Power generation bicycle composite energy storage grid-connected system and scheduling method thereof

Abstract

The invention provides a power generation bicycle composite energy storage grid-connected system and a scheduling method thereof. The grid-connected system comprises a three-phase uncontrolled rectifying circuit, a booster circuit, a DC / DC bidirectional buck-boost circuit, a single-phase full-bridge inverter circuit, a current tracking control unit, a constant-current charging and discharging control unit, a double-loop control unit, a storage battery and a power generation bicycle. The power generation bicycle comprises a power generator. According to the invention, a three-port system structure of generator-energy storage-grid connection is realized, efficient conversion of energy from biological energy to mechanical energy and then to electric energy is realized, and the grid-connected power generation efficiency is improved; meanwhile, a flexible energy scheduling strategy is provided, the power grid interactive scheduling requirement is met, and the grid-connected power generation benefit is integrally improved.

Description

Technical Field

[0001] The invention relates to the technical field of power electronic converters, and in particular to a composite energy storage grid-connected system for a power-generating bicycle and a dispatching method thereof. Background Art

[0002] When people use fitness equipment to keep fit, they expend a lot of energy, which can be converted into usable electrical energy through reasonable use and transformation.

[0003] The fitness power generating bicycle is such an energy-saving device that can be used for fitness and can also recycle energy. When people are exercising, they apply force to the pedals, which drives the rotor of the permanent magnet synchronous motor to rotate through mechanical transmission. The stator winding cuts the magnetic flux lines to generate the corresponding induced electromotive force, thus realizing the conversion of the energy consumed by people during fitness into electrical energy. Considering the different physical fitness of different individuals and the fatigue of the same individual, it is difficult for the output power of the permanent magnet synchronous motor to maintain an exact value. The amplitude and frequency of its induced electromotive force are changing at any time. Therefore, although its output is an AC quantity, it does not meet the requirements of grid connection and cannot be directly connected to the grid. Summary of the invention

[0004] The purpose of the present invention is to provide a composite energy storage grid-connected system for a power-generating bicycle and a scheduling method thereof, which are used to solve the problems that the prior art fitness power-generating bicycles do not meet the requirements for grid connection and cannot be directly connected to the grid, and can achieve efficient conversion of energy from bioenergy to mechanical energy and then to electrical energy, thereby improving the efficiency of grid-connected power generation; at the same time, it can meet the interactive scheduling needs of the power grid and improve the overall efficiency of grid-connected power generation.

[0005] In order to achieve the above-mentioned purpose, in the first aspect, the present invention provides a composite energy storage grid-connected system for a power-generating bicycle, comprising a three-phase uncontrolled rectifier circuit, a boost circuit, a DC / DC bidirectional buck-boost circuit, a single-phase full-bridge inverter circuit, a current tracking control unit, a constant current charge and discharge control unit, a dual-loop control unit, a battery and a power-generating bicycle; the power-generating bicycle comprises a generator; The three-phase uncontrolled rectifier circuit is connected to the generator through the first AC port, the three-phase uncontrolled rectifier circuit is connected to the boost circuit, the boost circuit is connected to the single-phase full-bridge inverter circuit, the boost circuit and the single-phase full-bridge inverter circuit are both connected to the DC / DC bidirectional buck-boost circuit, the single-phase full-bridge inverter circuit is connected to the grid through the second AC port, and the DC / DC bidirectional buck-boost circuit is connected to the battery through the DC port; The three-phase uncontrolled rectifier circuit is used to rectify the AC power output by the generator into DC power and transmit it to the boost circuit; the current tracking control unit is used to control the output voltage of the boost circuit; the constant current charge and discharge control unit is used to control the charge and discharge state of the battery through the DC / DC bidirectional buck-boost circuit; the dual-loop control unit is used to control the power output of the single-phase full-bridge inverter circuit to the power grid.

[0006] According to a power generation bicycle composite energy storage grid-connected system provided by the present invention, the three-phase uncontrolled rectifier circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode, the boost circuit includes a low-voltage side capacitor, a first inductor, a fifth switch tube, a fifth body diode, a seventh diode and a high-voltage side capacitor, the DC / DC bidirectional boost-boost circuit includes a battery side capacitor, a second inductor, a sixth switch tube, a sixth body diode, a seventh switch tube and a seventh body diode, the single-phase full-bridge inverter circuit includes a first switch tube, a first body diode, a second switch tube, a second body diode, a third switch tube, a third body diode, a fourth switch tube, a fourth body diode and an LC filter, and the LC filter includes a filter inductor and a filter capacitor; The anode of the first diode is connected to the cathode of the second diode, the anode of the third diode is connected to the cathode of the fourth diode, the anode of the fifth diode is connected to the cathode of the sixth diode, and the three connections are all connected to the first AC port; The cathode of the first diode, the cathode of the third diode, the cathode of the fifth diode, and the first end of the low-voltage side capacitor are connected to the first end of the first inductor, the second end of the first inductor, the anode of the seventh diode, and the cathode of the fifth body diode are connected to the drain of the fifth switch tube, the cathode of the seventh diode, the drain of the first switch tube, the cathode of the first body diode, the drain of the third switch tube, the cathode of the third body diode, the drain of the seventh switch tube, and the cathode of the seventh body diode are connected to the first end of the high-voltage side capacitor, the source of the first switch tube, the anode of the first body diode, the drain of the second switch tube, and the cathode of the second body diode are connected to the first end of the filter inductor, the second end of the filter inductor is connected to the first end of the filter capacitor, the source of the third switch tube, the anode of the third ... body diode, and the cathode of the seventh body diode are connected to the first end of the high-voltage side capacitor. The anode of the body diode, the drain of the fourth switch tube, and the cathode of the fourth body diode are connected to the second end of the filter capacitor, the first end of the battery side capacitor is connected to the first end of the second inductor, the second end of the second inductor, the drain of the sixth switch tube, the cathode of the sixth body diode, the source of the seventh switch tube and the anode of the seventh body diode are connected, the anode of the second diode, the anode of the fourth diode, the anode of the sixth diode, the second end of the low-voltage side capacitor, the source of the fifth switch tube, the anode of the fifth body diode, the second end of the high-voltage side capacitor, the source of the second switch tube, the anode of the second body diode, the source of the fourth switch tube, the anode of the fourth body diode, the source of the sixth switch tube, and the anode of the sixth body diode are connected to the second end of the battery side capacitor; The two ends of the filter capacitor are connected to the second AC port, and the two ends of the battery side capacitor are connected to the DC port; The current tracking control unit is connected to the gate of the fifth switch tube, and is used to output a fifth switch signal to the fifth switch tube; the constant current charge and discharge control unit is connected to the gate of the sixth switch tube and the gate of the seventh switch tube, and is used to output a sixth switch signal and a seventh switch signal to the sixth switch tube and the seventh switch tube respectively; the dual-loop control unit is connected to the gate of the first switch tube, the gate of the second switch tube, the gate of the third switch tube, and the gate of the fourth switch tube, and is used to output a first switch signal, a second switch signal, a third switch signal, and a fourth switch signal to the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube respectively.

[0007] According to a power generation bicycle composite energy storage grid-connected system provided by the present invention, the current tracking control unit includes: A generator starting module, used for reading the rotation speed of the generator and providing a corresponding first current reference value; A first subtractor, configured to obtain a first deviation value according to a difference between a first current reference value and an actual current value flowing through the first inductor; A first proportional-integral controller, used for taking a value obtained by adding the first deviation value through proportional calculation and integral calculation as a first duty cycle; The first signal generator is used to convert the first duty cycle into a fifth switching signal after PWM modulation.

[0008] According to a power-generating bicycle composite energy storage grid-connected system provided by the present invention, the value range of the first duty cycle is 0-1, and the fifth switch signal controls the percentage of the conduction time of the fifth switch tube in the entire switch cycle.

[0009] According to a composite energy storage grid-connected system for a power-generating bicycle provided by the present invention, a constant current charging and discharging control unit comprises: An instruction module, used for reading an external instruction and outputting a corresponding second current reference value; A second subtractor, used for obtaining a second deviation value according to a difference between a second current reference value and an actual current value flowing through the second inductor; A second proportional-integral controller, used for taking a value obtained by adding the second deviation value through proportional calculation and integral calculation as a second duty cycle; The second signal generator is used to convert the second duty cycle into a sixth switching signal and a seventh switching signal after PWM modulation.

[0010] According to a power-generating bicycle composite energy storage grid-connected system provided by the present invention, the value range of the second duty cycle is 0~1, the sixth switch signal is used to control the percentage of the conduction time of the sixth switch tube in the entire switch cycle, and the seventh switch signal is used to control the percentage of the conduction time of the seventh switch tube in the entire switch cycle. The sixth switch tube and the seventh switch tube are complementarily turned on.

[0011] According to a power generation bicycle composite energy storage grid-connected system provided by the present invention, the dual-loop control unit includes: SOGI module, used to obtain the grid voltage and grid angular frequency, and generate two orthogonal sine waves; The coordinate transformation module is used to read the angles of two orthogonal sine waves, the orthogonal voltage and the zero voltage to realize the transformation from the two-phase stationary coordinate system to the two-phase rotating coordinate system, and select the q-axis voltage output; A third subtractor, used for obtaining a third deviation value according to a difference between the q-axis voltage and the zero voltage; A third proportional-integral controller, used to obtain a value obtained by adding the third deviation value through proportional calculation and integral calculation as a control variable; The fourth subtractor is used to calculate the πf The difference between the control value and the output angular frequency is obtained; among them, f is the frequency; A first integrator is used to integrate the output angular frequency to obtain an output angle; a fifth subtractor, used for obtaining a voltage deviation value according to a difference between a DC voltage reference value and an actual voltage value at both ends of the high-voltage side capacitor; a fourth proportional-integral controller, used to obtain a value obtained by adding the voltage deviation value through proportional calculation and integral calculation as a third current reference value; A first multiplier is used to multiply the third current reference value by a sine function, the angle of the sine function being the output angle, to obtain an AC current reference value; a sixth subtractor, used for obtaining a grid-connected current deviation value according to a difference between the AC current reference value and the grid-connected current value; A fifth proportional-integral controller, used to obtain a value obtained by adding the grid-connected current deviation value through proportional calculation and integral calculation as a grid-connected voltage reference value; A first adder, used for adding the grid voltage reference value to the grid voltage to implement feedforward control; The third signal generator is used to output the first switch signal, the second switch signal, the third switch signal and the fourth switch signal after comparing the modulated wave with the carrier wave through unipolar modulation.

[0012] According to a power generation bicycle composite energy storage grid-connected system provided by the present invention, the first switch signal, the second switch signal, the third switch signal and the fourth switch signal are used to control the conduction or disconnection of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube respectively; When the modulated wave is greater than the carrier wave, the first switch tube and the fourth switch tube are turned on, and the second switch tube and the third switch tube are turned off; when the modulated wave is less than the carrier wave, the second switch tube and the third switch tube are turned on, and the first switch tube and the fourth switch tube are turned off.

[0013] In a second aspect, the present invention further provides a scheduling method for the power generation bicycle composite energy storage grid-connected system of the first aspect, comprising: The first working mode: the generator supplies power to the grid, and the battery is neither charged nor discharged; The second working mode: the generator supplies power to the grid and to the battery at the same time; The third working mode: the generator does not supply power, and the battery interacts with the power grid for energy; The fourth working mode: the generator and the battery jointly supply power to the grid.

[0014] The present invention provides a composite energy storage grid-connected system for a power-generating bicycle and a dispatching method thereof. The system includes a three-phase uncontrolled rectifier circuit, a boost circuit, a DC / DC bidirectional boost-boost circuit, a single-phase full-bridge inverter circuit, a current tracking control unit, a constant current charge-discharge control unit, a dual-loop control unit, a battery and a power-generating bicycle; the power-generating bicycle includes a generator. Among them, a DC port is connected to the battery to realize the access of energy storage, and two AC ports are respectively connected to the generator and the power grid of the power-generating bicycle, which can realize flexible power exchange between the generator, the power grid and the battery. The boost circuit adopts a current tracking control method, the battery adopts a constant current charge-discharge control method, the single-phase full-bridge inverter adopts a dual-loop control method of a voltage outer loop and a current inner loop, and phase locking is realized in combination with SOGI. The grid-connected system provided by the present invention can work in the following four working modes: 1. The generator supplies power to the power grid, and the battery does not charge or discharge; 2. The generator supplies power to the power grid and supplies power to the battery at the same time; 3. The generator does not supply power, and the battery and the power grid interact with each other; 4. The generator and the battery jointly supply power to the power grid. The present invention realizes a three-port system structure of generator-energy storage-grid connection, achieves efficient conversion of energy from bioenergy to mechanical energy and then to electrical energy, and improves the efficiency of grid-connected power generation; at the same time, it proposes a flexible energy scheduling strategy to meet the interactive scheduling needs of the power grid and improve the overall efficiency of grid-connected power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] In the attached picture: Figure 1 This is a structural block diagram of the composite energy storage grid-connected system for a power-generating bicycle of the present invention; Figure 2 It is a schematic diagram of the control principle of the current tracking control unit of the present invention; Figure 3This is a schematic diagram of the control principle of the constant current charge and discharge control unit of the present invention; Figure 4 It is a schematic diagram of the control principle of the SOGI phase-locked unit of the present invention; Figure 5 A schematic diagram of the control principle of the voltage and current control unit of the present invention; Figure 6 A permanent magnet synchronous motor speed output waveform diagram of a specific embodiment of the present invention; Figure 7 A waveform diagram of a direct voltage output voltage on the low voltage side of a boost circuit according to a specific embodiment of the present invention; Figure 8 A waveform diagram of a direct voltage output voltage on the high side of a boost circuit according to a specific embodiment of the present invention; Fig. 9 This is a circuit topology diagram of the composite energy storage grid-connected system for the power-generating bicycle of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Some embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0019] In order to make full use of the electric power generated by the fitness power generating bicycle and avoid injecting harmonics into the power grid to affect the stability of the power grid, the grid-connected system provided by the present invention mainly includes four parts, namely: a three-phase uncontrolled rectifier circuit, a boost circuit, a DC / DC (direct current / direct current) bidirectional boost and buck (Boost and Buck) circuit and a single-phase full-bridge inverter circuit. The unstable AC power output by the permanent magnet synchronous motor (generator) is rectified into a stable DC power by the three-phase uncontrolled rectifier circuit, and then the DC voltage is increased by the boost circuit. Finally, the DC voltage of the DC bus is inverted into an AC voltage whose amplitude and frequency match the power grid by the single-phase full-bridge inverter circuit. After filtering, the electric power is successfully transmitted to the power grid. In addition, the battery is connected by the DC / DC bidirectional boost and buck circuit. The grid-connected system of the present invention includes four working modes. Through a flexible energy scheduling strategy, it meets the interactive scheduling needs of the power grid and improves the overall grid-connected power generation efficiency. The following is a detailed description.

[0020] See also Figure 1 and Fig. 9 The embodiment of the present invention provides a composite energy storage grid-connected system for a power-generating bicycle, including: a three-phase uncontrolled rectifier circuit, a boost circuit, a DC / DC bidirectional buck-boost circuit, a single-phase full-bridge inverter circuit, a current tracking control unit, a constant current charge and discharge control unit, a dual-loop control unit based on SOGI (second-order generalized integrator) phase lock, a battery and a power-generating bicycle; the power-generating bicycle includes a generator, which is used to generate electricity when the bicycle is driven. For example, when a person is exercising on a fitness power-generating bicycle, the person applies force to the pedals, which drives the rotor of the generator to rotate through mechanical transmission, and the stator winding cuts the magnetic flux lines to generate corresponding induced electromotive force, thereby realizing the conversion of the bioenergy consumed by the person during fitness into electrical energy.

[0021] The three-phase uncontrolled rectifier circuit is connected to the generator through the first AC port, the three-phase uncontrolled rectifier circuit is connected to the boost circuit, the boost circuit is connected to the single-phase full-bridge inverter circuit, the boost circuit and the single-phase full-bridge inverter circuit are both connected to the DC / DC bidirectional buck-boost circuit, the single-phase full-bridge inverter circuit is connected to the grid through the second AC port, and the DC / DC bidirectional buck-boost circuit is connected to the battery through the DC port; The three-phase uncontrolled rectifier circuit is used to rectify the AC power output by the generator into DC power and transmit it to the boost circuit; the current tracking control unit is used to control the output voltage of the boost circuit; the constant current charge and discharge control unit is used to control the charge and discharge state of the battery through the DC / DC bidirectional buck-boost circuit; the dual-loop control unit is used to control the power output of the single-phase full-bridge inverter circuit to the power grid.

[0022] It should be noted that, in this embodiment, the topological structure of the composite energy storage grid-connected system of the power-generating bicycle includes three ports: a first AC port, a second AC port and a DC port; among the three ports, the DC port is connected to the battery to realize energy storage access, the first AC port is connected to the generator of the power-generating bicycle, and the second AC port is connected to the power grid.

[0023] In some embodiments, the three-phase uncontrolled rectifier circuit includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5 and a sixth diode D6, the boost circuit includes a low-voltage side capacitor Cdc1, a first inductor L1, a fifth switch tube Q5, a fifth body diode Dq5, a seventh diode Q7 and a high-voltage side capacitor Cdc2, the DC / DC bidirectional buck-boost circuit includes a battery side capacitor Cbat, a second inductor L2, a sixth switch tube Q6, a sixth body diode Dq6, a seventh switch tube Q7 and a seventh body diode Dq7, the single-phase full-bridge inverter circuit includes a first switch tube Q1, a first body diode Dq1, a second switch tube Q2, a second body diode Dq2, a third switch tube Q3, a third body diode Dq3, a fourth switch tube Q4, a fourth body diode Dq4 and an LC filter, the LC filter includes a filter inductor Lf and a filter capacitor Cf; The anode of the first diode D1 is connected to the cathode of the second diode D2, the anode of the third diode D3 is connected to the cathode of the fourth diode D4, the anode of the fifth diode D5 is connected to the cathode of the sixth diode D6, and the three connections are all connected to the first AC port; the three connections constitute three phases, and three wires (currents are Ia, Ib, and Ic, respectively) can be led out from one end of the three phases to connect to the first AC port.

[0024] The cathode of the first diode D1, the cathode of the third diode D3, the cathode of the fifth diode D5, and the first end of the low-voltage side capacitor Cdc1 are connected to the first end of the first inductor L1, the second end of the first inductor L2, the anode of the seventh diode D7, and the cathode of the fifth body diode Dq5 are connected to the drain of the fifth switch tube Q5, the cathode of the seventh diode D7, the drain of the first switch tube Q1, the cathode of the first body diode Dq1, the drain of the third switch tube Q3, the cathode of the third body diode Dq3, the drain of the seventh switch tube Q7, and the cathode of the seventh body diode Dq7 are connected to the first end of the high-voltage side capacitor Cdc2, the source of the first switch tube Q1, the anode of the first body diode Dq1, the drain of the second switch tube Q2, and the cathode of the second body diode Dq2 are connected to the first end of the filter inductor Lf, the second end of the filter inductor Lf is connected to the first end of the filter capacitor Cf, the source of the third switch tube Q3, the anode of the third ... The anode of the tube Dq3, the drain of the fourth switch tube Q4, and the cathode of the fourth body diode Dq4 are connected to the second end of the filter capacitor Cf, the first end of the battery side capacitor Cbat is connected to the first end of the second inductor L2, the second end of the second inductor L2, the drain of the sixth switch tube Q6, the cathode of the sixth body diode Dq6, the source of the seventh switch tube Q7 and the anode of the seventh body diode Dq7 are connected, the anode of the second diode D2, the anode of the fourth diode D4, the anode of the sixth diode D6, the second end of the low-voltage side capacitor Cdc1, the source of the fifth switch tube Q5, the anode of the fifth body diode Dq5, the second end of the high-voltage side capacitor Cdc2, the source of the second switch tube Q2, the anode of the second body diode Dq2, the source of the fourth switch tube Q4, the anode of the fourth body diode Dq4, the source of the sixth switch tube Q6, and the anode of the sixth body diode Dq6 are connected to the second end of the battery side capacitor Cbat; The two ends of the filter capacitor Cf are connected to the second AC port, and the two ends of the battery side capacitor Cbat are connected to the DC port; The current tracking control unit is connected to the gate of the fifth switch tube Q5, and is used to output the fifth switch signal s5 to the fifth switch tube Q5; the constant current charge and discharge control unit is connected to the gate of the sixth switch tube Q6 and the gate of the seventh switch tube Q7, and is used to output the sixth switch signal s6 and the seventh switch signal s7 to the sixth switch tube Q6 and the seventh switch tube Q7 respectively; the dual-loop control unit is connected to the gate of the first switch tube Q1, the gate of the second switch tube Q2, the gate of the third switch tube Q3, and the gate of the fourth switch tube Q4, and is used to output the first switch signal s1, the second switch signal s2, the third switch signal s3, and the fourth switch signal s4 to the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, and the fourth switch tube Q4 respectively.

[0025] It should be noted that in the three-phase uncontrolled rectifier circuit, the low-voltage side capacitor Cdc1 plays the role of filtering out the high-frequency components in the direct current and stabilizing the voltage. The current tracking control unit controls the on-off of the fifth switch tube Q5 by outputting the fifth switch signal, and the first inductor L1 works in two states of energy storage and energy release, thereby achieving the effect of boosting. When the low-voltage side voltage Udc1 remains unchanged, the output value of the high-voltage side voltage Udc2 can be changed by changing the duty cycle of the fifth switch tube Q5.

[0026] In the DC / DC bidirectional buck-boost circuit, the battery side capacitor Cbat plays the role of filtering out the high-frequency components of the DC power and stabilizing the voltage (stabilizing the voltage Ubat across the battery side capacitor Cbat). The DC / DC bidirectional buck-boost circuit can work in Boost mode and Buck mode respectively. When the DC / DC bidirectional buck-boost circuit works in Boost mode, the battery can discharge to the DC bus Idc2; when the DC / DC bidirectional buck-boost circuit works in Buck mode, the DC bus Idc2 can charge the battery.

[0027] Specifically, Figure 2 As shown, the current tracking control unit includes: A generator starting module, used for reading the rotation speed n of the generator and providing a corresponding first current reference value Iref1; A first subtractor, configured to obtain a first deviation value ΔIdc1 according to a difference between a first current reference value Iref1 and an actual current value Idc1 flowing through the first inductor L1; A first proportional integral controller (PI), configured to obtain a value obtained by adding the first deviation value ΔIdc1 by proportional calculation and integral calculation as a first duty cycle K1; The first signal generator is used for converting the first duty cycle K1 into a fifth switching signal s5 after PWM (Pulse Width Modulation).

[0028] The value range of the first duty cycle K1 is 0-1, and the fifth switch signal s5 is used to control the percentage of the conduction time of the fifth switch tube Q5 in the entire switch period.

[0029] like Figure 3 As shown, the constant current charge and discharge control unit includes: An instruction module, used for reading an external instruction and outputting a corresponding second current reference value Iref2; A second subtractor, configured to obtain a second deviation value ΔIbat according to a difference between the second current reference value Iref2 and an actual current value Ibat flowing through the second inductor L2; A second proportional-integral controller, used for adding the second deviation value ΔIbat by proportional calculation and integral calculation to obtain a value as the second duty cycle K2; The second signal generator is used to convert the second duty cycle K2 into a sixth switching signal s6 and a seventh switching signal s7 after PWM modulation.

[0030] The value range of the second duty cycle K2 is 0-1. The sixth switch signal s6 controls the percentage of the conduction time of the sixth switch tube Q6 in the entire switch cycle. The seventh switch signal s7 controls the percentage of the conduction time of the seventh switch tube Q7 in the entire switch cycle. The sixth switch tube Q6 and the seventh switch tube Q7 are complementary to each other ( Figure 3 “NOT” is used in the text).

[0031] The dual-loop control unit is a control unit based on SOGI phase locking, including a SOGI phase locking unit and a voltage and current control unit, wherein Figure 4 As shown, the SOGI phase-locked unit includes: SOGI module is used to obtain the grid voltage Ug and grid angular frequency , and generate two orthogonal sine waves; Coordinate transformation module ( ), used to read the angle of two orthogonal sine waves (angle value at time t), orthogonal voltage And 0 voltage realizes the transformation from the two-phase stationary coordinate system to the two-phase rotating coordinate system, and selects the q-axis voltage Uq output; A third subtractor, used for obtaining a third deviation value according to a difference between the q-axis voltage Uq and the zero voltage; The third proportional-integral controller is used to take the value obtained by adding the third deviation value through proportional calculation and integral calculation as the control quantity; it can be understood that the control quantity is adjusted to the controlled object through proportional calculation and integral calculation to reduce the deviation. The proportional regulation reacts quickly to the deviation, but there will be static error; the integral regulation can form a memory for the deviation and eliminate the static error; therefore, the control quantity obtained by combining the two adjustment methods can realize the static-free tracking of the controlled quantity to the reference value.

[0032] The fourth subtractor is used to calculate the πf The difference between the control value and the output angular frequency ω is obtained; where, f is the frequency; The first integrator ( ), which is used to integrate the output angular frequency ω to obtain the output angle ωt; like Figure 5 As shown, the voltage and current control unit includes: a fifth subtractor, configured to obtain a voltage deviation value ΔUdc2 according to a difference between a DC voltage reference value and an actual voltage value (DC bus voltage) Udc2 across the high-voltage side capacitor; a fourth proportional-integral controller, configured to obtain a value obtained by adding the voltage deviation value ΔUdc2 by proportional calculation and integral calculation as a third current reference value Iref3; A first multiplier is used to multiply the third current reference value Iref3 by a sine function, the angle of the sine function being the output angle ωt, to obtain an AC current reference value; Figure 5 In the above example, taking the remainder (mod) means taking the remainder of ωt / 2π to obtain , the sine function (sin) represents a sine function with an amplitude of 1.

[0033] The sixth subtractor is used to obtain the grid-connected current deviation value according to the difference between the AC current reference value and the grid-connected current value Ig. ; The fifth proportional integral controller is used to convert the grid-connected current deviation value The value obtained by adding the proportional calculation and the integral calculation is used as the grid-connected voltage reference value ; The first adder is used to add the grid voltage reference value Add it to the grid voltage Ug to realize feedforward control; The third signal generator is used to modulate the signal in a unipolar manner, that is, Figure 5 In the figure, 1 / 400 is to obtain the modulation wave Uref, wherein 400 is the DC voltage reference value, and after comparing the modulation wave with the carrier, the first switching signal s1, the second switching signal s2, the third switching signal s3 and the fourth switching signal s4 are output.

[0034] Specifically, the first switch signal s1, the second switch signal s2, the third switch signal s3 and the fourth switch signal s4 respectively control the conduction or disconnection of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4; wherein the first switch tube Q1 and the fourth switch tube Q4 are turned on at the same time, and the second switch tube Q2 and the third switch tube Q3 are turned on at the same time.

[0035] When the modulated wave is greater than the carrier wave, the first switch tube Q1 and the fourth switch tube Q4 are turned on, and the second switch tube Q2 and the third switch tube Q3 are turned off; when the modulated wave is less than the carrier wave, the second switch tube Q2 and the third switch tube Q3 are turned on, and the first switch tube Q1 and the fourth switch tube Q4 are turned off. Of course, when the modulated wave is equal to the carrier wave, it usually happens instantaneously, so the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 all maintain the state of the previous moment. The comparison of the size of the modulated wave and the carrier wave refers to the comparison of the voltage values ​​of the two at a certain moment.

[0036] Another embodiment of the present invention provides a scheduling method for the power-generating bicycle composite energy storage grid-connected system of the aforementioned embodiment, including the following four working modes: The first working mode: the generator supplies power to the grid, and the battery is neither charged nor discharged; When the generator of the power-generating bicycle generates electricity, and the amount of electricity generated by the power-generating bicycle just meets the demand of the power grid, and the energy of the power grid just meets the balance, the second current reference value output by the instruction module is 0, and the battery is neither charged nor discharged.

[0037] The second working mode: the generator supplies power to the grid and to the battery at the same time; When the generator of the power-generating bicycle generates electricity and the grid load is low, the electricity generated by the power-generating bicycle can not only meet the needs of the grid, but also have surplus. The excess energy can be stored in the battery. At this time, the second current reference value output by the instruction module is a negative number, so that the battery can be charged.

[0038] The third working mode: the generator does not supply power, and the battery interacts with the power grid for energy; When the generator of the power-generating bicycle does not generate electricity and the grid load is low, only the battery and the grid have energy interaction. If the grid has excess energy, the battery can be charged, and the second current reference value output by the instruction module is a negative number; if the grid has energy shortage, the battery can be discharged to provide energy to the grid, and the second current reference value output by the instruction module is a positive number; if the grid energy just meets the balance, the second current reference value output by the instruction module is 0, and the battery is neither charged nor discharged; The fourth working mode: the generator and the battery jointly supply power to the grid.

[0039] When the generator of the power-generating bicycle generates electricity and the grid load is high, the electricity generated by the power-generating bicycle is insufficient to meet the needs of the grid, so the battery is required to provide additional energy. At this time, the second current reference value output by the instruction module is a positive number.

[0040] The following is a specific embodiment of the present invention, which has achieved some positive results during the development or use process and does have great advantages over the prior art. It is described below in conjunction with data, charts, and other contents of the test process.

[0041] This specific embodiment builds a simulation model of a power-generating bicycle composite energy storage grid-connected system on a MATLAB / Simulink simulation experiment platform. The permanent magnet synchronous motor (generator) has a constant torque input, and the torque is . The low-voltage side capacitor Cdc1 of the boost circuit is 0.4mF, the first inductor L1 is 1mH, and the high-voltage side capacitor Cdc2 is 1mF. The battery voltage is 216V, the battery filter capacitor Cbat is 1mF, and the second inductor L2 is 1mH. The DC voltage reference value is 400V. In the LC filter, the filter inductor Lf is 2mH, and the filter capacitor Cf is 0.5uF. The effective value of the grid voltage is 220V, and the switching frequency of the seven switch tubes Q1~Q7 is 20kHz. The simulation results are as follows Figure 6~Figure 8 shown.

[0042] Figure 6 : is the speed output waveform of the permanent magnet synchronous motor of this specific embodiment. After two stages of acceleration, the speed n is finally stabilized at about 1000r / min.

[0043] Figure 7 It is the low voltage side DC output voltage waveform of the boost circuit of this specific embodiment. With the increase of the speed of the permanent magnet synchronous motor, its value increases continuously. When the speed is stable, the voltage Udc1 is stable at about 300V without obvious fluctuation.

[0044] Figure 8 It is the high-voltage side DC output voltage waveform of the boost circuit of this specific embodiment. When the speed is stable, the voltage Udc2 is stable at about 400V without obvious fluctuation.

[0045] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the embodiments disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A composite energy storage grid-connected system for a power-generating bicycle, characterized in that: It includes a three-phase uncontrolled rectifier circuit, a boost circuit, a DC / DC bidirectional buck-boost circuit, a single-phase full-bridge inverter circuit, a current tracking control unit, a constant current charge and discharge control unit, a dual-loop control unit, a battery and a power-generating bicycle; the power-generating bicycle includes a generator; The three-phase uncontrolled rectifier circuit is connected to the generator through a first AC port, the three-phase uncontrolled rectifier circuit is connected to the boost circuit, the boost circuit is connected to the single-phase full-bridge inverter circuit, the boost circuit and the single-phase full-bridge inverter circuit are both connected to a DC / DC bidirectional buck-boost circuit, the single-phase full-bridge inverter circuit is connected to a power grid through a second AC port, and the DC / DC bidirectional buck-boost circuit is connected to the battery through a DC port; The three-phase uncontrolled rectifier circuit is used to rectify the alternating current output by the generator into direct current and transmit it to the boost circuit; the current tracking control unit is used to control the output voltage of the boost circuit; the constant current charge and discharge control unit is used to control the charge and discharge state of the battery through the DC / DC bidirectional buck-boost circuit; the dual-loop control unit is used to control the power output from the single-phase full-bridge inverter circuit to the power grid.

2. The power generation bicycle composite energy storage grid-connected system according to claim 1 is characterized in that: The three-phase uncontrolled rectifier circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode, the boost circuit includes a low-voltage side capacitor, a first inductor, a fifth switch tube, a fifth body diode, a seventh diode and a high-voltage side capacitor, the DC / DC bidirectional buck-boost circuit includes a battery side capacitor, a second inductor, a sixth switch tube, a sixth body diode, a seventh switch tube and a seventh body diode, the single-phase full-bridge inverter circuit includes a first switch tube, a first body diode, a second switch tube, a second body diode, a third switch tube, a third body diode, a fourth switch tube, a fourth body diode and an LC filter, and the LC filter includes a filter inductor and a filter capacitor; The anode of the first diode is connected to the cathode of the second diode, the anode of the third diode is connected to the cathode of the fourth diode, the anode of the fifth diode is connected to the cathode of the sixth diode, and the three connections are all connected to the first AC port; The cathode of the first diode, the cathode of the third diode, the cathode of the fifth diode, and the first end of the low-voltage side capacitor are connected to the first end of the first inductor, the second end of the first inductor, the anode of the seventh diode, and the cathode of the fifth body diode are connected to the drain of the fifth switch tube, the cathode of the seventh diode, the drain of the first switch tube, the cathode of the first body diode, the drain of the third switch tube, the cathode of the third body diode, the drain of the seventh switch tube, and the cathode of the seventh body diode are connected to the first end of the high-voltage side capacitor, the source of the first switch tube, the anode of the first body diode, the drain of the second switch tube, and the cathode of the second body diode are connected to the first end of the filter inductor, the second end of the filter inductor is connected to the first end of the filter capacitor, and the source of the third switch tube is connected to the first end of the filter capacitor. , the anode of the third body diode, the drain of the fourth switch tube, and the cathode of the fourth body diode are connected to the second end of the filter capacitor, the first end of the battery side capacitor is connected to the first end of the second inductor, the second end of the second inductor, the drain of the sixth switch tube, the cathode of the sixth body diode, and the source of the seventh switch tube are connected to the anode of the seventh body diode, the anode of the second diode, the anode of the fourth diode, the anode of the sixth diode, the second end of the low-voltage side capacitor, the source of the fifth switch tube, the anode of the fifth body diode, the second end of the high-voltage side capacitor, the source of the second switch tube, the anode of the second body diode, the source of the fourth switch tube, the anode of the fourth body diode, the source of the sixth switch tube, and the anode of the sixth body diode are connected to the second end of the battery side capacitor; Two ends of the filter capacitor are connected to the second AC port, and two ends of the battery side capacitor are connected to the DC port; The current tracking control unit is connected to the gate of the fifth switch tube, and is used to output a fifth switch signal to the fifth switch tube; the constant current charge and discharge control unit is connected to the gate of the sixth switch tube and the gate of the seventh switch tube, and is used to output a sixth switch signal and a seventh switch signal to the sixth switch tube and the seventh switch tube respectively; the dual-loop control unit is connected to the gate of the first switch tube, the gate of the second switch tube, the gate of the third switch tube, and the gate of the fourth switch tube, and is used to output a first switch signal, a second switch signal, a third switch signal, and a fourth switch signal to the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube respectively.

3. The power generation bicycle composite energy storage grid-connected system according to claim 2 is characterized in that: The current tracking control unit comprises: A generator starting module, used for reading the rotation speed of the generator and providing a corresponding first current reference value; a first subtractor, configured to obtain a first deviation value according to a difference between the first current reference value and an actual current value flowing through the first inductor; A first proportional-integral controller, configured to obtain a value obtained by adding the first deviation value through proportional calculation and integral calculation as a first duty cycle; The first signal generator is used to convert the first duty cycle into the fifth switching signal after PWM modulation.

4. The composite energy storage grid-connected system for power-generating bicycle according to claim 3 is characterized in that: The value range of the first duty cycle is 0-1, and the fifth switching signal is used to control the percentage of the conduction time of the fifth switch tube in the entire switching period.

5. The composite energy storage grid-connected system for power-generating bicycle according to claim 2 is characterized in that: The constant current charge and discharge control unit comprises: An instruction module, used for reading an external instruction and outputting a corresponding second current reference value; a second subtractor, configured to obtain a second deviation value according to a difference between the second current reference value and an actual current value flowing through the second inductor; A second proportional-integral controller, configured to use a value obtained by adding the second deviation value through proportional calculation and integral calculation as a second duty cycle; The second signal generator is used to convert the second duty cycle into a sixth switching signal and a seventh switching signal after PWM modulation.

6. The power generation bicycle composite energy storage grid-connected system according to claim 5 is characterized in that: The value range of the second duty cycle is 0~1, the sixth switching signal is used to control the percentage of the conduction time of the sixth switching tube in the entire switching period, the seventh switching signal is used to control the percentage of the conduction time of the seventh switching tube in the entire switching period, and the sixth switching tube and the seventh switching tube are complementarily turned on.

7. The composite energy storage grid-connected system for power-generating bicycle according to claim 2 is characterized in that: The dual-loop control unit comprises: SOGI module, used to obtain the grid voltage and grid angular frequency, and generate two orthogonal sine waves; The coordinate transformation module is used to read the angles of two orthogonal sine waves, the orthogonal voltage and the zero voltage to realize the transformation from the two-phase stationary coordinate system to the two-phase rotating coordinate system, and select the q-axis voltage output; a third subtractor, configured to obtain a third deviation value according to a difference between the q-axis voltage and the zero voltage; A third proportional-integral controller, used to take a value obtained by adding the third deviation value through proportional calculation and integral calculation as a control variable; The fourth subtractor is used to calculate the πf The difference between the control value and the output angular frequency is obtained; wherein, f is the frequency; A first integrator is used to integrate the output angular frequency to obtain an output angle; a fifth subtractor, configured to obtain a voltage deviation value according to a difference between a DC voltage reference value and an actual voltage value across the high-voltage side capacitor; a fourth proportional-integral controller, configured to use a value obtained by adding the voltage deviation value through proportional calculation and integral calculation as a third current reference value; A first multiplier, configured to multiply the third current reference value by a sine function, the angle of the sine function being the output angle, to obtain an AC current reference value; a sixth subtractor, configured to obtain a grid-connected current deviation value according to a difference between the AC current reference value and the grid-connected current value; a fifth proportional-integral controller, configured to use a value obtained by adding the grid-connected current deviation value through proportional calculation and integral calculation as a grid-connected voltage reference value; A first adder, used for adding the grid-connected voltage reference value to the grid voltage to implement feedforward control; The third signal generator is used to output the first switch signal, the second switch signal, the third switch signal and the fourth switch signal after comparing the modulated wave with the carrier wave through unipolar modulation.

8. The composite energy storage grid-connected system for power-generating bicycle according to claim 7 is characterized in that: The first switch signal, the second switch signal, the third switch signal and the fourth switch signal are used to control the on or off of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube respectively; When the modulated wave is greater than the carrier wave, the first switch tube and the fourth switch tube are turned on, and the second switch tube and the third switch tube are turned off; when the modulated wave is less than the carrier wave, the second switch tube and the third switch tube are turned on, and the first switch tube and the fourth switch tube are turned off.

9. A dispatching method for a power-generating bicycle composite energy storage grid-connected system as claimed in any one of claims 1 to 8, characterized in that: include: The first working mode: the generator supplies power to the grid, and the battery does not charge or discharge; The second working mode: the generator supplies power to the grid and to the battery at the same time; The third working mode: the generator does not supply power, and the battery interacts with the power grid for energy; The fourth working mode: the generator and the battery jointly supply power to the grid.

Images