CN104796031A - Novel control system and method for auxiliary inverter of rail transit - Google Patents

Abstract

Disclosed is a novel control system and method for an auxiliary inverter of rail transit. The system comprises an output-voltage instantaneous value feedback module, a filter capacitor voltage feedforward module and a diode front busbar voltage differential feedforward module. The control method includes: firstly, controlling an effective value of output voltage to be stabilized through the output-voltage instantaneous value feedback module; secondly, inhibiting influence on output voltage due to busbar voltage fluctuation through the filter capacitor voltage feedforward module; thirdly, increasing dynamic response speed of the filter capacitor voltage feedforward module through the diode front busbar voltage differential feedforward module; fourthly, summing a feedback modulation ratio ao, a feedforward modulation ratio adc and a differential feedforward modulation ratio ad respectively outputted by the output-voltage instantaneous value feedback module, the filter capacitor voltage feedforward module and the diode front busbar voltage differential feedforward module to obtain a total modulation ratio. Based on multi-compound differential feedforward, resistance of the auxiliary inverter to busbar voltage change is improved, and stability and reliability in output voltage of the auxiliary inverter are guaranteed.

Description

For a kind of new control system and the method for track traffic subordinate inverter

Technical field

The present invention relates to subordinate inverter control technology field, a kind of a kind of new control system for track traffic subordinate inverter of concrete proposition and method.

Background technology

Track traffic subordinate inverter is the main power supply of the vehicles such as subway, motor-car, passenger vehicle, by this device, DC bus-bar voltage can be reverse into the three-phase alternating current of 380V/50Hz, realize powering to vehicle assisted system load (air-conditioning, cooling blower, air compressor etc.).Subordinate inverter control system, as the core of subordinate inverter, plays an important role to the performance of subordinate inverter and reliability.Along with the development of information technology, the research of high-performance, high reliability subordinate inverter becomes one of focus paid close attention in current electric drive field.

Track traffic subordinate inverter is in actual motion, because the fluctuation of railway distribution net is larger, there is DC bus-bar voltage to fall suddenly, raise suddenly or the situation of the busbar voltage such as cyclic fluctuation change, make the performance of subordinate inverter often can not meet system requirements.Therefore design a kind of novel control method, can respond busbar voltage change fast, thus suppress busbar voltage to change the impact caused output voltage, this is significant to the performance and reliability improving subordinate inverter.

Summary of the invention

The impact that output voltage is caused is changed in order to suppress busbar voltage, the object of the present invention is to provide a kind of a kind of new control system for track traffic subordinate inverter and method, feedover based on MULTIPLE COMPOSITE differential, to improve the ability of subordinate inverter anti-busbar voltage change, ensure subordinate inverter output voltage stabilization, reliable.

For achieving the above object, the technical solution adopted in the present invention is:

For a kind of new control system of track traffic subordinate inverter, comprise bus voltage derivative feed-forward module before output voltage instantaneous value feedback module, filter capacitor electric voltage feed forward module and diode; Described output voltage instantaneous value feedback module controls output voltage effective value and stablizes; Filter capacitor electric voltage feed forward module responds busbar voltage in time and changes the output voltage change caused; Before diode, bus voltage derivative feed-forward module employing busbar voltage does the deficiency that differential feedforward makes up filter capacitor electric voltage feed forward module.

The control method of a kind of new control system for track traffic subordinate inverter described above, comprises the steps:

Step 1: control output voltage effective value by output voltage instantaneous value feedback module and stablize:

First, using any 2 tunnel subordinate inverter output line voltages as the input signal of output voltage instantaneous value feedback module, calculated through Park conversion and amplitude by input signal, the numerical value reflection output line voltage effective value obtained, computing formula is such as formula shown in (1) and formula (2);

$\left[\begin{array}{c}{v}_{\mathrm{\α}}\\ v_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{cc}1& 0\\ \frac{1}{\sqrt{3}}& \frac{2}{\sqrt{3}}\end{array}\right]\left[\begin{array}{c}{v}_a\\ v_b\end{array}\right]---\left(1\right)$

$v_m=\sqrt{v_{\mathrm{\α}}^2+v_{\mathrm{\β}}^2}---\left(2\right)$

Wherein, v _aand v _bit is two-way subordinate inverter output line voltage; v _aand v _bthe component of three-phase output line voltage in two-phase rest frame; v _mit is output line voltage effective value;

Then, the output line voltage effective value v will obtained _mwith given output line voltage effective value v _refmake comparisons, i.e. v _e=v _ref-v _m, wherein v _efor error voltage;

Finally, by error voltage v _eobtain feedback modulation through segmentation PID adjustment and compare a _o, segmentation PID is namely according to error voltage v _esize, use different PI parameters: work as v _ebe greater than setting comparative voltage v _btime, use the PI parameter that P is larger; Work as v _ebe less than setting comparative voltage v _etime, use the PI parameter that P is less, use segmentation PID can improve the feedback dynamic responding speed of system;

Output voltage instantaneous value feedback module compares a by feedback modulation _ocan quick adjustment output voltage effective value, make it catch up with given output line voltage effective value v _ref, obtain stable output voltage effective value;

Step 2: the impact suppressing busbar voltage fluctuation to cause output voltage by filter capacitor electric voltage feed forward module:

If directly by filter capacitor voltage V _capas feedforward input, due to quick frequent fluctuation and the load variations of busbar voltage, very easily make the output of subordinate inverter occur concussion, the fluctuation of busbar voltage can be caused simultaneously; First make filter capacitor voltage V for this reason _capthrough DC filtering, obtain feed forward operation input voltage V ' _cap, then by feed forward operation input voltage V ' _capfeedforward modulation ratio a is calculated through formula (3) _dc;

a _dc＝k _dc/V′ _cap(3)

Wherein, k _dcfor feed-forward coefficients, its computing formula is such as formula shown in (4).

$k_{\mathrm{dc}}=V_{\mathrm{ab}}/\frac{\sqrt{6}}{4}---\left(4\right)$

Wherein, V _abit is subordinate inverter output line voltage effective value;

Filter capacitor electric voltage feed forward module is by feedforward modulation ratio a _dcregulation output voltage, makes output voltage not affect by busbar voltage fluctuation: when busbar voltage raises, feedforward modulation ratio a _dcreduce; When busbar voltage reduces, feedforward modulation ratio a _dcincrease, thus make output voltage keep constant;

Step 3: the dynamic responding speed being improved filter capacitor electric voltage feed forward module by bus voltage derivative feed-forward module before diode:

First busbar voltage V before diode is got _dcwith feed forward operation input voltage V ' _capdiffer from, and difference is differentiated, namely ((V ' _cap-V _dc)/T=V _d, wherein T is the sampling period; V _dit is differential feed forward operation input signal; Then, by differential feed forward operation input signal V _ddifferential feedforward modulation ratio a is calculated through formula (5) _d;

a _d＝V _d/k _{dc_d}(5)

Wherein, k _{dc_d}for differential feed-forward coefficients; Before supposing diode, bus scope range of the fluctuation of voltage is (V _min, V _max), corresponding feedforward modulation ratio scope is (a _{dc_min}, a _{dc_max}), the relation linearisation between busbar voltage change and feedforward modulation ratio being changed within the scope of busbar voltage fluctuation, thus, calculate differential feed-forward coefficients, computing formula is as shown in formula (6);

$k_{\mathrm{dc}\_d}=\frac{a_{\mathrm{dc}\_\max }-a_{\mathrm{dc}\_\min }}{V_{\max }-V_{\min }}---\left(6\right)$

Before diode, bus voltage derivative feed-forward module is by differential feedforward modulation ratio a _dthe dynamic response time delay that compensation filter capacitance voltage feed-forward module causes due to filtering algorithm, thus improve feedforward dynamic responding speed;

Step 4: the feedback modulation that bus voltage derivative feed-forward module before output voltage instantaneous value feedback module, filter capacitor electric voltage feed forward module and diode exports respectively is compared a _o, feedforward modulation ratio a _dcwith differential feedforward modulation ratio a _dsummation obtains total modulation ratio a, and total modulation ratio a, through amplitude limit, inputs to SPWM wave producer, generates the PWM ripple that 6 tunnels control inverter bridge IGBT break-make.

Compare with existing, tool of the present invention has the following advantages:

1) due to impact that bus voltage derivative feed-forward module before filter capacitor electric voltage feed forward module and diode can suppress busbar voltage fluctuation to cause output voltage fast and effectively, therefore, the ability of the anti-busbar voltage change of system obviously strengthens, and improves the performance and reliability of subordinate inverter;

2) because output voltage instantaneous value feedback module can follow given output line voltage effective value by quick adjustment output voltage effective value, and segmentation PID can improve the feedback dynamic responding speed of system in this module, therefore, the sinusoidal waveform of subordinate inverter output voltage is stable, harmonic content is low, Ability of Resisting Disturbance is strong, dynamic response is fast;

3) put forward subordinate inverter control system and method simple, be easy to canbe used on line.

Accompanying drawing explanation

Fig. 1 is the main circuit of subway subordinate inverter.

Fig. 2 is the subway subordinate inverter control system block diagram based on the feedforward of MULTIPLE COMPOSITE differential.

Fig. 3 is output voltage instantaneous value feedback module theory diagram.

Fig. 4 is segmentation PID theory diagram

Fig. 5 is filter capacitor electric voltage feed forward module principle block diagram.

Fig. 6 is bus voltage derivative feed-forward module theory diagram before diode.

Fig. 7 is the Matlab/Simulink simulation model of subway subordinate inverter.

Fig. 8 is subordinate inverter three-phase output line voltage waveform.

Fig. 9 is a phase output line voltage effective value waveform.

Figure 10 is subordinate inverter three-phase output current phase waveform.

Figure 11 is a phase output current phase effective value waveform.

Figure 12 is the FFT harmonic analysis result of subordinate inverter one phase output line voltage waveform.

Figure 13 is the dynamic response waveform of subordinate inverter when DC bus-bar voltage fluctuates when not adding differential feedforward.

Figure 14 is the dynamic response waveform of subordinate inverter when DC bus-bar voltage fluctuates when adding differential feedforward.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail.

The present invention is used for a kind of new control system of track traffic subordinate inverter, comprises bus voltage derivative feed-forward module before output voltage instantaneous value feedback module, filter capacitor electric voltage feed forward module and diode; Described output voltage instantaneous value feedback module controls output voltage effective value and stablizes; The response speed specific output voltage effective value feedback of its feedback is fast, and has better steady-state behaviour.Filter capacitor electric voltage feed forward module responds busbar voltage in time and changes the output voltage change caused; But owing to employing DC filtering algorithm in filter capacitor electric voltage feed forward, this makes voltage feedforward control can not reflect the change in voltage trend of DC bus in time, good inhibition can not be played to the big ups and downs on a large scale of busbar voltage, before introducing again diode, bus voltage derivative feedovers for this reason, and before diode, bus voltage derivative feed-forward module employing busbar voltage does the deficiency that differential feedforward makes up filter capacitor electric voltage feed forward module.The bus end of subway subordinate inverter is provided with a reverse blocking diode pipe, its cause filter capacitor voltage and true inlet wire busbar voltage different, therefore before adopting diode, the feedforward of bus voltage derivative effectively can improve the speed of subordinate inverter response busbar voltage change, to ensure the stability of subordinate inverter output voltage.

Below for a 200kVA subway subordinate inverter, design its control system, and give simulation model and simulation result thereof.

The main circuit of 200kVA subway subordinate inverter as shown in Figure 1, when using control system of the present invention to control this subordinate inverter, first need to gather busbar voltage before two-way output line voltage, filter capacitor voltage and diode, as the input signal of control system.As shown in Figure 2, control system comprises bus voltage derivative feed-forward module before output voltage instantaneous value feedback module, filter capacitor electric voltage feed forward module and diode to the control system of design, and each module is output feedack modulation ratio a respectively _o, feedforward modulation ratio a _dcwith differential feedforward modulation ratio a _d, three modulation ratio summations are obtained total modulation ratio a, and total modulation ratio a, through amplitude limit, inputs to SPWM wave producer, generates the PWM ripple SI that 6 tunnels control inverter bridge IGBT break-make ... S6.

The control method of the subway subordinate inverter control system based on the feedforward of MULTIPLE COMPOSITE differential is used to design by step.

Step 1: control output voltage effective value by output voltage instantaneous value feedback module and stablize, the theory diagram of output voltage instantaneous value feedback module as shown in Figure 3, first its 2 road input signal calculates through Park conversion and amplitude by this module, obtains the numerical value v reflecting output line voltage effective value _m; Then by numerical value v _mwith given output line voltage effective value v _refmake comparisons, obtain error voltage v _e; Finally by error voltage v _eobtain feedback modulation through segmentation PID process and compare a _o, wherein the theory diagram of segmentation PID as shown in Figure 4, namely according to error voltage v _esize, use different PI parameters, to improve the dynamic responding speed of system;

Step 2: the impact suppressing busbar voltage fluctuation to cause output voltage by filter capacitor electric voltage feed forward module, as shown in Figure 5, this module is first by its input signal filter capacitor voltage V for the theory diagram of filter capacitor electric voltage feed forward module _capthrough DC filtering, obtain feed forward operation input voltage V ' _cap; Then feed-forward coefficients k is used _dcdivided by V ' _cap, obtain the modulation ratio a that feedovers _dc;

Step 3: the dynamic responding speed being improved filter capacitor electric voltage feed forward module by bus voltage derivative feed-forward module before diode, before diode, the theory diagram of bus voltage derivative feed-forward module as shown in Figure 6, and this module is first by busbar voltage V before diode _dcwith feed forward operation input voltage V ' _capdiffer from, and differentiate to difference, obtaining is differential feed forward operation input signal V _d; Then V is used _ddivided by differential feed-forward coefficients k _{dc_d}, obtain differential feedforward modulation ratio a _d;

Step 4: the output feedack modulation ratio a that first three step is obtained respectively _o, feedforward modulation ratio a _dcwith differential feedforward modulation ratio a _dbe added, and input to SPWM modulating wave maker, obtain the PWM ripple that 6 tunnels control inverter bridge IGBT break-make.

The simulation model that Matlab/Simulink simulation software is built as shown in Figure 7, use the design parameter of subordinate inverter as shown in table 1.Control system is built according to design procedure introduced above, its key is PI parameter designing in feedback module, feed-forward coefficients calculates and differential feed-forward coefficients calculates, PI parameter is adjusted according to system, can feed-forward coefficients be calculated according to formula (4), differential feed-forward coefficients can be calculated according to formula (6).

Table 1

Static Simulation result is as shown in Fig. 8, Fig. 9, Figure 10, Figure 11 and Figure 12.Fig. 8 is subordinate inverter three-phase output line voltage waveform, Fig. 9 is a wherein phase output line voltage effective value waveform, from Fig. 8 and Fig. 9, subordinate inverter steady state output voltage waveform stabilization, stable state output line voltage steady-state value meets specified AC380 (1 ± 5%) V.Figure 10 is subordinate inverter three-phase output current phase waveform, and Figure 11 is a wherein phase output current phase effective value waveform, from Figure 10 and Figure 11, and subordinate inverter astable output electrical current waveform stabilization.Figure 12 is the FFT harmonic analysis result of subordinate inverter one phase output line voltage waveform, and as shown in Figure 12, harmonic wave of output voltage content is low, only has 1.25%.

As shown in Figure 13 and Figure 14, feedover in two kinds of situations to not adding differential feedforward and adding differential, the dynamic response of subordinate inverter when DC bus-bar voltage changes contrasts Dynamic Simulation Results.When not adding differential feedforward, as shown in figure 13, output line voltage effective value momentary fluctuation maximum off-rating 16.3%; When adding differential feedforward, as shown in figure 14, output line voltage effective value momentary fluctuation maximum off-rating 7%.Visible, before differential, energy regenerative significantly improves the ability of subordinate inverter anti-busbar voltage change, ensures output voltage stabilization, reliable.

Claims (2)

1. for a kind of new control system of track traffic subordinate inverter, it is characterized in that: comprise bus voltage derivative feed-forward module before output voltage instantaneous value feedback module, filter capacitor electric voltage feed forward module and diode; Described output voltage instantaneous value feedback module controls output voltage effective value and stablizes; Filter capacitor electric voltage feed forward module responds busbar voltage in time and changes the output voltage change caused; Before diode, bus voltage derivative feed-forward module employing busbar voltage does the deficiency that differential feedforward makes up filter capacitor electric voltage feed forward module.

2. described in claim 1 for the control method of a kind of new control system of track traffic subordinate inverter, it is characterized in that: comprise the steps:

Step 1: control output voltage effective value by output voltage instantaneous value feedback module and stablize:

First, using any 2 tunnel subordinate inverter output line voltages as the input signal of output voltage instantaneous value feedback module, calculated through Park conversion and amplitude by input signal, the numerical value reflection output line voltage effective value obtained, computing formula is such as formula shown in (1) and formula (2);

$\left[\begin{array}{c}{v}_{\mathrm{\α}}\\ v_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{cc}1& 0\\ \frac{1}{\sqrt{3}}& \frac{2}{\sqrt{3}}\end{array}\right]\left[\begin{array}{c}{v}_a\\ v_b\end{array}\right]---\left(1\right)$

$v_m=\sqrt{v_{\mathrm{\α}}^2+v_{\mathrm{\β}}^2}---\left(2\right)$

Wherein, v _aand v _bit is two-way subordinate inverter output line voltage; v _aand v _bthe component of three-phase output line voltage in two-phase rest frame; v _mit is output line voltage effective value;

Then, the output line voltage effective value v will obtained _mwith given output line voltage effective value v _refmake comparisons, i.e. v _e=v _ref-v _m, wherein v _efor error voltage;

Finally, by error voltage v _eobtain feedback modulation through segmentation PID adjustment and compare a _o, segmentation PID is namely according to error voltage v _esize, use different PI parameters: work as v _ebe greater than setting comparative voltage v _btime, use the PI parameter that P is larger; Work as v _ebe less than setting comparative voltage v _etime, use the PI parameter that P is less, use segmentation PID can improve the feedback dynamic responding speed of system;

Output voltage instantaneous value feedback module compares a by feedback modulation _ocan quick adjustment output voltage effective value, make it catch up with given output line voltage effective value v _ref, obtain stable output voltage effective value;

Step 2: the impact suppressing busbar voltage fluctuation to cause output voltage by filter capacitor electric voltage feed forward module:

If directly by filter capacitor voltage V _capas feedforward input, due to quick frequent fluctuation and the load variations of busbar voltage, very easily make the output of subordinate inverter occur concussion, the fluctuation of busbar voltage can be caused simultaneously; First make filter capacitor voltage V for this reason _capthrough DC filtering, obtain feed forward operation input voltage V ' _cap, then by feed forward operation input voltage V ' _capfeedforward modulation ratio a is calculated through formula (3) _dc;

a _dc＝k _dc/V′ _cap(3)

Wherein, k _dcfor feed-forward coefficients, its computing formula is such as formula shown in (4).

$k_{\mathrm{dc}}=V_{\mathrm{ab}}/\frac{\sqrt{6}}{4}---\left(4\right)$

Wherein, V _abit is subordinate inverter output line voltage effective value;

Filter capacitor electric voltage feed forward module is by feedforward modulation ratio a _dcregulation output voltage, makes output voltage not affect by busbar voltage fluctuation: when busbar voltage raises, feedforward modulation ratio a _dcreduce; When busbar voltage reduces, feedforward modulation ratio a _dcincrease, thus make output voltage keep constant;

Step 3: the dynamic responding speed being improved filter capacitor electric voltage feed forward module by bus voltage derivative feed-forward module before diode:

First busbar voltage V before diode is got _dcwith feed forward operation input voltage V ' _capdiffer from, and difference is differentiated, namely ((V ' _cap-V _dc)/T=V _d, wherein T is the sampling period; V _dit is differential feed forward operation input signal; Then, by differential feed forward operation input signal V _ddifferential feedforward modulation ratio a is calculated through formula (5) _d;

a _d＝V _d/k _{dc_d}(5)

Wherein, k _{dc_d}for differential feed-forward coefficients; Before supposing diode, bus scope range of the fluctuation of voltage is (V _min, V _max), corresponding feedforward modulation ratio scope is (a _{dc_min}, a _{dc_max}), the relation linearisation between busbar voltage change and feedforward modulation ratio being changed within the scope of busbar voltage fluctuation, thus, calculate differential feed-forward coefficients, computing formula is as shown in formula (6);

$k_{\mathrm{dc}\_d}=\frac{a_{\mathrm{dc}\_\max }-a_{\mathrm{dc}\_\min }}{V_{\max }-V_{\min }}---\left(6\right)$

Before diode, bus voltage derivative feed-forward module is by differential feedforward modulation ratio a _dthe dynamic response time delay that compensation filter capacitance voltage feed-forward module causes due to filtering algorithm, thus improve feedforward dynamic responding speed;

Step 4: the feedback modulation that bus voltage derivative feed-forward module before output voltage instantaneous value feedback module, filter capacitor electric voltage feed forward module and diode exports respectively is compared a _o, feedforward modulation ratio a _dcwith differential feedforward modulation ratio a _dsummation obtains total modulation ratio a, and total modulation ratio a, through amplitude limit, inputs to SPWM wave producer, generates the PWM ripple that 6 tunnels control inverter bridge IGBT break-make.