕组电压信号Vsmse为辅助绕组Naux两端电压经降压后的电压; [0043] (1) acquisition of the auxiliary winding voltage signal Vsense AC-DC converter, and get feedback on the amount of a periodic inverter AC-DC VFB [1-l]; the present embodiment by way of resistors R1 and R2 of the transformer T Naux voltage across the auxiliary winding is divided, so the collected signal voltage of the auxiliary winding the auxiliary winding Naux Vsmse voltage via the voltage across the step-down;

[0044] (2)对反馈量VFB[i_l]数模转换后得到反馈电压VI,并将反馈电压Vl的幅值抬升一个固定电压值后得到比较电压V2 ;本实施方式中,该固定电压值为IOOmV ; After [0044] (2) the amount of feedback VFB [i_l] DAC feedback voltage Vl, Vl and raising the magnitude of the feedback voltage a fixed voltage value obtained after the comparison voltage V2; the present embodiment, the fixed voltage value as IOOmV;

[0045] (3)将辅助绕组电压信号Vsmse分别与反馈电压Vl和比较电压V2进行比较,分别得到两个比较信号Vsi和Vs2 ; [0045] (3) the auxiliary winding voltage signal Vsmse were compared with the comparison voltage feedback voltage Vl and V2, respectively, to obtain two comparison signals and Vs2, Vsi;

[0046] (4)计算出两个比较信号Vsi和Vs2的下降沿时间差At,并将下降沿时间差At与基准时间差AtMf进行比较,根据两者的差值确定调节量AVfb; [0046] (4) to calculate the two comparison signals Vsi Vs2 and fall time difference At, and the difference between the reference time and the fall time difference At AtMf determined by comparing the amount of adjustment based on the difference between the two AVfb;

[0047] 本实施方式中,基准时间差AtMfS4clk,clk为一个时钟周期;At与Atref相差越大,Λ Vfb也越大;本实施方式中,I At-AtrefI与AVfb的具体确定关系如表1所示; [0047] In the present embodiment, the reference time difference AtMfS4clk, clk is a clock cycle; Atref At the larger the difference, Λ Vfb greater; the present embodiment, I At-AtrefI relationship with AVfb specifically identified in Table 1 shown;

[0048]表1 [0048] TABLE 1

[0049] [0049]

Figure CN102801340BD00063

[0050] 其中,若连续几个控制周期I At-AtrefI均较大,可适当加大其对应的调节量。 [0050] wherein, if the number of consecutive control cycles I At-AtrefI are large, the amount may be suitably adjusted corresponding to increase.

[0051] 通过以下反馈补偿算法利用调节量反馈量VFB[i_l]进行调节补偿,以求得AC-DC变换器当前周期的反馈量Vfb [ i ]; [0051] The algorithm makes use of the adjustment amount feedback VFB [i_l] be adjusted to compensate, in order to achieve feedback AC-DC converter current period Vfb [i] by feedback compensation;

[0052]当 At〉Atref 时:VFB[i] = Vfb [1-1]-AVfb [0052] When At> Atref: VFB [i] = Vfb [1-1] -AVfb

[0053]当 At = Atref 时:VFB[i] = Vfb[1-1] [0053] When At = Atref: VFB [i] = Vfb [1-1]

[0054]当 At< Atref 时:VFB[i] = Vfb[1-1]+ AVfb [0054] When At <Atref: VFB [i] = Vfb [1-1] + AVfb

[0055] 通过结合实际参数选择设定合适的固定电压值和基准时间差AtMf,使得当At等于Atref时,反馈量刚好反应了所需要的拐点电压,以实现对拐点电压的自动追踪并实现精确的原边采样。 [0055] By combining the actual parameter selection set appropriate fixed voltage value and the reference time difference ATMF, such that when At is equal ATREF, feedback amount just reflects the knee voltage required, for automatic tracking of the knee voltage and precise primary sampling.

[0056] (5)根据反馈量Vfb [i]构造出PWM信号,以控制AC-DC变换器中开关管Q的通断。 [0056] (5) The amount of feedback Vfb [i] a PWM signal configured to control on and off AC-DC converter of the switching transistor Q.

[0057] 如图3所示,本实施方式AC-DC变换器的控制器包括原边采样电路和数字补偿器;如图5所不,原边米样电路包括一波形实时分析模块、一单输入双输出数模转换器和两个比较器; [0057] 3, AC-DC converter controller according to the present embodiment includes a primary circuit and a digital sampling compensator; not shown in FIG 5, the primary circuit comprises a rice-like real-time waveform analysis module, a single two input and two output DAC and the comparator;

[0058] 单输入双输出数模转换器的输入端与波形实时分析模块的输出端相连,两个输出端分别与两个比较器的反相输入端相连;其接收波形实时分析模块输出的AC-DC变换器上一周期的反馈量VFB[i_l],对反馈量VFB[i_l]数模转换后得到反馈电压Vl并输出,将反馈电压Vl的幅值抬升一个固定电压值后得到比较电压V2并输出; [0058] one input and two output digital to analog converter input terminal and the output terminal of the waveform in real-time analysis module is connected to two output terminals connected to the two inverting inputs of the comparator respectively; real-time waveform analysis module that receives an AC output a feedback amount -DC converter cycle VFB [i_l], the amount of feedback VFB [i_l]-analog conversion and outputs obtained feedback voltage Vl, Vl after lifting magnitude of the feedback voltage a fixed voltage value to obtain a comparison voltage V2 and output;

[0059] 如图6所示,本实施方式中的单输入双输出数模转换器由两个多路选择器Muxl和Mux2,以及一串分压电阻R1~R511组成,R1~R511都是等值电阻。 [0059] FIG 6, the single-input dual-output DAC of the present embodiment is composed of two multiplexers and Mux2 Muxl, and a string dividing resistors R1 ~ R511 composition, and the like are R1 ~ R511 value of the resistor. 基准电压Vref通过分压电阻分压之后的电压作为多路选择器的输入。 After the reference voltage Vref by the voltage dividing resistors as dividing the input selector multiplexer. 多路选择器Muxl和Mux2编码存在一个初始的偏移量,通过这个偏移量此数模转换器将同一个输入量Vfb转换成两个具有固定电压差值的模拟电压V1和V2。 Muxl presence multiplexer and Mux2 encoding an initial offset, this offset digital to analog converter to convert the same into two analog inputs Vfb voltages V1 and V2 having a fixed voltage difference through this. 本实施方式中,数模转换的位数为9,基准电压VMf为1.2V ;V2和V1与 In the present embodiment, the number of bits for the DAC 9, the reference voltage is VMf 1.2V; V2 and V1 and

Vfb 的关系为 Vfb relationship is

Figure CN102801340BD00071

可见V1电压即为模拟的反馈电压。 V1 is the voltage seen analog feedback voltage.

[0060] 两个比较器COMPl~C0MP2的正相输入端均接收AC-DC变换器的辅助绕组电压信号Vsmse ;其分别将反馈电压Vl和比较电压V2与辅助绕组电压信号Vsense进行比较,分别得到两个比较信号Vsi和Vs2。 [0060] The two-inverting input terminal of the comparator COMPl ~ C0MP2 average received auxiliary winding voltage signal Vsmse AC-DC converter; respectively compare the feedback voltage Vl and the voltage V2 of the auxiliary winding voltage Vsense signal is compared, respectively two comparison signals Vsi and Vs2.

[0061] 波形实时分析模块的两个输入端分别与比较器COMPl~C0MP2的输出端相连;其用于计算出两个比较信号Vsi和Vs2的下降沿时间差At,并将下降沿时间差At与基准时间差进行比较,根据两者的差值确定调节量AVfb,进而通过反馈补偿算法利用调节量八^对反馈量¥^[卜1]进行调节补偿,以求得AC-DC变换器当前周期的反馈量VFB[i]。 [0061] Real-time analysis of the input waveform two modules are connected to the output of the comparator COMPl ~ C0MP2; it is used to calculate the two comparison signals Vsi Vs2 and fall time difference At, At the time difference and the falling edge of the reference the time difference determined by comparing the amount of AVfb adjusted according to the difference between the two, and further adjusting the amount of use of the eight feedback ¥ ^ ^ [BU 1] through feedback compensation algorithm to adjust the compensation, in order to achieve feedback AC-DC converter current period amount VFB [i].

[0062] 如图7所示,当PWM为零电平之后,Vsmse由负电压变为高电压,Vsi和Vs2翻转到高电平,之后随着Vsmse的逐渐下降,由于V2电压比Vl高,Vs2会在h时刻先翻转到低电平,经过Λ t时间之后Vsi在t2时刻翻转到低电平。 [0062] As shown in FIG 7, when the PWM zero level, a negative voltage to the Vsmse high voltage, Vsi and inverted to the high level Vs2, after Vsmse With decreasing due to the voltage V2 is higher than Vl, Vs2 will flip to a low level before time point h, Λ t elapsed after time Vsi inverted to a low level at time t2. 拐点电压出现的时刻TknM前后,Vsmse的变化斜率相差很大,因此V1和V2处在Vsmse上的不同位置所产生的At差别很大。 TknM time before and after the inflection point voltage appearing ramp rate Vsmse vary widely, and therefore greatly At V1 and V2 in different positions on different Vsmse generated. 如图7(b)所示,若Vfb偏大,则表示采样到的反馈电压高于拐点电压,则V2和V1也会相应变大,由于TknM时刻之前Vsense的下降斜率较小,则此时检测到的Λ t偏大。 FIG 7 (b), the Vfb if too large, it indicates that the sampled voltage is higher than the inflection point of the feedback voltage, V1 and V2 will be correspondingly larger, since the time before TknM Vsense small slope of decrease, at this time, detected Λ t too large. 如图7 (c)所示,若Vfb偏小,则此时检测到的At很小。 FIG. 7 (c), the small when Vfb is detected at this time At is small. 如图7(a)所示,选取合适的Atref AV,使得当Λ t等于Atref时,Vfb刚好是反应了所需要的拐点电压。 FIG. 7 (a), the appropriate selection Atref AV, such that when Λ t is equal Atref, Vfb exactly reflect the knee voltage required.

[0063] 如图8所示,波形实时分析模块首先对At时间进行检测并存储,然后将其与Δ tref相比较,对下一周期的反馈量Vfb进行调整,其中第i个周期得到的Vfb值记为Vfb[i]。 [0,063] As shown, the real-time waveform analysis module At time of first detected and stored, and then compares it with Δ tref, Vfb of the feedback amount is adjusted for the next cycle, wherein the i-th period. 8 Vfb obtained Note the value of Vfb [i]. 为了加快Vfb的建立,在图8所示的基本原理基础上对Vfb的调整值进行改进,前后周期之间Vfb的关系为Vfb [i+1] =VFB[i]±AVEB,At与预设Atref相差越大,调节量Λ Vfb也越大,具体对应关系因不同的参数设置而不同。 In order to accelerate the establishment of Vfb, an adjustment value Vfb improvement in the basic principles on the basis of FIG. 8, the relationship between the front and rear Vfb period is Vfb [i + 1] = VFB [i] ± AVEB, At preset Atref larger the difference, the greater the amount of adjustment Λ Vfb, due to their correspondence different parameter settings are different.

[0064] 数字补偿器的输入端与波形实时分析模块的输出端相连;其用于根据波形实时分析模块输出的AC-DC变换器当前周期的反馈量Vfb [i]调节占空比d,并提供零极点来实现系统环路的稳定性,相比模拟补偿不需要额外的电阻电容进行补偿,减小了片外器件的开销,同时根据占空比D构造出PWM信号,以控制AC-DC变换器中开关管Q的通断,实现对AC-DC变换器输出电压的调制。 Input [0064] The digital compensator and an output terminal connected to real-time waveform analysis module; d for adjusting the duty cycle of the feedback amount according to the current cycle AC-DC converter output waveform in real-time analysis module Vfb [i], and providing pole-zero loop to achieve stability of the system, no additional analog compensation compared to resistance and capacitance to compensate for reduced overhead off-chip devices, while the PWM signal is constructed according to the duty D, to control the AC-DC converter switch off transistor Q, to achieve modulation of the AC-DC converter output voltage.

[0065] 本实施方式中,波形实时分析模块和数字补偿器均通过FPGA编程实现。 [0065] The embodiment according to the present embodiment, the real-time waveform analysis module and the digital compensator are implemented by FPGA programming.

[0066] 本实施方式通过采集AC-DC变换器的辅助绕组电压信号,采用高精度原边采样技术,自动追踪拐点电压,以获得精确的反馈量;根据反馈量计算出占空比,并输出与占空比对应PWM信号以控制变换器中开关管的通断,最终实现对变换器输出电压的调制,实现稳压输出。 [0066] The embodiment according to the present embodiment acquired by the auxiliary winding voltage signal of the AC-DC converter, the primary high-precision sampling techniques, to automatically track the knee voltage, to obtain an accurate feedback amount; calculating a feedback amount according to the duty ratio, and outputs corresponding to the duty ratio of the PWM signal to control the on-off switch of the converter, ultimately modulating the inverter output voltage, output for regulation.

[0067] 本实施方式通过高精度原边采样技术实现在二极管正向压降Vd近乎为零的时刻对Vsense进行采样。 [0067] The present embodiment achieves forward voltage drop Vd in time in the near-zero diodes with high accuracy by sampling Vsense primary sampling techniques. 在外围参数取定的条件下,计算得到理想的反馈电压为883mV,通过本实施方法得到的反馈电压V1为890mV,反馈误差为7mV,而采用一般传统的采样控制方法无法消除二极管导通压降Vd的影响,采样得到的反馈电压将近IV,反馈误差将近117mv。 In the external parameter takes a predetermined condition, the calculated feedback voltage preferably is 883mV, obtained by the method according to the present embodiment the feedback voltage V1 is 890mV, the feedback error 7mV, generally employed control method of the conventional sampling diode voltage drop can not be eliminated Effect of Vd, a feedback voltage sampled nearly IV, feedback error nearly 117mv. 故通过与传统采样控制技术相比较,本实施方式反馈误差减少了94 %。 Therefore, by comparing with the conventional control sample, according to the present embodiment the feedback error is reduced by 94%.

Claims (4)

1.一种AC-DC变换器的控制方法,包括如下步骤: (1)采集AC-DC变换器的辅助绕组电压信号Vsmse,并获取AC-DC变换器上一周期的反馈量VFB[1-l]; (2)对所述的反馈量VFB[1-l]数模转换后得到反馈电压VI,并将反馈电压Vl的幅值抬升一个固定电压值后得到比较电压V2 ; (3)将所述的辅助绕组电压信号Vsmse分别与反馈电压Vl和比较电压V2进行比较,分别得到两个比较信号Vsi和Vs2 ; (4)计算出两个比较信号Vsi和Vs2的下降沿时间差At,并将下降沿时间差At与基准时间差Atref进行比较,根据两者的差值确定调节量AVfb,进而通过反馈补偿算法利用调节量AVfb对反馈量Vfb[1-Ι]进行调节补偿,以求得AC-DC变换器当前周期的反馈量Vfb [i]; 所述的反馈补偿算法基于如下算式: 当At〉Δ tref 时:Vfb [i] =Vfb [1-1]-AVfb ; 当At=Atraf 时:VFB[i]=VFB[i_l]; 当Δΐ< Δ tref 时:Vfb [i] =Vfb [1-1] +AVfb ; (5)根据所述的反馈量VFB[ 1. A method of controlling the AC-DC converter, comprising the steps of: (1) acquisition of the auxiliary winding voltage signal Vsmse AC-DC converter, and get feedback on the amount of a periodic inverter AC-DC VFB [1- l]; (2) the amount of feedback VFB [1-l to obtain feedback voltage VI] after digital to analog conversion, and the lifting magnitude of the feedback voltage Vl to give a fixed voltage value after the comparison voltage V2; (3) the Vsmse auxiliary winding voltage signal according to the feedback voltage Vl, respectively, and comparing the comparison voltage V2, respectively, to obtain two comparison signals Vsi and Vs2; (. 4) calculates the two comparison signals Vsi Vs2 and fall time difference At, and at the falling edge of the time difference and the reference time difference Atref determined by comparing the amount of AVfb adjusted according to the difference between the two, and then through the feedback compensation amount using the adjustment algorithm of the feedback amount AVfb Vfb [1-Ι] be adjusted to compensate, in order to achieve AC-DC feedback current cycle converter Vfb [i]; the feedback compensation algorithm is based on the equation: when At> when Δ tref: Vfb [i] = Vfb [1-1] -AVfb; when At = Atraf: VFB [i] = VFB [i_l]; when Δΐ <while Δ tref: Vfb [i] = Vfb [1-1] + AVfb; (5) VFB according to the feedback amount [ i]构造出PWM信号,以控制AC-DC变换器中开关管的通断。 i] a PWM signal configured to control the AC-DC converter switch-off.
2.—种AC-DC变换器的控制器,包括原边采样电路和数字补偿器;所述的数字补偿器用于根据原边采样电路输出的AC-DC变换器当前周期的反馈量VFB[i]构造出PWM信号,以控制AC-DC变换器中开关管的通断;其特征在于: 所述的原边采样电路包括一波形实时分析模块、一单输入双输出数模转换器和两个比较器; 所述的单输入双输出数模转换器接收波形实时分析模块输出的AC-DC变换器上一周期的反馈量VFB[1-l],对反馈量VFB[1-l]数模转换后得到反馈电压Vl并输出,将反馈电压Vl的幅值抬升一个固定电压值后得到比较电压V2并输出; 两个比较器分别将反馈电压Vl和比较电压V2与AC-DC变换器的辅助绕组电压信号Vsense进行比较,分别得到两个比较信号Vsi和Vs2 ; 所述的波形实时分析模块用于计算出两个比较信号Vsi和Vs2的下降沿时间差At,并将下降沿时间差At与基准时间差AtMf进行 2.- kinds of AC-DC converter of the controller, and the sampling circuit comprises a primary digital compensator; said digital feedback compensator according to the current cycle AC-DC converter primary sampling circuit outputted VFB [i ] constructed PWM signal to control the on-off switch in the AC-DC converter tubes; wherein: said sampling circuit comprises a primary real-time waveform analysis module, a single-input dual-output digital to analog converter and two comparator; feedback on the AC-DC converter one input and two output digital to analog converter module outputs the received waveform of a real-time analysis period VFB [1-l], the amount of feedback VFB [1-l] DAC after the converted feedback voltage Vl, and outputs the amplitude of the feedback voltage Vl lifting give a fixed voltage value and outputting a comparison voltage V2; two comparators respectively compare the feedback voltage Vl and the secondary voltage V2 of the AC-DC converter winding voltage Vsense signal is compared, respectively, to obtain two comparison signals Vsi and Vs2; real-time analysis of the waveform calculating means for comparing the two signals Vsi Vs2 and fall time difference At, At the time difference and the difference between the falling edge of the reference time AtMf be 比较,根据两者的差值确定调节量AVfb,进而通过反馈补偿算法利用调节量八¥^对反馈量¥^[卜1]进行调节补偿,以求得AC-DC变换器当前周期的反馈量Vfb [i]; 所述的反馈补偿算法基于如下算式: 当At〉Δ tref 时:Vfb [i] =Vfb [1-1]-AVfb ; 当At=Atraf 时:VFB[i]=VFB[i_l]; 当Δΐ< Δ tref Bi:VFB[i]=VFB[1-l] + A VFBo Comparison, according to the difference between the two determines the amount of adjustment AVfb, and further by using a feedback compensation algorithm to adjust the amount of feedback eight ¥ ^ ¥ ^ [BU 1] be adjusted to compensate, in order to achieve feedback AC-DC converter current period Vfb [i]; the feedback compensation algorithm is based on the equation: when At> when Δ tref: Vfb [i] = Vfb [1-1] -AVfb; when At = Atraf: VFB [i] = VFB [i_l ]; when Δΐ <Δ tref Bi: VFB [i] = VFB [1-l] + A VFBo
3.根据权利要求2所述的AC-DC变换器的控制器,其特征在于:所述的单输入双输出数模转换器由两个多路选择器和一串分压电阻构建。 The controller according to claim AC-DC converter according to claim 2, wherein: said one input and two output DAC constructed from two multiplexers and dividing resistor string.
4.根据权利要求2所述的AC-DC变换器的控制器,其特征在于:所述的波形实时分析模块和数字补偿器均通过FPGA编程实现。 The controller according to claim AC-DC converter according to claim 2, wherein: real-time analysis of the waveform and the digital compensator module are implemented by FPGA programming.
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