CN106230081A - The harmonic detecting of a kind of charging pile and filtering method - Google Patents

Abstract

The invention discloses harmonic detecting and the filtering method of a kind of charging pile, pass through the method, solve the problem that current electric automobile charging pile side harmonics comparision contents is big, and the fundamental reactive current in load current, negative-sequence current, zero-sequence current and harmonic current can be filtered, leave behind fundamental positive sequence real component, it is to avoid the impact of zero sequence lobe error.

Description

The harmonic detecting of a kind of charging pile and filtering method

Art

The present invention relates to harmonic detecting and the filtering method of a kind of charging pile.

Background technology

Along with the continuous intensification of global energy crisis, on increasingly exhausted and atmospheric pollution, the Global Temperature of petroleum resources The harm aggravation risen, energy-conservation and reduction of discharging is the main direction of future automobile technology development.Toyota Company of Japan takes the lead in developing mixed Close power vehicle Prius, open the epoch prelude of electric automobile.Electric automobile is as the vehicles of a new generation, energy-conservation Reduce discharging, the minimizing mankind possess, to the relying party face of traditional fossil energy, the advantage that orthodox car is incomparable.Since 2009, in Government of state is intensive to have put into effect and has encouraged electric automobile and the policies and measures of relevant industries development, and enterprise is to the research and development of electric automobile and product Industryization puts into and is obviously enhanced.

When electric automobile rechargeable battery energy resource consumption to a certain extent time, it is necessary to use energy resource supply device to this battery Being charged, to ensure that electric automobile is reused, reach the purpose of " replacing oil by electricity ", therefore energy resource supply device is to electronic vapour Promoting the use of of car has irreplaceable effect.Energy resource supply device mainly has two kinds of forms, and one is direct-current charging post, should Charging pile power is relatively big, about 100kW, and the charging interval is short, and volume ratio is relatively big, is therefore typically mounted at fixing place；Another Planting is alternating-current charging pile, directly utilizes AC network, output AC electric energy, and the vehicle-mounted charge stake carried by electric automobile will be handed over It is that rechargeable battery is charged that stream electric energy is converted to direct current energy.This kind of charged form power is less, and generally about 10kW fills The electricity time is long, and volume is little, and each corner that therefore can make full use of city is that electric automobile is charged.

The charging pile and the load carried that use due to charging pile are non-linear equipments, the most operationally can give electrical network The quality of power supply brings deleterious effect, is mainly reflected in power factor of electric network and declines and bring the aspects such as harmonic pollution to electrical network. The harm that wherein electrical network is caused by harmonic pollution mainly has the following aspects: voltage that harmonic current causes and heat condition meeting The service life causing power factor correction capacitor shortens；Owing to mechanical vibration can be by fundamental frequency magnetic field and harmonic current Impact, when mechanical resonant frequency and electric excitation frequency are equal, it may occur that resonance thus produce bigger mechanical stress, broken Bad equipment；Harmonic wave can cause system to the some error in judgement that voltage zero-cross and voltage are zero；Harmonic current can cause transformer fe Damage and the increase of copper loss；Electronic equipment and relay protection are produced interference；Harmonic current can cause equipment malfunction to be made, may in Disconnected production and operation.

Summary of the invention

For solving the problems referred to above, the present invention provides harmonic detecting and the filtering method of a kind of charging pile, with it, solve The problem that current electric automobile charging pile side harmonics comparision contents of having determined is big, and the fundamental wave reactive power in load current can be filtered Electric current, negative-sequence current, zero-sequence current and harmonic current, leave behind fundamental positive sequence real component, it is to avoid zero sequence lobe error Impact.

To achieve these goals, the present invention provides harmonic detecting and the filtering method of a kind of charging pile, and the method includes Following steps:

Detect System Reactive Power and the harmonic wave size of current of charging pile system the most in real time；

S2. according to the System Reactive Power detected and harmonic wave size of current, reactive-load dynamic compensation and harmonic filtration are carried out in real time；

In S1, the detection of harmonic current concretely comprises the following steps:

S11. by load current i_a、i_b、i_cResolve into first-harmonic i_a1、i_b1、i_c1With harmonic wave i_ak、i_bk、i_ckSum；

S12. in view of three-phase imbalance, by current first harmonics electric current i_a1、i_b1、i_c1It is divided into positive sequence, zero sequence and negative sequence component, Then harmonic current i_ak、i_bk、i_ckPositive sequence, zero sequence and negative sequence component can also be decomposed into；

S13. three-phase instantaneous powerDecomposition result above-mentioned steps obtained substitutes into this formula, can obtain:

Middle I₁₊、I_1-It is respectively fundamental positive sequence and negative sequence component, I_k+、I_k-It is respectively k subharmonic positive sequence and negative sequence component, θ_1-It is the initial phase of first-harmonic negative phase-sequence, θ_k+、θ_k-It is k subharmonic positive sequence and the initial phase of negative phase-sequence respectively.Above formula harmonic frequency is Low up to 100Hz, through low pass filter (LFP), then the harmonic component in three-phase instantaneous power just can filter off completely, the most remaining Steady-state valueSuch that it is able to the fundamental reactive current obtaining having filtered in load current, negative-sequence current, zero Sequence electric current and harmonic current, leave behind fundamental positive sequence real component, it is to avoid the impact of zero sequence lobe error.

Preferably, if in view of the situation of three-phase imbalance, then load-side fundamental current can be decomposed into positive sequence, negative phase-sequence With zero-sequence component i_a1、i_b1、i_c1, then harmonic current can also be decomposed into positive sequence, negative phase-sequence and zero-sequence component i_ak、i_bk、i_ck, wherein

Three-phase instantaneous power p isThe component of above-mentioned decomposition is substituted into this respectively Formula, can obtain；

$\begin{array}{c}{p}_k=e_a{i}_{ak}+e_b{i}_{bk}+e_c{i}_{ck}\\ =\frac{3}{2}{E}_{`m}{I}_{k+}\cos \left(\right(k-1)\mathrm{\ω}t+{\mathrm{\θ}}_{k+})-\frac{3}{2}{E}_m{I}_{k-}\cos \left(\right(k+1)\mathrm{\ω}t+{\mathrm{\θ}}_{k-)}\end{array}$

Wherein I₁₊、I_1-、I₁₀It is respectively fundamental positive sequence and negative sequence component, I_k+、I_k-、I_k0Be respectively k subharmonic positive sequence and Negative sequence component, θ_1-It is the initial phase of first-harmonic negative phase-sequence, θ_k+、θ_k-It is k subharmonic positive sequence and the initial phase of negative phase-sequence respectively,Merit Rate factor angle.

Preferably, in step s 2, the following reactive-load dynamic compensation method of concrete employing realizes reactive-load dynamic compensation and harmonic wave Filter:

S21. System Reactive Power and harmonic wave size of current detected by harmonic detecting module, as command signal, become with PWM The output electric current of stream device compares, and error size obtains one group of PWM ripple compared with the ring width of hysteresis comparator；

S22.PWM ripple is sent to the end that controls of power device and controls the switch of power device, follows idle and harmonic current；

S23.PWM current transformer will be with idle and harmonic wave size of current is equal, and electric current in opposite direction is injected into power distribution network side, Cancel out each other with the idle and harmonic current comprised in power distribution network side, thus it is idle and harmonic current to reach to eliminate power distribution network side Purpose.

Present invention have the advantage that (1) charging pile exports with firm power, start and stop and then control by charging pile are single Charging electric vehicle quantity in bit time, and make charger always work in energy conversion high efficient area, improve electric automobile The integral energy utilization rate of charging；(2) by this system, current electric automobile charging pile side harmonics comparision contents is solved big Problem, and the fundamental reactive current in load current, negative-sequence current, zero-sequence current and harmonic current can be filtered, leave behind Fundamental positive sequence real component, it is to avoid the impact of zero sequence lobe error.

Accompanying drawing explanation

Fig. 1 shows the block diagram of a kind of charging pile system detecting and filtering harmonic wave of the present invention；

Fig. 2 shows the flow chart of a kind of monitoring method of charging pile detecting and filtering harmonic wave.

Detailed description of the invention

Fig. 1 shows the block diagram of a kind of charging pile system 10 detecting and filtering harmonic wave, and this system 10 includes:

Harmonic detecting module 11, for acrobatic skill and the harmonic wave size of current of detection charging pile system in real time；

Multiple charging piles 12, for being charged the set of cells of multiple electric automobiles, the plurality of charging pile all includes AC/DC modular converter；

Active Power Filter-APF 13, carries out harmonic filtration, improves charging pile system 10 in real time to charging pile system 10 The power factor (PF) run；

Control module 14, for controlling 10 operations of charging pile system, including controlling above-mentioned each charging pile to set of cells Charge power, control Active Power Filter-APF charging pile system is carried out harmonic filtration.

Described Active Power Filter-APF 13 includes: inductance one L1, inductance two L2, nonlinear load W, PWM converter S, electricity Hold C, power distribution network respectively with inductance one L1, inductance two L2, the other end of inductance one L1 is connected to nonlinear load W, inductance two L2 The other end connect PWM converter S, PWM converter S is parallel with electric capacity C, and incoming end and the electric capacity C of power distribution network are adopted by voltage Sample A/D module 1 is connected respectively to instruction current input arithmetical unit and PWM generator input, and voltage is passed through at the two ends of electric capacity C Sampling A/D module and pi regulator are connected to instruction current input arithmetical unit, and the input of inductance one L1 connects current sample A/D module is connected to instruction current input arithmetical unit, and the input of PWM converter S is connected to by current sample A/D module Instruction current outfan arithmetical unit, instruction current outfan arithmetical unit is connected to PWM generator input.

Described harmonic detecting module 11 detects the harmonic component in charging pile system 10 in the following way:

By load current i_a、i_b、i_cResolve into first-harmonic i_a1、i_b1、i_c1With harmonic wave i_ak、i_bk、i_ckSum；

In view of three-phase imbalance, by current first harmonics electric current i_a1、i_b1、i_c1It is divided into positive sequence, zero sequence and negative sequence component, the most humorous Ripple electric current i_ak、i_bk、i_ckPositive sequence, zero sequence and negative sequence component can also be decomposed into；

Three-phase instantaneous powerDecomposition result above-mentioned steps obtained substitutes into this formula, can obtain:

Wherein I₁₊、I_1-It is respectively fundamental positive sequence and negative sequence component, I_k+、I_k-It is respectively k subharmonic positive sequence and negative phase-sequence is divided Amount, θ_1-It is the initial phase of first-harmonic negative phase-sequence, θ_k+、θ_k-It is k subharmonic positive sequence and the initial phase of negative phase-sequence respectively.Above formula harmonic wave frequency Rate is minimum, and up to 100Hz, through low pass filter (LFP), then the harmonic component in three-phase instantaneous power just can filter off completely, only Remaining steady-state valueSuch that it is able to the fundamental reactive current obtaining having filtered in load current, negative-sequence current, Zero-sequence current and harmonic current, leave behind fundamental positive sequence real component, it is to avoid the impact of zero sequence lobe error.

Described Active Power Filter-APF 13 harmonic carcellation in the following way:

System Reactive Power and harmonic wave size of current is detected, as command signal, with PWM unsteady flow by harmonic detecting module 11 The output electric current of device compares, and error size obtains one group of PWM ripple compared with the ring width of hysteresis comparator；

PWM ripple is sent to the end that controls of power device and controls the switch of power device, follows idle and harmonic current；

PWM converter will be with idle and harmonic wave size of current is equal, and electric current in opposite direction is injected into power distribution network side, and joins Idle and the harmonic current comprised in grid side is cancelled out each other, thus reaches to eliminate the idle mesh with harmonic current in power distribution network side 's.

Described control module 14 includes the equilibrium that controller and the charging pile corresponding with each Rechargeable vehicle set of cells are connected Device, described controller sends instruction according to the charge information of each set of cells to each equalizer, and each equalizer controls according to instruction With each charging pile charge power to each Rechargeable vehicle set of cells.

Preferably, described controller includes: time period division unit, electric automobile always charge load determination unit, vehicle Charging probability constant determines unit, random number generation unit and charging control unit, wherein:

Time period division unit is divided into J stage charge period scope T；

The electric automobile load determination unit that always charges determines that all electric automobiles load that always charges is:

$\begin{array}{c}{P}_{all}=\underset{j=1}{\overset{J}{\mathrm{\Σ}}}\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{P}_{EVi}\left(j\right)=\underset{j=1}{\overset{J}{\mathrm{\Σ}}}\underset{i=1}{\overset{M}{\mathrm{\Σ}}}\frac{\mathrm{\φ}-P_{base}\left(j\right)}{\underset{j=1}{\overset{J}{\mathrm{\Σ}}}(\mathrm{\φ}-P_{base}(j\left)\right)}\×C_i\\ =\underset{i=1}{\overset{M}{\mathrm{\Σ}}}\frac{\underset{j=1}{\overset{J}{\mathrm{\Σ}}}(\mathrm{\φ}-P_{base}(j\left)\right)}{\underset{j=1}{\overset{J}{\mathrm{\Σ}}}(\mathrm{\φ}-P_{base}(j\left)\right)}\×C_i=\underset{i=1}{\overset{M}{\mathrm{\Σ}}}{C}_i\end{array},$

WhereinExpect with charging electric vehicle load average for power distribution network conventional load, P_baseConventional for regional distribution network Load curve, P_EViJ () is i-th car charge power in the jth stage, C_iBeing the charge requirement of i-th car, M is electronic vapour Car sum；

According to all electric automobiles load that always charges, Vehicular charging probability constant determines that the charging of each electric automobile is average Power, determines any Vehicular charging probability constant according to average charge power；

Random number generation unit produces uniform random number,

Charging control unit determines arbitrarily with the magnitude relationship of any Vehicular charging probability constant Yu random number generation unit Charging electric vehicle power in the unit charging interval.

Fig. 2 shows harmonic detecting and the filtering method of a kind of charging pile, and the method comprises the steps:

Detect System Reactive Power and the harmonic wave size of current of charging pile system the most in real time；

S2. according to the System Reactive Power detected and harmonic wave size of current, reactive-load dynamic compensation and harmonic filtration are carried out in real time；

In S1, the detection of harmonic current concretely comprises the following steps:

S11. by load current i_a、i_b、i_cResolve into first-harmonic i_a1、i_b1、i_c1With harmonic wave i_ak、i_bk、i_ckSum；

S12. in view of three-phase imbalance, by current first harmonics electric current i_a1、i_b1、i_c1It is divided into positive sequence, zero sequence and negative sequence component, Then harmonic current i_ak、i_bk、i_ckPositive sequence, zero sequence and negative sequence component can also be decomposed into；

S13. three-phase instantaneous powerDecomposition result above-mentioned steps obtained substitutes into this formula, can obtain:

Middle I₁₊、I_1-It is respectively fundamental positive sequence and negative sequence component, I_k+、I_k-It is respectively k subharmonic positive sequence and negative sequence component, θ_1-It is the initial phase of first-harmonic negative phase-sequence, θ_k+、θ_k-It is k subharmonic positive sequence and the initial phase of negative phase-sequence respectively.Above formula harmonic frequency is Low up to 100Hz, through low pass filter (LFP), then the harmonic component in three-phase instantaneous power just can filter off completely, the most remaining Steady-state valueSuch that it is able to the fundamental reactive current obtaining having filtered in load current, negative-sequence current, zero Sequence electric current and harmonic current, leave behind fundamental positive sequence real component, it is to avoid the impact of zero sequence lobe error.

Preferably, if in view of the situation of three-phase imbalance, then load-side fundamental current can be decomposed into positive sequence, negative phase-sequence With zero-sequence component i_a1、i_b1、i_c1, then harmonic current can also be decomposed into positive sequence, negative phase-sequence and zero-sequence component i_ak、i_bk、i_ck, wherein

Three-phase instantaneous power p isThe component of above-mentioned decomposition is substituted into this respectively Formula, can obtain；

$\begin{array}{c}{p}_k=e_a{i}_{ak}+e_b{i}_{bk}+e_c{i}_{ck}\\ =\frac{3}{2}{E}_{`m}{I}_{k+}\cos \left(\right(k-1)\mathrm{\ω}t+{\mathrm{\θ}}_{k+})-\frac{3}{2}{E}_m{I}_{k-}\cos \left(\right(k+1)\mathrm{\ω}t+{\mathrm{\θ}}_{k-)}\end{array}$

Wherein I₁₊、I_1-、I₁₀It is respectively fundamental positive sequence and negative sequence component, I_k+、I_k-、I_k0Be respectively k subharmonic positive sequence and Negative sequence component, θ_1-It is the initial phase of first-harmonic negative phase-sequence, θ_k+、θ_k-It is k subharmonic positive sequence and the initial phase of negative phase-sequence respectively, Power-factor angle.

Preferably, in step s 2, the following reactive-load dynamic compensation method of concrete employing realizes reactive-load dynamic compensation and harmonic wave Filter:

S21. System Reactive Power and harmonic wave size of current detected by harmonic detecting module, as command signal, become with PWM The output electric current of stream device compares, and error size obtains one group of PWM ripple compared with the ring width of hysteresis comparator；

S22.PWM ripple is sent to the end that controls of power device and controls the switch of power device, follows idle and harmonic current；

S23.PWM current transformer will be with idle and harmonic wave size of current is equal, and electric current in opposite direction is injected into power distribution network side, Cancel out each other with the idle and harmonic current comprised in power distribution network side, thus it is idle and harmonic current to reach to eliminate power distribution network side Purpose.

Above content is to combine concrete preferred implementation further description made for the present invention, it is impossible to assert Being embodied as of the present invention is confined to these explanations.For general technical staff of the technical field of the invention, On the premise of present inventive concept, make some equivalents and substitute or obvious modification, and performance or purposes are identical, all should It is considered as belonging to protection scope of the present invention.

Claims (3)

1. the harmonic detecting of charging pile and a filtering method, the method comprises the steps:

Detect System Reactive Power and the harmonic wave size of current of charging pile system the most in real time；

S2. according to the System Reactive Power detected and harmonic wave size of current, reactive-load dynamic compensation and harmonic filtration are carried out in real time；

In S1, the detection of harmonic current concretely comprises the following steps:

S11. by load current i_a、i_b、i_cResolve into first-harmonic i_a1、i_b1、i_c1With harmonic wave i_ak、i_bk、i_ckSum；

S12. in view of three-phase imbalance, by current first harmonics electric current i_a1、i_b1、i_c1It is divided into positive sequence, zero sequence and negative sequence component, the most humorous Ripple electric current i_ak、i_bk、i_ckPositive sequence, zero sequence and negative sequence component can also be decomposed into；

S13. three-phase instantaneous powerDecomposition result above-mentioned steps obtained substitutes into this formula, can obtain:

Middle I₁₊、I_1-It is respectively fundamental positive sequence and negative sequence component, I_k+、I_k-It is respectively k subharmonic positive sequence and negative sequence component, θ_1-It is The initial phase of first-harmonic negative phase-sequence, θ_k+、θ_k-It is k subharmonic positive sequence and the initial phase of negative phase-sequence respectively.Above formula harmonic frequency is minimum can Reaching 100Hz, through low pass filter (LFP), then the harmonic component in three-phase instantaneous power just can filter off completely, the most remaining stable state ValueSuch that it is able to the fundamental reactive current obtaining having filtered in load current, negative-sequence current, zero sequence electricity Stream and harmonic current, leave behind fundamental positive sequence real component, it is to avoid the impact of zero sequence lobe error.

2. the method for claim 1, it is characterised in that if in view of the situation of three-phase imbalance, then can will load Side fundamental current is decomposed into positive sequence, negative phase-sequence and zero-sequence component i_a1、i_b1、i_c1, then harmonic current can also be decomposed into positive sequence, negative phase-sequence With zero-sequence component i_ak、i_bk、i_ck, wherein

Three-phase instantaneous power p isThe component of above-mentioned decomposition is substituted into this formula respectively, can ?；

$\begin{array}{c}{p}_k=e_a{i}_{ak}+e_b{i}_{bk}+e_c{i}_{ck}\\ =\frac{3}{2}{E}_{`m}{I}_{k+}cos\left(\right(k-1)\mathrm{\ω}t+{\mathrm{\θ}}_{k+})-\frac{3}{2}{E}_m{I}_{k-}\cos \left(\right(k+1)\mathrm{\ω}t+{\mathrm{\θ}}_{k-)}\end{array}$

Wherein I₁₊、I_1-、I₁₀It is respectively fundamental positive sequence and negative sequence component, I_k+、I_k-、I_k0It is respectively k subharmonic positive sequence and negative phase-sequence Component, θ_1-It is the initial phase of first-harmonic negative phase-sequence, θ_k+、θ_k-It is k subharmonic positive sequence and the initial phase of negative phase-sequence respectively,Power because of Number angle.

3. the method for claim 1, it is characterised in that in step s 2, the following reactive-load dynamic compensation side of concrete employing Method realizes reactive-load dynamic compensation and harmonic filtration:

S21. System Reactive Power and harmonic wave size of current are detected by harmonic detecting module, as command signal, with PWM converter Output electric current compare, error size obtains one group of PWM ripple compared with the ring width of hysteresis comparator；

S22.PWM ripple is sent to the end that controls of power device and controls the switch of power device, follows idle and harmonic current；

S23.PWM current transformer will be with idle and harmonic wave size of current is equal, and electric current in opposite direction is injected into power distribution network side, and joins Idle and the harmonic current comprised in grid side is cancelled out each other, thus reaches to eliminate the idle mesh with harmonic current in power distribution network side 's.