Bidirectional energy storage converter based on digital control

Abstract

The invention belongs to the technical field of converter control, and particularly discloses a bidirectional energy storage converter based on digital control. Comprising a converter charging detection module, a converter charging confirmation module, a converter discharging detection module, a converter discharging confirmation module, a converter battery detection module, a converter battery confirmation module and a converter feedback terminal. According to the charging quality information and the charging matching information of each detection time point of the bidirectional energy storage converter in the charging mode, the electric energy control information of the bidirectional energy storage converter in the charging mode is confirmed, the electric energy quality of the bidirectional energy storage converter is guaranteed, the operation efficiency of the bidirectional energy storage converter is improved, and the service life of the bidirectional energy storage converter is prolonged. And meanwhile, the battery control information of the bidirectional energy storage converter is confirmed according to the battery temperature of the bidirectional energy storage converter at each detection time point, so that the service life of the battery of the bidirectional energy storage converter is guaranteed, and the aging of the battery of the bidirectional energy storage converter is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of converter control and relates to a bidirectional energy storage converter based on digital control. Background Art

[0002] A bidirectional energy storage converter is a power electronic device that can realize bidirectional flow conversion of electric energy. It can convert alternating current (AC) into direct current (DC) to charge energy storage devices (such as batteries, supercapacitors, etc.), and it can also convert the DC power in the energy storage device into AC power to feed it back to the power grid or power AC loads.

[0003] The current control analysis of bidirectional energy storage inverters mainly focuses on the control of charging and discharging modes, and there are still the following deficiencies: 1. Currently, charging and discharging control is only performed based on the operating status of the bidirectional energy storage inverter, that is, insufficient attention is paid to the analysis of the charging and discharging quality control of the bidirectional energy storage inverter during the charging and discharging process, and the power quality of the bidirectional energy storage inverter cannot be guaranteed, which in turn leads to a decrease in the operating efficiency of the bidirectional energy storage inverter, and thus the stability of the charging and discharging process of the bidirectional energy storage inverter cannot be guaranteed.

[0004] 2. Currently, during the charging and discharging process of the bidirectional energy storage inverter, only the electrical parameter conditions during the charging and discharging process are considered, and the battery status of the bidirectional energy storage inverter during the charging and discharging process is not considered. The service life of the battery of the bidirectional energy storage inverter cannot be guaranteed, which leads to accelerated aging of the battery of the bidirectional energy storage inverter, resulting in a decrease in the performance of the battery of the bidirectional energy storage inverter, and at the same time leads to a decrease in the energy utilization efficiency of the bidirectional energy storage inverter, and an increase in the risk of failure of the bidirectional energy storage inverter. Summary of the invention

[0005] In view of this, in order to solve the problems raised in the above background technology, a bidirectional energy storage converter based on digital control is proposed.

[0006] The objective of the present invention can be achieved through the following technical solutions: The present invention provides a bidirectional energy storage inverter based on digital control, including: an inverter charging detection module, which is used to detect the charging quality information and charging matching information of the bidirectional energy storage inverter at each detection time point in the charging mode, the charging quality information includes the harmonic order, harmonic amplitude, harmonic phase, charging power and charging efficiency, and the charging matching information includes the charging current.

[0007] The converter charging confirmation module is used to confirm the power control information of the bidirectional energy storage converter in the charging mode according to the charging quality information and charging matching information of each detection time point of the bidirectional energy storage converter in the charging mode.

[0008] The converter discharge detection module is used to detect the discharge quality information and discharge matching information of the bidirectional energy storage converter at each detection time point in the discharge mode. The discharge quality information includes the harmonic order, harmonic amplitude, harmonic phase, discharge power and discharge efficiency, and the discharge matching information includes the discharge current.

[0009] The converter discharge confirmation module is used to confirm the power control information of the bidirectional energy storage converter in the discharge mode according to the charging quality information and charging matching information of the bidirectional energy storage converter at each detection time point in the discharge mode, and in accordance with the confirmation method of the power control information of the bidirectional energy storage converter in the charging mode.

[0010] The converter battery detection module is used to detect the battery temperature of the bidirectional energy storage converter at each detection time point.

[0011] The converter battery confirmation module is used to confirm the battery control information of the bidirectional energy storage converter according to the battery temperature of the bidirectional energy storage converter at each detection time point.

[0012] The converter feedback terminal is used to perform corresponding control feedback on the bidirectional energy storage converter control cloud platform according to the power control information of the bidirectional energy storage converter in the charging mode and the discharging mode and the battery control information of the bidirectional energy storage converter.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention confirms the power control information of the bidirectional energy storage inverter in the charging mode according to the charging quality information and charging matching information of the bidirectional energy storage inverter at each detection time point in the charging mode, thereby avoiding the current problem of insufficient attention to the analysis of the charging and discharging quality control of the bidirectional energy storage inverter during the charging and discharging process, ensuring the power quality of the bidirectional energy storage inverter, and further improving the operating efficiency of the bidirectional energy storage inverter, thereby ensuring the stability of the bidirectional energy storage inverter during the charging process.

[0014] (2) The present invention confirms the battery control information of the bidirectional energy storage inverter according to the battery temperature of the bidirectional energy storage inverter at each detection time point, thereby breaking the current deficiency of not considering the battery status of the bidirectional energy storage inverter during the charging and discharging process, ensuring the service life of the battery of the bidirectional energy storage inverter, and further reducing the aging of the battery of the bidirectional energy storage inverter, thereby improving the battery performance of the bidirectional energy storage inverter, while ensuring the energy utilization efficiency of the bidirectional energy storage inverter and reducing the risk of failure of the bidirectional energy storage inverter.

[0015] (3) The present invention confirms the harmonic qualified index of the bidirectional energy storage inverter in the charging mode by analyzing the harmonic order qualified index, the harmonic amplitude qualified index and the harmonic phase qualified index, thereby improving the accuracy of the harmonic impact analysis of the bidirectional energy storage inverter, and further improving the effectiveness of the power quality assessment of the bidirectional energy storage inverter, thereby reducing the damage of harmonics to the bidirectional energy storage inverter. At the same time, by setting the weights of the harmonic order qualified index, the harmonic amplitude qualified index and the harmonic phase qualified index, the accuracy of the confirmation of the harmonic qualified index of the bidirectional energy storage inverter in the charging mode is improved, and the comprehensiveness of the assessment of the harmonic impact of the bidirectional energy storage inverter is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the connection of each module of the system of the present invention.

[0018] Figure 2 It is a connection diagram of the electric energy control information confirmation step in the charging mode of the present invention.

[0019] Figure 3 This is a connection diagram of the battery control information confirmation step of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0021] See also Figure 1 As shown, the present invention provides a bidirectional energy storage converter based on digital control, including: a converter charging detection module, a converter charging confirmation module, a converter discharge detection module, a converter discharge confirmation module, a converter battery detection module, a converter battery confirmation module and a converter feedback terminal.

[0022] In the above, the converter charging confirmation module is respectively connected to the converter charging detection module and the converter feedback terminal, the converter discharging confirmation module is respectively connected to the converter discharging detection module, the converter charging confirmation module and the converter feedback terminal, and the converter battery confirmation module is also respectively connected to the converter battery detection module and the converter feedback terminal.

[0023] The converter charging detection module is used to detect the charging quality information and charging matching information of the bidirectional energy storage converter at each detection time point in the charging mode. The charging quality information includes the harmonic order, harmonic amplitude, harmonic phase, charging power and charging efficiency, and the charging matching information includes the charging current.

[0024] It should be added that the method of obtaining the harmonic order, harmonic amplitude and harmonic phase at each detection time point of the bidirectional energy storage converter in the charging mode is: through the detection of the power quality analyzer installed on the bidirectional energy storage converter, and its working principle is: the signal acquisition module equipped with the power quality analyzer is connected to the relevant circuit nodes of the bidirectional energy storage converter. For example, the power quality analyzer is connected to the key parts such as the AC side input terminal and the DC side port of the converter, so as to be able to obtain the voltage, current and other electrical signals in the circuit in real time. For the AC side signal, it can discretize the periodically changing voltage and current waveforms at a certain sampling frequency to ensure that enough data points are collected to accurately reflect the waveform characteristics. The DC side signal is also collected in real time with high precision to prepare for subsequent analysis. The collected electrical signal is usually in the form of analog quantity. The ADC circuit in the power quality analyzer will convert the analog voltage and current signals into digital signals according to the set resolution and conversion rate. The converted digital signals can use binary codes to represent the corresponding voltage, current amplitude and other information. After the digital signal enters the processor, a specific harmonic analysis algorithm will be used to extract harmonic related information. Common ones include the fast Fourier transform (FFT) algorithm, which can convert discrete signals in the time domain to the frequency domain, so as to clearly show the different frequency components contained in the signal, that is, accurately obtain the components corresponding to each harmonic order, and determine the amplitude of each harmonic by calculating the amplitude of the frequency domain signal. In addition, the corresponding harmonic phase can be obtained according to the phase information of each harmonic component in the frequency domain, that is, the harmonic order, harmonic amplitude and harmonic phase can be obtained through the harmonic analysis algorithm.

[0025] It should be added that the charging power of the bidirectional energy storage converter at each detection time point in the charging mode is obtained by detection by a power analyzer installed on the bidirectional energy storage converter. Its working principle is as follows: the power analyzer collects current signals through the Hall current sensor. The Hall current sensor is based on the Hall effect. When current passes through the current-carrying conductor, a Hall potential will be generated in the direction perpendicular to the current and the magnetic field. Its magnitude is proportional to the current. The current is indirectly measured by measuring the Hall potential. The voltage transformer can convert high voltage into low voltage in proportion to make it suitable for the measurement range of the power analyzer. The collected analog voltage and current signals are then processed through the built-in high-speed sampling circuit and high-precision analog-to-digital converter of the power analyzer. The converter discretizes and samples the analog signal according to the set sampling frequency and converts it into a digital signal. At the same time, in order to improve the signal quality and measurement accuracy, the power analyzer will filter the collected signal to remove the noise and interference components in the signal. Common filtering methods include low-pass filtering, high-pass filtering, band-pass filtering, etc. The appropriate filtering method can be selected according to the actual measurement needs. For the discrete voltage and current digital signals, the power analyzer will calculate its instantaneous power point by point. In the DC system, the instantaneous power is equal to the product of the voltage value and the current value. In the AC system, the calculation formula of the instantaneous power is P=U*I, where P is the instantaneous power, U is the instantaneous voltage, and I is the instantaneous current.

[0026] It should be added that the charging efficiency of the bidirectional energy storage inverter at each detection time point in the charging mode is obtained by detecting it with a power analyzer installed on the bidirectional energy storage inverter. Its working principle is as follows: the power analyzer can measure parameters such as voltage and current at the same time, and calculate the power based on the built-in algorithm. In the charging mode, it measures the AC power on the input side of the bidirectional energy storage inverter and the DC power on the output side, and then calculates the charging efficiency at each detection time point based on the charging efficiency calculation formula: Charging efficiency = (output DC power / input AC power).

[0027] It should be added that the charging current of the bidirectional energy storage converter at each detection time point in the charging mode is detected by a current sensor installed on the bidirectional energy storage converter.

[0028] The converter charging confirmation module is used to confirm the power control information of the bidirectional energy storage converter in the charging mode according to the charging quality information and charging matching information of each detection time point of the bidirectional energy storage converter in the charging mode.

[0029] See also Figure 2 As shown, exemplarily, the confirmation of the power control information of the bidirectional energy storage converter in the charging mode includes: A1, confirming the power quality control information of the bidirectional energy storage converter in the charging mode according to the charging quality information of the bidirectional energy storage converter at each detection time point in the charging mode.

[0030] Furthermore, the confirmation of the power quality control information of the bidirectional energy storage converter in the charging mode includes: A1-1, according to the harmonic order, harmonic amplitude and harmonic phase of each detection time point of the bidirectional energy storage converter in the charging mode, calculating the harmonic qualification index φ1 of the bidirectional energy storage converter in the charging mode.

[0031] Furthermore, the statistical harmonic qualification index of the bidirectional energy storage converter in the charging mode includes: A1-1-1, comparing the harmonic number of the bidirectional energy storage converter at each detection time point in the charging mode with the set permitted harmonic number.

[0032] A1-1-2. If the harmonic order of the bidirectional energy storage converter at a certain detection time point in the charging mode is less than or equal to the set permissible harmonic order, the detection time point is recorded as the harmonic qualified detection time point.

[0033] A1-1-3. Count the number of harmonic qualified detection time points and the number of detection time points, and use the ratio of the number of harmonic qualified detection time points to the number of detection time points as the harmonic order qualified index of the bidirectional energy storage converter in the charging mode, denoted as η1.

[0034] A1-1-4. According to the analysis method of η1, the harmonic amplitude qualification index and harmonic phase qualification index of the bidirectional energy storage converter in charging mode are obtained in the same way, and are recorded as η2 and η3 respectively.

[0035] A1-1-5. Calculate the harmonic qualification index φ1 of the bidirectional energy storage converter in charging mode. φ1=η1*w1+η2*w2+η3*w3. w1, w2 and w3 are the weights of the set harmonic order qualification index, harmonic amplitude qualification index and harmonic phase qualification index respectively. w1+w2+w3=1, w2>w1>w3.

[0036] It should be added that during the charging process, high-amplitude harmonics may cause the voltage or current to exceed the rated value of the equipment. For example, if the charging voltage output by the bidirectional energy storage inverter contains high-amplitude harmonics, when these harmonics are superimposed on the fundamental voltage, the voltage across the energy storage device (such as a battery) will exceed its maximum allowable charging voltage, causing the battery to overcharge. For lithium-ion batteries, overcharging may cause the electrolyte inside the battery to decompose, produce gas, and cause the battery to bulge. In severe cases, it may even cause combustion or explosion. Specific harmonic orders may cause circuit resonance. The bidirectional energy storage inverter charging circuit and the power grid and energy storage system connected to it contain energy storage elements such as inductors and capacitors. When the harmonic frequency (determined by the harmonic order and the fundamental frequency) is equal to the natural frequency of the circuit, resonance will occur. For example, in a circuit containing filter capacitors and line inductors, In the circuit, if a certain harmonic order occurs so that its frequency is exactly the same as the natural frequency of the LC circuit, the harmonic voltage or current will be greatly amplified, which may cause the device to withstand a voltage or current far exceeding the normal level, posing a serious threat to the safety of the device. The harmonic phase mainly affects the superposition effect of harmonics. In most cases, as long as the harmonic amplitude and order are within a reasonable range, the change in harmonic phase will have relatively little direct harm to the device. For example, during the charging process, the difference in harmonic phase will cause the shape of the voltage or current waveform to change, but as long as the harmonic amplitude does not exceed the withstand voltage and current carrying capacity of the device, the harmonic order will not cause resonance and other problems, and the device can usually operate normally. Therefore, w2>w1>w3 is set. For the convenience of analysis, w1 can be specifically taken as 0.3, w2 can be specifically taken as 0.5, and w3 can be specifically taken as 0.2.

[0037] The embodiment of the present invention confirms the harmonic qualified index of the bidirectional energy storage inverter in the charging mode by analyzing the harmonic order qualified index, the harmonic amplitude qualified index and the harmonic phase qualified index, thereby improving the accuracy of the harmonic impact analysis of the bidirectional energy storage inverter, and further improving the effectiveness of the power quality assessment of the bidirectional energy storage inverter, thereby reducing the damage of harmonics to the bidirectional energy storage inverter. At the same time, by setting the weights of the harmonic order qualified index, the harmonic amplitude qualified index and the harmonic phase qualified index, the accuracy of the confirmation of the harmonic qualified index of the bidirectional energy storage inverter in the charging mode is improved, and the comprehensiveness of the assessment of the harmonic impact of the bidirectional energy storage inverter is improved.

[0038] A1-2. According to the charging power rate of the bidirectional energy storage converter at each detection time point in the charging mode, the charging power qualification index φ2 of the bidirectional energy storage converter in the charging mode is calculated.

[0039] Furthermore, the statistical charging power qualification index of the bidirectional energy storage inverter in the charging mode includes: A1-2-1, importing the charging power and the charging power qualification range of the bidirectional energy storage inverter at each detection time point in the charging mode into the charging power qualification analysis model, and obtaining the charging power qualification index of the bidirectional energy storage inverter at each detection time point in the charging mode.

[0040] It should be added that the specific analysis steps of the charging power qualification analysis model are as follows: comparing the charging power of the bidirectional energy storage inverter at each detection time point in the charging mode with the charging power qualification range.

[0041] If the charging power of the bidirectional energy storage converter at a certain detection time point in the charging mode is greater than the upper limit value of the qualified charging power range, the ratio of the upper limit value of the qualified charging power range to the charging power is used as the charging power qualified index of the bidirectional energy storage converter at the detection time point in the charging mode.

[0042] If the charging power of the bidirectional energy storage converter at a certain detection time point in the charging mode is within the qualified charging power range, 1 is used as the qualified charging power index of the bidirectional energy storage converter at the detection time point in the charging mode.

[0043] If the charging power of the bidirectional energy storage inverter at a certain detection time point in the charging mode is less than the lower limit of the charging power qualified range, the ratio of the charging power to the lower limit of the charging power qualified range is used as the charging power qualified index of the bidirectional energy storage inverter at the detection time point in the charging mode, and then the charging power qualified index of the bidirectional energy storage inverter at each detection time point in the charging mode is obtained.

[0044] A1-2-2. Calculate the average value of the charging power qualification index of the bidirectional energy storage converter at each detection time point in the charging mode, and use the calculation result as the charging power qualification index of the bidirectional energy storage converter in the charging mode, denoted as φ2.

[0045] A1-3. The charging efficiency qualification index of the bidirectional energy storage converter in the charging mode is obtained by the same statistical method as φ2, which is recorded as φ3.

[0046] A1-4. Statistical power quality index of bidirectional energy storage converter in charging mode φ1′, φ2′ and φ3′ are respectively the reference harmonic qualified index, charging power qualified index and charging efficiency qualified index.

[0047] It should be added that φ1′, φ2′ and φ3′ are all historical data extracted from the bidirectional energy storage converter control cloud platform, and then analyzed in the same way as φ1, φ2 and φ3.

[0048] A1-5. Compare the power quality qualification index of the bidirectional energy storage converter in the charging mode with the set reference power quality qualification index.

[0049] A1-6. If the power quality qualification index of the bidirectional energy storage converter in the charging mode is greater than the set reference power quality qualification index, charging will continue as the power quality control information of the bidirectional energy storage converter in the charging mode. Otherwise, an abnormal charging quality warning will be issued as the power quality control information of the bidirectional energy storage converter in the charging mode.

[0050] A2. Confirm the power matching control information of the bidirectional energy storage converter in the charging mode according to the charging matching information of each detection time point of the bidirectional energy storage converter in the charging mode.

[0051] Furthermore, the confirmation of the power matching control information of the bidirectional energy storage converter in the charging mode includes: A2-1, based on the charging current of the bidirectional energy storage converter at each detection time point in the charging mode, counting the charging current change rate θ1 of the bidirectional energy storage converter in the charging mode.

[0052] Furthermore, the statistical charging current change rate of the bidirectional energy storage converter in the charging mode includes: A2-1-1, combining each detection time point of the bidirectional energy storage converter in the charging mode with its adjacent next detection time point in pairs to obtain each detection time group of the bidirectional energy storage converter in the charging mode.

[0053] A2-1-2. Subtract the charging current in each detection time group of the bidirectional energy storage converter in the charging mode to obtain the charging current difference of each detection time group of the bidirectional energy storage converter in the charging mode, and use the ratio of the charging current difference to the set reference charging current difference as the charging current change rate of each detection time group of the bidirectional energy storage converter in the charging mode.

[0054] A2-1-3. Filter out the maximum value from the above charging current change rates as the charging current change rate of the bidirectional energy storage converter in the charging mode, recorded as θ1.

[0055] A2-2. According to the charging current of the bidirectional energy storage converter at each detection time point in the charging mode, the charging current matching ratio θ2 of the bidirectional energy storage converter in the charging mode is calculated.

[0056] Furthermore, the statistical charging current matching ratio of the bidirectional energy storage converter in the charging mode includes: A2-2-1, matching and comparing the charging current of the bidirectional energy storage converter at each detection time point in the charging mode with the permitted current range of its energy storage device.

[0057] A2-2-2. If the charging current of the bidirectional energy storage converter at a certain detection time point in the charging mode is within the permitted current range of its energy storage device, the detection time point is recorded as the charging current matching detection time point.

[0058] A2-2-3. Count the number of charging current matching detection time points, and use the ratio of the number of detection time points to the charging current matching ratio of the bidirectional energy storage converter in the charging mode, denoted as θ2.

[0059] A2-3. Calculate the energy matching index ψ of the bidirectional energy storage converter in charging mode. e is a natural constant, θ1′ and θ2′ are the set charging current change rate and charging current matching ratio respectively.

[0060] It should be added that both θ1′ and θ2′ are historical data extracted from the bidirectional energy storage converter control cloud platform, and then analyzed in the same way as θ1 and θ2.

[0061] A2-4. Compare the power matching index of the bidirectional energy storage converter in the charging mode with the set reference power matching index.

[0062] A2-5. If the power matching index of the bidirectional energy storage converter in the charging mode is greater than or equal to the set reference power matching index, charging will continue as the power matching control information of the bidirectional energy storage converter in the charging mode. Otherwise, charging will be stopped as the power matching control information of the bidirectional energy storage converter in the charging mode.

[0063] A3. Use the power quality control information and power matching control information of the bidirectional energy storage converter in the charging mode as the power control information of the bidirectional energy storage converter in the charging mode.

[0064] The converter discharge detection module is used to detect the discharge quality information and discharge matching information of the bidirectional energy storage converter at each detection time point in the discharge mode. The discharge quality information includes the harmonic order, harmonic amplitude, harmonic phase, discharge power and discharge efficiency. The discharge matching information includes the discharge current.

[0065] It should be added that the methods for obtaining the harmonic order, harmonic amplitude, harmonic phase, discharge power, discharge efficiency and discharge current of the bidirectional energy storage inverter at each detection time point in the discharge mode are the same as the methods for obtaining the harmonic order, harmonic amplitude, harmonic phase, discharge power, discharge efficiency and discharge current of the above-mentioned bidirectional energy storage inverter at each detection time point in the charging mode, and will not be repeated here.

[0066] The converter discharge confirmation module is used to confirm the power control information of the bidirectional energy storage converter in the discharge mode according to the charging quality information and charging matching information of the bidirectional energy storage converter at each detection time point in the discharge mode, in accordance with the confirmation method of the power control information of the bidirectional energy storage converter in the charging mode.

[0067] The converter battery detection module is used to detect the battery temperature of the bidirectional energy storage converter at each detection time point.

[0068] It should be added that the battery temperature of the bidirectional energy storage converter at each detection time point is detected by a semiconductor temperature sensor installed on the bidirectional energy storage converter. Its working principle is: the temperature is measured by using the characteristic that the resistivity of the semiconductor material changes with temperature, or the characteristic that the forward voltage of the semiconductor PN junction changes with temperature. When the temperature rises, the resistivity of the semiconductor will decrease, or the forward voltage of the PN junction will decrease. The temperature value is obtained by measuring the change in the resistance value or voltage value of the semiconductor sensor and passing through the corresponding signal processing circuit.

[0069] The embodiment of the present invention confirms the power control information of the bidirectional energy storage inverter in the charging mode according to the charging quality information and charging matching information of the bidirectional energy storage inverter at each detection time point in the charging mode, thereby avoiding the current problem of insufficient attention to the analysis of the charging and discharging quality control of the bidirectional energy storage inverter during the charging and discharging process, ensuring the power quality of the bidirectional energy storage inverter, and further improving the operating efficiency of the bidirectional energy storage inverter, thereby ensuring the stability of the bidirectional energy storage inverter during the charging process.

[0070] The converter battery confirmation module is used to confirm the battery control information of the bidirectional energy storage converter according to the battery temperature of the bidirectional energy storage converter at each detection time point.

[0071] See also Figure 3 As shown, exemplarily, the confirming of the battery control information of the bidirectional energy storage converter includes: G1, according to the battery temperature of the bidirectional energy storage converter at each detection time point, counting the battery temperature qualification index ξ of the bidirectional energy storage converter.

[0072] Furthermore, the statistical calculation of the battery temperature qualification index of the bidirectional energy storage inverter includes: G1-1, matching and comparing the battery temperature of the bidirectional energy storage inverter at each detection time point with the battery temperature range corresponding to each battery temperature qualification index, and then obtaining the battery temperature qualification index of the bidirectional energy storage inverter at each detection time point.

[0073] G1-2. Filter out the minimum value from the battery temperature qualification index of the bidirectional energy storage converter at each detection time point as the battery temperature qualification index of the bidirectional energy storage converter, recorded as ξ.

[0074] G2. Compare the battery temperature qualification index of the bidirectional energy storage converter with the set reference battery temperature qualification index.

[0075] G3. If the battery temperature qualification index of the bidirectional energy storage converter is greater than or equal to the set reference battery temperature qualification index, the battery safety is used as the battery control information of the bidirectional energy storage converter. Otherwise, the battery abnormality warning is used as the battery control information of the bidirectional energy storage converter.

[0076] The embodiment of the present invention confirms the battery control information of the bidirectional energy storage inverter according to the battery temperature of the bidirectional energy storage inverter at each detection time point, thereby breaking the current deficiency of not considering the battery status of the bidirectional energy storage inverter during the charging and discharging process, ensuring the service life of the battery of the bidirectional energy storage inverter, and further reducing the aging of the battery of the bidirectional energy storage inverter, thereby improving the battery performance of the bidirectional energy storage inverter, while ensuring the energy utilization efficiency of the bidirectional energy storage inverter and reducing the risk of failure of the bidirectional energy storage inverter.

[0077] The converter feedback terminal is used to perform corresponding control feedback on the bidirectional energy storage converter control cloud platform according to the power control information of the bidirectional energy storage converter in the charging mode and the discharging mode and the battery control information of the bidirectional energy storage converter.

[0078] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, they shall all fall within the protection scope of the present invention.

Claims

1. A bidirectional energy storage converter based on digital control, characterized in that: include: The converter charging monitoring module is used to monitor the charging quality information and charging matching information of the bidirectional energy storage converter at each detection time point in the charging mode. The charging quality information includes the harmonic order, harmonic amplitude, harmonic phase, charging power and charging efficiency. The charging matching information includes the charging current. The converter charging confirmation module is used to confirm the power control information of the bidirectional energy storage converter in the charging mode according to the charging quality information and charging matching information of each detection time point of the bidirectional energy storage converter in the charging mode; The converter discharge monitoring module is used to monitor the discharge quality information and discharge matching information of the bidirectional energy storage converter at each detection time point in the discharge mode. The discharge quality information includes the harmonic order, harmonic amplitude, harmonic phase, discharge power and discharge efficiency. The discharge matching information includes the discharge current. The converter discharge confirmation module is used to confirm the power control information of the bidirectional energy storage converter in the discharge mode according to the charging quality information and charging matching information of the bidirectional energy storage converter at each detection time point in the discharge mode, and in accordance with the confirmation method of the power control information of the bidirectional energy storage converter in the charging mode; The converter battery monitoring module is used to monitor the battery temperature of the bidirectional energy storage converter at each detection time point; The converter battery confirmation module is used to confirm the battery control information of the bidirectional energy storage converter according to the battery temperature of the bidirectional energy storage converter at each detection time point; The converter feedback terminal is used to perform corresponding control feedback on the bidirectional energy storage converter control cloud platform according to the power control information of the bidirectional energy storage converter in the charging mode and the discharging mode and the battery control information of the bidirectional energy storage converter.

2. A bidirectional energy storage converter based on digital control according to claim 1, characterized in that: The step of confirming the electric energy control information of the bidirectional energy storage converter in the charging mode includes: A1. Confirming the power quality control information of the bidirectional energy storage converter in the charging mode according to the charging quality information of each detection time point of the bidirectional energy storage converter in the charging mode; A2. Confirming the power matching control information of the bidirectional energy storage converter in the charging mode according to the charging matching information of each detection time point of the bidirectional energy storage converter in the charging mode; A3. Use the power quality control information and power matching control information of the bidirectional energy storage converter in the charging mode as the power control information of the bidirectional energy storage converter in the charging mode.

3. A bidirectional energy storage converter based on digital control according to claim 2, characterized in that: The confirming of the power quality control information of the bidirectional energy storage converter in the charging mode includes: According to the harmonic order, harmonic amplitude and harmonic phase of the bidirectional energy storage converter at each detection time point in the charging mode, the harmonic qualification index φ1 of the bidirectional energy storage converter in the charging mode is calculated; According to the charging power of the bidirectional energy storage converter at each detection time point in the charging mode, the charging power qualification index φ2 of the bidirectional energy storage converter in the charging mode is calculated; According to the statistical method of φ2, the charging efficiency qualified index of the bidirectional energy storage converter in the charging mode is obtained, which is recorded as φ3; Statistical analysis of the power quality index of the bidirectional energy storage converter in charging mode φ1′, φ2′ and φ3′ are the reference harmonic qualified index, charging power qualified index and charging efficiency qualified index respectively; Compare the power quality qualified index of the bidirectional energy storage converter in the charging mode with the set reference power quality qualified index; If the power quality qualification index of the bidirectional energy storage inverter in the charging mode is greater than the set reference power quality qualification index, charging will continue as the power quality control information of the bidirectional energy storage inverter in the charging mode. Otherwise, an abnormal charging quality warning will be issued as the power quality control information of the bidirectional energy storage inverter in the charging mode.

4. A bidirectional energy storage converter based on digital control according to claim 3, characterized in that: The statistical harmonic qualification index of the bidirectional energy storage converter in the charging mode includes: Compare the harmonic order of the bidirectional energy storage converter at each detection time point in the charging mode with the set permissible harmonic order; If the harmonic order of a certain detection time point of the bidirectional energy storage converter in the charging mode is less than or equal to the set permissible harmonic order, the detection time point is recorded as the harmonic qualified detection time point; The number of harmonic qualified detection time points and the number of detection time points are counted, and the ratio of the number of harmonic qualified detection time points to the number of detection time points is used as the harmonic order qualified index of the bidirectional energy storage converter in the charging mode, which is recorded as η1; According to the analysis method of η1, the harmonic amplitude qualified index and harmonic phase qualified index of the bidirectional energy storage converter in the charging mode are analyzed in the same way, and are recorded as η2 and η3 respectively; The harmonic qualified index φ1 of the bidirectional energy storage converter in the charging mode is calculated, φ1=η1*w1+η2*w2+η3*w3, w1, w2 and w3 are the weights of the set harmonic order qualified index, harmonic amplitude qualified index and harmonic phase qualified index respectively, w1+w2+w3=1, w2>w1>w3.

5. The bidirectional energy storage converter based on digital control according to claim 3, characterized in that: The method of calculating the charging power qualification index of the bidirectional energy storage converter in the charging mode includes: The charging power of the bidirectional energy storage converter at each detection time point in the charging mode is introduced into the charging power qualification analysis model to obtain the charging power qualification index of the bidirectional energy storage converter at each detection time point in the charging mode; The charging power qualified index of the bidirectional energy storage converter at each detection time point in the charging mode is averaged and the calculation result is used as the charging power qualified index of the bidirectional energy storage converter in the charging mode, which is recorded as φ2.

6. A bidirectional energy storage converter based on digital control according to claim 2, characterized in that: The confirming of the power matching control information of the bidirectional energy storage converter in the charging mode includes: According to the charging current of the bidirectional energy storage converter at each detection time point in the charging mode, the charging current change rate θ1 of the bidirectional energy storage converter in the charging mode is calculated; According to the charging current of the bidirectional energy storage converter at each detection time point in the charging mode, the charging current matching ratio θ2 of the bidirectional energy storage converter in the charging mode is calculated; Statistical analysis of the energy matching index ψ of the bidirectional energy storage converter in charging mode, e is a natural constant, θ′1 and θ′2 are the set charging current change rate and charging current matching ratio respectively; Compare the power matching index of the bidirectional energy storage converter in the charging mode with the set reference power matching index; If the power matching index of the bidirectional energy storage inverter in the charging mode is greater than or equal to the set reference power matching index, charging will continue as the power matching control information of the bidirectional energy storage inverter in the charging mode; otherwise, charging will be stopped as the power matching control information of the bidirectional energy storage inverter in the charging mode.

7. A bidirectional energy storage converter based on digital control according to claim 6, characterized in that: The method of calculating the charging current change rate of the bidirectional energy storage converter in the charging mode includes: Combining each detection time point of the bidirectional energy storage converter in the charging mode with its adjacent next detection time point in pairs, to obtain each detection time group of the bidirectional energy storage converter in the charging mode; The charging current of each detection time group of the bidirectional energy storage converter in the charging mode is subtracted to obtain the charging current difference of each detection time group of the bidirectional energy storage converter in the charging mode, and the ratio of the charging current difference to the set reference charging current difference is used as the charging current change rate of each detection time group of the bidirectional energy storage converter in the charging mode; The maximum value is selected from the above charging current change rates as the charging current change rate of the bidirectional energy storage converter in the charging mode, which is recorded as θ1.

8. The bidirectional energy storage converter based on digital control according to claim 6, characterized in that: The method of calculating the charging current matching ratio of the bidirectional energy storage converter in the charging mode includes: Match and compare the charging current of the bidirectional energy storage converter at each detection time point in the charging mode with the permitted current range of its energy storage device; If the charging current of the bidirectional energy storage converter at a certain detection time point in the charging mode is within the permitted current range of its energy storage device, the detection time point is recorded as the charging current matching detection time point; The number of charging current matching detection time points is counted, and the ratio of the number of charging current matching detection time points to the number of detection time points is used as the charging current matching ratio of the bidirectional energy storage converter in the charging mode, which is recorded as θ2.

9. The bidirectional energy storage converter based on digital control according to claim 1, characterized in that: The confirming of the battery control information of the bidirectional energy storage converter includes: G1. According to the battery temperature of the bidirectional energy storage converter at each detection time point, the battery temperature qualification index ξ of the bidirectional energy storage converter is calculated; G2. Compare the battery temperature qualification index of the bidirectional energy storage converter with the set reference battery temperature qualification index; G3. If the battery temperature qualification index of the bidirectional energy storage converter is greater than or equal to the set reference battery temperature qualification index, the battery safety is used as the battery control information of the bidirectional energy storage converter. Otherwise, the battery abnormality warning is used as the battery control information of the bidirectional energy storage converter.

10. A bidirectional energy storage converter based on digital control according to claim 9, characterized in that: The statistical method for determining the battery temperature qualification index of the bidirectional energy storage converter includes: The battery temperature of the bidirectional energy storage converter at each detection time point is matched and compared with the battery temperature range corresponding to each battery temperature qualification index, so as to obtain the battery temperature qualification index of the bidirectional energy storage converter at each detection time point; The minimum value is selected from the battery temperature qualification index of the bidirectional energy storage converter at each detection time point as the battery temperature qualification index of the bidirectional energy storage converter, which is recorded as ξ.

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