Summary of the invention
It is an object of the invention in view of the above drawbacks of the prior art, provide a kind of flywheel energy storage two stage power transformation series
System and control method.
The purpose of the present invention can be realized by technical measures below:
The present invention provides a kind of flywheel energy storage two stage power transformation system, which includes:
The first end being connect with DC grid;
The second end being connect with energy accumulation device for fly wheel;
Sequentially connected first order power conversion unit, second level power between the first end and the second end
Converter unit, the first order power conversion unit include the first bidirectional converter converted for DC-DC, the first control
Device, the first order power conversion unit are configured as between the DC grid and the second level power conversion unit
Power is converted, the second level power conversion unit include the second bidirectional converter mutually converted for DC-AC,
With the second controller of first controller communication connection, the second level power conversion unit is configured as to described first
Power between grade power conversion unit and the energy accumulation device for fly wheel is converted;
First controller is configured as executing following steps: real-time monitoring DC bus-bar voltage, according to the direct current
Busbar voltage controls the operating status of the first bidirectional converter;Or external command is received, it is two-way according to external command control first
The operating status of current transformer;
The second controller be configured as execute following steps: in real time obtain the first controller operating status, not between
The DC voltage of disconnected monitoring second bidirectional converter, according to energy accumulation device for fly wheel described in the DC voltage control into
Row charge or discharge.
Preferably, between the DC grid and the first order power conversion unit, the first order power conversion list
It is first between the second level power conversion unit by DC bus connect, the second level power conversion unit with it is described
It is connected between energy accumulation device for fly wheel by three-phase alternating current line, is set between the DC grid and the first order power conversion unit
There is the first dc circuit breaker, it is straight that second is equipped between the first order power conversion unit and the second level power conversion unit
Flow breaker.
Preferably, first bidirectional converter includes: the first unsteady flow module and the first filter capacitor, and described second is two-way
Current transformer includes: the second unsteady flow module and the second filter capacitor.
Preferably, the first order power conversion unit further include: be set to the first dc circuit breaker output end and described the
The first preliminary filling circuit between one bidirectional converter, be set to the first dc circuit breaker input terminal and first bidirectional converter it
Between first protection circuit, between first preliminary filling circuit and first bidirectional converter be equipped with the first inductance.
Preferably, the second level power conversion unit further include: be set to the second dc circuit breaker output end and described the
The second preliminary filling circuit between two bidirectional converters is set to the first dc circuit breaker input terminal and second Bidirectional variable-flow
The second protection circuit between device.
The present invention also provides a kind of control method of flywheel energy storage two stage power transformation system, which includes:
First controller receives external command, and the operating status of the first bidirectional converter is controlled according to external command;Or it is real
When monitor DC bus-bar voltage, according to the DC bus-bar voltage control the first bidirectional converter operating status;
Second controller obtains the operating status of first controller in real time, the second bidirectional converter of uninterrupted monitoring
DC voltage carries out charge or discharge according to energy accumulation device for fly wheel described in the DC voltage control.
Preferably, the external command includes charging instruction and electric discharge instruction;
When first controller receives charging instruction, the power direction of first bidirectional converter is controlled from high pressure
Effluent is to low-pressure side;
When first controller receives electric discharge instruction, the power direction of first bidirectional converter is controlled from low pressure
Effluent is to high-pressure side.
Preferably,
When the DC bus-bar voltage is greater than or equal to the first charging voltage threshold value, described in the first controller control
The power direction of first bidirectional converter flows to low-pressure side from high-pressure side;
When the DC bus-bar voltage is less than or equal to the first discharge voltage threshold value, first bidirectional converter is controlled
Power direction flow to high-pressure side from low-pressure side.
Preferably, when first controller control the power direction of first bidirectional converter flow to from high-pressure side it is low
When pressing side,
When the second controller monitors that the DC voltage of second bidirectional converter is greater than or equal to second and fills
When piezoelectric voltage threshold value, the energy accumulation device for fly wheel charging is controlled.
Preferably, when the power direction that first controller controls first bidirectional converter flows to height from low-pressure side
When pressing side,
When the second controller monitors that the DC voltage of second bidirectional converter is less than or equal to second and puts
When piezoelectric voltage threshold value, the energy accumulation device for fly wheel electric discharge is controlled.
Preferably, it is described when the second controller monitor the DC voltage of second bidirectional converter be greater than or
When equal to the second charging voltage threshold value, controlling the step of energy accumulation device for fly wheel charges includes:
When the DC voltage is greater than or equal to the second charging voltage threshold value, second bidirectional converter is controlled
Power direction flows to exchange side from DC side;
When the revolving speed of flywheel is lower than maximum speed, control charge power is that DC voltage is maintained to be maintained at the second charging
Power needed for voltage threshold;
When the revolving speed of flywheel reaches maximum speed, control charge power is power needed for maintaining the maximum speed of flywheel.
Preferably, it is described when the second controller monitor the DC voltage of second bidirectional converter be less than or
When equal to the second discharge voltage threshold value, controlling the step of energy accumulation device for fly wheel discharges includes:
When the DC voltage is less than or equal to the second discharge voltage threshold value, second bidirectional converter is controlled
Power direction is from effluent is exchanged to DC side;
When the revolving speed of flywheel is not less than minimum speed, control discharge power is to maintain DC voltage to be maintained at second to put
Power needed for piezoelectric voltage threshold value;
When the revolving speed of flywheel is lower than minimum speed, the energy accumulation device for fly wheel stops electric discharge.
System and control method of the invention can solve energy accumulation device for fly wheel applied to high straightening using two stage power transformation
Power conversion problem when streaming system.The system utilizes two-stage in the case where not using the bidirectional converter with isolating transformer
Power conversion meets the conventional implacable DC voltage level of flywheel energy storage power conversion system and flywheel alternating voltage etc.
Grade gap is big, the big requirement of transimission power, expands the use scope and adaptability of the system, improves system effectiveness.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawing and specific implementation
Invention is further described in detail for example.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention,
It is not intended to limit the present invention.
In order to keep the narration of this disclosure more detailed with it is complete, below for embodiments of the present invention and specific real
It applies example and proposes illustrative description;But this not implements or uses the unique forms of the specific embodiment of the invention.Embodiment
In cover multiple specific embodiments feature and to construction with operate these specific embodiments method and step it is suitable with it
Sequence.However, can also reach identical or impartial function and sequence of steps using other specific embodiments.
The present invention provides a kind of flywheel energy storage two stage power transformation system, which can be solved using two stage power transformation
Energy accumulation device for fly wheel is applied to power conversion problem when high-voltage direct current.
Referring to Figure 1, Fig. 1 shows a kind of flywheel energy storage two stage power transformation system, which includes: and DC grid
The first end 20 of 10 connections, the second end 30 being connect with energy accumulation device for fly wheel 40, first order power conversion unit 50, second level function
Rate converter unit 60.First order power conversion unit 50 and second level power conversion unit 60 are sequentially arranged in first end 20 and second
Between end 30, between DC grid 10 and first order power conversion unit 50, first order power conversion unit 50 and second level function
Connected by DC bus 100 between rate converter unit 60, second level power conversion unit 60 and energy accumulation device for fly wheel 40 it
Between by three-phase alternating current line 1000 connect.In the present embodiment, first order power conversion unit 50 can realize DC grid 10 with
Power conversion between second level power conversion unit 60, second level power conversion unit 60 can realize first order power conversion list
Power conversion between member 50 and energy accumulation device for fly wheel 40.
Wherein, first order power conversion unit 50 include for DC-DC conversion the first bidirectional converter 501, with
First controller 502 of PERCOM peripheral communication, the high-pressure side voltage rating of the first bidirectional converter 501 are 1500V, connect DC grid
10, low-pressure side voltage rating is 750V;Second level power conversion unit 60 includes second pair mutually converted for DC-AC
The second controller 602 communicated to connect to current transformer 601 and the first controller 502, second controller 602 and PERCOM peripheral communication, the
The DC side voltage rating of two bidirectional converters 601 is 750V, connects the low-pressure side of the first bidirectional converter 501, and exchange side is
Three-phase alternating current connects energy accumulation device for fly wheel 40.
Wherein, the first controller 502 is configured as two kinds of control modes, both control modes select a progress, the first
Control mode executes following steps: 502 real-time monitoring DC bus-bar voltage of the first controller, according to DC bus-bar voltage control the
The operating status of one bidirectional converter 501;When DC bus-bar voltage is greater than or equal to the first charging voltage threshold value, the first control
The power direction that device 502 controls the first bidirectional converter 501 flows to low-pressure side from high-pressure side, when DC bus-bar voltage is less than or waits
When the first discharge voltage threshold value, the power direction that the first controller 502 controls the first bidirectional converter 501 is flowed to from low-pressure side
High-pressure side.Second of control mode executes following steps: the first controller 502 receives external command, is controlled according to external command
The operating status of first bidirectional converter 501;External command includes: charging instruction and electric discharge instruction, when the first controller 502 connects
When receiving charging instruction, the power direction of the first bidirectional converter 501 of control flows to low-pressure side from high-pressure side, when the first controller
When 502 reception electric discharge instruction, the power direction of the first bidirectional converter 501 of control flows to high-pressure side from low-pressure side.Second control
Device 602 is configured as executing following steps: obtaining the operating status of the first controller 502 in real time, uninterrupted monitoring second is two-way
The DC voltage of current transformer 601, the charge or discharge carried out according to DC voltage control energy accumulation device for fly wheel 40.
It is 1500V and direct current system below that the system of the present embodiment, which is suitable for voltage rating, and band isolation is not being used to become
The conventional flywheel energy storage power conversion system of satisfaction is converted using two stage power in the case where the bidirectional converter of depressor to be difficult to completely
For DC voltage level and the flywheel alternating voltage rank difference of foot away from big, the big requirement of transimission power expands the use of the system
Range and adaptability improve system effectiveness.
Further, Fig. 2 is referred to, it is disconnected that the first direct current is equipped between DC grid 10 and first order power conversion unit 50
Road device QF1 is equipped with the second dc circuit breaker QF2 between first order power conversion unit 50 and second level power conversion unit 60.
Further, Fig. 2 is referred to, the first bidirectional converter 501 includes: the first unsteady flow module (not shown) and
One filter capacitor C1, the second bidirectional converter 601 include: the second unsteady flow module (not shown) and the second filter capacitor C2.
The second inductance L2 and third filter capacitor C3 is equipped between first bidirectional converter 501 and the second bidirectional converter 601.
Second unsteady flow module uses non-isolated bridge-type topological structure, and each bridge wall is by IGBT high-power switch tube group
At being controlled using PWM, not needing to save equipment volume using isolation boosting transformer, improve whole efficiency, reduce into
This.
Further, Fig. 2, first order power conversion unit 50 are referred to further include: be set to the first dc circuit breaker QF1
The first preliminary filling circuit 503 between output end and the first bidirectional converter 501, be set to the first dc circuit breaker QF1 input terminal with
The first protection circuit 504 between first bidirectional converter 501, between the first preliminary filling circuit 503 and the first bidirectional converter 501
Equipped with the first inductance L1.
First preliminary filling circuit 503, for reducing dash current when connecting DC grid 10, is protected with the first protection circuit 504
Protection circuit.Fig. 2 is referred to, the first preliminary filling circuit 503 includes: first contactor KM1, second contactor KM2, first fuse
FU1, second fuse FU2 and first resistor R1, one end of first contactor KM1 are connect with the first dc circuit breaker QF1, and first
The other end of contactor KM1 is connect with one end of first fuse FU1, the other end of first fuse FU1 and the first inductance L1
One end of connection, second contactor KM2 is set between first contactor KM1 and the first dc circuit breaker QF1, second contactor
The KM2 other end is connect with one end of first resistor R1, and the other end of first resistor R1 is connect with one end of second fuse FU2,
The other end of second fuse FU2 is set between first fuse FU1 and the first inductance L1.First protection circuit 504 include: according to
The third contactor KM3 and third fuse FU3 of secondary connection.When energization, the first dc circuit breaker QF1 closes a floodgate, successively by first
Contactor KM1 is disconnected, third contactor KM3 closure, second contactor KM2 are closed, and current limliting is carried out by first resistor R1, when straight
After galvanic electricity stream is less than preset value, successively first contactor KM1 closure, second contactor KM2 are disconnected, complete preliminary filling.
On the basis of the above embodiments, in the present embodiment, Fig. 2, second level power conversion unit 60 are referred to further include:
The second preliminary filling circuit 603 between the second dc circuit breaker QF2 output end and the second bidirectional converter 601 is set to first
The second protection circuit 604 between dc circuit breaker QF1 input terminal and the second bidirectional converter 601.
Further, the second preliminary filling circuit 603 is used to reduce punching when connecting DC grid 10 with the second protection circuit 604
Electric current is hit, circuit is protected.Fig. 2 is referred to, the second preliminary filling circuit 603 includes: the 4th contactor KM4, the 5th contactor KM5,
Four fuse FU4, the 5th fuse FU5 and second resistance R2, one end of the 4th contactor KM4 and the second dc circuit breaker QF2
Connection, the other end of the 4th contactor KM4 connect with one end of the 4th fuse FU4, the other end of the 4th fuse FU4 and the
The connection of two bidirectional converters 601, one end of the 5th contactor KM5 be set to the 4th contactor KM4 and the second dc circuit breaker QF2 it
Between, the 5th contactor KM5 other end is connect with one end of second resistance R2, the other end of second resistance R2 and the 5th fuse
One end of KM5 connects, and the other end of the 5th fuse FU5 is set between the 4th fuse FU4 and the second bidirectional converter 601.
Second protection circuit 604 includes: sequentially connected 6th contactor KM6 and the 6th fuse FU6.When energization, the second direct current is disconnected
Road device QF2 closes a floodgate, and successively disconnects the 4th contactor KM4, the 6th contactor KM6 closure, the 5th contactor KM5 closure, passes through
Second resistance R2 carries out current limliting, after DC current is less than preset value, successively by the 4th contactor KM4 closure, the 5th contactor
KM5 is disconnected, and completes preliminary filling.
First order power conversion unit 50 and second level power conversion unit 60 use modularized design, compact-sized, can
It can also be used as independent device using the inside for being integrated in a device as independent module, it is convenient for installation and maintenance.
The present invention provides a kind of control methods of flywheel energy storage two stage power transformation system, refer to Fig. 3, and Fig. 3 is shown
The control flow of the first control method, the control method include:
The S2: the first controller of step 502 receives external command;
The S3: the first controller of step 502 controls the operating status of the first bidirectional converter 501 according to external command;
Step S4: second controller 602 obtains the operating status of the first controller 502 in real time;Uninterrupted monitoring second pair
To the DC voltage of current transformer 601;
Step S5: second controller 602 carries out charge or discharge according to DC voltage control energy accumulation device for fly wheel 40.
The control method can support one of following three kinds of control models or a variety of:
Charge mode: 10 transmission power of DC grid successively passes through first order power conversion unit 50, second level power becomes
Unit 60 is changed to energy accumulation device for fly wheel 40, energy accumulation device for fly wheel 40 converts electrical energy into kinetic energy.
Discharge mode: store kinetic energy is converted power output by energy accumulation device for fly wheel 40, and output electric energy successively passes through second
Grade power conversion unit 60, first order power conversion unit 50 are delivered to DC grid 10.
Standby mode: first order power conversion unit 50 and the normal connection of second level power conversion unit 60, but be in
Idle running state stops working without power conversion or energy accumulation device for fly wheel 40, converts without energy.
Further, Fig. 4 is referred to, the first control method further includes step S1: 50 He of first order power conversion unit
Second level power conversion unit 60 carries out preliminary filling.The control method is since starting up's step S1, in starting up's step,
50 starting up of first order power conversion unit, the first dc circuit breaker QF1 closes a floodgate and completes preliminary filling, into standby mode;So
60 starting up of second level power conversion unit afterwards, the second dc circuit breaker QF2 closes a floodgate and completes preliminary filling, into standby mode.
In standby mode, first order power conversion unit 50 and the normal connection of second level power conversion unit 60, but in zero load
Operating status.
Specifically, Fig. 5 is referred to, in starting up's step S101, first order power conversion unit 50 and second level function
Rate converter unit 60 carries out preliminary filling, in step s 201, when the first controller 502 is using the first control mode, when the first control
When device 502 processed receives external charging instruction, in step S301, the power direction of the first bidirectional converter 501 is controlled from height
Press effluent to low-pressure side, the DC voltage of low-pressure side rises, and in step S401, second controller 602 obtains the first control in real time
The operating status of device 502 processed, and the DC voltage of the second bidirectional converter 601 is uninterruptedly monitored, in judgment step S501,
When second controller 602 monitors that the DC voltage of the second bidirectional converter 601 is greater than or equal to the second charging voltage threshold value
When, the power direction for controlling the second bidirectional converter 601 flows to exchange side from DC side, and control energy accumulation device for fly wheel 40 charges.
In next judgment step S601, by judging whether the revolving speed of flywheel reaches maximum speed, to control charge power
Output state, when the revolving speed of flywheel is lower than maximum speed, control charge power is to maintain DC voltage to be maintained at second to fill
Power needed for piezoelectric voltage threshold value;When the revolving speed of flywheel reaches maximum speed, control charge power is that the highest of flywheel is maintained to turn
Power needed for speed.
In judgment step S501, when second controller 602 monitors that the DC voltage of the second bidirectional converter 601 is small
When the second charging voltage threshold value, the second bidirectional converter 601 of control without power conversion, control energy accumulation device for fly wheel 40 to
Machine.
Fig. 6 is referred to, in starting up's step S102, first order power conversion unit 50 and second level power conversion list
Member 60 carries out preliminary filling, in step S202, when the first controller 502 receives external electric discharge instruction, in step s 302, control
The power direction for making the first bidirectional converter 501 flows to high-pressure side, low-pressure side DC voltage decline, in step S402 from low-pressure side
In, second controller 602 obtains the operating status of the first controller 502 in real time, and uninterruptedly monitors the second bidirectional converter 601
DC voltage, in judgment step S502, when second controller 602 monitors the DC side of the second bidirectional converter 601
Voltage be less than or equal to the second discharge voltage threshold value when, control the second bidirectional converter 601 power direction from exchange effluent to
DC side, control energy accumulation device for fly wheel 40 discharge.In next judgment step S602, by judge flywheel revolving speed whether
Reach minimum speed, to control the output state of charge power, when the revolving speed of flywheel is not less than minimum speed, control electric discharge function
Rate is power needed for maintaining DC voltage to be maintained at the second discharge voltage threshold value.
In judgment step S502, when second controller 602 monitors that the DC voltage of the second bidirectional converter 601 is big
When the second discharge voltage threshold value, the second bidirectional converter 601 of control without power conversion, control energy accumulation device for fly wheel 40 to
Machine.In judgment step S602, when the revolving speed of flywheel be lower than minimum speed when, energy accumulation device for fly wheel 40 stop electric discharge, into
Machine mode.
When first order power conversion unit 50 and/or second level power conversion unit 60 are in abnormality, the first control
Device 502 and/or second controller 602 and PERCOM peripheral communication issue alarm signal, and system stops charging, electric discharge.
First order power conversion unit 50 and 60 Collaborative Control power of second level power conversion unit in the present embodiment become
It changes, energy accumulation device for fly wheel 40 is made to be suitable for the direct current system that voltage rating is up to 1500V.
It being preferably carried out in mode at another, refers to Fig. 7, Fig. 7 shows the control flow of second of control method,
The control method includes:
502 real-time monitoring DC bus-bar voltage of the S20: the first controller of step;
The S30: the first controller of step 502 controls the operating status of the first bidirectional converter 501 according to DC bus-bar voltage;
Step S40: second controller 602 obtains the operating status of the first controller 502 in real time;Uninterrupted monitoring second pair
To the DC voltage of current transformer 601;
Step S50: second controller 602 carries out charge or discharge according to DC voltage control energy accumulation device for fly wheel 40.
Fig. 8 is referred to, second of control method further includes step S10, and step S10 is consistent with above-mentioned steps S1, herein not
It is repeating.In second of control method, Fig. 9 is referred to, in starting up's step S103, first order power conversion unit 50
Preliminary filling is carried out with second level power conversion unit 60, in step S203, the first controller 502 uses second of control mode
When, 502 real-time monitoring DC bus-bar voltage of the first controller, in judgment step S703, when DC bus-bar voltage is less than first
When charging voltage threshold value, the first controller 502 controls the first bidirectional converter 501 without power conversion;When DC bus electricity
It when pressure is greater than or equal to the first charging voltage threshold value, carries out in step S303, the first controller 502 controls the first bidirectional converter
501 power direction flows to low-pressure side from high-pressure side, following step S403, S503, S603 respectively with above-mentioned steps S401,
S501, S601 are the same, and details are not described herein.
Referring to Figure 10, in starting up's step S104, first order power conversion unit 50 and second level power conversion
Unit 60 carries out preliminary filling, and in step S204, the first controller 502 uses second of control mode, and the first controller 502 is in real time
DC bus-bar voltage is monitored, in judgment step S704, when DC bus-bar voltage is greater than the first discharge voltage threshold value, the first control
Device 502 processed controls the first bidirectional converter 501 without power conversion;When DC bus-bar voltage is less than or equal to the first electric discharge electricity
When pressing threshold value, step S304 is carried out, the first controller 502 controls the power direction of the first bidirectional converter 501 from low pressure effluent
To high-pressure side, following step S404, S504, S604 are respectively as above-mentioned steps S402, S502, S602, herein no longer
It repeats.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the invention
Made any modifications, equivalent replacements, and improvements etc., should all be included in the protection scope of the present invention within mind and principle.