CN105137200A

CN105137200A - Monitoring device of CCM Buck-Boost convertor output capacitor and method thereof

Info

Publication number: CN105137200A
Application number: CN201510624913.5A
Authority: CN
Inventors: 曹诚; 姚凯; 周世林; 杨思文; 韩旭芝
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2015-09-25
Filing date: 2015-09-25
Publication date: 2015-12-09

Abstract

The invention discloses a monitoring device and method for the output capacitance of a CCM buck-boost converter. The device includes a Buck-Boost converter main power circuit, a drive circuit, a display unit and a signal processing module, wherein the signal processing module includes a power circuit control unit, a switching frequency f _s calculation unit, a duty ratio D calculation unit, and an output voltage trigger sampling unit, capacitor ESR and C calculation unit; the method is to obtain the duty ratio through the duty ratio D calculation unit by detecting the PWM driving pulse signal of the switch tube, and obtain the switching frequency of the converter through the switching frequency f _s calculation unit, and the output voltage On the one hand, the trigger sampling unit detects the average value of the output voltage, and on the other hand, triggers sampling to obtain the instantaneous value of the output voltage, and sends the above data to the capacitor ESR and C calculation unit to obtain the current ESR and C of the output filter capacitor in the Buck-Boost converter. value. The invention does not need a current sensor, does not affect the normal operation of the converter, and provides a basis for life prediction of capacitors and power supplies.

Description

Monitoring device and method for output capacitance of CCM buck-boost converter

技术领域technical field

本发明属于电能变换装置中的监测技术领域，特别是一种CCM升降压(Buck-Boost)变换器输出电容ESR和C的监测装置及方法。The invention belongs to the technical field of monitoring in electric energy conversion devices, in particular to a monitoring device and method for output capacitance ESR and C of a CCM Buck-Boost converter.

背景技术Background technique

由于效率高、体积小等优点，开关电源在日常生产生活中应用十分广泛。一般而言，为了得到较为稳定的输出电压，必须采用电容有效滤除高频噪声。变换器工作一段时间之后，电容的容值(Capacitance,C)和等效串联电阻(EquivalentSeriesResistance,ESR)会发生变化，与初电容值C和阻值ESR相比，当该变化量较大时，即可认为该电容已失效，电容的失效将会造成电源和系统的运行故障。降压(Buck)、升压(Boost)、升降压(Buck-Boost)变换器是三种最基本的开关电源变换器，其他的变换器均可以由这三种变换器衍变而来。其中，CCM(ContinuousCurrentMode，电流连续模式)Buck-Boost变换器在计算机电源、通讯电源、航空航天等领域广泛使用，因此监测CCMBuck-Boost变换器的输出滤波电容的ESR和C，预测其寿命非常重要。Due to the advantages of high efficiency and small size, switching power supplies are widely used in daily production and life. Generally speaking, in order to obtain a relatively stable output voltage, capacitors must be used to effectively filter out high-frequency noise. After the converter works for a period of time, the capacitance (Capacitance, C) and equivalent series resistance (EquivalentSeries Resistance, ESR) of the capacitor will change. Compared with the initial capacitance C and resistance ESR, when the change is large, That is to say, the capacitor has failed, and the failure of the capacitor will cause the operation failure of the power supply and the system. Buck, Boost, and Buck-Boost converters are the three most basic switching power converters, and other converters can be derived from these three converters. Among them, the CCM (Continuous Current Mode, current continuous mode) Buck-Boost converter is widely used in computer power supply, communication power supply, aerospace and other fields, so it is very important to monitor the ESR and C of the output filter capacitor of the CCMBuck-Boost converter and predict its life .

国内外学者近年来对开关电源中电解电容的参数监测作了一定的研究，主要可分为两类，分别为离线式和在线式。但是使用离线式监测电解电容时需要停止设备运行。而在线式监测虽然无须停止设备运行，但是它在除电流模式控制可以利用现有的开关管电流检测信号外，需要增加电流传感器以检测电容、电感等电流。Scholars at home and abroad have done some research on the parameter monitoring of electrolytic capacitors in switching power supplies in recent years, which can be mainly divided into two categories, namely off-line and on-line. However, when using offline monitoring of electrolytic capacitors, it is necessary to stop the operation of the equipment. Although the on-line monitoring does not need to stop the operation of the equipment, in addition to the current mode control, which can use the existing switch current detection signal, it needs to increase the current sensor to detect the capacitance, inductance and other currents.

发明内容Contents of the invention

本发明的目的在于提供一种CCM升降压变换器输出电容ESR和C的监测装置及方法，能够实时监测等效串联电阻ESR和电容的容值C的变化，对电解电容和电源的寿命进行准确预测。The purpose of the present invention is to provide a kind of monitoring device and method of CCM buck-boost converter output capacitance ESR and C, can real-time monitor the variation of equivalent series resistance ESR and capacitance C of electric capacity, the life-span of electrolytic capacitance and power supply is checked Predict accurately.

实现本发明目的的技术解决方案为：一种CCM升降压变换器输出电容的监测装置，包括Buck-Boost变换器主功率电路、驱动电路、显示单元和信号处理模块，所述信号处理模块包括功率电路控制单元、开关频率f_s计算单元、占空比D计算单元、输出电压触发采样单元、电容ESR和C计算单元；The technical solution to realize the object of the present invention is: a monitoring device for the output capacitance of a CCM buck-boost converter, including a Buck-Boost converter main power circuit, a drive circuit, a display unit and a signal processing module, and the signal processing module includes Power circuit control unit, switching frequency f _s calculation unit, duty cycle D calculation unit, output voltage trigger sampling unit, capacitor ESR and C calculation unit;

所述Buck-Boost变换器主功率电路包括输入电压源V_in、开关管Q_b、续流二极管D_b、滤波电感L、输出滤波电容和负载R_L，所述输出滤波电容包括等效串联电阻ESR和电容C，其中开关管Q_b的漏极、电压源V_in的正极连接，滤波电感L一端分别与开关管Q_b的漏极和续流二极管D_b的阴极连接，滤波电感L另一端与电压源V_in的负极连接，续流二极管D_b的阳极分别与等效串联电阻ESR的一端、负载R_L的一端连接，等效串联电阻ESR的另一端与电容C的一端连接，电容C的另一端及负载R_L的另一端均与电压源V_in的负极连接，负载R_L两端为输出电压v_o；The main power circuit of the Buck-Boost converter includes an input voltage source V _in , a switch tube Q _b , a freewheeling diode D _b , a filter inductor L, an output filter capacitor and a load R _L , and the output filter capacitor includes an equivalent series resistance ESR and capacitor C, where the drain of the switching tube _Qb is connected to the anode of the voltage source V _in , one end of the filter inductor L is connected to the drain of the switch tube _{Qb and the cathode of the freewheeling diode Db} _respectively , and the other end of the filter inductor L It is connected to the negative pole of the voltage source V _in , the anode of the freewheeling diode D _b is respectively connected to one end of the equivalent series resistance ESR and one end of the load _RL , the other end of the equivalent series resistance ESR is connected to one end of the capacitor C, and the capacitor C The other end of the load R _L and the other end of the load R L are both connected to the negative pole of the voltage source V _in , and the two ends of the load R _L are the output voltage v _o ;

所述功率电路控制单元的输入端分别与Buck-Boost变换器主功率电路的电压源V_in和输出电压v_o连接，功率电路控制单元输出端的PWM信号分别接入开关频率f_s计算单元和占空比D计算单元，Buck-Boost变换器主功率电路的输出电压v_o和功率电路控制单元输出端的PWM信号均接入输出电压触发采样单元，开关频率f_s计算单元、占空比D计算单元、输出电压触发采样单元的输出端均接入电容ESR和C计算单元，电容ESR和C计算单元的输出端接入显示单元；The input terminals of the power circuit control unit are respectively connected to the voltage source V _in and the output voltage v _o of the main power circuit of the Buck-Boost converter, and the PWM signals at the output terminals of the power circuit control unit are connected to the switching frequency f _s calculation unit and the duty cycle respectively. Duty ratio D calculation unit, the output voltage v _o of the main power circuit of the Buck-Boost converter and the PWM signal at the output end of the power circuit control unit are connected to the output voltage trigger sampling unit, the switching frequency f _s calculation unit, and the duty ratio D calculation unit , The output terminals of the output voltage trigger sampling unit are connected to the capacitor ESR and the C calculation unit, and the output terminals of the capacitor ESR and the C calculation unit are connected to the display unit;

所述驱动电路的输入端与功率电路控制单元输出端的PWM信号连接，驱动电路的输出端接入开关管Q_b的栅极。The input end of the drive circuit is connected to the PWM signal at the output end of the power circuit control unit, and the output end of the drive circuit is connected to the gate of the switch tube _Qb .

一种CCM升降压变换器输出电容ESR和C的监测方法，包括以下步骤：A method for monitoring the output capacitance ESR and C of a CCM buck-boost converter, comprising the following steps:

步骤1，在信号处理模块中创建功率电路控制单元、开关频率f_s计算单元、占空比D计算单元、输出电压触发采样单元、电容ESR和C计算单元；Step 1, create a power circuit control unit, a switching frequency f _s calculation unit, a duty cycle D calculation unit, an output voltage trigger sampling unit, a capacitor ESR and a C calculation unit in the signal processing module;

步骤2，信号处理模块的功率电路控制单元采集Buck-Boost变换器主功率电路的输出电压v_o和输入电压源V_in，得到PWM信号并经驱动电路驱动开关管Q_b；Step 2, the power circuit control unit of the signal processing module collects the output voltage v _o and the input voltage source V _in of the main power circuit of the Buck-Boost converter, obtains the PWM signal and drives the switching tube Q _b through the drive circuit;

步骤3，功率电路控制单元输出的PWM信号分别送入开关频率f_s计算单元和占空比D计算单元，经开关频率f_s计算单元处理得出变换器当前的开关频率f_s，经占空比D计算单元处理得出变换器当前的占空比D；Step 3, the PWM signal output by the power circuit control unit is sent to the switching frequency f _s calculation unit and the duty cycle D calculation unit respectively, and the current switching frequency f _s of the converter is obtained through the processing of the switching frequency f _s calculation unit. The ratio D calculation unit processes to obtain the current duty ratio D of the converter;

步骤4，功率电路控制单元输出的PWM信号和Buck-Boost变换器主功率电路的输出电压v_o同时送入输出电压触发采样单元，经输出电压触发采样单元处理得到输出电压的瞬时值v_o(0)、v_o(DT_s/2)、v_o[(1+D)T_s/2]和输出电压的平均值V_o；T_s为变换器开关周期，D为变换器的占空比，v_o(0)为PWM信号上升沿时刻对应的瞬时输出电压，v_o(DT_s/2)为PWM信号上升沿和下降沿之间的中点时刻对应的瞬时输出电压,v_o[(1+D)T_s/2]为PWM信号下降沿和上升沿之间的中点时刻对应的瞬时输出电压；Step 4, the PWM signal output by the power circuit control unit and the output voltage v _o of the main power circuit of the Buck-Boost converter are sent to the output voltage trigger sampling unit at the same time, and the instantaneous value of the output voltage v _o ( 0), v _o (DT _s /2), v _o [(1+D)T _s /2] and the average value V _o of the output voltage; T _s is the switching period of the converter, and D is the duty cycle of the converter , v _o (0) is the instantaneous output voltage corresponding to the rising edge of the PWM signal, v _o (DT _s /2) is the instantaneous output voltage corresponding to the midpoint between the rising edge and the falling edge of the PWM signal, v _o [( 1+D)T _s /2] is the instantaneous output voltage corresponding to the midpoint moment between the falling edge and the rising edge of the PWM signal;

步骤5，将得到的开关频率f_s、占空比D、以及输出电压的瞬时值v_o(0)、v_o(DT_s/2)、v_o[(1+D)T_s/2]和输出电压的平均值V_o送入电容ESR和C计算单元进行综合处理，得到Buck-Boost变换器中输出滤波电容当前等效串联电阻ESR和电容C的值；Step 5, the obtained switching frequency f _s , duty cycle D, and instantaneous value of output voltage v _o (0), v _o (DT _s /2), v _o [(1+D)T _s /2] and the average value V _o of the output voltage are sent to the capacitor ESR and C calculation unit for comprehensive processing, and the values of the current equivalent series resistance ESR and capacitor C of the output filter capacitor in the Buck-Boost converter are obtained;

步骤6，电容ESR和C计算单元将所得的等效串联电阻ESR和电容C的值送入显示单元实时显示。In step 6, the capacitance ESR and C calculation unit sends the obtained values of the equivalent series resistance ESR and capacitance C to the display unit for real-time display.

本发明与现有技术相比，其显著优点为：(1)不影响变换器的正常工作；(2)在线监测电容的ESR和C值，为电容和电源的寿命预测提供依据；(3)无需电流传感器及其辅助电路检测电容电流，减小了参数监测的难度。Compared with the prior art, the present invention has significant advantages as follows: (1) does not affect the normal operation of the converter; (2) monitors the ESR and C value of the capacitor on-line, and provides a basis for life prediction of the capacitor and the power supply; (3) There is no need for a current sensor and its auxiliary circuit to detect the capacitive current, which reduces the difficulty of parameter monitoring.

附图说明Description of drawings

图1是CCMBuck-Boost变换器开关周期中的工作波形。Fig. 1 is the working waveform in the switching cycle of CCMBuck-Boost converter.

图2是本发明CCM升降压变换器输出电容ESR和C的监测装置的结构示意图。FIG. 2 is a structural schematic diagram of a monitoring device for output capacitance ESR and C of a CCM buck-boost converter according to the present invention.

其中：V_in-输入电压，I_in-输入电流，i_L-电感电流，i_C-电容电流，I_o-输出电流，v_o-输出电压，V_o-输出电压平均值，Q_b-开关管，D_b-二极管，L-电感，C-输出滤波电容值，ESR-等效串联电阻值，R_L-负载，V_gs-开关管Q_b的驱动电压，D-占空比，t-时间，T_s-变换器开关周期，f_s-变换器开关频率，ΔI_L-电感电流纹波峰峰值，v_ESR-等效串联电阻上的电压，v_C-电容上的电压。Among them: V _in - input voltage, I _in - input current, i _L - inductor current, i _C - capacitor current, I _o - output current, v _o - output voltage, V _o - average value of output voltage, Q _b - switch Tube, D _b -diode, L-inductance, C-output filter capacitor value, ESR-equivalent series resistance value, R _L -load, V _gs -driving voltage of switching tube Q _b , D-duty cycle, t- Time, T _s - converter switching period, f _s - converter switching frequency, ΔI _L - peak-to-peak inductor current ripple, v _ESR - voltage on equivalent series resistance, v _C - voltage on capacitor.

具体实施方式Detailed ways

下面结合附图及具体实施例对本发明作出进一步详细说明。The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

本发明设计一种在线监测工作于电感电流连续模式(ContinuousConductionMode,CCM)的升降压(Buck-Boost)变换器输出滤波电容ESR和C的装置及方法。The present invention designs an on-line monitoring device and method for output filter capacitor ESR and C of a Buck-Boost converter working in an inductor current continuous mode (Continuous Conduction Mode, CCM).

1、理论推导：1. Theoretical derivation:

图1为CCMBuck-Boost变换器开关周期中的工作波形。当开关管Q_b导通时，二极管D_b截止，电感L两端的电压为V_in，其电感电流i_L以V_in/L的斜率线性上升。当二极管D_b关断时，电感电流i_L通过二极管D_b续流，此时电感L两端的电压为-V_o，电感电流i_L以V_o/L的斜率下降。由于Buck-Boost变换器工作在CCM模式，因此在开关周期结束前，电感电流i_L未下降到零。电感电流i_L在一个开关周期内的平均值为 Fig. 1 is the working waveform in the switching period of CCMBuck-Boost converter. When the switch tube Q _b is turned on, the diode D _b is turned off, the voltage across the inductor L is V _in , and the inductor current i _L rises linearly with the slope of V _in /L. When the diode D _b is turned off, the inductor current i _L continues to flow through the diode D _b . At this time, the voltage across the inductor L is -V _o , and the inductor current i _L drops with a slope of V _o /L. Since the Buck-Boost converter works in CCM mode, the inductor current i _L does not drop to zero before the switching cycle ends. The average value of the inductor current i _L in one switching cycle is

电感电流i_L在一个周期中的表达式如下：The expression of the inductor current i _L in one cycle is as follows:

${i i}_{L L} ((t t)) = = \{\begin{matrix} \frac{{V V}_{i i n no}}{L L} t t - - \frac{{V V}_{o o} ((11 - - D D.))}{22 {Lf Lf}_{s the s}} + + \frac{{I I}_{o o}}{11 - - D D.} & 00 \leq \leq t t < < {DT DT}_{s the s} \\ - - \frac{{V V}_{o o}}{L L} t t + + \frac{{V V}_{o o} ((11 + + D D.))}{22 {Lf Lf}_{s the s}} + + \frac{{I I}_{o o}}{11 - - D D.} & {DT DT}_{s the s} \leq \leq t t < < {T T}_{s the s} \end{matrix} - - - - - - ((11))$

其中V_in为输入电压，V_o为输出电压平均值，L为电感值，f_s为Buck-Boost变换器的开关频率，D为开关管的占空比，T_s为Buck-Boost变换器的开关周期,t为时间。Among them, V _in is the input voltage, V _o is the average value of the output voltage, L is the inductance value, f _s is the switching frequency of the Buck-Boost converter, D is the duty cycle of the switch tube, T _s is the buck-boost converter Switching period, t is time.

电容电流i_C的表达式为：The expression of the capacitive current i _C is:

${i i}_{C C} ((t t)) = = \{\begin{matrix} - - {I I}_{o o} & 00 \leq \leq t t < < {DT DT}_{s the s} \\ - - \frac{{V V}_{o o}}{L L} t t + + \frac{{V V}_{o o} ((11 + + D D.))}{22 {Lf Lf}_{s the s}} + + \frac{{I I}_{o o} D D.}{11 - - D D.} & {DT DT}_{s the s} \leq \leq t t < < {T T}_{s the s} \end{matrix} - - - - - - ((22))$

电容电流i_C在电容C和等效串联电阻ESR上的压降分别为v_C(t)和v_ESR(t)，其波形如结合图1，等效串联电阻ESR上的电压v_ESR(t)波形与电容电流i_C(t)波形形状一致，The voltage drop of the capacitor current i _C on the capacitor C and the equivalent series resistance ESR are respectively v _C (t) and v _ESR (t), and its waveform is as shown in Fig. 1, the voltage v ESR on the equivalent series resistance _ESR (t ) waveform is consistent with the capacitive current i _C (t) waveform shape,

其表达式为：Its expression is:

${v v}_{E E. S S R R} ((t t)) = = E E. S S R R \cdot \cdot {i i}_{C C} ((t t)) = = \{\begin{matrix} - - E E. S S R R \cdot &Center Dot; {I I}_{o o} & 00 \leq \leq t t < < {DT DT}_{s the s} \\ E E. S S R R \cdot &Center Dot; [[- - \frac{{V V}_{o o}}{L L} t t + + \frac{{V V}_{o o} ((11 + + D D.))}{22 {Lf Lf}_{s the s}} + + \frac{{I I}_{o o} D D.}{11 - - D D.}]] & {DT DT}_{s the s} \leq \leq t t < < {T T}_{s the s} \end{matrix} - - - - - - ((33))$

电容电压v_C(t)与电容电流i_C(t)的关系如下式：The relationship between capacitor voltage v _C (t) and capacitor current i _C (t) is as follows:

${v v}_{C C} ((t t)) = = \{\begin{matrix} {V V}_{C C} ((00)) + + \frac{11}{C C} {&Integral; &Integral;}_{00}^{t t} {i i}_{C C} ((t t)) d d t t = = {V V}_{C C} ((00)) - - \frac{{I I}_{o o}}{C C} t t & 00 \leq \leq t t < < {DT DT}_{s the s} \\ \begin{matrix} {V V}_{C C} ((00)) + + \frac{11}{C C} {&Integral; &Integral;}_{00}^{{DT DT}_{S S}} {i i}_{C C} ((t t)) d d t t + + \frac{11}{C C} {&Integral; &Integral;}_{{DT DT}_{s the s}}^{t t} {i i}_{C C} ((t t)) d d t t = = {V V}_{C C} ((00)) - - \frac{{V V}_{o o}}{22 L L C C} {t t}^{22} \\ + + [[\frac{{V V}_{o o} ((11 + + D D.))}{22 {LCf LC}_{s the s}} + + \frac{{I I}_{o o} D D.}{C C ((11 - - D D.))}]] t t - - \frac{{DV DV}_{o o}}{22 {LCf LC}_{s the s}^{22}} - - \frac{{I I}_{o o} D D.}{C C ((11 - - D D.)) {f f}_{s the s}} \end{matrix} & {DT DT}_{s the s} \leq \leq t t < < {T T}_{s the s} \end{matrix} - - - - - - ((44))$

其中V_C(0)为零时刻对应的电容电压。Among them, V _C (0) is the capacitor voltage corresponding to the zero moment.

显然，等效串联电阻ESR上的电压直流分量为0，即v_ESR(t)在开关周期内的平均值为0，因此，将式(4)在变换器的一个开关周期T_s内求平均值，即为输出电压平均值V_o，如下式所示：Obviously, the DC component of the voltage on the equivalent series resistance ESR is 0, that is, the average value of v _ESR (t) in the switching cycle is 0, so the average value of Equation (4) in one switching cycle T _s of the converter The value is the average value of the output voltage V _o , as shown in the following formula:

$\begin{matrix} {V V}_{o o} = = \frac{11}{{T T}_{s the s}} {&Integral; &Integral;}_{00}^{{T T}_{s the s}} {v v}_{C C} ((t t)) d d t t \\ = = \frac{11}{{T T}_{s the s}} {{{&Integral; &Integral;}_{00}^{{DT DT}_{s the s}} [[{V V}_{C C} ((00)) - - \frac{{I I}_{o o}}{C C} t t]] d d t t + + {&Integral; &Integral;}_{{DT DT}_{s the s}}^{{T T}_{s the s}} {{{V V}_{C C} ((00)) - - \frac{{V V}_{o o}}{22 L L C C} {t t}^{22} + + [[\frac{{V V}_{o o} ((11 + + D D.))}{22 {LCf LC}_{s the s}} + + \frac{{I I}_{o o} D D.}{C C ((11 - - D D.))}]] t t - - \frac{{DV DV}_{o o}}{22 {LCf LC}_{s the s}^{22}} - - \frac{{I I}_{00} D D.}{C C ((11 - - D D.)) {f f}_{s the s}}}} d d t t}} \\ = = {V V}_{C C} ((00)) + + \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{1212 {LCf LC}_{s the s}^{22}} - - \frac{{I I}_{o o} D D.}{22 {Cf Cf}_{s the s}} \end{matrix} - - - - - - ((55))$

由式可(5)得：It can be obtained from formula (5):

${V V}_{C C} ((00)) = = {V V}_{o o} - - \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{1212 {LCf LC}_{s the s}^{22}} + + \frac{{I I}_{o o} D D.}{22 {Cf Cf}_{s the s}} - - - - - - ((66))$

从附图1可以看出，电容C上的电压为电容电压v_C(t)与ESR电压v_ESR(t)的合成电压，该电压与电容电流i_C、电容C、等效串联电阻ESR等有关，实际电路中，根据检测所得的纹波电流i_C(t)和合成电压v_C(t)+v_ESR(t)的信息即可反推出电容C和等效串联电阻ESR值。为此，重点考察0时刻、DT_s/2和(1+D)T_s/2三个时刻点。It can be seen from Figure 1 that the voltage on the capacitor C is the composite voltage of the capacitor voltage v _C (t) and the ESR voltage v _ESR (t), which is related to the capacitor current i _C , the capacitor C, the equivalent series resistance ESR, etc. Relevant, in the actual circuit, according to the detected ripple current i _C (t) and the synthesized voltage v _C (t) + v _ESR (t) information, the capacitor C and the equivalent series resistance ESR value can be deduced inversely. For this reason, we focus on three time points: time 0, DT _s /2 and (1+D)T _s /2.

电容电压v_C(t)与等效串联电阻ESR电压v_ESR(t)的合成电压即为输出电压瞬时值v_o(t)，根据式(3)、式(4)和式(6)，可得：The composite voltage of the capacitor voltage v _C (t) and the equivalent series resistance ESR voltage v _ESR (t) is the instantaneous value of the output voltage v _o (t), according to formula (3), formula (4) and formula (6), Available:

$\begin{matrix} {v v}_{o o} ((t t)) = = {v v}_{E E. S S R R} ((t t)) + + {v v}_{C C} ((t t)) \\ = = \{\begin{matrix} - - E E. S S R R \cdot \cdot {I I}_{o o} - - \frac{{I I}_{o o}}{C C} t t + + {V V}_{o o} - - \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{1212 {LCf LC}_{s the s}^{22}} + + \frac{{I I}_{o o} D D.}{22 {Cf Cf}_{s the s}} & 00 \leq \leq t t < < {DT DT}_{s the s} \\ \begin{matrix} E E. S S R R \cdot \cdot [[- - \frac{{V V}_{o o}}{L L} t t + + \frac{{V V}_{o o} ((11 + + D D.))}{22 {Lf Lf}_{s the s}} + + \frac{{I I}_{o o} D D.}{11 - - D D.}]] - - \frac{{V V}_{o o}}{22 L L C C} {t t}^{22} + + [[\frac{{V V}_{o o} ((11 + + D D.))}{22 {LCf LC}_{s the s}} + + \frac{{I I}_{o o} D D.}{C C ((11 - - D D.))}]] t t \\ - - \frac{{DV DV}_{o o}}{22 {LCf LC}_{s the s}^{22}} - - \frac{{I I}_{o o} D D.}{C C ((11 - - D D.)) {f f}_{s the s}} + + {V V}_{o o} - - \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{1212 {LCf LC}_{s the s}^{22}} + + \frac{{I I}_{o o} D D.}{22 {Cf Cf}_{s the s}} \end{matrix} & {DT DT}_{s the s} \leq \leq t t < < {T T}_{s the s} \end{matrix} \end{matrix} - - - - - - ((77))$

根据式(7)的输出电压表达式，去除直流平均值V_o可得输出电压的交流分量如下：According to the output voltage expression of formula (7), the AC component of the output voltage can be obtained by removing the DC average value V _o as follows:

$\begin{matrix} {\overset{~ ~}{v v}}_{o o} ((t t)) = = {v v}_{o o} ((t t)) - - {V V}_{o o} \\ = = \{\begin{matrix} - - E E. S S R R \cdot &Center Dot; {I I}_{o o} - - \frac{{I I}_{o o}}{C C} t t - - \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{1212 {LCf LC}_{s the s}^{22}} + + \frac{{I I}_{o o} D D.}{22 {Cf Cf}_{s the s}} & 00 \leq \leq t t < < {DT DT}_{s the s} \\ \begin{matrix} E E. S S R R \cdot &Center Dot; [[- - \frac{{V V}_{o o}}{L L} t t + + \frac{{V V}_{o o} ((11 + + D D.))}{22 {Lf Lf}_{s the s}} + + \frac{{I I}_{o o} D D.}{11 - - D D.}]] - - \frac{{V V}_{o o}}{22 L L C C} {t t}^{22} + + [[\frac{{V V}_{o o} ((11 + + D D.))}{22 {LCf LC}_{s the s}} + + \frac{{I I}_{o o} D D.}{C C ((11 - - D D.))}]] t t - - \\ \frac{{DV DV}_{o o}}{22 {LCf LC}_{s the s}^{22}} - - \frac{{I I}_{o o} D D.}{C C ((11 - - D D.)) {f f}_{s the s}} - - \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{1212 {LCf LC}_{s the s}^{22}} + + \frac{{I I}_{o o} D D.}{22 {Cf Cf}_{s the s}} \end{matrix} & {DT DT}_{s the s} \leq \leq t t < < {T T}_{s the s} \end{matrix} \end{matrix} - - - - - - ((88))$

0时刻、DT_s/2和(1+D)T_s/2时刻，输出电压的交流分量分别为：At 0 time, DT _s /2 and (1+D)T _s /2 time, the AC component of the output voltage They are:

${\overset{~ ~}{v v}}_{o o} ((00)) = = - - E E. S S R R \cdot \cdot {I I}_{o o} - - \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{1212 {LCf LC}_{s the s}^{22}} + + \frac{{I I}_{o o} D D.}{22 {Cf Cf}_{s the s}} - - - - - - ((99))$

${\overset{~ ~}{v v}}_{o o} ((\frac{{DT DT}_{s the s}}{22})) = = - - E E. S S R R \cdot &Center Dot; {I I}_{o o} - - \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{1212 {LCf LC}_{S S}^{22}} - - - - - - ((1010))$

${\overset{~ ~}{v v}}_{o o} [[\frac{((11 + + D D.)) {T T}_{s the s}}{22}]] = = E E. S S R R \cdot &Center Dot; \frac{{I I}_{o o} D D.}{11 - - D D.} + + \frac{{V V}_{o o} {((11 - - D D.))}^{22}}{88 {LCf LC}_{s the s}^{22}} - - \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{1212 {LCf LC}_{s the s}^{22}} - - - - - - ((1111))$

根据式(9)、式(10)和式(11)可得：According to formula (9), formula (10) and formula (11):

$\begin{matrix} C C = = \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{24 twenty four {Lf Lf}_{s the s}^{22} {{((11 - - D D.)) {\overset{~ ~}{v v}}_{o o} [[\frac{((11 + + D D.)) {T T}_{s the s}}{22}]] + + D D. {\overset{~ ~}{v v}}_{o o} ((\frac{{DT DT}_{s the s}}{22}))}}} \\ = = \frac{{V V}_{o o} {((11 - - D D.))}^{33}}{24 twenty four {Lf Lf}_{s the s}^{22} {{((11 - - D D.)) {{{v v}_{o o} [[\frac{((11 + + D D.)) {T T}_{s the s}}{22}]] - - {V V}_{o o}}} + + D D. [[{v v}_{o o} ((\frac{{DT DT}_{s the s}}{22})) - - {V V}_{o o}]]}}} \end{matrix} - - - - - - ((1212))$

$\begin{matrix} E E. S S R R = = \frac{1212 {Lf Lf}_{s the s} D D. [[22 ((11 - - D D.)) {\overset{~ ~}{v v}}_{o o} [[\frac{((11 + + D D.)) {T T}_{s the s}}{22}]] + + 33 {\overset{~ ~}{v v}}_{o o} ((\frac{{DT DT}_{s the s}}{22}))]] \cdot &Center Dot; [[((11 - - D D.)) {\overset{~ ~}{v v}}_{o o} [[\frac{((11 + + D D.)) {T T}_{s the s}}{22}]] + + D D. {\overset{~ ~}{v v}}_{o o} ((\frac{{DT DT}_{s the s}}{22}))]]}{{V V}_{o o} {((11 - - D D.))}^{33} [[{\overset{~ ~}{v v}}_{o o} ((00)) - - {\overset{~ ~}{v v}}_{o o} ((\frac{{DT DT}_{s the s}}{22}))]]} \\ = = \frac{1212 {Lf Lf}_{s the s} D D. {{22 ((11 - - D D.)) {{{v v}_{o o} [[\frac{((11 + + D D.)) {T T}_{s the s}}{22}]] - - {V V}_{o o}}} + + 33 [[{v v}_{o o} ((\frac{{DT DT}_{s the s}}{22})) - - {V V}_{o o}]]}} \cdot \cdot {{((11 - - D D.)) {{{v v}_{o o} [[\frac{((11 + + D D.)) {T T}_{s the s}}{22}]] - - {V V}_{o o}}} + + D D. [[{v v}_{o o} ((\frac{{DT DT}_{s the s}}{22})) - - {V V}_{o o}]]}}}{{V V}_{o o} {((11 - - D D.))}^{33} [[{v v}_{o o} ((00)) - - {v v}_{o o} ((\frac{{DT DT}_{s the s}}{22}))]]} \end{matrix} - - - - - - ((1313))$

式中，ESR为等效串联电阻的阻值，C为电容的容值，L为电感值，f_s为变换器开关频率，T_s为变换器开关周期，V_o为输出电压平均值，D为变换器的占空比，v_o(0)为PWM信号上升沿时刻对应的瞬时输出电压，为PWM信号上升沿和下降沿之间的中点时刻对应的瞬时输出电压，为PWM信号下降沿和上升沿之间的中点时刻对应的瞬时输出电压。In the formula, ESR is the resistance value of the equivalent series resistance, C is the capacitance value of the capacitor, L is the inductance value, f _s is the switching frequency of the converter, T _s is the switching period of the converter, V _o is the average value of the output voltage, D is the duty cycle of the converter, v _o (0) is the instantaneous output voltage corresponding to the rising edge of the PWM signal, is the instantaneous output voltage corresponding to the midpoint between the rising and falling edges of the PWM signal, It is the instantaneous output voltage corresponding to the midpoint between the falling edge and the rising edge of the PWM signal.

基于式(12)和式(13)，可以得到CCMBuck-Boost变换器输出滤波电容ESR和C的监测方法。Based on formula (12) and formula (13), the monitoring method of output filter capacitor ESR and C of CCMBuck-Boost converter can be obtained.

2、本发明CCM升降压变换器输出电容ESR和C的监测装置及方法2. The monitoring device and method of the output capacitor ESR and C of the CCM buck-boost converter of the present invention

结合图2，本发明CCM升降压变换器输出电容ESR和C的监测装置，包括Buck-Boost变换器主功率电路1、驱动电路3、显示单元8和信号处理模块，所述信号处理模块包括功率电路控制单元2、开关频率f_s计算单元4、占空比D计算单元5、输出电压触发采样单元6、电容ESR和C计算单元7；In conjunction with Fig. 2, the monitoring device of the output capacitor ESR and C of the CCM buck-boost converter of the present invention includes a Buck-Boost converter main power circuit 1, a drive circuit 3, a display unit 8 and a signal processing module, and the signal processing module includes Power circuit control unit 2, switching frequency f _s calculation unit 4, duty ratio D calculation unit 5, output voltage trigger sampling unit 6, capacitor ESR and C calculation unit 7;

所述Buck-Boost变换器主功率电路包括输入电压源V_in、开关管Q_b、续流二极管D_b、滤波电感L、输出滤波电容和负载R_L，所述输出滤波电容包括等效串联电阻ESR和电容C，其中开关管Q_b的漏极与电压源V_in的正极连接，滤波电感L一端分别与开关管Q_b的源极和续流二极管D_b的阴极连接，滤波电感L另一端与电压源V_in的负极连接，续流二极管D_b的阳极分别与等效串联电阻ESR的一端及负载R_L的一端连接，等效串联电阻ESR的另一端与电容C的一端连接，电容C的另一端及负载R_L的另一端均与电压源V_in的负极连接，负载R_L两端为输出电压V_o。The main power circuit of the Buck-Boost converter includes an input voltage source V _in , a switch tube Q _b , a freewheeling diode D _b , a filter inductor L, an output filter capacitor and a load R _L , and the output filter capacitor includes an equivalent series resistance ESR and capacitor C, where the drain of the switch tube _Qb is connected to the positive pole of the voltage source V _in , one end of the filter inductor L is respectively connected to the source of the switch tube _{Qb and the cathode of the freewheeling diode Db} _, and the other end of the filter inductor L It is connected to the negative pole of the voltage source V _in , the anode of the freewheeling diode D _b is respectively connected to one end of the equivalent series resistance ESR and one end of the load _RL , the other end of the equivalent series resistance ESR is connected to one end of the capacitor C, and the capacitor C The other end of the load _RL and the other end of the load RL are both connected to the negative pole of the voltage source V _in , and both ends of the load _RL are the output voltage V _o .

所述功率电路控制单元2的输入端分别与Buck-Boost变换器主功率电路1的电压源V_in和输出电压v_o连接，功率电路控制单元2输出端的PWM信号分别接入开关频率f_s计算单元4和占空比D计算单元5，Buck-Boost变换器主功率电路1的输出电压V_o和功率电路控制单元2输出端的PWM信号均接入输出电压触发采样单元6，开关频率f_s计算单元4、占空比D计算单元5、输出电压触发采样单元6的输出端均接入电容ESR和C计算单元7，电容ESR和C计算单元7的输出端接入显示单元8；所述驱动电路3的输入端与功率电路控制单元2输出端的PWM信号连接，驱动电路3的输出端接入开关管Q_b的栅极。所述信号处理模块为DSP芯片TMS320F28335；所述显示单元8为1602液晶显示屏。The input terminals of the power circuit control unit 2 are respectively connected to the voltage source V _in and the output voltage v _o of the main power circuit 1 of the Buck-Boost converter, and the PWM signals at the output terminals of the power circuit control unit 2 are respectively connected to the switching frequency f _s to calculate Unit 4 and duty cycle D calculation unit 5, the output voltage V _o of the main power circuit 1 of the Buck-Boost converter and the PWM signal at the output end of the power circuit control unit 2 are connected to the output voltage trigger sampling unit 6, and the switching frequency f _s is calculated The output terminals of the unit 4, the duty ratio D calculation unit 5, and the output voltage trigger sampling unit 6 are all connected to the capacitor ESR and the C calculation unit 7, and the output terminals of the capacitor ESR and the C calculation unit 7 are connected to the display unit 8; The input end of the circuit 3 is connected to the PWM signal at the output end of the power circuit control unit 2, and the output end of the drive circuit 3 is connected to the gate of the switch tube _Qb . The signal processing module is a DSP chip TMS320F28335; the display unit 8 is a 1602 liquid crystal display.

基于本发明CCM升降压变换器输出电容ESR和C的监测装置的监测方法，包括以下步骤：The monitoring method based on the monitoring device of the output capacitor ESR and C of the CCM buck-boost converter of the present invention may further comprise the steps:

步骤1，在信号处理模块中创建功率电路控制单元2、开关频率f_s计算单元4、占空比D计算单元5、输出电压触发采样单元6、电容ESR和电容量C计算单元7；Step 1, create a power circuit control unit 2, a switching frequency f _s calculation unit 4, a duty cycle D calculation unit 5, an output voltage trigger sampling unit 6, and a capacitor ESR and capacitance C calculation unit 7 in the signal processing module;

步骤2，信号处理模块的功率电路控制单元2采集Buck-Boost变换器主功率电路1的输出电压v_o和输入电压V_in，得到PWM信号并经驱动电路3驱动开关管Q_b；Step 2, the power circuit control unit 2 of the signal processing module collects the output voltage v _o and the input voltage V _in of the main power circuit 1 of the Buck-Boost converter, obtains a PWM signal and drives the switching tube Q _b through the drive circuit 3;

步骤3，功率电路控制单元2输出的PWM信号送入开关频率f_s计算单元4和占空比D计算单元5，经开关频率f_s计算单元4处理得出变换器当前的开关频率f_s，经占空比D计算单元5处理得出变换器当前的占空比D；Step 3, the PWM signal output by the power circuit control unit 2 is sent to the switching frequency f _s calculation unit 4 and the duty ratio D calculation unit 5, and the current switching frequency f _s of the converter is obtained through the processing of the switching frequency f _s calculation unit 4, The current duty ratio D of the converter is obtained through the processing of the duty ratio D calculation unit 5;

步骤4，功率电路控制单元2输出的PWM信号和Buck-Boost变换器主功率电路1的输出电压v_o同时送入输出电压触发采样单元6，经输出电压触发采样单元6处理得到输出电压的瞬时值v_o(0)、v_o(DT_s/2)、v_o[(1+D)T_s/2]和输出电压的平均值V_o；Step 4, the PWM signal output by the power circuit control unit 2 and the output voltage v _o of the main power circuit 1 of the Buck-Boost converter are simultaneously sent to the output voltage trigger sampling unit 6, and the instantaneous output voltage is obtained through the output voltage trigger sampling unit 6. Values v _o (0), v _o (DT _s /2), v _o [(1+D)T _s /2] and the average value V _o of the output voltage;

步骤5，将得到的开关频率f_s、占空比D、以及输出电压的瞬时值v_o(0)、v_o(DT_s/2)、v_o[(1+D)T_s/2]和输出电压的平均值V_o送入电容ESR和C计算单元7进行综合处理，根据公式(12)得到Buck-Boost变换器中输出滤波电容当前电容C的值，根据公式(13)得到Buck-Boost变换器中输出滤波电容当前等效串联电阻ESR的值；Step 5, the obtained switching frequency f _s , duty cycle D, and instantaneous value of output voltage v _o (0), v _o (DT _s /2), v _o [(1+D)T _s /2] and the average value V _o of the output voltage are sent to the capacitor ESR and C calculation unit 7 for comprehensive processing, and the value of the current capacitor C of the output filter capacitor in the Buck-Boost converter is obtained according to the formula (12), and the Buck-Boost is obtained according to the formula (13). The value of the current equivalent series resistance ESR of the output filter capacitor in the Boost converter;

步骤6，电容ESR和C计算单元7将所得的等效串联电阻ESR和电容C的值送入显示单元8实时显示。In step 6, the capacitance ESR and C calculation unit 7 sends the obtained values of the equivalent series resistance ESR and capacitance C to the display unit 8 for real-time display.

本发明针对CCMBuck-Boost变换器的输出滤波电容，设计出一种高效稳定的输出滤波电容等效串联电阻ESR和电容C的在线监测装置及方法，该方法可以在不影响电路正常工作的情况下对电容的参数ESR和C进行监测，为电容和电源的寿命预测提供依据，并且无需电容电流检测部分，方便实现，具有重要的实际应用价值。Aiming at the output filter capacitor of the CCMBuck-Boost converter, the present invention designs an efficient and stable online monitoring device and method for the equivalent series resistance ESR and capacitance C of the output filter capacitor, which can be used without affecting the normal operation of the circuit The parameters ESR and C of the capacitor are monitored to provide a basis for the life prediction of the capacitor and the power supply, and there is no need for a capacitor current detection part, which is convenient to realize and has important practical application value.

Claims

1. the monitoring device of a CCM buck-boost converter output capacitance, it is characterized in that, comprise One Buck-Boost converter body main power circuit (1), driving circuit (3), display unit (8) and signal processing module, described signal processing module comprises power circuit control module (2), switching frequency f _scomputing unit (4), dutycycle D computing unit (5), output voltage trigger sampling unit (6), electric capacity ESR and C computing unit (7);

Described One Buck-Boost converter body main power circuit (1) comprises input voltage source V _in, switching tube Q _b, sustained diode _b, filter inductance L, output filter capacitor and load R _l, described output filter capacitor comprises equivalent series resistance ESR and electric capacity C, wherein switching tube Q _bdrain electrode and voltage source V _inpositive pole connect, filter inductance L one end respectively with switching tube Q _bsource electrode, sustained diode _bnegative electrode connect, the filter inductance L other end and voltage source V _innegative pole connect, sustained diode _banode respectively with one end, the load R of equivalent series resistance ESR _lone end connect, the other end of equivalent series resistance ESR is connected with one end of electric capacity C, the other end of electric capacity C and load R _lthe other end all and voltage source V _innegative pole connect, load R _ltwo ends are output voltage v _o;

The input end of described power circuit control module (2) respectively with the voltage source V of One Buck-Boost converter body main power circuit (1) _inwith output voltage v _oconnect, the pwm signal of power circuit control module (2) output terminal accesses switching frequency f respectively _scomputing unit (4) and dutycycle D computing unit (5), the output voltage v of One Buck-Boost converter body main power circuit (1) _oall access output voltage with the pwm signal of power circuit control module (2) output terminal and trigger sampling unit (6), switching frequency f _sthe output terminal that computing unit (4), dutycycle D computing unit (5), output voltage trigger sampling unit (6) all accesses electric capacity ESR and C computing unit (7), output terminal access display unit (8) of electric capacity ESR and C computing unit (7);

The input end of described driving circuit (3) is connected with the pwm signal of power circuit control module (2) output terminal, the output terminal access switching tube Q of driving circuit (3) _bgrid.

2. the monitoring device of CCM buck-boost converter output capacitance according to claim 1, is characterized in that, described signal processing module is dsp chip TMS320F28335.

3. the monitoring device of CCM buck-boost converter output capacitance according to claim 1, is characterized in that, described display unit (8) is 1602 LCDs.

4. a monitoring method for CCM buck-boost converter output capacitance, is characterized in that, comprises the following steps:

Step 1, creates power circuit control module (2), switching frequency f in signal processing module _scomputing unit (4), dutycycle D computing unit (5), output voltage trigger sampling unit (6), electric capacity ESR and C computing unit (7);

Step 2, the power circuit control module (2) of signal processing module gathers the output voltage v of One Buck-Boost converter body main power circuit (1) _owith input voltage source V _in, obtain pwm signal and through driving circuit (3) driving switch pipe Q _b

Step 3, the pwm signal that power circuit control module (2) exports sends into switching frequency f respectively _scomputing unit (4) and dutycycle D computing unit (5), through switching frequency f _scomputing unit (4) process draws the switching frequency f that transducer is current _s, draw through dutycycle D computing unit (5) process the dutycycle D that transducer is current;

Step 4, the output voltage v of the pwm signal that power circuit control module (2) exports and One Buck-Boost converter body main power circuit (1) _osend into output voltage simultaneously and trigger sampling unit (6), trigger through output voltage the instantaneous value v that sampling unit (6) process obtains output voltage _o(0), v _o(DT _s/ 2), v _o[(1+D) T _s/ 2] and the mean value V of output voltage _o; T _sfor the converter switches cycle, D is the dutycycle of transducer, v _o(0) be the instantaneous output voltage that pwm signal rising edge time is corresponding, v _o(DT _s/ 2) be the instantaneous output voltage that the mid point moment between pwm signal rising edge and negative edge is corresponding, v _o[(1+D) T _s/ 2] be instantaneous output voltage that the mid point moment between pwm signal negative edge and rising edge is corresponding;

Step 5, by the switching frequency f obtained _s, dutycycle D and output voltage instantaneous value v _o(0), v _o(DT _s/ 2), v _o[(1+D) T _s/ 2] and the mean value V of output voltage _ofeeding electric capacity ESR and C computing unit (7) carry out overall treatment, obtain the value of the current equivalent series resistance ESR and electric capacity C of output filter capacitor in One Buck-Boost converter body;

Step 6, the value of the equivalent series resistance ESR of gained and electric capacity C is sent into display unit (8) and is shown in real time by electric capacity ESR and C computing unit (7).

5. the monitoring method of CCM buck converter output capacitance according to claim 4, is characterized in that, the formula of the computing unit of ESR and C described in step 5 (7) overall treatment is as follows:

E S R = \frac{12 {Lf}_{s} D {2 (1 - D) {v_{o} [\frac{(1 + D) T_{s}}{2}] - V_{o}} + 3 [v_{o} (\frac{{DT}_{s}}{2}) - V_{o}]} \cdot {(1 - D) {v_{o} [\frac{(1 + D) T_{s}}{2}] - V_{o}} + D [v_{o} (\frac{{DT}_{s}}{2}) - V_{o}]}}{V_{o} {(1 - D)}^{3} [v_{o} (0) - v_{o} (\frac{{DT}_{s}}{2})]}

C = \frac{V_{o} {(1 - D)}^{3}}{24 {Lf}_{s}^{2} {(1 - D) {v_{o} [\frac{(1 + D) T_{s}}{2}] - V_{o}} + D [v_{o} (\frac{{DT}_{s}}{2}) - V_{o}]}}

In formula, ESR is the resistance of equivalent series resistance, and C is the capacitance of electric capacity, and L is inductance value, f _sfor converter switches frequency, T _sfor the converter switches cycle, V _ofor output voltage average value, D is the dutycycle of transducer, v _o(0) be the instantaneous output voltage that pwm signal rising edge time is corresponding, for the instantaneous output voltage that the mid point moment between pwm signal rising edge and negative edge is corresponding, for the instantaneous output voltage that the mid point moment between pwm signal negative edge and rising edge is corresponding.