Energy management system for flexibly scheduling energy of photovoltaic energy compensation battery

Abstract

The invention discloses an energy management system for flexibly scheduling energy of a photovoltaic energy compensation battery, which comprises an energy management system connected with a system load, a photovoltaic panel and a battery. The energy management system comprises a main controller, a switching converter, two current detection circuits and three voltage detection circuits. The switching mode converter is used for converting energy of the photovoltaic panel into energy available for a system load, and the type of the switching mode converter is selected according to the relation between the voltage VPV of the photovoltaic panel and the voltage Vbat of the battery; according to the invention, the current Iload required by the system load after the energy management module can be tracked in real time, and the energy generated by the photovoltaic panel can be converted into the current Iout to the load to the maximum extent in time, so that the load of the battery is reduced, namely, the Ibat is reduced, and the cruising ability of the battery is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of energy management, and in particular to an energy management system that flexibly schedules photovoltaic energy to compensate for battery energy. Background Art

[0002] In remote control models (such as remote control aircraft models, ship models, car models, etc.), batteries are a common source of driving energy; their common application scenarios in remote control models, such as Figure 7 As shown, the battery is limited by its capacity and its usage time is not too long. Taking fixed-wing aircraft models as an example, the general battery life is about 20 minutes.

[0003] With the popularization of photovoltaic technology, solar panels are occasionally used in remote control models. Common application scenarios in remote control include: Figure 8 As shown in Figure 2, its penetration rate is still relatively low. The reason is that photovoltaic energy has inherent and insurmountable volatility when applied. That is, the amount of energy it provides is affected by many factors such as season, light angle, and light intensity.

[0004] In order to address the inherent shortcomings of a single energy supply system, namely the short battery life of a battery-powered system and the large power supply fluctuations of a photovoltaic power supply system, the present invention proposes an energy management system that can flexibly dispatch photovoltaic energy and compensate for battery energy output. Summary of the Invention

[0005] The object of the present invention is to provide an energy management system that flexibly schedules photovoltaic energy to compensate for battery energy, so as to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solutions: an energy management system for flexibly scheduling photovoltaic energy to compensate for battery energy, comprising an energy management system to which a system load, a photovoltaic panel, and a battery are connected;

[0007] The energy management system includes a main controller, a switch-mode converter, two current detection circuits and three voltage detection circuits;

[0008] Switching converter: used to convert the energy of photovoltaic panels into energy that can be used by system loads. Its type depends on the photovoltaic panel voltage V PV With the battery voltage V bat relationship selection;

[0009] When V PV <V bat When , a Boost converter or a Buck-Boost converter is used;

[0010] When V PV ≈Vbat When using Buck-Boost converter;

[0011] When V PV >V bat When using Buck converter or Buck-Boost converter;

[0012] Two current detection circuits: used to detect the system load current I load And generate a voltage signal V io2 and detect the output current I of the switching converter out And generate a voltage signal V io1 ;

[0013] Three-way voltage detection circuit: used to sense the photovoltaic panel voltage V PV The size of the switching converter output voltage V o1 The size and battery voltage V bat size;

[0014] Main controller: electrically connected to two current detection circuits, three voltage detection circuits and the switch-mode converter, used to compare V io1 With V io2 , by adjusting the PWM signal through the algorithm, controlling the switching converter to make I out Follow I load , to reduce the battery supply current I bat .

[0015] Preferably, when the switching converter adopts a Boost converter, the Boost converter comprises an inductor L1, a switch tube Q1, a synchronous rectifier tube Q2 and an output capacitor C1, which is used for V PV <V bat When boosting.

[0016] Preferably, when the switching converter adopts a Buck-Boost converter, the Buck-Boost converter comprises an inductor L1, switch tubes Q1, Q3 and synchronous rectifier tubes Q2, Q4, for V PV <V bat or V PV ≈V bat or V PV >V bat Time boost and drop.

[0017] Preferably, when the switching converter adopts a Buck converter, the Buck converter comprises an inductor L1, a switch tube Q3, a synchronous rectifier tube Q4 and an output capacitor C1, which is used for V PV >V bat Time blood pressure reduction.

[0018] Preferably, the main controller is any one of a DSP, an MCU or an FPGA programmable control chip.

[0019] Preferably: the current detection circuit adopts an intrusive or non-intrusive solution;

[0020] The intrusive solution consists of a shunt resistor and a differential amplifier;

[0021] The non-intrusive solution consists of a Hall sensor and an amplifier.

[0022] Preferably, the voltage detection circuit is implemented using a resistor divider.

[0023] Preferably: the energy management system further includes a step-down circuit, a low-pass filter and a diode D1;

[0024] The step-down circuit adopts a linear voltage stabilization circuit or a switching step-down circuit;

[0025] The low-pass filter adopts a hardware filter circuit connected in series between the main controller and the current detection circuit or a digital low-pass filter algorithm integrated in the main controller;

[0026] The diode D1 is connected between the switching converter and the battery to prevent the battery energy from flowing back to the photovoltaic panel.

[0027] Preferably: the energy management system further includes interfaces J1, J2 and J3;

[0028] The interface J1 is connected to the battery, the interface J2 is connected to the system load, and the interface J3 is connected to the photovoltaic panel.

[0029] Compared with the prior art, the present invention has the following advantages: it can track the current required by the system load after the energy management module in real time. load , timely convert the energy generated by the photovoltaic panel into current I to the maximum extent possible out to the load, thereby reducing the load on the battery, that is, reducing I bat , extending its battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A diagram of the electric drive system of a remote control model equipped with the energy management system of the present invention;

[0031] Figure 2 This is a diagram of an energy management system based on a Boost switching converter according to the present invention;

[0032] Figure 3 This is a diagram of the energy management system based on the Buck-Boost switching converter of the present invention;

[0033] Figure 4 This is a diagram of the energy management system based on the Buck switching converter of the present invention;

[0034] Figure 5 When the light is sufficient and the control target is I out =I load The current follows the test waveform when ;

[0035] Figure 6 When the light is insufficient and the control target is I out =αI load , where the current follows the test waveform when 0<α<1;

[0036] Figure 7 A diagram of a battery-powered remote control model electric drive system in the prior art;

[0037] Figure 8 Diagram of the electric drive system of a remote-controlled model that powers photovoltaic panels in the prior art. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0039] See also Figure 1-4 , the present invention provides a technical solution: Figure 1 As shown, the energy management device of the present invention includes a main controller, a switch-mode converter, two current detection circuits (Current Detection Circuit-1 and Current Detection Circuit-2), three voltage detection circuits (Voltage Detection Circuit-1, Voltage Detection Circuit-2, and Voltage Detection Circuit-3), a diode D1, and a step-down circuit to power the main controller and the detection circuits. During operation, the device's external interfaces are J1 (connected to the battery powering the system), J2 (connected to the system load), and J3 (connected to the photovoltaic panel).

[0040] In the application scenario of remote control model, the energy consumed by the system load in real time depends on the remote control command, which may be large or small. The function of the energy management device proposed in the present invention is to track the system load (including Figure 1 The current required by the motor drive module, RF transceiver, servo, etc. load , timely convert the energy generated by the photovoltaic panel into current I to the maximum extent possible out to the load, thereby reducing the load on the battery, that is, reducing I bat , extending its battery life.

[0041] Specifically, its working process is as follows: the system load current I load The current detection circuit-2 generates Vio2 , sent to the main controller, and compared with the voltage signal V obtained by the current detection circuit -1 io1 Compare and adjust the PWM signal output by the main controller through the corresponding algorithm in the main controller to adjust the switching converter from V PV to V o1 The energy conversion is controlled to achieve I out to I load Fully follow the original power supply battery I bat value to extend its battery life.

[0042] Voltage detection circuit-1 is used to sense V PV The voltage detection circuit-2 is used to sense the output voltage V of the switching converter. o1 The voltage detection circuit-3 is used to sense the original power supply battery voltage V bat size.

[0043] The selection of the specific circuit structure of the switching converter in this device mainly depends on V PV 、V bat The size relationship.

[0044] When V PV <V bat When , the switching converter can generally use a Boost converter or a Buck-Boost converter;

[0045] When V PV ≈V bat When the switching converter is , the Buck-Boost converter can generally be used;

[0046] When V PV >V bat When the switching converter is used, a Buck converter or a Buck-Boost converter can generally be used.

[0047] The low-pass filter is primarily used to suppress high-frequency noise (primarily from the motor driver) in the signal from Current Sense Circuit-2 to an acceptable level. This low-pass filter can be a hardware circuit connected in series between the main controller and Current Sense Circuit-2, or it can be integrated into the main controller, using a digital low-pass filter to perform its filtering function.

[0048] The main controller can be a control chip such as DSP, MCU or FPGA that requires software programming to run.

[0049] The voltage detection circuit can be implemented using a common resistor divider.

[0050] Current detection circuits can be implemented using either intrusive or non-intrusive methods. Intrusive methods often use a circuit combining a small shunt resistor with a differential amplifier; non-intrusive current detection methods often use a Hall effect sensor and its corresponding amplifier.

[0051] The introduction of a step-down circuit is primarily due to the fact that the operating voltage required by the main controller and the current sensing circuit's amplifier (e.g., 3.3V or 5.0V) is generally much lower than the voltage of the system's battery or photovoltaic panel (e.g., 12V, 24V). Therefore, the step-down circuit can be implemented using a linear voltage regulator, such as an LDO chip, or a switching step-down circuit, such as a buck converter.

[0052] Diode D1 is mainly used to prevent the battery energy from flowing back to the photovoltaic panel side, thereby cutting off the impact of the switching converter on the original power supply system.

[0053] Example 1

[0054] like Figure 2 As shown; Figure 1 The switching converter in Figure 2 The boost circuit is implemented with synchronous rectification, where Q2 can also be replaced with a diode, that is, the boost circuit is changed to asynchronous rectification, which can also achieve the same boost function; the basic components of the boost circuit are composed of L1, Q1, Q2, and C1 in the figure. The introduction of the current sampling resistor Rs1 and the amplifier Acs is mainly used to monitor the inductor current in real time. The acquisition of this current signal can be used for closed-loop control of the entire boost circuit, such as CPM (current peak control) type control strategy, and can also be used to trigger the protection mechanism when the current in the inductor is overcurrent, cutting off the drive signal of Q1 and Q2. If the closed-loop control strategy of the entire boost circuit does not introduce CPM and overcurrent protection is not required, the Rs1+Acs circuit part can be omitted. The output voltage of the boost circuit V o1 The level of V depends on the duty cycle D1 of the drive signal on Q1, or the duty cycle D2 of the drive signal on Q2 (D2 = 1-D1). o1 The relationship between D1 or D2 follows the following equation:

[0055]

[0056] Figure 1 The medium voltage detection circuit Figure 2 In the embodiment, the voltage dividing resistors R1 / R2, R3 / R4 and R5 / R6 are used; Figure 1 In the current detection circuit, Figure 2In this example, a current detection resistor (Rs1 / 2 / 3) and a differential amplifier Acs are connected in series to the circuit being detected. Rs1+Acs is the current detection circuit introduced by the switching converter Boost circuit for its closed-loop control. The other two sets of current detection circuits have been described above. Figure 1 The main controller in Figure 2 The DSP chip solution is used for implementation.

[0057] During operation, because V PV <V bat Therefore, a Boost circuit is needed to increase the voltage V generated by the photovoltaic panel. PV Boost voltage to higher than battery V bat The voltage value V o1 , the energy generated by the photovoltaic panel can be pushed to the load end through the anti-backflow diode D1. The target value of the converter output current mainly depends on the light conditions of the photovoltaic panel. That is, the stronger the light, the higher the voltage and the larger the output current. At this time, it can be controlled so that I out =I load On the contrary, if the light is weak, the voltage generated by the photovoltaic panel is low and the output current is also small. At this time, the control algorithm needs to be adjusted so that I out =αI load , where 0<α<1, is considered a constant value when the lighting conditions are constant. Taking sufficient lighting conditions as an example, the control target is I out =I load In the case of the converter output current I out Less than the load current I load When the control algorithm inside the DSP will increase D1, then according to formula (4-1), V o1 will increase accordingly; and V o1 The increase in I out The increase in I out to I load In this way, the battery V bat The current I obtained load , it is I out It can greatly reduce or even offset the energy consumption of lithium batteries.

[0058] Example 2

[0059] like Figure 3 As shown; Figure 1 The switching converter in Figure 3The buck-boost circuit is implemented with synchronous rectification, where Q2 and Q4 can be replaced with diodes, that is, the buck-boost circuit is converted to asynchronous rectification, which can also achieve the same conversion function. The basic components of the buck-boost circuit are L1, Q1, Q2, Q3, Q4, and C1 in the figure. The current sampling resistor Rs1 and the amplifier Acs are introduced mainly for real-time monitoring of the inductor current. The acquisition of this current signal can be used for closed-loop control of the entire buck-boost circuit, such as the CPM (current peak control) control strategy. It can also be used to trigger a protection mechanism when the current in the inductor is overcurrent, cutting off the drive signal of Q1, Q2, Q3, and Q4. If the closed-loop control strategy of the entire buck-boost circuit does not introduce CPM and overcurrent protection is not required, the Rs1+Acs circuit section can be omitted. The output voltage Vo1 of the buck-boost circuit depends on the duty cycle D1 of the drive signal on Q1 and Q3, or the duty cycle D2 of the drive signal on Q2 and Q4 (D2 = 1-D1). V o1 The relationship between D1 and D2 follows the following equation:

[0060]

[0061] When working, take the lighting condition as an example, that is, the control target is I out =I load In the case of the converter output current I out Less than the load current I load When the control algorithm inside the DSP will increase D1, then according to formula (4-2), V o1 will increase accordingly; and V o1 The increase in I out The increase in I out to I load In this way, the battery V bat The current I obtained load , it is I out It can greatly reduce or even offset the energy consumption of lithium batteries.

[0062] Implementation Three

[0063] like Figure 4 As shown; Figure 1 The switching converter in Figure 4The Buck circuit is realized by synchronous rectification, and Q4 can also be replaced by a diode, that is, the Buck circuit is changed to non-synchronous rectification, and the same voltage reduction function can also be realized; the basic components of the Buck circuit are composed of L1, Q3, Q4 and C1 in the figure, and the introduction of current sampling resistor Rs1 and amplifier Acs is mainly used for real-time monitoring of inductor current. The collection of this current signal can be used for closed-loop control of the entire Buck circuit, such as CPM (current peak value control) type control strategy, and can also be used for triggering protection mechanism when the current in the inductor overflows, cutting off the driving signal of Q3 and Q4. If the closed-loop control strategy of the entire Buck circuit does not introduce CPM, and does not need overcurrent protection, the Rs1+Acs circuit part can be omitted. The high and low of the output voltage V o1 of the Buck circuit depends on the duty ratio D1 of the driving signal on Q3, or the duty ratio D2 (D2=1-D1) of the driving signal on Q4, and V o1 and D1 follow the following equation:

[0064] V o1 =D1V PV =(1-D2)V PV (4-3)

[0065] In operation, taking sufficient light conditions as an example, the control target is I out =I load , when the current I out output by the converter is less than the load current I load , the control algorithm in the DSP will increase D1, so according to equation (4-3), V o1 will be correspondingly increased; and the increase of V o1 will inevitably lead to the increase of I out , thereby realizing the effect that I out closely follows I load . In this way, the current I bat originally required to be obtained from the battery V load is topped up by I out , thereby greatly reducing or even offsetting the energy consumption of the lithium battery.

[0066] According to the design of embodiment three, the actually measured performance waveform is shown in FIGS. Figure 5 , Figure 6 . Among them: yellow CH1: DRV_H; the driving waveform of the upper tube of the Buck circuit;

[0067] purple CH2: I out ; the output current waveform of the Buck circuit;

[0068] blue CH3: I load ; the current consumed by the electronic governor module;

[0069] Green CH4:V o1 ;Output voltage of the Buck circuit.

[0070] From the above waveforms, we can see that I load It will fluctuate randomly with the throttle control; but no matter how the throttle is adjusted, the Buck output current I out Always closely follow the current I required by the subsequent load load This naturally improves the endurance of the system originally powered by batteries alone, and also solves the stability problem of the system powered by photovoltaic panels alone.

[0071] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An energy management system for flexibly scheduling photovoltaic energy to compensate for battery energy, comprising an energy management system characterized by: The energy management system is connected to a system load, a photovoltaic panel and a battery; The energy management system includes a main controller, a switch-mode converter, two current detection circuits and three voltage detection circuits; Switching converter: used to convert the energy of photovoltaic panels into energy that can be used by system loads. Its type depends on the photovoltaic panel voltage V PV With the battery voltage V bat relationship selection; When V PV <V bat When , a Boost converter or a Buck-Boost converter is used; When V PV ≈V bat When using Buck-Boost converter; When V PV >V bat When using Buck converter or Buck-Boost converter; Two current detection circuits: used to detect the system load current I load And generate a voltage signal V io2 and detect the output current I of the switching converter out And generate a voltage signal V io1 ; Three-way voltage detection circuit: used to sense the photovoltaic panel voltage V PV The size of the switching converter output voltage V o1 The size and battery voltage V bat size; Main controller: electrically connected to two current detection circuits, three voltage detection circuits and the switch-mode converter, used to compare V io1 With V io2 , by adjusting the PWM signal through the algorithm, controlling the switching converter to make I out Follow I load , to reduce the battery supply current I bat .

2. The energy management system for flexibly scheduling photovoltaic energy to compensate for battery energy according to claim 1, characterized in that: When the switching converter adopts a Boost converter, the Boost converter includes an inductor L1, a switch tube Q1, a synchronous rectifier tube Q2 and an output capacitor C1, which is used to PV <V bat When boosting.

3. The energy management system for flexibly scheduling photovoltaic energy to compensate for battery energy according to claim 1, characterized in that: When the switching converter adopts a Buck-Boost converter, the Buck-Boost converter includes an inductor L1, switch tubes Q1, Q3 and synchronous rectifier tubes Q2, Q4, which are used to PV <V bat or V PV ≈V bat or V PV >V bat Time boost and drop.

4. The energy management system for flexibly scheduling photovoltaic energy to compensate for battery energy according to claim 1, characterized in that: When the switching converter adopts a Buck converter, the Buck converter includes an inductor L1, a switch tube Q3, a synchronous rectifier tube Q4 and an output capacitor C1, which is used for V PV >V bat Time blood pressure reduction.

5. The energy management system for flexibly scheduling photovoltaic energy to compensate for battery energy according to claim 1, characterized in that: The main controller is any one of a DSP, an MCU or an FPGA programmable control chip.

6. The energy management system for flexibly scheduling photovoltaic energy to compensate for battery energy according to claim 1, characterized in that: The current detection circuit adopts an intrusive or non-intrusive solution; The intrusive solution consists of a shunt resistor and a differential amplifier; The non-intrusive solution consists of a Hall sensor and an amplifier.

7. The energy management system for flexibly scheduling photovoltaic energy to compensate for battery energy according to claim 1, characterized in that: The voltage detection circuit is implemented by using a resistor divider.

8. The energy management system for flexibly scheduling photovoltaic energy to compensate for battery energy according to claim 1, characterized in that: The energy management system further includes a step-down circuit, a low-pass filter and a diode D1; The step-down circuit adopts a linear voltage stabilization circuit or a switching step-down circuit; The low-pass filter adopts a hardware filter circuit connected in series between the main controller and the current detection circuit or a digital low-pass filter algorithm integrated in the main controller; The diode D1 is connected between the switching converter and the battery to prevent the battery energy from flowing back to the photovoltaic panel.

9. The energy management system for flexibly scheduling photovoltaic energy to compensate for battery energy according to claim 1, characterized in that: The energy management system also includes interfaces J1, J2 and J3; The interface J1 is connected to the battery, the interface J2 is connected to the system load, and the interface J3 is connected to the photovoltaic panel.

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