阅读说明：本技术 一种电力电子变压器能量流辨识方法、系统及设备 (A kind of electric power electric transformer energy stream discrimination method, system and equipment ) 是由 尚敬 苏亮亮 张志学 刘华东 黄子昊 陈涛 罗文广 彭赟 黄超 孙璐 王跃 于 2018-05-25 设计创作，主要内容包括：本发明公开了一种电力电子变压器能量流辨识方法,包括：获得中间环节的直流电压和直流电流；将直流电压与直流电流的乘积确定为能量流稳态量；根据直流电压的一次变化率和二次变化率、直流电流的一次变化率和二次变化率以及电力电子变压器的主电路参数确定能量流波动量；将能量流稳态量和能量流波动量的叠加量确定为目标能量流。应用本发明所提供的方法,能够准确地辨识出通过PET的能量流,提高供电系统的稳定性。本发明还提供了一种电力电子变压器能量流辨识系统及设备,具有相应技术效果。(The invention discloses a kind of electric power electric transformer energy stream discrimination methods, comprising: obtains the DC voltage and DC current of intermediate link；The product of DC voltage and DC current is determined as energy stream steady-state quantity；Energy stream undulate quantity is determined according to the main circuit parameter of the one-shot change rate of DC voltage and secondary change rate, the one-shot change rate of DC current and secondary change rate and electric power electric transformer；The superposition amount of energy stream steady-state quantity and energy stream undulate quantity is determined as target energy stream.Using method provided by the present invention, the energy stream by PET can be accurately picked out, the stability of power supply system is improved.The present invention also provides a kind of electric power electric transformer energy stream identification system and equipment, have relevant art effect.)

1. a kind of electric power electric transformer energy stream discrimination method characterized by comprising

Obtain the DC voltage and DC current of intermediate link；

The product of the DC voltage and the DC current is determined as energy stream steady-state quantity；

According to the one-shot change rate of the DC voltage and secondary change rate, the one-shot change rate of the DC current and secondary change The main circuit parameter of rate and electric power electric transformer determines energy stream undulate quantity；

The superposition amount of the energy stream steady-state quantity and the energy stream undulate quantity is determined as target energy stream.

2. electric power electric transformer energy stream discrimination method according to claim 1, which is characterized in that further include:

When the DC voltage is higher than preset first threshold, and the one-shot change rate of the DC voltage is timing, will be described The control mode of intermediate link is switched to reversely by forward direction；

It, will be described when the DC voltage is lower than preset second threshold, and the one-shot change rate of the DC voltage is negative The control mode of intermediate link is by being reversely switched to forward direction；

Wherein, the second threshold is lower than the first threshold, when energy supplies power to subordinate load by main power grid, the centre The control mode of link is forward direction, otherwise the control mode of the intermediate link is reversed.

3. electric power electric transformer energy stream discrimination method according to claim 2, which is characterized in that pass through following steps Determine the second threshold:

Judge the energy stream undulate quantity when whether the number of transitions of target time section is higher than preset frequency threshold value；

If it is, the first numerical value is determined as the second threshold, otherwise, second value is determined as the second threshold, Wherein, first numerical value is less than the second value.

4. electric power electric transformer energy stream discrimination method according to claim 1, which is characterized in that among the acquisition The DC voltage and DC current of link, comprising:

Load information obtains the DC voltage and DC current of intermediate link based on the received.

5. electric power electric transformer energy stream discrimination method according to claim 2, which is characterized in that further include:

When the DC voltage is higher than the preset first threshold, and duration exceeds target duration, output prompt letter Breath.

6. electric power electric transformer energy stream discrimination method according to claim 1, which is characterized in that described according to The one-shot change rate and secondary change rate of DC voltage, the one-shot change rate of the DC current and secondary change rate and electric power The main circuit parameter of electronic transformer determines energy stream undulate quantity, comprising:

According to the one-shot change rate of the DC voltage and secondary change rate, the one-shot change rate of the DC current and secondary change The main circuit parameter of rate and electric power electric transformer determines the phase voltage and phase of the exchange side of electric power electric transformer Electric current, and determine using the phase voltage and the phase current as the voltage side of the circuit under three phase coordinate systems of parameter Journey；

Determine the table after the voltage equation carries out rotating coordinate transformation and carries out discretization to Euler's formula after Up to formula；

It is determined by the expression formula after rating formula and the backward Euler's formula progress discretization in rotational coordinates Active power fluctuation amount and reactive power fluctuation amount under system；

By under the rotating coordinate system active power fluctuation amount and reactive power fluctuation amount be converted under three phase coordinate systems Active power fluctuation amount and reactive power fluctuation amount are simultaneously superimposed, as the energy stream undulate quantity determined.

7. electric power electric transformer energy stream discrimination method according to any one of claims 1 to 6, which is characterized in that In The superposition amount by the energy stream steady-state quantity and the energy stream undulate quantity is determined as after target energy stream, further includes:

According to the target energy stream calculation object feedforward component；

The object feedforward component is input to prime rectifier.

8. a kind of electric power electric transformer energy stream identification system characterized by comprising

DC quantity obtains module, for obtaining the DC voltage and DC current of intermediate link；

Steady-state quantity determining module, for the product of the DC voltage and the DC current to be determined as energy stream steady-state quantity；

Undulate quantity determining module, for according to the one-shot change rate and secondary change rate of the DC voltage, the DC current One-shot change rate and the main circuit parameter of secondary change rate and electric power electric transformer determine energy stream undulate quantity；

Aim parameter determining module, for the superposition amount of the energy stream steady-state quantity and the energy stream undulate quantity to be determined as target Energy stream.

9. electric power electric transformer energy stream identification system according to claim 8, which is characterized in that further include:

First switching module, for being higher than preset first threshold, and the primary change of the DC voltage when the DC voltage Rate is timing, and the control mode of the intermediate link is switched to reversely by forward direction；

Second switching module, for being lower than preset second threshold, and the primary change of the DC voltage when the DC voltage When rate is negative, by the control mode of the intermediate link by being reversely switched to forward direction；

Wherein, the second threshold is lower than the first threshold, when energy supplies power to subordinate load by main power grid, the centre The control mode of link is forward direction, otherwise the control mode of the intermediate link is reversed.

10. a kind of electric power electric transformer energy stream identification apparatus characterized by comprising

Memory is used for storage energy stream identification program；

Processor, for executing the energy stream identification program to realize any one of claim 1 to 7 power electronics transformation The step of device energy stream discrimination method.

Technical field

The present invention relates to power electronics and transformation of electrical energy technical fields, more particularly to a kind of electric power electric transformer energy Flow discrimination method, system and equipment.

Background technique

Energy router is a kind of multidirectional flowing of achievable energy and can be to energy stream as open energy carrier The equipment for carrying out active control has the various functions such as each port electrical amount of transformation, real-time control and acquisition electric network data. PET (Power electronic transformer, electric power electric transformer) have electrical isolation, power active control and The functions such as the AC and DC interface of multi-voltage grade are provided, energy router is can be used as and comes using to cope with the multidirectional flowing of electric energy Development trend.Such as in Fig. 1, using PET as the transfer of energy flow between power distribution network, AC microgrids and direct-current micro-grid It stands.

In the prior art, the working condition that PET is determined by detecting energy stream, when energy stream recognize it is unpunctual, The stability of system may be will affect, such as cause the links of PET that can not timely and accurately carry out state switching, lead to energy Amount is accumulated in intermediate link, and then is caused the over-voltage of intermediate link and led to power supply system failure, and therefore, energy stream is accurately distinguished Know particularly significant.Energy stream, that is, power flow is influenced by the load variation in circuit, such as increases an electricity consumption device in load newly, Energy stream just changes correspondingly.The DC-DC of the forward and reverse control of realization energy stream in intermediate link, that is, PET described in this application Link.Such as be illustrated with common three-phase PET construction, Fig. 2 is seen, three-phase PET is prime cascade connection type PET.Prime It is in series by the n H bridge inputted to rectify link, referred to as AC-DC link, intermediate link by high frequency transformer two sides 2n H Bridge and itself composition, referred to as the part DC-DC, output stage can carry out DC-AC transformation as needed, be not shown in Fig. 2, such as Output stage can also be made of the inverter that n H bridge forms.

When carrying out the detection of energy stream, the product of the voltage and current of intermediate link is usually determined as energy stream, Such as corresponding data are obtained by low-voltage direct bus rod in Fig. 2.Since the variation of voltage or electric current needs certain prolong When, so that the variation is not that can embody from size of current or voltage swing at once, yet when energy stream variation It is to say, is inaccurate according to the energy stream that the product of the voltage and current of intermediate link is determined.Especially in junior's power grid Simultaneously comprising in the occasion of alternating current-direct currents mixing power grid such as electrical equipment, generation of electricity by new energy device and energy storage device, energy stream Flow direction may continually change, it is difficult to predict, it is easier to the problems such as generating system overvoltage caused by energy stream identification is not allowed.

It is mesh to improve the stability of power supply system in conclusion how accurately to pick out the energy stream by PET Preceding those skilled in the art's technical problem urgently to be solved.

Summary of the invention

The object of the present invention is to provide a kind of electric power electric transformer energy stream discrimination method, system and equipment.With accurate Ground picks out the energy stream by PET, improves the stability of power supply system.

In order to solve the above technical problems, the invention provides the following technical scheme:

A kind of electric power electric transformer energy stream discrimination method, this method comprises:

Obtain the DC voltage and DC current of intermediate link；

The product of the DC voltage and the DC current is determined as energy stream steady-state quantity；

According to the one-shot change rate of the DC voltage and secondary change rate, the one-shot change rate and two of the DC current The main circuit parameter of secondary change rate and electric power electric transformer determines energy stream undulate quantity；

The superposition amount of the energy stream steady-state quantity and the energy stream undulate quantity is determined as target energy stream.

Preferably, further includes:

When the DC voltage be higher than preset first threshold, and the one-shot change rate of the DC voltage be timing, will The control mode of the intermediate link is switched to reversely by forward direction；

It, will when the DC voltage is lower than preset second threshold, and the one-shot change rate of the DC voltage is negative The control mode of the intermediate link is by being reversely switched to forward direction；

Wherein, the second threshold is lower than the first threshold, described when energy supplies power to subordinate load by main power grid The control mode of intermediate link is forward direction, otherwise the control mode of the intermediate link is reversed.

Preferably, the second threshold is determined by following steps:

Judge the energy stream undulate quantity when whether the number of transitions of target time section is higher than preset frequency threshold value；

If it is, the first numerical value is determined as the second threshold, otherwise, second value is determined as second threshold Value, wherein first numerical value is less than the second value.

Preferably, the DC voltage and DC current for obtaining intermediate link, comprising:

Load information obtains the DC voltage and DC current of intermediate link based on the received.

Preferably, further includes:

When the DC voltage is higher than the preset first threshold, and duration exceeds target duration, output is mentioned Show information.

Preferably, the one of the one-shot change rate and secondary change rate, the DC current according to the DC voltage The main circuit parameter of secondary change rate and secondary change rate and electric power electric transformer determines energy stream undulate quantity, comprising:

According to the one-shot change rate of the DC voltage and secondary change rate, the one-shot change rate and two of the DC current The main circuit parameter of secondary change rate and electric power electric transformer determine electric power electric transformer exchange side phase voltage with And phase current, and determine using the phase voltage and the phase current as the voltage of the circuit under three phase coordinate systems of parameter Equation；

After determining that the voltage equation carries out rotating coordinate transformation and carries out discretization to Euler's formula after Expression formula；

It determines rotating by the expression formula after rating formula and the backward Euler's formula progress discretization Active power fluctuation amount and reactive power fluctuation amount under coordinate system；

By under the rotating coordinate system active power fluctuation amount and reactive power fluctuation amount be converted to three phase coordinate systems Under active power fluctuation amount and reactive power fluctuation amount and be superimposed, as the energy stream undulate quantity determined.

Preferably, which is characterized in that in the superposition amount by the energy stream steady-state quantity and the energy stream undulate quantity It is determined as after target energy stream, further includes:

According to the target energy stream calculation object feedforward component；

The object feedforward component is input to prime rectifier.

A kind of electric power electric transformer energy stream identification system, the system include:

DC quantity obtains module, for obtaining the DC voltage and DC current of intermediate link；

Steady-state quantity determining module, for the product of the DC voltage and the DC current to be determined as energy stream stable state Amount；

Undulate quantity determining module, for according to the one-shot change rate and secondary change rate of the DC voltage, the direct current The one-shot change rate and secondary change rate of electric current and the main circuit parameter of electric power electric transformer determine energy stream undulate quantity；

Aim parameter determining module, for the superposition amount of the energy stream steady-state quantity and the energy stream undulate quantity to be determined as Target energy stream.

Preferably, further includes:

First switching module, for being higher than preset first threshold, and the one of the DC voltage when the DC voltage Secondary change rate is timing, and the control mode of the intermediate link is switched to reversely by forward direction；

Second switching module, for being lower than preset second threshold, and the one of the DC voltage when the DC voltage When secondary change rate is negative, by the control mode of the intermediate link by being reversely switched to forward direction；

Wherein, the second threshold is lower than the first threshold, described when energy supplies power to subordinate load by main power grid The control mode of intermediate link is forward direction, otherwise the control mode of the intermediate link is reversed.

A kind of electric power electric transformer energy stream identification apparatus, comprising:

Memory is used for storage energy stream identification program；

Processor, for executing the energy stream identification program to realize electric power electric transformer energy described in any of the above-described The step of amount stream discrimination method.

Using technical solution provided by the embodiment of the present invention, comprising: obtain the DC voltage and direct current of intermediate link Stream；The product of DC voltage and DC current is determined as energy stream steady-state quantity；According to the one-shot change rate of DC voltage and two The main circuit parameter of secondary change rate, the one-shot change rate of DC current and secondary change rate and electric power electric transformer determines energy Amount stream undulate quantity；The superposition amount of energy stream steady-state quantity and energy stream undulate quantity is determined as target energy stream.

When determining energy stream, energy stream steady-state quantity is determined according to the DC voltage of intermediate link and DC current first, The energy stream steady-state quantity it is corresponding be energy stream variation before at the time of energy stream, due to energy stream variation after, electricity Although stream size will not be mutated, can be embodied in the variation of electric current and voltage, therefore according to the one-shot change of DC voltage The main circuit parameter of rate and secondary change rate, the one-shot change rate of DC current and secondary change rate and electric power electric transformer Determine energy stream undulate quantity, after which is superimposed with energy stream steady-state quantity, the result obtained is variation Energy stream later also just improves the stability of power supply system so that the result picked out is more accurate.

Detailed description of the invention

In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with It obtains other drawings based on these drawings.

Fig. 1 is structural schematic diagram of the PET as the alternating current-direct current microgrid of energy router；

Fig. 2 is a kind of topological structure schematic diagram of three-phase PET；

Fig. 3 is a kind of implementation flow chart of electric power electric transformer energy stream discrimination method in the present invention；

Fig. 4 is a kind of topological structure schematic diagram of single-phase PET；

Fig. 5 is a kind of structural schematic diagram of electric power electric transformer energy stream identification system in the present invention；

Fig. 6 is a kind of structural schematic diagram of electric power electric transformer energy stream identification apparatus in the present invention.

Specific embodiment

Core of the invention is to provide a kind of electric power electric transformer energy stream discrimination method, so that the energy stream picked out It is more accurate, also just improve the stability of power supply system.

In order to enable those skilled in the art to better understand the solution of the present invention, with reference to the accompanying drawings and detailed description The present invention is described in further detail.Obviously, described embodiments are only a part of the embodiments of the present invention, rather than Whole embodiments.Based on the embodiments of the present invention, those of ordinary skill in the art are not making creative work premise Under every other embodiment obtained, shall fall within the protection scope of the present invention.

Referring to FIG. 3, Fig. 3 is a kind of implementation flow chart of electric power electric transformer energy stream discrimination method in the present invention, Method includes the following steps:

S101: the DC voltage and DC current of intermediate link are obtained.

The DC-DC link of the forward and reverse control of realization energy stream in intermediate link, that is, PET, such as the three-phase PET knot of Fig. 2 In composition, for each phase, the intermediate link of the phase includes 2n H bridge of high frequency transformer and two sides.It can be used The equipment such as voltage, current sensor detect the DC voltage and DC current of intermediate link, and will test result and be sent to energy To carry out subsequent step in stream identification system.Such as in the embodiment of fig. 2, corresponding sensor can be arranged in each phase At low-voltage direct bus rod, to obtain DC voltage U_dAnd DC current I_d。

It should be pointed out that shown in Figure 2 is the topological structure of the PET in specific embodiment a kind of, actually answering , can be there are many topological form in, such as distinguished by the number of phases, three-phase, single-phase and multiport form can be divided into；For preceding For grade input stage, can there are the more level of cascade connection type, MMC, diode clamp type, the more level of flying capacitor type, simple two electricity Equality diversified forms, correspondingly, output stage can be there are many topological structure.Different topological forms has no effect on the reality of this programme It applies.

In the specific implementation, corresponding DC current can also be calculated by DC voltage.By net side and DC side it Between the conservation of energy can obtain: P_E=P_L+P_C+P_R, and due to:

It can obtain:

Wherein, I_a,b,cFor the input current of three-phase net side, e_a,b,cFor the input voltage of three-phase net side, L_sFor net side inductance, C_dDC side Support Capacitor, U_dFor DC voltage, I_dFor DC current.

For thereinAndThat is the primary change of the one-shot change rate of net side input current and DC voltage Rate can carry out approximate calculation by front and back double sampling value, such as can be with are as follows:

T therein_sFor the sampling period.

Certainly, the description that DC current is determined by DC voltage has been carried out in above-mentioned example by taking three-phase PET construction as an example, For monophase system, can similarly obtain:

The structure principle chart of single-phase PET can be found in Fig. 4, wherein I_aFor three-phase The input current of net side, e_aFor the input voltage of three-phase net side, L_sFor net side inductance, C_dDC side Support Capacitor, U_dFor direct current Pressure, I_dFor DC current.

S102: the product of DC voltage and DC current is determined as energy stream steady-state quantity.

After the DC voltage and DC current for obtaining intermediate link, DC voltage and direct current can be determined The product is determined as energy stream steady-state quantity by the product of stream.In the occasion that circuit load hardly happens variation, DC voltage And the product of DC current is actual energy stream, i.e., energy stream undulate quantity at this time levels off to zero, but in circuit In the changed occasion of load frequent, frequently, the variation of energy stream cannot be embodied on DC current immediately for energy stream variation, It needs to be determined that energy stream undulate quantity out, is superimposed with energy stream steady-state quantity for the energy stream undulate quantity, so that calculated energy stream It is more accurate.

When determining energy stream steady-state quantity, the accuracy of data can also be improved by modes such as least square methods.For example, The DC voltage and DC current that multiple moment in a period of time can be obtained, determine this period by least square method Energy stream steady-state quantity, the error of calculated energy stream steady-state quantity can be reduced, especially can exclusive segment it is obviously abnormal Influence of the data to result, such as the exception of the measurement data at a certain moment as caused by sensor.

S103: according to the one-shot change rate of DC voltage and secondary change rate, the one-shot change rate of DC current and secondary The main circuit parameter of change rate and electric power electric transformer determines energy stream undulate quantity.

When causing energy stream to change in view of the variation of load, although the size of DC current will not change immediately, energy Amount stream variation degree is different, and the change rate of DC current and DC voltage can be correspondingly different, therefore, can be according to direct current One-shot change rate and secondary change rate, the main circuit ginseng of the one-shot change rate of DC current and secondary change rate and PET of pressure Number determines energy stream undulate quantity.Such as at a time, the energy stream of circuit fades to P2, the energy determined in step S102 by P1 Amount stream steady-state quantity is the equal of P1, and the energy stream undulate quantity determined in step S103 is P2-P1.It can indicate are as follows:

The one-shot change rate of DC current, directly The secondary change rate of the secondary change rate of galvanic electricity stream, the one-shot change rate of DC voltage and DC voltage can pass through front and back Double sampling value carries out approximate calculation, can be with by taking the one-shot change rate of DC voltage as an example are as follows:Its In T_sFor the sampling period.Certainly, the method for determination of specific energy stream undulate quantity can carry out according to the actual situation setting and Adjustment, such as according to factors such as specific circuit structure and circuit parameters, selection is directed to the energy stream undulate quantity of physical circuit Determination method.

S104: the superposition amount of energy stream steady-state quantity and energy stream undulate quantity is determined as target energy stream.

After determining energy stream steady-state quantity and energy stream undulate quantity, energy stream steady-state quantity and energy stream undulate quantity are folded Add, being superposed to herein is vector superposed, and stack result is the target energy stream determined.In above-mentioned a certain moment circuit Energy stream is faded in the example of P2 by P1, and the target energy stream that step S104 is determined is energy stream P2.

Using method provided by the embodiment of the present invention, comprising: obtain the DC voltage and DC current of intermediate link；It will The product of DC voltage and DC current is determined as energy stream steady-state quantity；According to the one-shot change rate and secondary change of DC voltage The main circuit parameter of rate, the one-shot change rate of DC current and secondary change rate and electric power electric transformer determines energy stream wave Momentum；The superposition amount of energy stream steady-state quantity and energy stream undulate quantity is determined as target energy stream.

When determining energy stream, energy stream steady-state quantity is determined according to the DC voltage of intermediate link and DC current first, The energy stream steady-state quantity it is corresponding be energy stream variation before at the time of energy stream, due to energy stream variation after, electricity Although stream size will not be mutated, can be embodied in the variation of electric current and voltage, therefore according to the one-shot change of DC voltage The main circuit parameter of rate and secondary change rate, the one-shot change rate of DC current and secondary change rate and electric power electric transformer Determine energy stream undulate quantity, after which is superimposed with energy stream steady-state quantity, the result obtained is variation Energy stream later also just improves the stability of power supply system so that the result picked out is more accurate.

Further include following two step in a kind of specific embodiment of the invention:

First step: when DC voltage be higher than preset first threshold, and the one-shot change rate of DC voltage be timing, The control mode of intermediate link is switched to reversely by forward direction；

Second step: when DC voltage is lower than preset second threshold, and the one-shot change rate of DC voltage is negative, By the control mode of intermediate link by being reversely switched to forward direction；

Wherein, second threshold is lower than first threshold, when energy supplies power to subordinate load by main power grid, the control of intermediate link Mode processed is forward direction, otherwise the control mode of intermediate link is reversed.

The positive control mode of intermediate link refers to that energy is powered from main power grid to subordinate load, specifically, can be right Converter on the left of high frequency transformer applies pulse, and the converter on right side realizes the diode rectification of high frequency.Correspondingly, to high frequency Converter on the right side of transformer applies pulse, and the converter in left side realizes the diode rectification of high frequency, control energy can be realized The reverse flow of stream, i.e. energy stream feed back to main power grid by junior's power grid.In the prior art, the DC current by detecting Direction determine intermediate link forward and reverse control, in the occasion of energy stream frequent switching, such control mode will be frequent Ground switches the working condition of the converter of the two sides of intermediate link, therefore can generate unnecessary excess loss, and then influences to supply The efficiency of electric system entirety.

In this kind of embodiment of the application, the forward and reverse control of intermediate link is determined in the way of the stagnant ring of dynamic System, specifically, working as DC voltage U_dHigher than preset first threshold U_dH, and the one-shot change rate of DC voltage is positive, i.e.,When, the control mode of intermediate link is switched to reversely by forward direction.First threshold U_dHSize usually can be by having The circuit of body is configured, such as it is contemplated that the voltage that bears of transformer and storage capacitor carries out in specific circuit structure The setting of corresponding first threshold.Correspondingly, working as DC voltage U_dLower than preset second threshold U_dL, and DC voltage is primary Change rate is negative, i.e.,When, by the control mode of intermediate link by being reversely switched to forward direction.Second threshold U_dLIt can also be with It is set according to the actual situation, such as according to change frequency of energy in circuit in fact stream etc. because usually determining taking for second threshold Value.Therefore, when DC voltage is higher than second threshold and is lower than first threshold, when DC voltage is higher than first threshold but one Secondary change rate is negative, i.e., when DC voltage is reducing, and when DC voltage is lower than second threshold but its change rate is Just, i.e., when DC voltage is increasing, the control mode of intermediate link is not changed, also meaning that reduces intermediate link The switching frequency of forward and reverse control.Such as in a specific embodiment, frequently, DC current is continually for energy stream transformation Switch between forward and reverse flowing, but DC voltage fluctuates between first threshold and second threshold always, the application's should Kind embodiment does not switch over control mode then, reduces the switching frequency between forward and reverse control, also just improves confession The efficiency of electric system entirety.

In a kind of specific embodiment of the invention, second threshold is determined by following steps:

Judge energy stream undulate quantity when whether the number of transitions of target time section is higher than preset frequency threshold value；

If it is, the first numerical value is determined as second threshold, otherwise, second value is determined as second threshold, wherein First numerical value is less than second value.

In view of the fluctuation situation of energy stream in different occasions is different, the ring of stagnant ring can be dynamically adjusted according to the situation It is wide.The ring width of stagnant ring is determined by the first threshold as the upper limit and the second threshold as lower limit, it is contemplated that first threshold by The influence for bearing voltage of transformer and storage capacitor, the i.e. setting of first threshold usually will be in view of to transformer and storages Energy capacitor carries out certain protection, avoids DC voltage excessively high and damages corresponding device, therefore, can when adjusting first threshold To carry out small-scale adjustment according to the actual situation.

For second threshold, it can be determined that it is preset whether energy stream undulate quantity is higher than in the number of transitions of target time section When frequency threshold value, if it is, the first numerical value is determined as second threshold, otherwise, second value is determined as second threshold, the One numerical value is less than second value.The transformation of energy stream undulate quantity is the sign change of the value, within a certain period of time, energy stream wave The number of transitions of momentum is more, illustrates that the variation of the period self-energy stream is more frequent, in order to further decrease forward and reverse control Switching frequency, the ring width of stagnant ring can be improved at this time, that is to say, that second threshold can be configured lower, such as this kind Second threshold can be set as to the first numerical value in embodiment.It, can be with correspondingly, when the number of transitions of energy stream undulate quantity is less The ring width of low-hysteresis is dropped, such as second threshold is set as second value.It should be pointed out that in this kind of embodiment, with first For numerical value and second value, as two values of second threshold, in the specific implementation, second threshold can also have other Value has no effect on implementation of the invention.In addition, target time section be a preset period, the period specifically across Degree can be set and be adjusted according to the actual situation, and frequency threshold value can also be chosen according to the actual situation, not influence Implementation of the invention.

In a kind of specific embodiment of the invention, step S101 may include:

Load information obtains the DC voltage and DC current of intermediate link based on the received.

For power supply system known to part, i.e., the system of the loadtype connected in known circuit can be according to reception Load information obtain intermediate link DC voltage and DC current.It can be obtained by equipment such as Load Torque Observers corresponding negative The load information of information carrying breath, different loads can be different.Load Torque Observer can be calculated by the control being arranged in corresponding controllers Method is realized.And it is pointed out that for fractional load, the corresponding load information of the load can be obtained with into one The DC voltage and DC current for determining intermediate link are walked, and for certain loads, it can be direct or indirect by load information The power of these loads is determined on ground, further can then determine the energy stream steady-state quantity in the circuit.For example, for motor Load can obtain the revolving speed and torque and the energy stream that motor is converted by parameters such as energy conversion efficiencies of motor load.

In a kind of specific embodiment of the invention, further includes:

When DC voltage is higher than preset first threshold, and duration exceeds target duration, prompt information is exported.

As it was noted above, the setting of first threshold would generally bear voltage in view of transformer, for example, transformer Can bear voltage is A, first threshold can be configured to be slightly less than A.When DC voltage is constantly higher than preset first threshold When, adverse effect, such as DC voltage may be caused persistently to increase to circuit, switch positive and negative control and make circuit not in time In component be destroyed.In this kind of embodiment of the invention, when DC voltage be higher than preset first threshold, and continue When duration exceeds target duration, prompt information is exported.It is prompted specifically, the devices such as indicator light or buzzer can be used The output of information, target duration can also be set according to the actual situation, when exporting prompt information, illustrate DC voltage compared with High and continue for the regular hour, there may be certain risk, this kind of embodiments can make staff for power supply system It obtains analysis situation in time to be handled, improves the safety of power supply system.

In a kind of specific embodiment of the invention, step S103 the following steps are included:

According to the one-shot change rate of DC voltage and secondary change rate, the one-shot change rate of DC current and secondary change rate And the main circuit parameter of electric power electric transformer determines the phase voltage and phase current of the exchange side of electric power electric transformer, And it determines using phase voltage and phase current as the voltage equation of the circuit under three phase coordinate systems of parameter；

Determine the table after voltage equation carries out rotating coordinate transformation and carries out discretization to Euler's formula after Up to formula；

It is determined by the expression formula after rating formula and backward Euler's formula progress discretization in rotational coordinates Active power fluctuation amount and reactive power fluctuation amount under system；

By under rotating coordinate system active power fluctuation amount and reactive power fluctuation amount be converted under three phase coordinate systems Active power fluctuation amount and reactive power fluctuation amount are simultaneously superimposed, as the energy stream undulate quantity determined.

Above-mentioned steps are merged into explanation convenient for description.It should be pointed out that is provided in this kind of embodiment is one The calculation of energy stream undulate quantity in kind specific embodiment, in practical applications, the difference of power supply system, power supply circuit construction The factors such as difference, and the algorithm difference specifically chosen, can produce the calculation of different energy stream undulate quantities.

This kind of embodiment is described primarily directed to common three-phase PET construction model, also briefly carries out to single-phase PET Explanation.Firstly, according to the one-shot change rate of DC voltage and secondary change rate, the one-shot change rate of DC current and secondary change rate And the main circuit parameter of electric power electric transformer determines the phase voltage and phase current of the exchange side of electric power electric transformer. For common three-phase symmetrical system, can specifically indicate are as follows:I_d =i_as_a+i_bs_b+i_cs_c。

Wherein, u_a,u_b,u_cThe phase voltage of side, i are exchanged for rectifier_a,i_b,i_cThe phase current of side, U are exchanged for rectifier_dFor DC voltage, I_dFor DC current.Cascade rectifier can be equivalent to the PWM rectifier of two level, then define unipolarity two It is worth the switch function s of logic_kAre as follows:Wherein, when upper bridge arm is connected, and lower bridge arm turns off, s_kIt is 1, Conversely, when upper bridge arm turns off, when lower bridge arm is connected, s_kIt is 0.And s_kSpecific value it is related with modulation system, such as sinusoidal pulsewidth It is modulated to the pulse signal of triangular wave generation compared with modulating wave, space vector pulse width modulation is selected according to vector sector Vector, specific 0 and 1 duration are determined by vector action time.Certainly, for monophase system, it is based on identical principle, it can To obtain u_a=(s_a-s_b)U_d.And it should be noted that in addition to that can be calculated by the expression formula of power supply circuit itself Obtain corresponding modulation voltage u_a,b,cValue, when it is implemented, can also pass through state space the methods of estimate to carry out it is related Data are sought calculating.

After the phase voltage for the exchange side for determining electric power electric transformer and phase current, it can determine with mutually electricity The voltage equation of pressure and phase current as the circuit under three phase coordinate systems of parameter.Specifically, for example for the three-phase in Fig. 2 PET construction figure, available according to Kirchhoff's second law:

Wherein, e_a,b,cFor the input voltage of three-phase net side, R_sAnd L_sThe respectively equivalent resistance and electricity of ac filter reactance Sense, can be considered the parameter of main circuit.u_a,u_b,u_cThe phase voltage of side, i are exchanged for rectifier_a,i_b,i_cSide is exchanged for rectifier Phase current, u_a,u_b,u_cAnd i_a,i_b,i_cIt can be obtained by DC voltage and DC current.Certainly, it is based on identical principle, it is right In monophase system, can similarly obtain:

After the voltage equation for determining the circuit under three phase coordinate systems using phase voltage and phase current as parameter, D-q transformation can be carried out to it, obtain expression formula of the voltage equation under d-q coordinate system.Specifically, under d-q coordinate system Expression formula can be with are as follows:

Wherein, u_sd,u_sq,i_sd,i_sq,e_sd,e_sqRespectively u_a,b,c,i_a,b,c,e_a,b,cD axis and q axis under d-q coordinate system Component.

Discretization is carried out to the expression formula under the d-q coordinate system to Euler's formula after, can be obtained:

By rating formula it is found that the active power and reactive power at k moment are as follows:

Wherein, P indicates active power, and Q indicates reactive power.

Therefore, the variable quantity of the active power and reactive power of two neighboring sampling instant can indicate are as follows:

And due to having in dq coordinate system:

Then by above-mentioned two formula simultaneous hereinbefore use after to Euler's formula carry out discretization after expression formula, can To determine the active power fluctuation amount and reactive power fluctuation amount under rotating coordinate system, can indicate are as follows:

Later, only need to by under rotating coordinate system active power fluctuation amount and reactive power fluctuation amount be converted to three-phase sit It marks the active power fluctuation amount and reactive power fluctuation amount under system and is superimposed, can determine the energy stream wave at the moment Momentum.

In a kind of specific embodiment of the invention, after step s 104, can also include:

According to target energy stream calculation object feedforward component；

Object feedforward component is input to prime rectifier.

When carrying out the identification of energy stream, the energy stream picked out can be used as the feedforward point of prime rectifier controlling unit Amount, can reduce the fluctuating range of medium voltage, and then the stability of lifting system.And in the prior art not due to energy stream identification Accurately, will affect control effect, and due to real-time calculated feed-forward component have when being transferred to prime rectifier it is certain Delay, can make control effect worse.

In the scheme of the application, since calculated target energy stream is more accurate, before calculated target can be improved Present the accuracy of component.Also, due to including the change information of energy stream, i.e. energy stream undulate quantity in target energy stream, make It obtains in the specific implementation, feed-forward component can be estimated in advance according to the of different sizes of energy stream undulate quantity.For example, In Higher, the occasion that energy stream changes greatly of transmitting delay, will in advance can estimate feed-forward component, so as to reduce control The pressure that link processed is adjusted also just optimizes the adaptability of prime rectification link reply different random sudden load, Jin Erti Rise the ride-through capability under the applicability and complex working condition or failure of total system.

Corresponding to above method embodiment, the embodiment of the invention also provides a kind of electric power electric transformer energy streams to distinguish Knowledge system, electric power electric transformer energy stream identification system described below and above-described electric power electric transformer energy stream Discrimination method can correspond to each other reference.

It is shown in Figure 5, it, should for a kind of structural schematic diagram of electric power electric transformer energy stream identification system in the present invention System comprises the following modules:

DC quantity obtains module 501, for obtaining the DC voltage and DC current of intermediate link；

Steady-state quantity determining module 502, for the product of DC voltage and DC current to be determined as energy stream steady-state quantity；

Undulate quantity determining module 503, for according to the one-shot change rate and secondary change rate of DC voltage, DC current The main circuit parameter of one-shot change rate and secondary change rate and electric power electric transformer determines energy stream undulate quantity；

Aim parameter determining module 504, for the superposition amount of energy stream steady-state quantity and energy stream undulate quantity to be determined as target Energy stream.

In a kind of specific embodiment of the invention, further includes:

First switching module, for being higher than preset first threshold, and the one-shot change rate of DC voltage when DC voltage For timing, the control mode of intermediate link is switched to reversely by forward direction；

Second switching module, for being lower than preset second threshold, and the one-shot change rate of DC voltage when DC voltage When being negative, by the control mode of intermediate link by being reversely switched to forward direction；

Wherein, second threshold is lower than first threshold, when energy supplies power to subordinate load by main power grid, the control of intermediate link Mode processed is forward direction, otherwise the control mode of intermediate link is reversed.

In a kind of specific embodiment of the invention, second threshold is determined by following steps:

Judge energy stream undulate quantity when whether the number of transitions of target time section is higher than preset frequency threshold value；

If it is, the first numerical value is determined as second threshold, otherwise, second value is determined as second threshold, wherein First numerical value is less than second value.

In a kind of specific embodiment of the invention, DC quantity obtains module 501, is specifically used for:

Load information obtains the DC voltage and DC current of intermediate link based on the received.

In a kind of specific embodiment of the invention, further includes:

Prompt information output module, for being higher than preset first threshold when DC voltage, and duration exceeds target When duration, prompt information is exported.

In a kind of specific embodiment of the invention, undulate quantity determining module 503, including following submodule:

Three phase coordinate system voltage equations determine submodule, for the one-shot change rate and secondary change according to DC voltage The main circuit parameter of rate, the one-shot change rate of DC current and secondary change rate and electric power electric transformer determines electric power electricity The phase voltage and phase current of the exchange side of sub- transformer, and determine to sit using phase voltage and phase current as the three-phase of parameter The voltage equation of circuit under mark system；

Euler's formula discretization expression formula determines submodule, for determine voltage equation carry out rotating coordinate transformation and Expression formula after carrying out discretization to Euler's formula after；

Active power fluctuation amount and reactive power fluctuation meter operator module under rotating coordinate system, for by power calculation Expression formula after formula and backward Euler's formula progress discretization determines the active power fluctuation under rotating coordinate system Amount and reactive power fluctuation amount；

Energy stream undulate quantity determines submodule, for by the active power fluctuation amount and reactive power under rotating coordinate system Undulate quantity is converted to active power fluctuation amount under three phase coordinate systems and reactive power fluctuation amount and is superimposed, as what is determined Energy stream undulate quantity.

In a kind of specific embodiment of the invention, further includes:

Feed-forward component determining module, for the superposition amount of energy stream steady-state quantity and energy stream undulate quantity to be determined as target After energy stream, according to target energy stream calculation object feedforward component；

Feed-forward component input module, for object feedforward component to be input to prime rectifier.

Corresponding to above method embodiment, the embodiment of the invention also provides a kind of electric power electric transformer energy streams to distinguish Know equipment, see Fig. 6, Fig. 6 is a kind of structural schematic diagram of electric power electric transformer energy stream identification apparatus in the present invention.It should Electric power electric transformer energy stream identification apparatus includes: memory 601, is used for storage energy stream identification program；Processor 602, For executing the energy stream identification program to realize the electric power electric transformer energy stream discrimination method in any of the above-described embodiment The step of.Electric power electric transformer energy stream identification apparatus can be with the electric power electric transformer energy stream identification system that is described above And electric power electric transformer energy stream discrimination method corresponds to each other reference, herein not repeated explanation.

Each embodiment in this specification is described in a progressive manner, the highlights of each of the examples are with it is other The difference of embodiment, same or similar part may refer to each other between each embodiment.For being disclosed in embodiment For system and device, since it is corresponded to the methods disclosed in the examples, so be described relatively simple, related place referring to Method part illustration.

Professional further appreciates that, unit described in conjunction with the examples disclosed in the embodiments of the present disclosure And algorithm steps, can be realized with electronic hardware, computer software, or a combination of the two, in order to clearly demonstrate hardware and The interchangeability of software generally describes each exemplary composition and step according to function in the above description.These Function is implemented in hardware or software actually, the specific application and design constraint depending on technical solution.Profession Technical staff can use different methods to achieve the described function each specific application, but this realization is not answered Think beyond the scope of this invention.The step of method described in conjunction with the examples disclosed in this document or algorithm, can directly be used The combination of software module or the two that hardware, processor execute is implemented.Software module can be placed in random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, removable magnetic In any other form of storage medium well known in disk, CD-ROM or technical field.

Used herein a specific example illustrates the principle and implementation of the invention, and above embodiments are said It is bright to be merely used to help understand technical solution of the present invention and its core concept.It should be pointed out that for the common of the art , without departing from the principle of the present invention, can be with several improvements and modifications are made to the present invention for technical staff, these Improvement and modification are also fallen within the protection scope of the claims of the present invention.