Control method of grid-side converter in slope type gravity energy storage system and related device

Abstract

The invention discloses a control method of a grid-side converter in a slope type gravity energy storage system and a related device. The control method comprises the following steps: determining a phase synchronization angle theta g based on three-phase voltage; converting the three-phase current based on the theta g to obtain igd and igq; inputting the difference between the Udc * and the Udc into a sliding mode voltage controller to obtain igd *; inputting the difference value between igd * and igd into a first PI controller to obtain ugd *, and inputting the difference value between igq * and igq into a second PI controller to obtain ugq *; subtraction is carried out on the ugd * and the first feed-forward compensation item to obtain ugd, and summation is carried out on the ugq * and the second feed-forward compensation item to obtain ugq; performing coordinate transformation on the ugd and the ugq to obtain ug alpha and ug beta; carrying out SVPWM (Space Vector Pulse Width Modulation) processing on the ug alpha and the ug beta to obtain a PWM signal for driving the grid-side converter to work; and driving the grid-side converter based on the PWM signal. The method has a better control effect.

Description

Technical Field

[0001] The present application relates to the field of converter control technology, and in particular to a control method and related devices for a grid-side converter in a slope-type gravity energy storage system. Background Art

[0002] Currently, more and more wind, solar and other renewable energy sources are being developed and utilized. Due to the uncertainty of environmental factors, the output power of wind and photovoltaic power plants varies greatly, so the large number of wind and photovoltaic power generation devices connected to the power grid poses a huge challenge to the safe and stable operation of the power system.

[0003] In order to achieve large-scale grid connection of renewable energy and ensure stable operation of the power grid at the same time, especially when renewable energy becomes the main energy source of future power systems, energy storage technology will become an indispensable core technology for power systems and wind and solar new energy companies.

[0004] In recent years, based on the basic principle of pumped storage, the industry has conducted research on gravity energy storage technology. Gravity energy storage is to convert and store excess electrical energy into the potential energy of heavy objects by transporting and lifting heavy objects. Gravity energy storage power stations are flexible in site selection and can utilize free space such as wasteland and mountains, avoiding agricultural and ecological land. To a certain extent, they can get rid of the restrictions of geographical conditions and have important value. Slope gravity energy storage system is an important field of gravity energy storage.

[0005] Slope gravity energy storage systems usually use electric energy to drive motors to transport heavy carriers from the bottom of the slope to the top, thereby converting the electric energy into the gravitational potential energy of the heavy objects for storage, thereby charging the energy storage system; under the action of gravity, the heavy carrier moves from the top of the slope to a lower place and pulls the motor to generate electricity, converting the gravitational potential energy into electric energy and feeding it back to the power grid, thereby enabling the energy storage system to generate electricity.

[0006] The grid-side converter is an important component that connects the permanent magnet synchronous motor to the power grid. Its function is to control the active and reactive power transmitted to the power grid to maintain the stability of the DC bus voltage.

[0007] Currently, the control strategy of the grid-side converter based on PI control is generally adopted. The inventors of the present application have found through research that the control strategy of the grid-side converter based on PI control has a slow adjustment speed, a large fluctuation range, and the control effect needs to be improved. Summary of the invention

[0008] In view of the above problems, the present application provides a control method and related device for a grid-side converter in a ramp-type gravity energy storage system to achieve the purpose of accelerating the adjustment speed of the grid-side converter. The specific scheme is as follows:

[0009] The first aspect of the present application provides a control method for a grid-side converter in a ramp-type gravity energy storage system, comprising:

[0010] The three-phase grid voltage u in the slope gravity energy storage system ga 、u gb and u gc Detect the three-phase grid current i in the slope gravity energy storage system ga 、i gb and i gc Conduct testing;

[0011] Based on the u ga 、u gb and u gc Determine the phase synchronization angle θ g ;

[0012] Based on the θ g For the i ga 、i gb and i gc Transform to obtain the component i of the grid-side current on the d axis gd and the grid-side current component i on the q axis gq ;

[0013] The DC bus voltage reference value U dc * The actual value of the DC bus voltage U dc The difference is input into the synovial voltage controller to obtain the d-axis current reference value i output by the synovial voltage controller gd * ;

[0014] The i gd * With the i gd The difference is input into the first PI controller to obtain the d-axis voltage reference value u of the AC side input terminal of the grid-side converter output by the first PI controller. gd * , the preset grid-side q-axis current reference value i gq * With the i gq The difference is input into the second PI controller to obtain the q-axis voltage reference value u of the AC side input terminal of the grid-side converter output by the second PI controller. gq * ;

[0015] The u gd * Subtract the first feedforward compensation term to obtain the grid-side d-axis voltage reference value u gd , the u gq *Add it to the second feedforward compensation term to obtain the grid-side q-axis voltage reference value u gq ;

[0016] For the u gd and the u gq Perform coordinate transformation to obtain the grid-side α-axis voltage u gα and grid-side β-axis voltage u gβ ;

[0017] For the u gα and u gβ Performing space vector pulse width modulation (SVPWM) processing to obtain a PWM signal for driving the grid-side converter to work;

[0018] The grid-side converter is driven based on the PWM signal.

[0019] In a possible implementation, the sliding membrane voltage controller is configured to dc * with U dc The difference between the i gd * The process includes:

[0020] The sliding film voltage controller is based on the formula

[0021]

[0022] Calculate the i gd * , where C is the DC bus support capacitor, e gd is the component of the grid voltage on the d-axis, R g is the line resistance on the AC side, ε is the dielectric constant, is the sliding film approach rate parameter, m and n are both natural numbers greater than 0, e is the natural logarithm, s is the sliding surface function, q is the number of slots per pole per phase of the permanent magnet synchronous motor, i dc is the DC load current.

[0023] In a possible implementation, the ga 、u gb and u gc Determine the phase synchronization angle θ g ,include:

[0024] The u ga 、u gb and u gc Input the phase-locked loop to obtain the phase synchronization angle θ output by the phase-locked loop g .

[0025] In a possible implementation, the first feedforward compensation term is: gd R g +ω g L gd i gd +e gd ; The second feedforward compensation term is: -i gq R g +ω g L gq i gq +e gq , where R g is the line resistance on the AC side, ω g is the mechanical angular velocity of the permanent magnet synchronous motor in the ramp gravity energy storage system, L gd is the d-axis inductance, L gq is the q-axis inductance, e gd is the component of the grid voltage on the d-axis, e gd is the component of the grid voltage on the d-axis, e gq is the component of the grid voltage on the q axis.

[0026] A second aspect of the present application provides a control device for a grid-side converter in a ramp-type gravity energy storage system, comprising:

[0027] Detection unit, used to detect the three-phase grid voltage u in the slope gravity energy storage system ga 、u gb and u gc Detect the three-phase grid current i in the slope gravity energy storage system ga 、i gb and i gc Conduct testing;

[0028] An angle determination unit for determining an angle based on the u ga 、u gb and u gc Determine the phase synchronization angle θ g ;

[0029] The first current obtaining unit is used to obtain a current based on the θ g For the i ga 、i gb and i gc Transform to obtain the component i of the grid-side current on the d axis gd and the grid-side current component i on the q axis gq ;

[0030] The second current acquisition unit is used to obtain the DC bus voltage reference value U dc * The actual value of the DC bus voltage U dcThe difference is input into the synovial voltage controller to obtain the d-axis current reference value i output by the synovial voltage controller gd * ;

[0031] The first voltage obtaining unit is used to obtain the voltage gd * With the i gd The difference is input into the first PI controller to obtain the d-axis voltage reference value u of the AC side input terminal of the grid-side converter output by the first PI controller. gd * , the preset grid-side q-axis current reference value i gq * With the i gq The difference is input into the second PI controller to obtain the q-axis voltage reference value u of the AC side input terminal of the grid-side converter output by the second PI controller. gq * ;

[0032] The second voltage obtaining unit is used to convert the u gd * Subtract the first feedforward compensation term to obtain the grid-side d-axis voltage reference value u gd , the u gq * Add it to the second feedforward compensation term to obtain the grid-side q-axis voltage reference value u gq ;

[0033] The third voltage obtaining unit is used to respectively gd and the u gq Perform coordinate transformation to obtain the grid-side α-axis voltage u gα and grid-side β-axis voltage u gβ ;

[0034] A driving signal obtaining unit, used for gα and u gβ Performing space vector pulse width modulation (SVPWM) processing to obtain a PWM signal for driving the grid-side converter to work;

[0035] A driving unit is used to drive the grid-side converter based on the PWM signal.

[0036] In a possible implementation, the sliding membrane voltage controller further includes:

[0037] The sliding film voltage controller is used according to the formula

[0038]

[0039] Calculate the i gd *, where C is the DC bus support capacitor, e gd is the component of the grid voltage on the d-axis, R g is the line resistance on the AC side, ε is the dielectric constant, is the sliding film approach rate parameter, m and n are both natural numbers greater than 0, e is the natural logarithm, s is the sliding surface function, q is the number of slots per pole per phase of the permanent magnet synchronous motor, i dc is the DC load current.

[0040] In a possible implementation manner, the angle determination unit is specifically configured to:

[0041] The u ga 、u gb and u gc Input the phase-locked loop to obtain the phase synchronization angle θ output by the phase-locked loop g .

[0042] A third aspect of the present application provides a computer program product, including computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements a control method for a grid-side converter in a ramp-type gravity energy storage system according to any implementation of the first aspect.

[0043] A fourth aspect of the present application provides an electronic device, comprising at least one processor and a memory connected to the processor, wherein:

[0044] The memory is used to store computer programs;

[0045] The processor is used to execute the computer program so that the electronic device can implement the control method of the grid-side converter in the ramp-type gravity energy storage system of any implementation manner of the first aspect.

[0046] A fifth aspect of the present application provides a computer storage medium, which carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement a control method for a grid-side converter in a ramp-type gravity energy storage system according to any implementation method of the first aspect.

[0047] With the help of the above technical scheme, the control method and related devices of the grid-side converter in the sloped gravity energy storage system provided by the present application can comprehensively utilize the sliding film voltage controller and the PI controller to realize the control of the grid-side converter. The present application has a faster adjustment speed for each target parameter, a smaller fluctuation range, and a better control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0049] Figure 1 A schematic diagram of the system architecture of a slope-type gravity energy storage system provided in this application;

[0050] Figure 2 A schematic diagram of a control method for a grid-side converter in a ramp-type gravity energy storage system provided in an embodiment of the present application;

[0051] Figure 3 A logic diagram of a control method for a grid-side converter in a ramp-type gravity energy storage system provided in an embodiment of the present application;

[0052] Figure 4 A DC voltage waveform diagram under energy storage conditions provided in an embodiment of the present application;

[0053] Figure 5 A grid-side q-axis current waveform diagram based on SMC under energy storage conditions provided in an embodiment of the present application;

[0054] Figure 6 A grid-side q-axis current waveform diagram based on PI control under energy storage conditions provided in an embodiment of the present application;

[0055] Figure 7 A grid-side a-phase voltage and current waveform diagram based on SMC under energy storage conditions provided in an embodiment of the present application;

[0056] Figure 8 This is an amplified diagram of the voltage and current of phase a on the grid side based on SMC under the energy storage condition provided in the embodiment of the present application;

[0057] Fig. 9 A grid-side a-phase voltage and current waveform diagram based on PI control under energy storage conditions provided in an embodiment of the present application;

[0058] Fig.10 This is an amplified diagram of the grid-side a-phase voltage and current based on PI control under the energy storage condition provided in the embodiment of the present application;

[0059] Fig.11 A DC voltage waveform diagram under energy release conditions provided in an embodiment of the present application;

[0060] Fig.12 A grid-side q-axis current waveform diagram based on SMC under energy release conditions provided in an embodiment of the present application;

[0061] Fig.13A grid-side q-axis current waveform diagram based on PI control under energy release conditions provided in an embodiment of the present application;

[0062] Fig.14 A grid-side a-phase voltage and current waveform diagram based on SMC under the energy release condition provided in an embodiment of the present application;

[0063] Fig.15 This is an amplified diagram of the voltage and current of phase a on the grid side based on SMC under the energy release condition provided in the embodiment of the present application;

[0064] Fig.16 A grid-side a-phase voltage and current waveform diagram based on PI control under energy release conditions provided in an embodiment of the present application;

[0065] Fig.17 This is an amplified diagram of the voltage and current of phase a on the grid side based on PI control under the energy release condition provided in the embodiment of the present application;

[0066] Fig.18 A schematic diagram of the structure of a control device for a grid-side converter in a ramp-type gravity energy storage system provided in an embodiment of the present application;

[0067] Fig.19 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0068] The following describes the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation method section of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0069] The embodiments of the present application are described below in conjunction with the accompanying drawings. Those skilled in the art will appreciate that, with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0070] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and need not be used to describe a specific order or sequential order. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, which is only to describe the distinction mode adopted by the objects of the same attributes when describing in the embodiments of the present application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or equipment comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0071] The present application can be applied in the field of converter control. Taking the control method and related devices of the grid-side converter in the slope-type gravity energy storage system as an example, multiple application scenarios implemented in the product will be introduced below.

[0072] First, the application scenario of this application is introduced.

[0073] This application can be applied to, but is not limited to, applications with grid-side converter control functions or cloud services provided by cloud-side servers, etc., which are introduced below:

[0074] See also Figure 1 , Figure 1 A schematic diagram of the system architecture of a slope-type gravity energy storage system is shown. The slope-type gravity energy storage system may include: a transformer, a grid-side converter, a generator-side converter, a permanent magnet synchronous motor, a winch, a hinge, a weight vehicle, a slope track, and a control system. Among them, the connection between the winch and the permanent magnet synchronous motor may be a coaxial connection, that is, the speed and direction of the winch are the same as those of the permanent magnet synchronous motor, and the weight vehicle is connected to the winch through a hinge to achieve up and down movement on the slope track.

[0075] The basic working principle of the slope gravity energy storage system is as follows:

[0076] The heavy-duty vehicle moves up and down on the slope track according to the instructions of the control system, thereby realizing energy storage and release. Under the energy storage condition, the permanent magnet synchronous motor consumes electrical energy, and drives the heavy-duty vehicle from a low place to a high place through the winch and hinge according to the instructions of the control system, converting the electrical energy into gravitational potential energy; under the energy release condition, the heavy-duty vehicle moves steadily downward under its own gravity according to the instructions of the control system, and drives the permanent magnet synchronous motor to rotate through the hinge and winch, converting the gravitational potential energy of the heavy-duty vehicle itself into electrical energy. Regardless of the working conditions, the slope gravity energy storage system realizes the transmission of electrical energy between the permanent magnet synchronous motor and the power grid through the converter.

[0077] Among them, the grid-side converter can control the active and reactive output of the permanent magnet synchronous motor, and can also rectify the AC output of the permanent magnet synchronous motor. It can be seen that the grid-side converter is very important for the slope gravity energy storage system.

[0078] Please combine Figure 2 and Figure 3 , Figure 2 The following is a flow chart of a control method for a grid-side converter in a ramp-type gravity energy storage system provided in an embodiment of the present application. Figure 3 A logic schematic diagram of a control method for a grid-side converter in a ramp-type gravity energy storage system provided in an embodiment of the present application.

[0079] like Figure 2 As shown, a control method for a grid-side converter in a ramp-type gravity energy storage system provided in an embodiment of the present application may include steps S100 to S800, and these steps are described in detail below.

[0080] S100, the three-phase grid voltage u in the slope gravity energy storage system ga 、u gb and u gc Detect the three-phase grid current i in the slope gravity energy storage system ga 、i gb and i gc Conduct testing.

[0081] S200, based on u ga 、u gb and u gc Determine the phase synchronization angle θ g .

[0082] Optionally, step S200 may ga 、u gb and u gc Input the phase-locked loop to obtain the phase synchronization angle θ of the phase-locked loop output g .

[0083] A phase-locked loop (PLL) is a circuit or algorithm that can output a signal so that its phase is synchronized with the phase of the input signal. In power systems, PLL is often used to track the phase of the grid voltage, thereby providing a reference angle that is synchronized with the grid voltage.

[0084] This application can choose u ga 、u gb and u gc As a reference voltage, or through u ga 、u gb and u gc A composite voltage is calculated and then used as a reference voltage. Furthermore, the present application can utilize the phase detector portion of the PLL to compare the reference voltage with the reference signal generated inside the PLL to detect the phase difference between the two. Based on the detected phase difference, the voltage-controlled oscillator (VCO) or digital control portion of the PLL adjusts its output frequency and phase to reduce or eliminate the phase difference. The output of the PLL is an angle signal that is synchronized with the input voltage phase, and this angle signal can be used as the rotation angle in the dq conversion.

[0085] S300, based on θ g to i ga 、i gb and igc Transform to obtain the component i of the grid-side current on the d axis gd and the grid-side current component i on the q axis gq .

[0086] Optionally, step S300 may be based on the following conversion formula ga 、i gb and i gc To transform:

[0087]

[0088] It can be understood by those skilled in the art that the grid-side current component i on the d axis is gd That is, the actual value of the grid-side d-axis current, and the component i of the grid-side current on the q-axis gq That is the actual value of the grid-side q-axis current.

[0089] S400, set the DC bus voltage reference value U dc * The actual value of the DC bus voltage U dc The difference is input into the synovial voltage controller to obtain the d-axis current reference value i output by the synovial voltage controller gd * .

[0090] Sliding mode control (SMC) is a control strategy for variable structure control systems. The fundamental difference between this control strategy and conventional control lies in the discontinuity of control, that is, a switching characteristic that causes the system structure to change over time. This characteristic can make the system move up and down with a small amplitude and high frequency along a specified state trajectory under certain conditions. This is the so-called "sliding mode". This sliding mode can be designed and is independent of the system parameters and disturbances. Therefore, the system in sliding mode has good robustness.

[0091] Optionally, the present application may define the sliding surface of the voltage sliding film as:

[0092]

[0093] Deriving the sliding mode surface of the voltage sliding mode, that is, derivation of the above formula, we can get:

[0094]

[0095] From the derivation result, we can know that at i gq = 0, in the steady state

[0096]

[0097] but

[0098]

[0099] In order to reduce the error and improve the dynamic quality of the sliding mode system, a new sliding film approach law is also adopted. ε>0, q>0 method design, we can get:

[0100]

[0101] That is, the grid-side d-axis current reference value is

[0102]

[0103] The Lyapunov stability theorem is selected to verify the stability of the sliding mode speed controller, and the Lyapunov function is designed as:

[0104]

[0105] Taking the derivative of the above formula, we can get:

[0106]

[0107] because ε>0、q>0, it is easy to know: Therefore, the designed sliding mode voltage controller can achieve stability.

[0108] Specifically, the synovial voltage controller is based on U dc * with U dc The difference between gd * The process includes:

[0109] The sliding membrane voltage controller is based on the formula

[0110]

[0111] Calculate i gd * , where C is the DC bus support capacitor, e gd is the component of the grid voltage on the d-axis, R g is the line resistance on the AC side, ε is the dielectric constant, is the sliding film approach rate parameter, m and n are both natural numbers greater than 0, e is the natural logarithm, s is the sliding surface function, q is the number of slots per pole per phase of the permanent magnet synchronous motor, i dc is the DC load current.

[0112] S500, i gd * with i gdThe difference is input into the first PI controller to obtain the d-axis voltage reference value u of the AC side input terminal of the grid-side converter output by the first PI controller. gd * , the preset grid-side q-axis current reference value i gq * with i gq The difference is input into the second PI controller to obtain the q-axis voltage reference value u of the AC side input terminal of the grid-side converter output by the second PI controller. gq * .

[0113] PI controller, full name Proportional Integral Controller, is a linear controller widely used in various automatic control systems. It achieves precise control of the controlled object by combining proportional (P) and integral (I) regulation methods.

[0114] Optionally, the first PI controller can be based on the formula

[0115]

[0116] The d-axis voltage reference value u at the AC input end of the grid-side converter is calculated gd * . K gdp , K gdi are the proportional coefficient and integral coefficient of the d-axis current respectively, and s is the frequency variable in the complex function.

[0117] Optionally, a second PI controller can be calculated according to the formula

[0118]

[0119] The q-axis voltage reference value u at the AC input end of the grid-side converter gq * . K gqp , K gqi are the proportional coefficient and integral coefficient of the q-axis current, and s is the frequency variable in the complex function.

[0120] S600, will u gd * Subtract the first feedforward compensation term to obtain the grid-side d-axis voltage reference value u gd , will u gq * Add it to the second feedforward compensation term to obtain the grid-side q-axis voltage reference value u gq .

[0121] Optionally, the first feedforward compensation term is: -i gd R g+ω g L gd i gd +e gd ; The second feedforward compensation term is: -i gq R g +ω g L gq i gq +e gq , where R g is the line resistance on the AC side, ω g is the mechanical angular velocity of the permanent magnet synchronous motor in the ramp gravity energy storage system, L gd is the d-axis inductance, L gq is the q-axis inductance, e gd is the component of the grid voltage on the d-axis, e gd is the component of the grid voltage on the d-axis, e gq is the component of the grid voltage on the q axis.

[0122] S700, respectively for u gd and u gq Perform coordinate transformation to obtain the grid-side α-axis voltage u gα and grid-side β-axis voltage u gβ .

[0123] Optionally, step S700 may utilize inverse Park transformation to obtain the grid-side α-axis voltage u gα and grid-side β-axis voltage u gβ .

[0124] Inverse Park transform, also known as inverse Park transform, is an important transformation method in the field of motor control, which is mainly used to convert the voltage or current components on the dq axis (i.e., rotating coordinate system) back to the components on the α-β axis (i.e., stationary coordinate system). This transformation plays a key role in motor control systems, especially in the vector control (FOC) of permanent magnet synchronous motors (PMSM).

[0125] S800, for u gα and u gβ Perform space vector pulse width modulation (SVPWM) processing to obtain a PWM signal for driving the grid-side converter.

[0126] In motor control systems, especially when using permanent magnet synchronous motors (PMSM), space vector pulse width modulation (SVPWM) is a commonly used modulation technique to generate PWM (pulse width modulation) signals that drive inverters (also called converters). These PWM signals are then used to control the voltage and current of the motor, thereby achieving precise control of the motor.

[0127] Optionally, the process of performing SVPWM processing in step S700 may include the following steps 1 to 5:

[0128] Step 1: Determine the reference voltage vector:

[0129] First, u gα and u gβ Determined as the reference voltage vector of SVPWM.

[0130] Step 2: Sector determination:

[0131] According to the position of the reference voltage vector on the α-β plane, the sector it is located in is determined. SVPWM usually divides the α-β plane into 6 sectors, each of which corresponds to a different combination of switch states.

[0132] Step 3: Calculate the action time of adjacent vectors:

[0133] In each sector, the reference voltage vector can be synthesized by two adjacent basic voltage vectors (also called non-zero vectors) and a zero vector of the sector. By calculating the action time of these vectors, it can be ensured that the synthesized voltage vector is equal to the reference voltage vector.

[0134] Step 4: Calculate the PWM duty cycle:

[0135] Based on the action time of adjacent vectors and the PWM period, the duty cycle of each switch is calculated. These duty cycles determine the width of the PWM signal.

[0136] Step 5: Generate PWM signal:

[0137] Using the calculated duty cycle, PWM signals are generated for each phase (usually three phases) of the inverter. These signals are used to control the switching elements (such as IGBTs) of the inverter to generate the required voltage waveform.

[0138] S900 drives the grid-side converter based on the PWM signal.

[0139] A control method for a grid-side converter in a ramp-type gravity energy storage system provided in an embodiment of the present invention can comprehensively utilize a sliding film voltage controller and a PI controller to realize the control of the grid-side converter. The present application has a faster adjustment speed for each target parameter, a smaller fluctuation range, and a better control effect.

[0140] In order to verify the effectiveness and feasibility of the control method of the grid-side converter in the ramp-type gravity energy storage system of the present application, the inventor of the present application conducted a simulation comparison between the control method of the grid-side converter in the ramp-type gravity energy storage system of the present application and the method of controlling the grid-side converter in the ramp-type gravity energy storage system based solely on PI. In order to avoid the influence of the winch model and the mass of the heavy object vehicle on the simulation results, the present application only analyzes the ramp-type gravity energy storage system with the permanent magnet synchronous motor working in the rated state.

[0141] In actual engineering applications, the slope gravity energy storage power station should be composed of several groups of slope gravity energy storage systems. The dispatching center issues control instructions by judging the actual operation of the power grid. The slope gravity energy storage power station controls the operation status of the appropriate number of slope gravity energy storage systems according to the dispatching instructions to ensure the smooth operation of the power grid. For the convenience of analysis, this paper only conducts simulation analysis on one group of slope gravity energy storage systems.

[0142] The simulation parameters of the permanent magnet synchronous motor of the ramp-type gravity energy storage system of the present application may be as shown in Table 1, and the simulation parameters of the grid-side converter and filter may be as shown in Table 2.

[0143] Table 1 Permanent magnet synchronous motor simulation parameters

[0144] parameter Numeric Rotor flux (Wb) 1.849 Stator resistance(Ω) 0.077 D-axis inductance (mH) 2.696 Q-axis inductance (mH) 6.621 Rated torque (N·m) 35001.56 Moment of inertia (kg·m2) 999.434

[0145] Table 2 Grid-side converter and filter simulation parameters

[0146]

[0147]

[0148] The following are the simulation analysis results under energy storage conditions:

[0149] Under the energy storage condition, the permanent magnet synchronous motor operates in the motoring state (positive speed and positive torque), the grid-side converter operates in the rectification state, and the machine-side converter operates in the inverter state.

[0150] The grid-side simulation waveform under energy storage conditions is as follows: Figures 4 to 10 As shown, Figure 4 is the DC voltage waveform under energy storage conditions, Figure 5 This is the grid-side q-axis current waveform based on SMC under energy storage conditions. Figure 6 This is the grid-side q-axis current waveform based on PI control. Figure 7 The voltage and current waveform of phase a on the grid side based on SMC under energy storage conditions is shown in Figure 2. Figure 8 This is the voltage and current magnification diagram of phase a on the grid side based on SMC under energy storage conditions. Fig. 9 This is the grid-side a-phase voltage and current waveform based on PI control under energy storage conditions. Fig.10This is the voltage and current magnification diagram of phase a on the grid side based on PI control under energy storage conditions.

[0151] Depend on Figures 4 to 10 It can be seen that: the DC voltage stabilizes in about 0.2s and reaches the rated value of 700V; the maximum absolute value of the grid-side q-axis current after stabilization is about 3A, with a small fluctuation range, which meets the grid-side control requirements; the grid-side a-phase current stabilizes in about 0.1s, and the stable value is approximately the same phase as the grid-side a-phase current and a-phase voltage, and the power factor is 1.

[0152] from Figures 4 to 10 It can be seen that compared with the method of controlling the grid-side converter in the slope-type gravity energy storage system based solely on PI, the control method of the grid-side converter in the slope-type gravity energy storage system of the present application has a faster adjustment speed for each target parameter, a smaller fluctuation range, and a better control effect.

[0153] The following are the simulation analysis results under the energy release condition:

[0154] Under the energy release condition, the permanent magnet synchronous motor operates in the generating state (the speed is negative and the torque is positive), the grid-side converter operates in the inverter state, and the machine-side converter operates in the rectifying state.

[0155] The grid-side simulation waveform under energy release conditions is as follows: Figures 11 to 17 As shown, Fig.11 is the DC voltage waveform under energy release conditions, Fig.12 This is the grid-side q-axis current waveform based on SMC under energy release conditions. Fig.13 This is the grid-side q-axis current waveform based on PI control under energy release conditions. Fig.14 This is the voltage and current waveform of phase a on the grid side based on SMC under energy release conditions. Fig.15 This is the voltage and current magnification diagram of phase a on the grid side based on SMC under energy release conditions. Fig.16 This is the grid-side a-phase voltage and current waveform based on PI control under energy release conditions. Fig.17 This is the voltage and current amplification diagram of the grid side phase a based on PI control under energy release conditions.

[0156] Depend on Figures 11 to 17 It can be seen that compared with the method of controlling the grid-side converter in the slope gravity energy storage system based solely on PI, the control method of the grid-side converter in the slope gravity energy storage system of the present application has a faster adjustment speed for each target parameter, a smaller fluctuation range, and a better control effect.

[0157] A control method for a grid-side converter in a ramp-type gravity energy storage system provided in an embodiment of the present application is introduced above. A device for executing the control method for a grid-side converter in a ramp-type gravity energy storage system will be introduced below.

[0158] See also Fig.18 , Fig.18 This is a schematic diagram of the structure of a control device for a grid-side converter in a ramp-type gravity energy storage system provided in an embodiment of the present application. Fig.18 As shown, the control device of the grid-side converter in the ramp-type gravity energy storage system includes:

[0159] Detection unit 1801, used to detect the three-phase grid voltage u in the slope gravity energy storage system ga 、u gb and u gc Detect the three-phase grid current i in the slope gravity energy storage system ga 、i gb and i gc Conduct testing;

[0160] Angle determination unit 1802, for determining the angle of the ga 、u gb and u gc Determine the phase synchronization angle θ g ;

[0161] Optionally, the angle determination unit 1802 is specifically configured to:

[0162] will u ga 、u gb and u gc Input the phase-locked loop to obtain the phase synchronization angle θ of the phase-locked loop output g .

[0163] The first current obtaining unit 1803 is used to obtain the current based on θ g to i ga 、i gb and i gc Transform to obtain the component i of the grid-side current on the d axis gd and the grid-side current component i on the q axis gq ;

[0164] The second current obtaining unit 1804 is used to obtain the DC bus voltage reference value U dc * The actual value of the DC bus voltage U dc The difference is input into the synovial voltage controller to obtain the d-axis current reference value i output by the synovial voltage controller gd * ;

[0165] The first voltage obtaining unit 1805 is used to obtain i gd * with i gd The difference is input into the first PI controller to obtain the d-axis voltage reference value u of the AC side input terminal of the grid-side converter output by the first PI controller.gd * , the preset grid-side q-axis current reference value i gq * with i gq The difference is input into the second PI controller to obtain the q-axis voltage reference value u of the AC side input terminal of the grid-side converter output by the second PI controller. gq * ;

[0166] The second voltage obtaining unit 1806 is used to obtain u gd * Subtract the first feedforward compensation term to obtain the grid-side d-axis voltage reference value u gd , will u gq * Add it to the second feedforward compensation term to obtain the grid-side q-axis voltage reference value u gq ;

[0167] Optionally, the first feedforward compensation term is: -i gd R g +ω g L gd i gd +e gd ; The second feedforward compensation term is: -i gq R g +ω g L gq i gq +e gq , where R g is the line resistance on the AC side, ω g is the mechanical angular velocity of the permanent magnet synchronous motor in the ramp gravity energy storage system, L gd is the d-axis inductance, L gq is the q-axis inductance, e gd is the component of the grid voltage on the d-axis, e gq is the component of the grid voltage on the q axis.

[0168] The third voltage obtaining unit 1807 is used to respectively gd and u gq Perform coordinate transformation to obtain the grid-side α-axis voltage u gα and grid-side β-axis voltage u gβ ;

[0169] The driving signal obtaining unit 1808 is used to gα and u gβ Perform space vector pulse width modulation (SVPWM) processing to obtain a PWM signal for driving the grid-side converter;

[0170] The driving unit 1809 is used to drive the grid-side converter based on the PWM signal.

[0171] Optional, Fig.18 The control device of the grid-side converter in the ramp-type gravity energy storage system shown in the figure also includes: a sliding film voltage controller,

[0172] The sliding membrane voltage controller is used according to the formula

[0173]

[0174] Calculate i gd * , where C is the DC bus support capacitor, e gd is the component of the grid voltage on the d-axis, R g is the line resistance on the AC side, ε is the dielectric constant, is the sliding film approach rate parameter, m and n are both natural numbers greater than 0, e is the natural logarithm, s is the sliding surface function, q is the number of slots per pole per phase of the permanent magnet synchronous motor, i dc is the DC load current.

[0175] A control device for a grid-side converter in a ramp-type gravity energy storage system provided in an embodiment of the present invention can comprehensively utilize a sliding membrane voltage controller and a PI controller to realize control of the grid-side converter. The present application has a faster adjustment speed for each target parameter, a smaller fluctuation range, and a better control effect.

[0176] The present application also provides an electronic device in an embodiment. Fig.19 As shown, it shows a schematic diagram of the structure of an electronic device suitable for implementing the embodiments of the present application. The electronic device in the embodiments of the present application may include but is not limited to fixed terminals such as mobile phones, notebook computers, PDAs (personal digital assistants), PADs (tablet computers), desktop computers, etc. Fig.19 The electronic device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0177] like Fig.19 As shown, the electronic device may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 601, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage device 608 into a random access memory (RAM) 603. When the electronic device is powered on, various programs and data required for the operation of the electronic device are also stored in the RAM 603. The processing device 601, the ROM 602, and the RAM 603 are connected to each other via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0178] Typically, the following devices may be connected to the I / O interface 605: an input device 606 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 607 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 608 including, for example, a memory card, a hard disk, etc.; and a communication device 609. The communication device 609 may allow the electronic device to communicate with other devices wirelessly or by wire to exchange data. Although Fig.19 An electronic device having various devices is shown, but it should be understood that it is not required to implement or possess all the devices shown. More or fewer devices may be implemented or possessed instead.

[0179] Also provided in an embodiment of the present application is a computer program product including computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements a control method for a grid-side converter in any ramp-type gravity energy storage system provided in an embodiment of the present application.

[0180] A computer-readable storage medium is also provided in an embodiment of the present application. The storage medium carries one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement any method for controlling a grid-side converter in a slope-type gravity energy storage system provided in an embodiment of the present application.

[0181] It should also be noted that the device embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the drawings of the device embodiments provided by the present application, the connection relationship between the modules indicates that there is a communication connection between them, which may be specifically implemented as one or more communication buses or signal lines.

[0182] Through the description of the above implementation mode, the technicians in the field can clearly understand that the present application can be implemented by means of software plus necessary general hardware, and of course, it can also be implemented by special hardware including special integrated circuits, special CPUs, special memories, special components, etc. In general, all functions completed by computer programs can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be various, such as analog circuits, digital circuits or special circuits. However, for the present application, software program implementation is a better implementation mode in more cases. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a readable storage medium, such as a computer floppy disk, a U disk, a mobile hard disk, a ROM, a RAM, a disk or an optical disk, etc., including a number of instructions to enable a computer device (which can be a personal computer, a training device, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0183] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product.

[0184] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website site, a computer, a training device, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, training device, or data center. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device, a data center, etc. that includes one or more available media integrations. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)), etc.

Claims

1. A control method for a grid-side converter in a ramp-type gravity energy storage system, It is characterized in that include: The three-phase grid voltage u in the slope gravity energy storage system ga 、u gb and u gc Detect the three-phase grid current i in the slope gravity energy storage system ga 、i gb and i gc Conduct testing; Based on the u ga 、u gb and u gc Determine the phase synchronization angle θ g ; Based on the θ g For the i ga 、i gb and i gc Transform to obtain the component i of the grid-side current on the d axis gd and the grid-side current component i on the q axis gq ; Set the DC bus voltage reference value The actual value of the DC bus voltage U dc The difference is input into the synovial voltage controller to obtain the d-axis current reference value output by the synovial voltage controller The With the i gd The difference is input into the first PI controller to obtain the d-axis voltage reference value of the AC side input terminal of the grid-side converter output by the first PI controller. Set the preset grid-side q-axis current reference value With the i gq The difference is input into the second PI controller to obtain the q-axis voltage reference value of the AC side input terminal of the grid-side converter output by the second PI controller. The Subtract the first feedforward compensation term to obtain the grid-side d-axis voltage reference value u gd , the Add it to the second feedforward compensation term to obtain the grid-side q-axis voltage reference value u gq ; For the u gd and the u gq Perform coordinate transformation to obtain the grid-side α-axis voltage u gα and grid-side β-axis voltage u gβ ; For the u gα and u gβ Performing space vector pulse width modulation (SVPWM) processing to obtain a PWM signal for driving the grid-side converter to work; The grid-side converter is driven based on the PWM signal.

2. The control method of the grid-side converter in the ramp-type gravity energy storage system according to claim 1, It is characterized in that The sliding film voltage controller is based on the with U dc The difference is obtained as The process includes: The sliding film voltage controller is based on the formula Calculate the Where C is the DC bus support capacitor, e gd is the component of the grid voltage on the d-axis, R g is the line resistance on the AC side, ε is the dielectric constant, is the sliding film approach rate parameter, m and n are both natural numbers greater than 0, e is the natural logarithm, s is the sliding surface function, q is the number of slots per pole per phase of the permanent magnet synchronous motor, i dc is the DC load current.

3. The control method of the grid-side converter in the ramp-type gravity energy storage system according to claim 1, It is characterized in that Based on the u ga 、u gb and u gc Determine the phase synchronization angle θ g ,include: The u ga 、u gb and u gc Input the phase-locked loop to obtain the phase synchronization angle θ output by the phase-locked loop g .

4. The control method of the grid-side converter in the ramp-type gravity energy storage system according to claim 1, It is characterized in that The first feedforward compensation term is: gd R g +ω g L gd i gd +e gd ; The second feedforward compensation term is: -i gq R g +ω g L gq i gq +e gq , where R g is the line resistance on the AC side, ω g is the mechanical angular velocity of the permanent magnet synchronous motor in the ramp gravity energy storage system, L gd is the d-axis inductance, L gq is the q-axis inductance, e gd is the component of the grid voltage on the d-axis, e gd is the component of the grid voltage on the d-axis, e gq is the component of the grid voltage on the q axis.

5. A control device for a grid-side converter in a ramp-type gravity energy storage system, It is characterized in that include: Detection unit, used to detect the three-phase grid voltage u in the slope gravity energy storage system ga 、u gb and u gc Detect the three-phase grid current i in the slope gravity energy storage system ga 、i gb and i gc Conduct testing; An angle determination unit for determining an angle based on the u ga 、u gb and u gc Determine the phase synchronization angle θ g ; The first current obtaining unit is used to obtain a current based on the θ g For the i ga 、i gb and i gc Transform to obtain the component i of the grid-side current on the d axis gd and the grid-side current component i on the q axis gq ; The second current acquisition unit is used to obtain the DC bus voltage reference value The actual value of the DC bus voltage U dc The difference is input into the synovial voltage controller to obtain the d-axis current reference value output by the synovial voltage controller The first voltage obtaining unit is used to obtain the With the i gd The difference is input into the first PI controller to obtain the d-axis voltage reference value of the AC side input terminal of the grid-side converter output by the first PI controller. Set the preset grid-side q-axis current reference value With the i gq The difference is input into the second PI controller to obtain the q-axis voltage reference value of the AC side input terminal of the grid-side converter output by the second PI controller. The second voltage obtaining unit is used to obtain the Subtract the first feedforward compensation term to obtain the grid-side d-axis voltage reference value u gd , the Add it to the second feedforward compensation term to obtain the grid-side q-axis voltage reference value u gq ; The third voltage obtaining unit is used to respectively gd and the u gq Perform coordinate transformation to obtain the grid-side α-axis voltage u gα and grid-side β-axis voltage u gβ ; A driving signal obtaining unit, used for gα and u gβ Performing space vector pulse width modulation (SVPWM) processing to obtain a PWM signal for driving the grid-side converter to work; A driving unit is used to drive the grid-side converter based on the PWM signal.

6. The control device for the grid-side converter in the ramp-type gravity energy storage system according to claim 5, It is characterized in that Also includes: The sliding film voltage controller, The sliding film voltage controller is used according to the formula Calculate the Where C is the DC bus support capacitor, e gd is the component of the grid voltage on the d-axis, R g is the line resistance on the AC side, ε is the dielectric constant, is the sliding film approach rate parameter, m and n are both natural numbers greater than 0, e is the natural logarithm, s is the sliding surface function, q is the number of slots per pole per phase of the permanent magnet synchronous motor, i dc is the DC load current.

7. The control device for the grid-side converter in the ramp-type gravity energy storage system according to claim 5, It is characterized in that The angle determination unit is specifically used for: The u ga 、u gb and u gc Input the phase-locked loop to obtain the phase synchronization angle θ output by the phase-locked loop g .

8. A computer program product, It is characterized in that It includes computer-readable instructions. When the computer-readable instructions are executed on an electronic device, the electronic device implements the control method of the grid-side converter in the ramp-type gravity energy storage system as claimed in any one of claims 1 to 4.

9. An electronic device, It is characterized in that The method comprises at least one processor and a memory connected to the processor, wherein: The memory is used to store computer programs; The processor is used to execute the computer program so that the electronic device can implement the control method of the grid-side converter in the ramp-type gravity energy storage system as described in any one of claims 1 to 4.

10. A computer storage medium, It is characterized in that The storage medium carries one or more computer programs, and when the one or more computer programs are executed by an electronic device, the electronic device can implement the control method of the grid-side converter in the ramp-type gravity energy storage system as described in any one of claims 1 to 4.

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