Hybrid power distribution method, hybrid power distribution circuit and electric device

Abstract

This application discloses a hybrid power distribution method, hybrid power distribution circuit, and electrical equipment. By acquiring bus voltage, battery voltage, and battery current, it provides real-time feedback data for charge and discharge control. It generates a discharge current adapted to the discharge condition based on a second bus reference voltage and the bus voltage, and generates a compensated charging current adapted to the charging condition based on a first bus reference voltage, battery reference voltage, and the battery voltage combined with the bus voltage. Then, it selects the corresponding current as the battery reference current according to the charge and discharge mode. Finally, it combines the charge and discharge mode, battery reference current, and battery current to generate the drive signal for the buck-boost module. This method ensures bus voltage stability during the discharge phase and balances battery charging control requirements with bus voltage stability requirements during the charging phase. It also avoids control logic conflicts during charge and discharge mode switching. This effectively solves the system anomaly problem caused by battery charging lowering the bus voltage in pure photovoltaic power supply scenarios, improving system operational reliability.

Description

Technical Field

[0001] This application relates to the field of photovoltaic energy storage technology, specifically to a hybrid power distribution method, hybrid power distribution circuit, and power-consuming equipment. Background Technology

[0002] In traditional photovoltaic energy storage systems operating in scenarios with pure photovoltaic power supply and no AC auxiliary input, the battery charging process lacks effective coordinated control of the DC bus voltage. When the photovoltaic output power fluctuates or is insufficient to support the battery charging power, the DC bus voltage will be continuously pulled down, which can easily trigger the system's low-voltage protection shutdown or even hardware damage. At the same time, the battery charging and discharging mode switching process has a response lag, making it difficult to simultaneously meet the dual requirements of bus voltage stabilization and battery safety management. Summary of the Invention

[0003] This application provides a hybrid power distribution method, hybrid power distribution circuit, and electrical equipment to alleviate the aforementioned technical problems.

[0004] In a first aspect, this application provides a hybrid power distribution method applied to a hybrid power distribution circuit. The hybrid power distribution circuit includes a photovoltaic boost module and a buck-boost module. The photovoltaic boost module is connected between the photovoltaic module and the DC bus, and the buck-boost module is connected between the energy storage battery and the DC bus. The hybrid power distribution method includes: acquiring the bus voltage of the DC bus and the battery voltage and battery current of the energy storage battery; generating a compensated charging current based on a first bus reference voltage, battery reference voltage, battery voltage, and bus voltage; generating a discharging current based on a second bus reference voltage and bus voltage; selecting either the discharging current or the compensated charging current according to the charging / discharging mode to generate a battery reference current; and generating drive signals to control two switching transistors in the buck-boost module based on the charging / discharging mode using the battery reference current and battery current.

[0005] Secondly, this application also provides a hybrid power distribution circuit, which includes a photovoltaic boost module, a buck-boost module, a sampling module, and a drive control module. The photovoltaic boost module is connected between the photovoltaic module and the DC bus; the buck-boost module is connected between the energy storage battery and the DC bus; the sampling module is connected to the DC bus and the energy storage battery, and is used to acquire the bus voltage of the DC bus and the battery voltage and current of the energy storage battery; the drive control module is connected to the photovoltaic boost module, the buck-boost module, and the sampling module, and is used to: generate a compensated charging current based on a first bus reference voltage, a battery reference voltage, the battery voltage, and the bus voltage; generate a discharging current based on a second bus reference voltage and the bus voltage; select either the discharging current or the compensated charging current according to the charging / discharging mode to generate a battery reference current; and generate drive signals to control two switching transistors in the buck-boost module based on the battery reference current and the battery current according to the charging / discharging mode.

[0006] Thirdly, this application also provides an electrical appliance that performs the above-described hybrid power distribution method when in operation, or the electrical appliance includes the above-described hybrid power distribution circuit.

[0007] The hybrid power distribution method, hybrid power distribution circuit, and electrical equipment provided in this application acquire the DC bus voltage, the battery voltage, and the battery current of the energy storage battery to provide real-time feedback data for charge and discharge control. It generates a discharge current adapted to the discharge condition based on the second bus reference voltage and the bus voltage, and generates a compensated charging current adapted to the charging condition based on the first bus reference voltage, the battery reference voltage, and the battery voltage combined with the bus voltage. Then, it selects the corresponding current as the battery reference current according to the charge and discharge mode. Finally, it combines the charge and discharge mode, the battery reference current, and the battery current to generate the drive signal for the buck-boost module. This ensures bus voltage stability during the discharge phase and balances battery charging control requirements with bus voltage stability requirements during the charging phase. It also avoids control logic conflicts during charge and discharge mode switching, effectively solving the system anomaly problem caused by battery charging lowering the bus voltage in pure photovoltaic power supply scenarios and improving system operational reliability. Attached Figure Description

[0008] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0009] Figure 1 The circuit diagram of the hybrid power distribution circuit provided in the embodiments of this application.

[0010] Figure 2 This is a first flowchart illustrating the hybrid power distribution method provided in an embodiment of this application.

[0011] Figure 3 This is a second flowchart illustrating the hybrid power distribution method provided in an embodiment of this application.

[0012] Figure 4 This is a schematic diagram of the third process of the hybrid power distribution method provided in the embodiments of this application.

[0013] Figure 5 This is a schematic diagram of the structure of the electrical equipment provided in the embodiments of this application.

[0014] Figure label: 10. Photovoltaic boost module; C1, first capacitor; C2, second capacitor; L1, first inductor; Q1, first switching transistor; D1, first diode; 20. Buck-boost module; C5, third capacitor; L2, second inductor; Q2, upper transistor; Q3, lower transistor; 30. Sampling module; 31. First sampling unit; 32. Second sampling unit; 33. Third sampling unit; 34. Fourth sampling unit; 35. Fifth sampling unit; 40. Drive control module; 41. First drive unit; 42. Second drive unit; 43. Third drive unit; 44. Fourth drive unit; 45. Control unit; 50. Active rectifier module; 51. Rectifier bridge; 52. Power factor correction circuit; C4. Fourth capacitor; L3. Third inductor; Q4. Second switching transistor; D2. Second diode; 60. Inverter module; C3. Fifth capacitor; Q5. Third switch; Q6. Fourth switch; Q7. Fifth switch; Q8. Sixth switch; Q9. Seventh switch; Q10. Eighth switch; RS. Sampling resistor; 110. Photovoltaic modules; 120. Energy storage batteries; 130. AC power supply; 140. Compressors; 100. Mixed power distribution circuit; 200. Electrical equipment. Detailed Implementation

[0015] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0016] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features thus defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more unless otherwise explicitly specified.

[0017] Figure 1 This is a circuit diagram of a hybrid power distribution circuit 100 provided in an embodiment of this application. The hybrid power distribution circuit 100 includes a photovoltaic boost module 10, a buck-boost module 20, a sampling module 30, and a drive control module 40. The photovoltaic boost module 10 is connected between the photovoltaic module 110 and the DC bus. The buck-boost module 20 is connected between the energy storage battery 120 and the DC bus. The sampling module 30 is connected to both the DC bus and the energy storage battery 120.

[0018] The sampling module 30 is used to acquire the bus voltage of the DC bus and the battery voltage and current of the energy storage battery 120. The drive control module 40 is connected to the photovoltaic boost module 10, the buck-boost module 20 and the sampling module 30.

[0019] The drive control module 40 is used to: generate a compensated charging current based on the first bus reference voltage, battery reference voltage, battery voltage, and bus voltage; generate a discharging current based on the second bus reference voltage and bus voltage; generate a battery reference current by selecting either the discharging current or the compensated charging current according to the charging / discharging mode; and generate drive signals to control the two switching transistors in the buck-boost module 20 based on the battery reference current and battery current according to the charging / discharging mode.

[0020] It is understood that the hybrid power distribution circuit 100 provided in this application obtains the bus voltage of the DC bus, the battery voltage and battery current of the energy storage battery 120 to provide real-time feedback data for charging and discharging control. It generates a discharge current adapted to the discharge condition based on the second bus reference voltage and the bus voltage, and generates a compensated charging current adapted to the charging condition based on the first bus reference voltage, the battery reference voltage, and the battery voltage combined with the bus voltage. Then, it selects the corresponding current as the battery reference current according to the charging and discharging mode. Finally, it generates the drive signal of the buck-boost module 20 by combining the charging and discharging mode, the battery reference current and the battery current. It can ensure the stability of the bus voltage during the discharge stage and take into account the battery charging control requirements and the bus voltage stability requirements during the charging stage. At the same time, it avoids control logic conflicts when switching charging and discharging modes. It can effectively solve the system abnormality problem caused by the battery charging pulling down the bus voltage in the pure photovoltaic power supply scenario and improve the system operation reliability.

[0021] It should be noted that the photovoltaic boost module 10 is used to boost the variable DC voltage output by the photovoltaic module 110 to match the working voltage level of the DC bus. In a pure photovoltaic power supply scenario, it can efficiently feed the electrical energy generated by the photovoltaic module 110 into the DC bus, providing stable voltage support for downstream load power supply or battery charging. At the same time, in conjunction with the system control strategy, it participates in the bus voltage regulation when there is excess photovoltaic power to avoid the bus voltage from being too high.

[0022] The DC bus includes a positive bus and a negative bus, and the bus voltage is the voltage difference between the positive bus and the negative bus. The bus voltage is higher than the battery voltage; for example, the range of battery voltage is 80V~200V, and the range of bus voltage is 200V~400V.

[0023] In some embodiments, the photovoltaic boost module 10 includes a first inductor L1, a first switch Q1, and a first diode D1. The positive terminal of the photovoltaic module 110 is connected to the first end of the first inductor L1, the second end of the first inductor L1 is connected to the first terminal of the first switch Q1 and the positive terminal of the first diode D1, and the negative terminal of the first diode D1 is connected to the positive bus. The second terminal of the first switch Q1 is connected to the negative terminal of the photovoltaic module 110, the negative bus, and the ground terminal (GND1). The control terminal of the first switch Q1 is connected to the drive control module 40.

[0024] It should be noted that when the photovoltaic boost module 10 is working, the drive control module 40 outputs a pulse width modulation signal to the control electrode of the first switch Q1. When the first switch Q1 is turned on, the positive current of the photovoltaic module 110 flows back to the negative electrode of the photovoltaic module 110 through the first inductor L1 and the first switch Q1. The first inductor L1 stores magnetic energy. At this time, the first diode D1 is cut off due to the reverse voltage, preventing the DC bus power from flowing back. When the first switch Q1 is turned off, the first inductor L1 generates a reverse electromotive force. Its induced voltage is superimposed with the output voltage of the photovoltaic module 110, and then supplies power to the DC positive bus through the turned-on first diode D1, realizing voltage boost conversion. The drive control module 40 can adjust the voltage amplitude output to the DC bus by adjusting the duty cycle of the first switch Q1. In a pure photovoltaic power supply scenario, the unstable DC voltage of the photovoltaic module 110 is converted into a stable high voltage that meets the requirements of the bus, providing energy support for downstream load power supply or battery charging.

[0025] In some embodiments, the photovoltaic boost module 10 further includes a first capacitor C1 and a second capacitor C2. The first end of the first capacitor C1 is connected to the positive terminal of the photovoltaic module 110, the second end of the first capacitor C1 is connected to the first end of the second capacitor C2 and the ground terminal (CH1), and the second end of the second capacitor C2 is connected to the negative terminal of the photovoltaic module 110.

[0026] It should be noted that the first capacitor C1 and the second capacitor C2 are connected in series across the output terminal of the photovoltaic module 110. The two capacitors form a voltage divider network with the ground terminal as the midpoint. On the one hand, the output voltage of the photovoltaic module 110 is evenly distributed to the two capacitors, reducing the withstand voltage requirement of a single capacitor. On the other hand, the charging and discharging characteristics of the capacitors further filter out common-mode interference and electromagnetic noise in the circuit. At the same time, it provides a local low-impedance loop for the current surge generated when the first switching transistor Q1 is turned on, avoiding voltage spikes from damaging the device and ensuring the stability and reliability of the photovoltaic boost module 10 during the boost conversion process.

[0027] The step-up / step-down module 20 is used to realize bidirectional energy transfer and voltage matching between the DC bus and the energy storage battery 120. In charging mode, it steps down or steps up the power of the DC bus to charge the energy storage battery 120. In discharging mode, it converts the power of the energy storage battery 120 to the DC bus to support the load operation. At the same time, in conjunction with the charging and discharging control strategy, it dynamically adapts to the photovoltaic power fluctuation through the current compensation mechanism during the charging process to prevent the battery charging power from being too high and pulling down the DC bus voltage, thus ensuring the stable operation of the system under different operating conditions.

[0028] In some embodiments, the buck-boost module 20 includes a second inductor L2, an upper tube Q2, and a lower tube Q3. The first end of the upper tube Q2 is connected to the positive bus, and the second end of the lower tube Q3 is connected to the negative bus and the negative terminal of the energy storage battery 120. The first end of the second inductor L2 is connected to the positive terminal of the energy storage battery 120, and the second end of the second inductor L2 is connected to the second end of the upper tube Q2 and the first end of the lower tube Q3. The control terminals of the upper tube Q2 and the lower tube Q3 are both connected to the drive control module 40 to receive the first drive signal (G7) and the second drive signal (G8) respectively.

[0029] It should be noted that when the buck-boost module 20 is working, the drive control module 40 outputs complementary drive signals to the upper transistor Q2 and the lower transistor Q3 according to the charging and discharging mode. In the discharging mode, the upper transistor Q2 receives the pulse width modulation signal and is periodically turned on, while the lower transistor Q3 is set to a low level and kept off. The electrical energy released by the energy storage battery 120 is pumped to the DC positive bus through the second inductor L2 and the turned-on upper transistor Q2. The second inductor L2 realizes the boost conversion through magnetic energy storage and release to power the bus load.

[0030] In charging mode, the lower transistor Q3 receives the pulse width modulation signal and is periodically turned on, while the upper transistor Q2 is set to a low level and kept off. The high voltage power of the DC bus is stepped down by the turned-on lower transistor Q3 and the second inductor L2 to charge the energy storage battery 120. During this process, the second inductor L2 limits the rate of change of current to achieve stable charging.

[0031] The upper tube Q2 and the lower tube Q3 always follow the interlock logic to avoid direct short circuits. The drive control module 40 can flexibly control the direction and magnitude of energy transmission by adjusting the duty cycle of the drive signal. With the current closed loop, it can achieve precise control of charging and discharging current. In pure photovoltaic scenarios, it can respond to changes in bus voltage by dynamically adjusting the charging duty cycle to prevent the battery charging from pulling down the system voltage.

[0032] In some embodiments, the buck-boost module 20 further includes a third capacitor C5, the first end of which is connected to the positive terminal of the energy storage battery 120, and the second end of which is connected to the negative terminal of the energy storage battery 120.

[0033] It should be noted that the third capacitor C5 is connected in parallel across the positive and negative terminals of the energy storage battery 120, serving as a local energy storage and filtering unit on the battery side. In charging mode, it can absorb the high-frequency ripple current generated by the switching action of the lower transistor Q3 of the buck-boost module 20, smoothing the charging current waveform flowing into the energy storage battery 120, avoiding current pulsation that exacerbates battery polarization and thus extending battery life. At the same time, in discharging mode, it provides a low-impedance loop for the freewheeling current of the second inductor L2, suppressing the voltage spikes generated during the switching process of the upper transistor Q2 and reducing electromagnetic interference.

[0034] In addition, the third capacitor C5 can provide transient energy buffer when the charging and discharging modes switch instantaneously, which can alleviate the impact caused by voltage changes on the DC bus and the battery side. Together with the energy storage characteristics of the second inductor L2, it can maintain the stability of the battery port voltage and ensure the smooth operation of the buck-boost module 20 in the bidirectional energy conversion process.

[0035] In some embodiments, the hybrid power distribution circuit 100 further includes an active rectifier module 50, which is connected between the AC power supply 130 and the DC bus. The active rectifier module 50 includes a rectifier bridge 51 and a power factor correction circuit 52. The rectifier bridge 51 is connected between the AC power supply 130 and the power factor correction circuit 52, and the power factor correction circuit 52 is connected between the rectifier bridge 51 and the DC bus.

[0036] The active rectifier module 50 is used to rectify and convert the AC power input from the AC power supply 130 through the rectifier bridge 51 into DC power that meets the DC bus voltage requirements; and optimizes the input current waveform through the power factor correction circuit 52 to improve the power utilization efficiency. In the case of AC power supply, it provides a stable and reliable power source for the DC bus, supporting the normal operation of the system and the charging needs of the energy storage battery 120.

[0037] In some embodiments, the power factor correction circuit 52 includes a third inductor L3, a second switch Q4, and a second diode D2. The first end of the third inductor L3 is connected to the positive terminal of the rectifier bridge 51, the second end of the third inductor L3 is connected to the first terminal of the second switch Q4 and the positive terminal of the second diode D2, the negative terminal of the second diode D2 is connected to the positive bus, the second terminal of the second switch Q4 is connected to the negative terminal of the rectifier bridge 51 and the negative bus, and the control terminal of the second switch Q4 is connected to the drive control module 40.

[0038] It should be noted that when the power factor correction circuit 52 is working, the rectifier bridge 51 first converts the AC input AC power into pulsating DC power. The drive control module 40 outputs a high-frequency pulse width modulation signal to the control electrode of the second switch Q4. When the second switch Q4 is turned on, the rectified current flows back to the negative terminal of the rectifier bridge 51 through the third inductor L3 and the second switch Q4. The third inductor L3 stores magnetic energy. At this time, the second diode D2 is turned off due to reverse bias, preventing backflow of DC bus power. When the second switch Q4 is turned off, the third inductor L3 generates a reverse electromotive force. Its induced voltage is superimposed with the rectified input voltage and supplies power to the DC positive bus through the conducting second diode D2. The drive control module 40 adjusts the duty cycle of the second switch Q4 to force the input current waveform to track the sinusoidal waveform of the grid voltage in real time, thereby achieving unity power factor operation, effectively suppressing harmonic pollution, and simultaneously boosting the unstable voltage after rectification to a stable high voltage that meets the requirements of the DC bus, providing high-quality DC power supply support for the system.

[0039] In some embodiments, the power factor correction circuit 52 further includes a fourth capacitor C4, the first end of which is connected to the positive terminal of the rectifier bridge 51, and the second end of which is connected to the negative terminal of the rectifier bridge 51.

[0040] It should be noted that the fourth capacitor C4 is connected in parallel between the positive and negative output terminals of the rectifier bridge 51. As the input filter and energy storage element of the power factor correction circuit 52, it can smooth the pulsating DC output of the rectifier bridge 51, filter out the low-frequency ripple components after rectification, and provide a stable DC input voltage for the energy storage conversion of the third inductor L3 in the subsequent stage.

[0041] Meanwhile, the fourth capacitor C4 can provide transient discharge current to the circuit at the moment the second switch Q4 is turned on, making up for the discontinuous gap in the output current of the rectifier bridge 51, reducing the harmonic feedback of the current surge to the front AC power supply 130, and absorbing the voltage spikes generated during the commutation process of the rectifier bridge 51, suppressing electromagnetic interference, and forming a collaborative filter network with the second diode D2 and the DC bus capacitor in the subsequent stage, ensuring the voltage stability and sinusoidal nature of the input current of the power factor correction circuit 52 during the boost conversion process, and improving the overall energy efficiency of the active rectifier module 50.

[0042] In some embodiments, the hybrid power distribution circuit 100 further includes an inverter module 60, which is connected between the DC bus and an AC load such as the compressor 140.

[0043] The inverter module 60 is used to invert the DC power on the DC bus into AC power that meets the required frequency and voltage, providing driving power for inductive loads such as the compressor 140. During system operation, it dynamically adjusts the output characteristics in accordance with the voltage status of the DC bus, ensuring stable operation of the load while avoiding severe impacts on the DC bus voltage caused by sudden load changes, thus maintaining the overall coordination of system operation.

[0044] In some embodiments, the inverter module 60 includes a third switch Q5, a fourth switch Q6, a fifth switch Q7, a sixth switch Q8, a seventh switch Q9, and an eighth switch Q10.

[0045] The first terminal of the third switch Q5 is connected to the first terminals of the fourth switch Q6 and the fifth switch Q7, as well as the positive busbar. The second terminal of the third switch Q5 is connected to the first terminal of the sixth switch Q8 and the first phase line. The second terminal of the fourth switch Q6 is connected to the first terminal of the seventh switch Q9 and the second phase line. The second terminal of the fifth switch Q7 is connected to the first terminal of the eighth switch Q10 and the third phase line, and is connected to the compressor 140 through the first, second, and third phase lines. The second terminal of the sixth switch Q8 is connected to the second terminals of the seventh switch Q9, the eighth switch Q10, and the negative busbar.

[0046] It should be noted that when the inverter module 60 is working, the drive control module 40 generates six complementary pulse width modulation signals to drive the third to eighth switching transistors Q10 respectively. At any time, by controlling the alternating conduction and cutoff of the bridge arm and lower bridge arm switching transistors on the same phase line, the high voltage DC power between the positive and negative poles of the DC bus is converted into three-phase AC power with a phase difference of 120 degrees.

[0047] Specifically, the third switch Q5 and the sixth switch Q8 work together to control the first phase line voltage, the fourth switch Q6 and the seventh switch Q9 work together to control the second phase line voltage, and the fifth switch Q7 and the eighth switch Q10 work together to control the third phase line voltage. By adjusting the duty cycle of each switch and the carrier frequency of the pulse width modulation wave, a three-phase sinusoidal voltage and current suitable for the operation of the compressor 140 are precisely synthesized. While driving the compressor 140 to operate stably, the high-speed switching characteristics of the switches are used to realize the flexible adjustment of the output voltage amplitude and frequency, which meets the requirements of the compressor 140 for variable frequency speed regulation. Furthermore, the interlocking logic of the upper and lower bridge arms is used to prevent the DC bus from being short-circuited, ensuring the safety and reliability of the energy conversion process.

[0048] In some embodiments, the inverter module 60 further includes a fifth capacitor C3, which is connected between the positive bus and the negative bus.

[0049] It should be noted that the fifth capacitor C3 is connected in parallel between the positive and negative DC bus, serving as the front-end DC support and filtering unit of the inverter module 60. It can effectively absorb the high-frequency ripple and voltage spikes of the DC bus voltage, filter out the voltage fluctuations brought by the upstream photovoltaic boost or active rectifier module 50, and provide a stable DC input voltage for the inverter bridge arm.

[0050] Meanwhile, the fifth capacitor C3 can provide a low-impedance transient charging and discharging circuit during the high-speed switching of the inverter module 60 switching transistor, buffering the back electromotive force impact generated when inductive loads such as compressor 140 start-up, shutdown, or sudden speed changes, suppressing large-scale oscillations in the bus voltage, and preventing voltage over-limit damage to downstream switching devices. Its close cooperation with the inverter bridge not only improves the sinusoidality and stability of the three-phase AC output waveform, but also enhances the system's anti-electromagnetic interference capability, ensuring the efficient and reliable operation of compressor 140 during frequency conversion speed regulation.

[0051] In some embodiments, the sampling module 30 includes at least one of a first sampling unit 31, a second sampling unit 32, a third sampling unit 33, a fourth sampling unit 34, and a fifth sampling unit 35.

[0052] The first sampling unit 31 is connected to the DC bus and the drive control module 40, and is used to sample the DC bus voltage to obtain the bus voltage.

[0053] The second sampling unit 32 is connected to the energy storage battery 120 and the drive control module 40, and is used to sample the voltage and current of the energy storage battery 120 to obtain the battery voltage and battery current.

[0054] The third sampling unit 33 is connected to the photovoltaic module 110 and the drive control module 40, and is used to sample the voltage and current of the photovoltaic module 110 to obtain the photovoltaic voltage and photovoltaic current.

[0055] The fourth sampling unit 34 is connected to the rectifier bridge 51 and the drive control module 40, and is used to sample the voltage and current of the AC power supply 130 to obtain the AC voltage and AC current.

[0056] A sampling resistor RS is connected in series between the grounding terminal (GND1) on the negative bus and the inverter module 60. The fifth sampling unit 35 is connected to the sampling resistor RS and the drive control module 40 to sample the current of the compressor 140.

[0057] In some embodiments, the drive control module 40 includes at least one of a first drive unit 41, a second drive unit 42, a third drive unit 43, and a fourth drive unit 44, and a control unit 45.

[0058] The first drive unit 41 is connected to the control electrode of the first switch Q1 and the control unit 45, and is used to improve the driving capability of the control signal output by the control unit 45 so as to drive the first switch Q1.

[0059] The second drive unit 42 is connected to the control electrode of the upper transistor Q2, the control electrode of the lower transistor Q3, and the control unit 45. It is used to improve the driving capability of the control signal output by the control unit 45 to generate the first drive signal (G7) and the second drive signal (G8) to drive the upper transistor Q2 and the lower transistor Q3.

[0060] The third drive unit 43 is connected to the control electrode of the second switch Q4 and the control unit 45, and is used to improve the driving capability of the control signal output by the control unit 45 to drive the second switch Q4.

[0061] The fourth drive unit 44 is connected to the control electrode of the third switch Q5 to the eighth switch Q10 and the control unit 45, and is used to improve the driving capability of the control signal output by the control unit 45, so as to generate drive signals (G1~G6) to drive the third switch Q5 to the eighth switch Q10.

[0062] This embodiment also provides a hybrid power distribution method, applied to a hybrid power distribution circuit 100. For example... Figure 2 As shown, the hybrid power distribution method includes the following steps: Step S10: Obtain the DC bus voltage and the battery voltage and current of the energy storage battery.

[0063] Step S20: Generate the compensated charging current based on the first bus reference voltage, battery reference voltage, battery voltage, and bus voltage.

[0064] Step S30: Generate a discharge current based on the second bus reference voltage and the bus voltage.

[0065] Step S40: Select the discharge current or the compensated charging current according to the charging and discharging mode, and generate the battery reference current.

[0066] Step S50: Based on the charging / discharging mode, generate drive signals to control the two switching transistors in the buck-boost module using the battery reference current and battery current.

[0067] It is understood that the hybrid power distribution method provided in this application obtains the bus voltage of the DC bus, the battery voltage and battery current of the energy storage battery 120 to provide real-time feedback data for charge and discharge control. It generates a discharge current adapted to the discharge condition based on the second bus reference voltage and the bus voltage, and generates a compensated charging current adapted to the charging condition based on the first bus reference voltage, the battery reference voltage, and the battery voltage and bus voltage. Then, it selects the corresponding current as the battery reference current according to the charge and discharge mode. Finally, it generates the drive signal of the buck-boost module 20 by combining the charge and discharge mode, the battery reference current and the battery current. It can ensure the stability of the bus voltage during the discharge stage and take into account the battery charging control requirements and the bus voltage stability requirements during the charging stage. At the same time, it avoids control logic conflicts when switching between charge and discharge modes. It can effectively solve the system abnormality problem caused by the battery charging pulling down the bus voltage in the pure photovoltaic power supply scenario and improve the system operation reliability.

[0068] In some embodiments, a compensated charging current is generated based on the first bus reference voltage, the battery reference voltage, the battery voltage, and the bus voltage, such as... Figure 3 As shown, it includes the following steps: Step S21: Generate the charging base current based on the battery reference voltage and the battery voltage.

[0069] Step S22: Generate charging compensation current based on the first bus reference voltage and the bus voltage.

[0070] Step S23: Generate the compensated charging current based on the difference between the base charging current and the compensation charging current.

[0071] It should be noted that this embodiment first uses a battery voltage closed-loop to perform a proportional-integral calculation on the difference between the battery reference voltage and the actual battery voltage to generate a base charging current that ensures safe and stable battery charging. Simultaneously, a bus voltage protection closed-loop operates in parallel, performing a proportional-integral calculation on the difference between the set first bus reference voltage and the actual bus voltage to generate a charging compensation current to suppress bus voltage drops. This compensation current is then subject to a lower limit to ensure a positive output only when the bus voltage is low. Finally, by subtracting the charging compensation current from the base charging current, the compensated charging current is obtained. This mechanism allows the system to ensure normal battery charging while automatically reducing charging power when insufficient photovoltaic energy causes a bus voltage drop, thus balancing battery management needs with bus voltage stability and achieving smooth switching between charging and discharging modes.

[0072] In some embodiments, generating a charging base current based on a battery reference voltage and a battery voltage includes: generating a first voltage error signal based on the difference between the battery reference voltage and the battery voltage; and performing a proportional-integral operation on the first voltage error signal to obtain the charging base current.

[0073] It should be noted that this embodiment constructs a closed-loop control of battery voltage, using the difference between the battery reference voltage and the actual sampled battery voltage as the first voltage error signal. After proportional-integral calculation, a charging base current is generated, which can achieve accurate tracking and zero steady-state error control of the battery charging voltage. It can dynamically adjust the charging current according to the battery characteristics to adapt to constant voltage or constant current charging requirements, avoiding overcharging or over-discharging of the battery. At the same time, it can suppress battery voltage fluctuations through the fast response characteristics of proportional-integral calculation, ensuring a stable and controllable charging process. It provides a stable and reliable benchmark for the subsequent collaborative generation of the final charging current with the bus voltage compensation stage, thereby improving the safety of battery charging and the overall operational stability of the system from the source.

[0074] In some embodiments, generating a charging compensation current based on a first bus reference voltage and a bus voltage includes: generating a second voltage error signal based on the difference between the first bus reference voltage and the bus voltage; performing a proportional-integral operation on the second voltage error signal to obtain an initial charging compensation current; and limiting the initial charging compensation current to obtain the final charging compensation current.

[0075] It should be noted that this embodiment constructs a bus voltage monitoring closed loop with the first bus reference voltage as the protection threshold. The difference between the first bus reference voltage and the actual bus voltage is used as the second voltage error signal. The initial charging compensation current is generated through proportional-integral calculation. By implementing lower limit limiting processing on this initial current, an effective positive compensation current is output only when the bus voltage is lower than the set threshold, and clamped to zero when the bus voltage is normal. This can accurately identify the power deficit risk in pure photovoltaic power supply scenarios, avoid the bus voltage being continuously pulled down by battery charging, and prevent unnecessary interference to the charging base current when the bus voltage is normal. It ensures that the charging compensation link intervenes only when necessary, achieving a dynamic balance between battery charging demand and bus voltage stability, and effectively avoiding system shutdown or damage caused by low voltage anomalies.

[0076] In some embodiments, the initial charging compensation current is limited to obtain the charging compensation current, including: when the initial charging compensation current is negative, setting the charging compensation current to zero; when the initial charging compensation current is zero or positive, setting the charging compensation current to the initial charging compensation current.

[0077] It should be noted that this embodiment constructs a one-way action mechanism for the charging compensation stage. By clamping negative values ​​to zero, the effective compensation amount is output only when the bus voltage is lower than the first bus reference voltage, resulting in a positive initial charging compensation current. This fundamentally avoids the problem of artificially increased charging current caused by the reverse superposition of compensation current when the bus voltage is normal or high. This ensures that the compensation stage only intervenes to adjust when there is a risk of bus voltage drop, preventing ineffective interference to the normal charging process. Furthermore, the zero-value cutoff simplifies the control logic and avoids the integral saturation phenomenon of proportional-integral calculation when the bus voltage is sufficient. This ensures that the system can quickly respond to the bus voltage stabilization requirements when photovoltaic energy fluctuates, and maintain the high efficiency of battery charging when energy is sufficient. This significantly improves the control reliability and bus voltage anti-disturbance capability in the charging mode.

[0078] In some embodiments, generating a discharge current based on a second bus reference voltage and a bus voltage includes: generating a third voltage error signal based on the difference between the second bus reference voltage and the bus voltage; and performing a proportional-integral operation on the third voltage error signal to obtain the discharge current.

[0079] It should be noted that this embodiment constructs an independent closed-loop control path for the bus voltage in the discharge mode. By using the difference between the second bus reference voltage and the actual bus voltage as the third voltage error signal, and generating the discharge current through proportional-integral calculation, it is possible to achieve high-precision, zero-steady-state-error tracking of the DC bus voltage, ensuring the stability of the voltage amplitude when the energy storage battery 120 discharges to support the bus.

[0080] This control strategy utilizes the dynamic response characteristics of the proportional-integral regulator to error signals, which can quickly suppress bus voltage fluctuations caused by compressor 140 start-up or load sudden changes, while avoiding regulation lag caused by integral saturation. This not only ensures a stable power supply for the downstream inverter load, but also achieves adaptive adjustment of the discharge current according to the bus voltage deviation, effectively improving the dynamic response capability and power supply reliability of the system under off-grid or pure energy storage power supply conditions.

[0081] In some embodiments, the charge / discharge mode includes a charging mode and a discharging mode. A battery reference current is generated by selecting a discharging current or a compensated charging current based on the charge / discharge mode. This includes: when the charge / discharge mode is a discharging mode, selecting the discharging current as the initial reference current; when the charge / discharge mode is a charging mode, selecting the compensated charging current as the initial reference current; and applying current-limiting control to the initial reference current to obtain the battery reference current.

[0082] It should be noted that this embodiment achieves dynamic switching of the dual-mode control strategy through the discrimination logic of charging and discharging modes. In the discharging mode, the discharge current with the bus voltage stabilization target is accurately selected as the initial reference. In the charging mode, the compensated charging current that integrates battery management and bus protection requirements is selected as the initial reference. From the architecture, the instruction conflict that may be caused by the parallel operation of the dual-loop control logic is avoided, ensuring the uniqueness and determinism of the control strategy.

[0083] The current limiting control circuit introduced on this basis constitutes the last safety barrier for power devices. Regardless of the mode, it can hard-constrain the initial reference current based on the tolerance of the battery and the switching transistor, effectively preventing overcurrent damage caused by sudden command changes or extreme operating conditions. Thus, while achieving smooth switching between charging and discharging, it also takes into account the stability of system operation and the safety of power devices, significantly improving the robustness of the hybrid power distribution system under complex operating conditions.

[0084] In some embodiments, the two switching transistors include an upper transistor Q2 driven by a first driving signal and a lower transistor Q3 driven by a second driving signal. Based on the charging / discharging mode and the battery reference current and battery current, drive signals are generated to control the two switching transistors in the buck-boost module 20. This includes: generating a current error signal based on the difference between the battery reference current and the battery current; performing a proportional-integral operation on the current error signal to obtain a pulse-width modulation (PWM) signal; when the charging / discharging mode is discharging mode, selecting the PWM signal as the first driving signal and setting the level of the second driving signal to low; when the charging / discharging mode is charging mode, selecting the PWM signal as the second driving signal and setting the level of the first driving signal to low.

[0085] It should be noted that this embodiment constructs a unified charging and discharging current inner loop control architecture. By performing proportional-integral calculations on the deviation between the battery reference current and the actual battery current to generate a pulse width modulation signal, millisecond-level precise tracking and zero steady-state error control of the charging and discharging current are achieved.

[0086] With the mutual exclusion logic of charging and discharging modes, in discharging mode, the modulation signal is dedicated to driving the upper MOSFET Q2 to turn on and forcing the lower MOSFET Q3 to turn off, and in charging mode, the modulation signal is dedicated to driving the lower MOSFET Q3 to turn on and forcing the upper MOSFET Q2 to turn off. This eliminates the risk of direct short circuit between the upper and lower MOSFETs Q3 at the hardware level, while ensuring the uniqueness of the inductor current path.

[0087] This control strategy enables the system to maintain excellent dynamic response characteristics in any mode, quickly suppress current surges, and smoothly transition load changes. It not only ensures the safe operation of the power switching transistors in the step-up / step-down module 20, but also achieves efficient management of bidirectional energy flow between the battery and the bus, greatly improving the stability and reliability of the system under all operating conditions.

[0088] Figure 4 The third process diagram of the hybrid power distribution method provided in the embodiments of this application is as follows: According to the battery reference voltage (Ubat) The difference between the voltage of the battery and the voltage of the mains (Ubat) generates a first voltage error signal. A proportional-integral (PI) operation is performed on the first voltage error signal to obtain the charging base current.

[0089] Based on the first bus reference voltage (Udc2) The difference between the voltage and the bus voltage (Udc) generates a second voltage error signal. A proportional-integral (PI) operation is performed on the second voltage error signal to obtain the initial charging compensation current. The initial charging compensation current is then limited to obtain the charging compensation current (ΔI).

[0090] When the initial charging compensation current is negative, the charging compensation current (ΔI) is set to zero. When the initial charging compensation current is zero or positive, the charging compensation current (ΔI) is set to the initial charging compensation current.

[0091] Based on the second bus reference voltage (Udc) The difference between the voltage and the bus voltage (Udc) generates a third voltage error signal. A proportional-integral (PI) operation is performed on the third voltage error signal to obtain the discharge current.

[0092] When the charging / discharging mode is discharge mode, the discharge current is selected as the initial reference current (Iref). When the charging / discharging mode is charging mode, the compensated charging current is selected as the initial reference current (Iref). Current limiting control is applied to the initial reference current (Iref) to obtain the battery reference current (Ibat). ).

[0093] According to the battery reference current (Ibat) The difference between the battery current (Ibat) and the current is used to generate a current error signal. A proportional-integral (PI) operation is performed on the current error signal to obtain a pulse width modulation (PWM) signal.

[0094] When the charging / discharging mode is the discharge mode, the pulse width modulation signal (PWM) is selected as the first drive signal (G7), and the level of the second drive signal (G8) is set to low level (0).

[0095] When the charging / discharging mode is charging mode, the pulse width modulation signal (PWM) is selected as the second drive signal (G8), and the level of the first drive signal (G7) is set to low level (0).

[0096] Discharge Mode: After the system determines that it has entered discharge mode, the control logic selects the second bus reference voltage (Udc) as the reference voltage. A voltage loop targeting the actual bus voltage (Udc) is constructed. This loop uses the actual bus voltage (Udc) as feedback. The output discharge current, after being controlled by current limiting (which is calculated in real-time by the battery management system (BMS) based on parameters such as battery temperature, SOC, and SOH) and undergoing current closed-loop processing, generates the final battery reference current (Ibat). The drive control module 40 outputs a pulse width modulation signal accordingly and configures the switching transistor drive logic: sets the first drive signal (G7) of the upper transistor Q2 to a low level and the second drive signal (G8) of the lower transistor Q3 to a pulse width modulation signal.

[0097] Corresponding to Figure 1 In this step-up / step-down topology, the circuit operates in Boost mode. During the conduction of the lower transistor Q3, the energy storage battery 120 stores energy through the second inductor L2. During the turn-off of the lower transistor Q3, the energy stored in the second inductor L2 is released to the DC bus through the freewheeling diode of the upper transistor Q2 to maintain the stability of the bus voltage.

[0098] Charging Mode: After the system determines that it has entered charging mode, it selects the voltage loop (Ubat) of the 120 kWh energy storage battery. (Calculated by BMS scheduling), the output of the voltage loop of the energy storage battery 120 is obtained after current limiting control (current limiting control is calculated in real time by the battery cell BMS scheduling based on parameters such as battery temperature, SOC, and SOH). The current loop calculates the PWM through PI. At this time, the first drive signal of the upper transistor Q2 is PWM, and the level of the second drive signal of the lower transistor Q3 is low (0).

[0099] correspond Figure 1 At this time, the battery charging is running in the BUCK mode of the BUCK-BOOST circuit. When the upper transistor Q2 is turned on, it charges the second inductor L2 and the battery. When the upper transistor Q2 is turned off, the energy stored in the second inductor L2 continues to supply energy to the battery through the freewheeling diode of the lower transistor Q3 for a short period of time until the energy of the second inductor L2 is completely released.

[0100] In pure photovoltaic (PV) power supply scenarios, the PV-side control strategy works in synergy with the battery-side strategy. When the PV output power (Ppv) exceeds the power consumed by battery charging (Pload), the PV side maintains a stable bus voltage (Udc) through curtailment control. At this time, Udc is higher than the set Udc2. The charging compensation current (ΔI) is limited to 0, and the energy storage battery 120 is based on Ubat. Free charging.

[0101] When the photovoltaic energy is insufficient (Ppv<Pload), the photovoltaic side operates in the maximum power point tracking mode and cannot maintain the bus voltage independently, at this time Udc shows a downward trend. When Udc is lower than Udc2 , ΔI is a positive value, which automatically reduces the basic charging current of the battery to lower the charging power, until Ppv=Pload is satisfied again, so as to stabilize the bus voltage at Udc2 , effectively preventing the bus voltage from collapsing and ensuring the continuous operation of the system.

[0102] Wherein, Udc2 is exemplarily one of 290V to 310V, such as 295V, 300V or 305V.

[0103] As shown in Figure 5 , the present embodiment further provides an electrical device 200, which executes the above-mentioned hybrid power distribution method during operation, or comprises the above-mentioned hybrid power distribution circuit 100.

[0104] It can be understood that, since the electrical device 200 provided by the present application executes the above-mentioned hybrid power distribution method or comprises the above-mentioned hybrid power distribution circuit 100 during operation, it can also obtain the bus voltage of the DC bus, the battery voltage and battery current of the energy storage battery 120 to provide real-time feedback data for charge and discharge control, generate the discharge current adapted to the discharge condition based on the second bus reference voltage and the bus voltage respectively, generate the compensated charging current adapted to the charging condition based on the first bus reference voltage and the battery reference voltage in combination with the battery voltage and the bus voltage, then select the corresponding current as the battery reference current according to the charge and discharge mode, and finally generate the drive signal of the buck-boost module 20 in combination with the charge and discharge mode, the battery reference current and the battery current. It can ensure the stability of the bus voltage in the discharge stage, take into account the battery charging control requirements and the bus voltage stability requirements in the charging stage, avoid the control logic conflict when switching between the charge and discharge modes, effectively solve the system abnormality problem caused by the battery charging pulling down the bus voltage in the pure photovoltaic power supply scenario, and improve the operation reliability of the system.

[0105] It should be noted that, in addition to the photovoltaic energy storage air conditioner, the electrical device 200 may also be a photovoltaic energy storage heat pump water heater, an off-grid communication base station power supply, an outdoor mobile energy storage power station, a photovoltaic energy storage cold chain transport unit, a recreational vehicle photovoltaic energy storage power supply system, etc. All such devices have a DC bus architecture, need to realize bidirectional energy management between the energy storage battery 120 and the bus through the buck-boost module 20, and face the common technical problem of cooperative control of battery charging and bus voltage stabilization under pure photovoltaic power supply, so all of them can apply the hybrid power distribution method of the present application to improve operation reliability.

[0106] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0107] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A hybrid power distribution method, characterized in that, The method is applied to a hybrid power distribution circuit, which includes a photovoltaic boost module and a buck-boost module. The photovoltaic boost module is connected between the photovoltaic module and the DC bus, and the buck-boost module is connected between the energy storage battery and the DC bus. The hybrid power distribution method includes: Obtain the bus voltage of the DC bus and the battery voltage and battery current of the energy storage battery; A compensated charging current is generated based on the first bus reference voltage, the battery reference voltage, the battery voltage, and the bus voltage. A discharge current is generated based on the second bus reference voltage and the bus voltage; The battery reference current is generated by selecting the discharge current or the compensated charging current according to the charging and discharging mode. Based on the charging and discharging mode, drive signals are generated to control the two switching transistors in the buck-boost module using the battery reference current and the battery current.

2. The hybrid power distribution method according to claim 1, characterized in that, The step of generating a compensated charging current based on the first bus reference voltage, the battery reference voltage, the battery voltage, and the bus voltage includes: A charging base current is generated based on the battery reference voltage and the battery voltage; A charging compensation current is generated based on the first bus reference voltage and the bus voltage; The compensated charging current is generated based on the difference between the base charging current and the compensation charging current.

3. The hybrid power distribution method according to claim 2, characterized in that, The step of generating the charging base current based on the battery reference voltage and the battery voltage includes: A first voltage error signal is generated based on the difference between the battery reference voltage and the battery voltage; The charging base current is obtained by performing proportional-integral calculation on the first voltage error signal.

4. The hybrid power distribution method according to claim 2, characterized in that, The step of generating a charging compensation current based on the first bus reference voltage and the bus voltage includes: A second voltage error signal is generated based on the difference between the first bus reference voltage and the bus voltage; Perform proportional-integral calculation on the second voltage error signal to obtain the initial charging compensation current; The initial charging compensation current is limited to obtain the charging compensation current.

5. The hybrid power distribution method according to claim 4, characterized in that, The step of limiting the initial charging compensation current to obtain the charging compensation current includes: When the initial charging compensation current is negative, the charging compensation current is set to zero. When the initial charging compensation current is zero or a positive value, the charging compensation current is set to the initial charging compensation current.

6. The hybrid power distribution method according to claim 1, characterized in that, The step of generating a discharge current based on the second bus reference voltage and the bus voltage includes: A third voltage error signal is generated based on the difference between the second bus reference voltage and the bus voltage. The discharge current is obtained by performing proportional-integral calculation on the third voltage error signal.

7. The hybrid power distribution method according to any one of claims 1-6, characterized in that, The charging and discharging modes include a charging mode and a discharging mode. The step of selecting the discharging current or the compensated charging current based on the charging and discharging mode to generate a battery reference current includes: When the charging / discharging mode is the discharge mode, the discharge current is selected as the initial reference current; When the charging / discharging mode is the charging mode, the compensated charging current is selected as the initial reference current; The initial reference current is current-limited to obtain the battery reference current.

8. The hybrid power distribution method according to claim 7, characterized in that, The two switching transistors include an upper transistor driven by a first driving signal and a lower transistor driven by a second driving signal. The step of generating driving signals to control the two switching transistors in the buck-boost module based on the charging / discharging mode, the battery reference current, and the battery current includes: A current error signal is generated based on the difference between the battery reference current and the battery current; Perform a proportional-integral operation on the current error signal to obtain a pulse width modulation signal; When the charging / discharging mode is the discharging mode, the pulse width modulation signal is selected as the first driving signal, and the level of the second driving signal is set to low. When the charging / discharging mode is the charging mode, the pulse width modulation signal is selected as the second driving signal, and the level of the first driving signal is set to low.

9. A hybrid power distribution circuit, characterized in that, The hybrid power distribution circuit includes: A photovoltaic boost module is connected between the photovoltaic module and the DC bus. A step-up / step-down module is connected between the energy storage battery and the DC bus; A sampling module, connected to the DC bus and the energy storage battery, is used to acquire the bus voltage of the DC bus and the battery voltage and battery current of the energy storage battery; The drive control module is connected to the photovoltaic boost module, the buck-boost module, and the sampling module. The drive control module is used for: A compensated charging current is generated based on the first bus reference voltage, the battery reference voltage, the battery voltage, and the bus voltage. A discharge current is generated based on the second bus reference voltage and the bus voltage; The battery reference current is generated by selecting the discharge current or the compensated charging current according to the charging and discharging mode. Based on the charging and discharging mode, drive signals are generated to control the two switching transistors in the buck-boost module using the battery reference current and the battery current.

10. An electrical appliance, characterized in that, When the electrical equipment is in operation, it performs the hybrid power distribution method as described in any one of claims 1-8, or the electrical equipment includes the hybrid power distribution circuit as described in claim 9.

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