CN100385781C

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Info

Publication number: CN100385781C
Application number: CNB031577598A
Authority: CN
Inventors: 张庆友; 邱爱斌; 应建平; 曾剑鸿
Original assignee: Delta Electronics Inc
Current assignee: Delta Electronics Inc
Priority date: 2003-08-28
Filing date: 2003-08-28
Publication date: 2008-04-30
Anticipated expiration: 2023-08-28
Also published as: CN1592063A

Abstract

A current sharing method and a control circuit for interleaving control power factor correction circuit, the control circuit comprises: the first control circuit comprises a current control loop, wherein the first control current generates a current reference by utilizing the output voltage, the feedforward voltage and the input reference voltage of the parallel boost type power factor correction circuit, and sends the current reference to the input end of the current control loop so as to generate a first pulse width modulation signal to drive the first boost circuit; the input end of the current control loop of the second control circuit receives the current reference to generate a second pulse width modulation signal to drive the second booster circuit; the synchronous pulse signal generator is used for respectively providing synchronous staggered signals with staggered specific phases for the first control circuit and the second control circuit so as to be respectively added into two same-frequency oscillation voltage signals for synchronization, so that first sawtooth wave signals and second sawtooth wave signals with staggered specific phases are obtained, the first control circuit and the second control circuit are enabled to be staggered specific phases, staggered frequency multiplication is obtained through synchronous staggering, and the parallel connection boost type power factor correction circuit is enabled to share current.

Description

Translated fromChinese

用于交错控制功率因数校正电路的均流方法及装置Current sharing method and device for interleaved control power factor correction circuit

(1)技术领域(1) Technical field

本发明是为一种用于交错控制功率因数校正电路的均流方法及装置，尤指应用于一种并联升压式功率因数校正电路均流的控制电路。The invention relates to a current sharing method and device for interleaved control of a power factor correction circuit, in particular to a current sharing control circuit applied to a parallel boost type power factor correction circuit.

(2)背景技术(2) Background technology

传统的升压(BOOST)型功率因数校正装置因它的简单，升压特性，高效率而得到广泛的应用。随着电源功率等级的不断提高，常常需要将几路这样的模块化装置串、并联使用，如在高电压应用场合，常采用三电位BOOST功率因数校正电路，使得开关元件的电压应力限制在输出电压的一半，而在大电流应用场合，则常采用多个BOOST型变换器并联使用，两并联功率因数校正装置如图1所示。The traditional boost (BOOST) power factor correction device is widely used because of its simplicity, boost characteristics and high efficiency. With the continuous improvement of the power level of the power supply, it is often necessary to use several such modular devices in series or in parallel. For example, in high-voltage applications, a three-potential BOOST power factor correction circuit is often used to limit the voltage stress of the switching elements to the output Half of the voltage, and in high current applications, multiple BOOST converters are often used in parallel. Two parallel power factor correction devices are shown in Figure 1.

它由一桥式整流电路后接两个BOOST单元组成。和传统的BOOST型变换器相比较，两路并联交叉工作的BOOST型变换器具有以下优点：(1)每个单元的电流等级可减小一半，(2)交流线电流和输出电流的涟波可削弱。然而另一方面，这种线路架构又有它的问题：(1)线路比较复杂；(2)由于两组元件的离散性，使得两支路之间的电流不平衡，特别在整个装置操作在电感电流连续模式时，这种现象更为严重。正因如此，对这种线路需寻求一种简单有效的控制方法，既能实现两并联支路之间的均流，又可以对总电感电流进行控制，使其追踪桥式整流电路的整流输出电压。It consists of a bridge rectifier circuit followed by two BOOST units. Compared with the traditional BOOST converter, the two-way parallel crossover BOOST converter has the following advantages: (1) The current level of each unit can be reduced by half, (2) The ripple of the AC line current and the output current can be weakened. On the other hand, however, this circuit structure has its problems: (1) the circuit is relatively complex; (2) due to the discrete nature of the two groups of components, the current between the two branches is unbalanced, especially when the entire device operates at This phenomenon is more serious when the inductor current is in continuous mode. For this reason, it is necessary to find a simple and effective control method for this kind of circuit, which can not only realize the current sharing between the two parallel branches, but also control the total inductor current so that it can track the rectified output of the bridge rectifier circuit Voltage.

习知解决技术如下：两路并联功率因数校正装置，既要保证总电感电流i_L与整流电压保持一致，从而使交流线电流与交流输入电压保持同相位，又要保证两路模块之间的电流均衡(参见图1)。这种装置在控制实现上有一定的困难，首先是电流的取样上，若取总电感电流i_L，则可方便控制总电感电流，但难以保证每一路之间的电流均衡。The known solution technology is as follows: two parallel power factor correction devices, it is necessary to ensure that the total inductor current i_L is consistent with the rectified voltage, so that the AC line current and the AC input voltage are kept in the same phase, and the power factor between the two modules must be ensured. Current balancing (see Figure 1). This kind of device has certain difficulties in the realization of control. The first is the sampling of the current. If the total inductor current i_L is taken, the total inductor current can be easily controlled, but it is difficult to ensure the current balance between each channel.

另一方面，若取样每一支路的电感电流，虽然可实现均流控制，但若要保证总电感电流能与整流电压同相位，尚需采取另外的措施。传统的两路并联功率因数校正装置控制实现方法，如″多路并联升压式功率因数校正装置(中国专利号：00130365)″，它取样总电感电流，由功率因数控制电路UC3854加以控制，从而确保总电感电流与整流电压同相位。与此同时，将UC3854的输出控制信号两分频，得到相位差180°的两路驱动信号，分别控制两路主功率元件，使两路主功率元件分别交错导通。这种控制方法的特点是：总电感电流得到了控制，使得交流线电流与交流输入电压同相位，且控制电路简化。但这种控制显然没有真正实现均流，由于两支路元件间的离散性，(功率元件，BOOST电感，输出二极管，控制线路分立元件等)，会造成两支路电流不均衡，此控制方法并不能消除两者之间的电流差。最后导致流过电流大的功率元件过热，BOOST电感饱和，使系统效率下降，系统可靠性大大降低。On the other hand, if the inductor current of each branch is sampled, although the current sharing control can be realized, if it is to ensure that the total inductor current can be in phase with the rectified voltage, additional measures need to be taken. The traditional two-way parallel power factor correction device control implementation method, such as "multi-channel parallel boost power factor correction device (China Patent No.: 00130365)", which samples the total inductor current and is controlled by the power factor control circuit UC3854, thereby Make sure the total inductor current is in phase with the rectified voltage. At the same time, the output control signal of UC3854 is divided by two to obtain two driving signals with a phase difference of 180°, and the two main power components are respectively controlled to make the two main power components conduct alternately. The characteristics of this control method are: the total inductor current is controlled, so that the AC line current is in phase with the AC input voltage, and the control circuit is simplified. However, this control obviously does not really achieve current sharing. Due to the discreteness between the components of the two branches (power components, BOOST inductors, output diodes, discrete components of the control line, etc.), the currents of the two branches will be unbalanced. This control method does not eliminate the current difference between the two. In the end, the power components with large current flow will be overheated, and the BOOST inductor will be saturated, which will reduce the system efficiency and greatly reduce the system reliability.

此外还有一种具有代表性的控制方法，(参见论文Laszlo Balogh and RichardRedl.″Power-Factor Correction With Interleaved Boost Converters inContinuous-Inductor-Current Mode″，Proceedings of APEC’93，pp.168-174)，用一块UC3854控制总电感电流，同时检测每一单元功率开关元件的电流，将两路电流信号进行差分放大，而差分放大器的输出会影响两路控制脉冲用的锯齿波的斜率，从而实现电流均衡。这种控制发方法既要采样总电感电流，又要检测每支路的电流，而且需要产生交叉控制信号的外围电路，使得整个控制线路因分立元件数目增多而变得复杂。In addition, there is a representative control method, (see the paper Laszlo Balogh and Richard Redl. "Power-Factor Correction With Interleaved Boost Converters in Continuous-Inductor-Current Mode", Proceedings of APEC'93, pp.168-174), using A UC3854 controls the total inductor current, detects the current of each unit power switching element at the same time, and differentially amplifies the two current signals, and the output of the differential amplifier will affect the slope of the sawtooth wave used for the two control pulses, so as to achieve current balance. This control method not only needs to sample the total inductor current, but also detects the current of each branch, and needs to generate a peripheral circuit for cross control signals, which makes the entire control circuit complicated due to the increase in the number of discrete components.

(3)发明内容(3) Contents of the invention

本发明的目的在于提供一种用于交错控制功率因数校正电路的均流方法及装置，分别取样两个并联单元的电感电流，采用平均电流控制法，由两片控制芯片分别控制两个功率开关且两个控制芯片共用同一个电流基准，确保每路的电感电流基本相等，以实现均流。The object of the present invention is to provide a current sharing method and device for interleaved control of power factor correction circuits, which respectively sample the inductor currents of two parallel units, adopt the average current control method, and control two power switches respectively by two control chips And the two control chips share the same current reference to ensure that the inductor current of each channel is basically equal to achieve current sharing.

根据本发明的一方面提供一种用于交错控制并联升压式功率因数校正电路均流的控制电路，该并联升压式功率因数校正电路包含第一升压电路以及第二升压电路，该控制电路包含：第一控制电路以及第二控制电路；该第一控制电路，包含电流控制回路，其中该第一控制电路是利用该并联升压式功率因数校正电路的输出电压、前馈电压与输入参考电压产生电流基准，将该电流基准送入该电流控制回路输入端，以产生第一脉宽调变信号驱动该第一升压电路；该第二控制电路，其电流控制回路输入端接收该电流基准，以产生第二脉宽调变信号驱动该第二升压电路；以及同步脉冲信号产生器，用以分别向该第一控制电路与该第二控制电路提供错开特定相位的同步交错信号，其中，该同步脉冲信号产生器是利用两个错开特定相位的数字脉冲信号分别加到两个同频振荡电压信号中进行同步，以得到错开特定相位的第一锯齿波信号与第二锯齿波信号分别做为该第一控制电路与该第二控制电路的同步交错信号，以使该第一控制电路与该第二控制电路错开特定相位，以同步交错获得交错倍频，并使该并联升压式功率因数校正电路均流。According to one aspect of the present invention, there is provided a control circuit for interleavedly controlling current sharing of a parallel boosted power factor correction circuit, the parallel boosted power factor correction circuit includes a first boosting circuit and a second boosting circuit, the The control circuit includes: a first control circuit and a second control circuit; the first control circuit includes a current control loop, wherein the first control circuit utilizes the output voltage, feed-forward voltage and Input a reference voltage to generate a current reference, and send the current reference to the input terminal of the current control loop to generate a first pulse width modulation signal to drive the first booster circuit; the second control circuit receives the input terminal of the current control loop The current reference is used to generate a second pulse width modulation signal to drive the second booster circuit; and a synchronous pulse signal generator is used to provide synchronous interleaving with a specific phase shift to the first control circuit and the second control circuit respectively signal, wherein the synchronous pulse signal generator uses two digital pulse signals staggered in specific phases to add to two oscillating voltage signals of the same frequency for synchronization, so as to obtain the first sawtooth wave signal and the second sawtooth wave signal staggered in specific phases Wave signals are respectively used as the synchronous interleaving signals of the first control circuit and the second control circuit, so that the first control circuit and the second control circuit are staggered by a specific phase, and interleaved frequency multiplication is obtained by synchronous interleaving, and the parallel connection Step-up power factor correction circuit current sharing.

根据本发明，所述的控制电路，其中该第一升压电路包含串接的第一电感、第一二极管与第一电容，以及一个第一开关元件，其中该第一开关元件与串接的第二二极管及第一电容并联连接。According to the present invention, the control circuit, wherein the first boost circuit includes a first inductor, a first diode and a first capacitor connected in series, and a first switch element, wherein the first switch element and the series The connected second diode and the first capacitor are connected in parallel.

根据上述的构想，其中该第二升压电路包含串接的第二电感、第二二极管与第一电容，以及一个第二开关元件，其中该第二开关元件与串接的第二二极管及第一电容并联连接。According to the above idea, the second boost circuit includes a second inductor, a second diode and a first capacitor connected in series, and a second switch element, wherein the second switch element and the second switch element connected in series The pole tube and the first capacitor are connected in parallel.

根据上述的构想，其中该特定相位是180度。According to the above concept, the specific phase is 180 degrees.

根据上述的构想，该第一升压电路包含第一电感，该第二升电压路包含第二电感，该第一控制电路的电流控制回路接收反映该第一电感的电流信号，该第二控制电路的电流控制回路接收反映该第二电感的电流信号；其中该电流基准与反映该第一电感的电流信号比较后产生的信号，再与该第一锯齿波信号比较，以产生该第一脉宽调变信号。According to the idea above, the first boost circuit includes a first inductor, the second boost circuit includes a second inductor, the current control loop of the first control circuit receives a current signal reflecting the first inductor, and the second control The current control loop of the circuit receives the current signal reflecting the second inductance; the signal generated after comparing the current reference with the current signal reflecting the first inductance is then compared with the first sawtooth wave signal to generate the first pulse wide modulation signal.

根据上述的构想，其中该电流基准与反映该第二电感的电流信号比较后产生的信号，再与该第二锯齿波信号比较，以产生该第二脉宽调变信号。According to the above concept, the signal generated after the current reference is compared with the current signal reflecting the second inductor is then compared with the second sawtooth wave signal to generate the second pulse width modulation signal.

根据本发明另一方面提供一种用于交错控制并联升压式功率因数校正电路均流的控制方法，该并联升压式功率因数校正电路包含第一升压电路以及第二升压电路，该控制方法包含：利用该并联升压式功率因数校正电路的输出电压、前馈电压与输入参考电压产生电流基准；将该电流基准送入第一电流控制回路，以产生第一脉宽调变信号驱动该第一升压电路；将该电流基准送入第二电流控制回路，以产生第二脉宽调变信号驱动该第二升压电路；分别向该第一电流控制回路与该第二电流控制回路提供错开特定相位的同步交错信号，利用两个错开特定相位的数字脉冲信号分别加到两个同频振荡电压信号去进行同步，以得到错开特定相位的第一锯齿波信号与第二锯齿波信号分别做为该第一电流控制回路与该第二电流控制回路的同步交错信号，以使该第一电流控制回路与该第二电流控制回路错开特定相位，以同步交错获得交错倍频，并使该并联升压式功率因数校正电路均流。According to another aspect of the present invention, there is provided a control method for interleavedly controlling current sharing of a parallel boosted power factor correction circuit, the parallel boosted power factor correction circuit includes a first boosting circuit and a second boosting circuit, the The control method includes: using the output voltage, the feed-forward voltage and the input reference voltage of the parallel boost power factor correction circuit to generate a current reference; sending the current reference to a first current control loop to generate a first pulse width modulation signal driving the first boost circuit; sending the current reference into the second current control loop to generate a second pulse width modulation signal to drive the second boost circuit; respectively feeding the first current control loop and the second current The control loop provides a synchronous interleaving signal with a specific phase stagger, and uses two digital pulse signals with a specific phase stagger to add to two oscillating voltage signals of the same frequency for synchronization, so as to obtain the first sawtooth wave signal and the second sawtooth signal with a specific phase stagger Wave signals are respectively used as synchronous interleaving signals of the first current control loop and the second current control loop, so that the first current control loop and the second current control loop are staggered by a specific phase, and interleaved frequency multiplication is obtained by synchronous interleaving, And make the parallel step-up power factor correction circuit share the current.

根据上述的构想，其中该第一升压电路包含串接的第一电感、第一二极管与第一电容，以及一个第一开关元件，其中该第一开关元件与串接的第二二极管及第一电容并联连接。According to the above idea, the first boost circuit includes a first inductor, a first diode and a first capacitor connected in series, and a first switching element, wherein the first switching element is connected in series with the second The pole tube and the first capacitor are connected in parallel.

根据上述的构想，其中该第二升压电路包含串接的第二电感、第二二极管与第一电容，以及一个第二开关元件，该第二开关元件与串接的第二二极管及第一电容并联连接。According to the above idea, wherein the second boost circuit includes a second inductance, a second diode and a first capacitor connected in series, and a second switch element, the second switch element and the second diode connected in series The tube and the first capacitor are connected in parallel.

根据上述的构想，该第一升压电路包含第一电感，该第二升电压路包含第二电感，该第一电流控制回路接收反映该第一电感的电流信号，该第二电流控制回路接收反映该第二电感的电流信号；其中该电流基准与反映该第一电感的电流信号比较后产生的信号，再与该第一锯齿波信号比较，以产生该第一脉宽调变信号。According to the above idea, the first boost circuit includes a first inductor, the second boost circuit includes a second inductor, the first current control loop receives a current signal reflecting the first inductor, and the second current control loop receives Reflecting the current signal of the second inductor; wherein the signal generated after comparing the current reference with the current signal reflecting the first inductor is compared with the first sawtooth wave signal to generate the first pulse width modulation signal.

本发明得藉由以下列附图与详细说明，而可获得一更深入的了解。A deeper understanding of the present invention can be obtained through the following figures and detailed description.

(4)附图说明(4) Description of drawings

图1是为一典型的两并联功率因数校正装置电路示意图；FIG. 1 is a schematic circuit diagram of a typical two-parallel power factor correction device;

图2是为本发明较佳实施例利用两个控制芯片共用同一个电流基准的电路示意图；Fig. 2 is a schematic circuit diagram of using two control chips to share the same current reference in a preferred embodiment of the present invention;

图3是为本发明较佳实施例同步脉冲信号产生示意图；Fig. 3 is a synchronous pulse signal generation schematic diagram for a preferred embodiment of the present invention;

图4是为本发明较佳实施例的相位错开180°的锯齿波信号示意图；Fig. 4 is a schematic diagram of a sawtooth wave signal with a phase shift of 180° according to a preferred embodiment of the present invention;

图5是为本发明较佳实施例的电流控制回路示意图；以及FIG. 5 is a schematic diagram of a current control loop in a preferred embodiment of the present invention; and

图6是为本发明较佳实施例的主电路和控制电路的并联交错功率因数校正电路示意图。Fig. 6 is a schematic diagram of a parallel interleaved power factor correction circuit of a main circuit and a control circuit in a preferred embodiment of the present invention.

(5)具体实施方式(5) specific implementation

本发明采取的控制方案为：分别取样两个并联单元的电感电流，采用平均电流控制法，由两片控制芯片(如：UC3854)分别控制两个功率开关。与前述均流方法不同的是，这里的两个控制芯片共用同一个电流基准IMUL，如图2所示。The control scheme adopted by the present invention is: respectively sampling the inductance currents of two parallel units, adopting the average current control method, and controlling two power switches respectively by two control chips (such as: UC3854). Different from the aforementioned current sharing method, the two control chips here share the same current reference IMUL, as shown in Figure 2.

两控制芯片共用一个电流基准可确保每路的电感电流基本相等，实现均流的目的。采用常见的控制芯片UC3854控制以后，每路的电感电流可以很好地跟踪整流电压，且两路的电感电流平均值相同，所以总的电感电流也能很好地跟踪整流电压，以确保高的功率因数。与此同时，两片UC3854采用两路错开180°的交错信号去同步，使各自的输出控制脉冲相位错开180°以获得精确的交错倍频效果。The two control chips share a current reference to ensure that the inductor current of each channel is basically equal to achieve the purpose of current sharing. After being controlled by the common control chip UC3854, the inductor current of each channel can track the rectified voltage well, and the average value of the inductor current of the two channels is the same, so the total inductor current can also track the rectified voltage well to ensure high power factor. At the same time, two UC3854s use two staggered 180° interleaved signals to synchronize, so that the respective output control pulse phases are staggered by 180° to obtain an accurate interleaved frequency multiplication effect.

为得到两路错开180°的交叉信号，采用了模拟信号和数字脉冲相结合的方法。如图3所示，用一数字同步脉冲信号VSYNC加到控制芯片振荡器的电容电压波形VCT上，同步脉冲迅速将该电容电压提高至控制芯片内部PWM比较器的上限值之上，这将改变振荡电路的充放电状态，然后振荡器放电周期就与同步脉冲信号的周期相同。In order to obtain two cross signals staggered by 180°, the method of combining analog signal and digital pulse is adopted. As shown in Figure 3, a digital synchronous pulse signal VSYNC is added to the capacitor voltage waveform VCT of the control chip oscillator, and the synchronous pulse quickly raises the capacitor voltage above the upper limit of the internal PWM comparator of the control chip, which will Change the charge and discharge state of the oscillator circuit, then the oscillator discharge cycle is the same as the cycle of the sync pulse signal.

基于上述原理，两同频的振荡电压信号VCT1，VCT2用两路相位错开180°的脉冲信号VSYSNC1，VSYSNC2去同步，就可得到相位错开180°的两路锯齿波信号COMBINED VCT1，COMBINED VCT2，如图4所示。用这两个信号作为两块控制芯片的周期信号，就可保证两块UC3854的输出脉冲错开180°。Based on the above principle, two oscillating voltage signals VCT1 and VCT2 with the same frequency are desynchronized with two pulse signals VSYSNC1 and VSYSNC2 with a 180° phase stagger, and then two sawtooth wave signals COMBINED VCT1 and COMBINED VCT2 with a 180° phase stagger can be obtained, as Figure 4 shows. Using these two signals as the period signals of the two control chips can ensure that the output pulses of the two UC3854s are staggered by 180°.

通常控制芯片(如：UC3854)的电流基准由反馈电压，前馈电压，乘法器的输入电流(与输入电压瞬时值成正比)三者共同决定。在两路并联功率因数校正装置中，前馈电压，输入电压瞬时值，反馈电压(仅有一个输出电压)都是一致的。为避免两电流基准值由元件的离散性引起偏差，在本控制方案中，只使用一片控制芯片内的模拟乘法/除法器单元，而另一片控制芯片中的单元不用，如图5所示。这样，只有一片UC3854有电流基准(Imul)输出，而另一片UC3854没有电流基准信号输出，将Imul同时送到两片控制芯片的电流控制回路的同相输入端，作为共同的电流基准信号，就可实现两支路电感电流同时跟踪单一电流基准。Usually the current reference of the control chip (such as: UC3854) is jointly determined by the feedback voltage, the feedforward voltage, and the input current of the multiplier (proportional to the instantaneous value of the input voltage). In the two parallel power factor correction devices, the feed-forward voltage, the instantaneous value of the input voltage, and the feedback voltage (only one output voltage) are consistent. In order to avoid the deviation of the two current reference values caused by the discreteness of the components, in this control scheme, only the analog multiplier/divider unit in one control chip is used, while the unit in the other control chip is not used, as shown in Figure 5. In this way, only one UC3854 has a current reference (Imul) output, while the other UC3854 has no current reference signal output. Send Imul to the non-inverting input terminals of the current control loops of the two control chips at the same time as a common current reference signal. Realize that the inductor currents of two branches track a single current reference at the same time.

请参阅图6，图6所示的主电路和控制电路架构是该控制方案在两路并联交错工作功率因数校正电路中的应用，属于本发明的范畴。其中整流部分可以采用一个整流单元或采用两个整流单元分别作为两个单元的输入。其中：Please refer to FIG. 6. The architecture of the main circuit and the control circuit shown in FIG. 6 is the application of the control scheme in a two-way parallel interleaved power factor correction circuit, which belongs to the scope of the present invention. The rectification part can use one rectification unit or two rectification units as the input of the two units respectively. in:

(1)同步脉冲产生器(Sync pulse generator)可采用TLC494，MCU，DSP或其他分频器电路产生。(1) The Sync pulse generator can be generated by TLC494, MCU, DSP or other frequency divider circuits.

(2)多路(3路或更多的单元)并联交错工作的功率因数校正电路也属于本发明的实施例。(2) A power factor correction circuit with multiple (3 or more units) connected in parallel and interleaved also belongs to the embodiments of the present invention.

(3)本发明不排除三相交流电源输入的功率因数校正电路并联交错工作应用场合。(3) The present invention does not rule out the application of power factor correction circuits connected in parallel and interleaved with three-phase AC power input.

(4)本发明是针对并联交错工作方式的变换器的一种通用的均流方法，对于电流断续模式工作的变换器仍然有效。(4) The present invention is a general current sharing method for converters working in parallel interleaved mode, and is still effective for converters working in discontinuous current mode.