An auxiliary power supply multi-channel power supply active selection circuit

Abstract

The present invention discloses an auxiliary power supply multi-channel power supply active selection circuit, including the following circuit modules: AC rectifier power supply circuit; battery rectifier power supply circuit; bus power supply circuit; RTC buffer circuit: using thermistor as a buffer circuit for power supply voltage; supporting capacitor circuit: electrolytic capacitor as a support for the input voltage of the auxiliary power supply system, ensuring the stability of the auxiliary system power supply voltage during the DC power supply circuit switch switching process; DC power supply circuit switch and switch control circuit. The present invention improves on the original passive auxiliary power supply multi-channel power supply circuit, adds an active switching circuit, and when the AC voltage is established and reaches a constant amplitude, cuts off the battery and bus power supply circuit of the auxiliary power supply, and switches to the AC side for power supply alone, avoiding the continuous loss of system battery energy. After the energy storage system is discharged, the standby state will not consume battery power, and the energy storage system can maintain a long standby operation after discharge without entering a power loss state.

Description

Technical Field

[0001] The present invention relates to the technical field of auxiliary power supply power supply, and in particular to an auxiliary power supply multi-channel power supply active selection circuit. Background Art

[0002] Energy storage converters have different working modes such as grid-connected, off-grid, and constant voltage. The control system needs to be able to get power and operate normally after being powered by the battery, bus or grid. Therefore, the auxiliary power supply circuit design adopts an AC / DC multi-channel power supply solution. The AC voltage and battery voltage are rectified and combined with the bus voltage to power the auxiliary power system. Any voltage can be established to reliably power the auxiliary power supply. The current auxiliary power supply multi-channel power supply circuits all adopt a passive power supply method. In this circuit, the auxiliary power supply depends on the circuit with the highest voltage amplitude after rectification. It is impossible to actively select the power supply circuit, nor can it control the source of energy loss.

[0003] The most common working mode of energy storage converter is grid-connected mode, with the DC side connected to the battery and the AC side connected to the grid. Usually the battery voltage is higher than the peak value of the grid voltage. Even when the battery SOC is 0% or even in the undervoltage protection state, the battery voltage is still higher than the amplitude of the grid voltage after rectification. Therefore, when using a passive auxiliary power multi-way power supply circuit, all control system and heat dissipation system losses of the converter are provided by the battery.

[0004] In actual applications, when the energy storage system completes battery discharge but has not reached the charging time of the control strategy, the energy storage system will continue to be in standby mode. In this state, all control power consumption of the converter and power consumption of the cooling system need to be provided by the battery, resulting in continuous loss of battery energy. After the energy storage system maintains standby mode for a long time, it will enter the power-loss protection state due to long-term battery loss and cannot operate normally. Many energy storage system manufacturers require the maximum standby time after the battery discharge is completed to prevent the battery from being depleted due to long-term standby. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an auxiliary power supply multi-channel power selection circuit to solve the problem that when the energy storage system is in a long-term standby state after the battery discharge is completed, the system auxiliary power system continues to draw power from the battery and consumes energy, causing the battery to over-discharge and enter power loss and undervoltage protection and cannot operate normally.

[0006] In order to solve the above technical problems, the present invention provides an auxiliary power supply multi-channel power supply active selection circuit, including the following circuit modules: AC rectification power supply circuit: rectifying AC power into DC power through a diode to supply power to the auxiliary power supply; battery rectification power supply circuit: converting positive and negative battery DC power into positive DC power through diode rectification to supply power to the auxiliary power supply; bus power supply circuit: the bus DC power is supplied by the diode and the battery rectification power supply circuit together to supply power to the subsequent auxiliary power supply, and the diode plays an anti-reverse role to prevent the energy after AC and battery rectification from flowing into the bus through the circuit; RTC buffer circuit: using resistors as a buffer circuit for the power supply voltage; support capacitor circuit: the electrolytic capacitor is used as a support for the input voltage of the auxiliary power supply system to ensure the stability of the auxiliary system power supply voltage during the switching process of the DC power supply circuit.

[0007] Furthermore, the resistor used in the RTC buffer circuit is a negative temperature coefficient thermistor.

[0008] Furthermore, it includes a DC power circuit switch: the switch uses a normally closed relay, and when the switch is closed, the AC side, the battery side and the bus side jointly supply power to the auxiliary power supply. When the switch is open, the DC power supply circuit is cut off and the AC circuit alone supplies power.

[0009] Furthermore, it includes a DC power switch control circuit: the DC power circuit switch control circuit is passively controlled by the AC side voltage, and controls the DC power circuit switch to disconnect after the rectified AC side voltage reaches the required amplitude. The control circuit does not need to occupy system control port resources.

[0010] Beneficial effects of the present invention: 1. The present invention adds an AC voltage power supply priority selection function while maintaining the function of multi-channel power supply, thereby avoiding the continuous loss of the battery by the energy storage converter in the standby state;

[0011] 2. The DC power circuit switch control circuit of the present invention is completely controlled by combining the AC side voltage rectification and voltage division with the TL431 reference power supply, which is simple to control and does not need to occupy the port resources of the control system;

[0012] 3. The DC power circuit switch uses a normally closed contact switch. Even if the switch control circuit fails, the normal operation of the entire circuit can be guaranteed. It only fails to realize the priority AC circuit power function, which has no impact on the overall control system and has high circuit fault tolerance. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a module diagram of the present invention.

[0014] Figure 2 It is a schematic diagram of the circuit structure of the present invention.

[0015] Figure 3 It is a schematic diagram of the operation of the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0017] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0018] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0019] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0021] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0022] Reference Figures 1 to 3 As shown, an embodiment of an auxiliary power supply multi-channel power supply active selection circuit of the present invention is composed of an AC rectifier power supply circuit, a battery rectifier power supply circuit, a bus power supply circuit, a DC power supply loop switch, a DC power supply switch control circuit, an RTC buffer circuit and a support capacitor circuit.

[0023] AC rectifier power circuit: rectifies AC power into DC power through diodes to supply auxiliary power;

[0024] Battery rectifier power supply circuit: converts the positive and negative battery DC power into positive DC power through diode rectification to supply auxiliary power;

[0025] Bus power supply circuit: The bus DC power passes through the diode and the battery rectifier power supply circuit to supply power to the subsequent auxiliary power supply. The diode plays an anti-reverse role to prevent the AC and battery rectified energy from flowing into the bus through this circuit;

[0026] DC power circuit switch: Use a normally closed relay, which remains closed before the AC voltage reaches the corresponding amplitude, and the DC power circuit is connected. After the AC voltage is established and reaches the required amplitude, the switch is opened, cutting off the DC power supply circuit, and the AC circuit is used for power supply alone;

[0027] DC power switch control circuit: The DC power circuit switch control circuit is passively controlled by the AC side voltage. When the voltage after rectification on the AC side reaches the required amplitude, the DC power circuit switch is controlled to disconnect. This control circuit does not need to occupy the system control port resources.

[0028] RTC buffer circuit: Use a negative temperature coefficient thermistor as a buffer circuit for the power supply voltage;

[0029] Support capacitor circuit: Large-capacity electrolytic capacitors serve as support for the input voltage of the auxiliary power system to ensure the stability of the auxiliary system power supply voltage during the switching process of the DC power supply circuit.

[0030] The specific instructions are as follows:

[0031] (1) First, the auxiliary power supply circuit needs to have the function of taking power from the AC side, battery side and bus side at the same time. When any circuit is powered on, the auxiliary power supply system can be powered and work normally. The specific circuit design is as follows:

[0032] The circuit is composed of a three-phase AC rectifier circuit composed of diodes D1 / D2 / D3 / D4 / D5 / D6, a battery rectifier circuit composed of D8 / D9 / D10 / D11, and a busbar power supply circuit composed of D12 / D13, which together provide a DC voltage for the auxiliary power input terminal. The auxiliary power supply can be powered on and work when any port voltage is established.

[0033] (2) Secondly, the power supply circuit needs to be protected. When the auxiliary power supply has an abnormal short circuit or a quasi-short circuit fault, it needs to be disconnected from the main circuits on the AC and DC sides in time to prevent the fault from spreading to the main circuit. The specific circuit design is as follows:

[0034] Fu1 / Fu2 / Fu3 form the protection circuit of AC and DC main circuits. When the auxiliary power supply is abnormal, it can disconnect from the AC or DC main circuit in time to ensure the safety of the main circuit. The specific parameters of the insurance are reasonably selected according to the power of the auxiliary power supply and the voltage on the power supply side;

[0035] Fuse Fu4 provides protection for the DC circuit switch control circuit. When the control circuit is abnormal, Fuse Fu4 will be disconnected first. At this time, the switch control circuit is disconnected, and the auxiliary power supply circuit still operates normally. The specific parameters of Fuse Fu4 are reasonably selected according to the control circuit and must be smaller than Fuse Fu1 / Fu2 / Fu3;

[0036] (3) A capacitor support filter circuit needs to be added at the input end of the auxiliary power supply to filter out the ripple voltage after AC rectification and support the input end of the auxiliary power supply. The specific design circuit is as follows:

[0037] The circuit consists of a negative temperature coefficient thermistor RT1, electrolytic capacitors C1 / C2, and voltage-equalizing resistors R1 / R2. Thermistor RT1 acts as a power-on buffer. It uses its negative temperature coefficient resistance characteristics to have a large resistance value when powered on, which acts as a buffer. After operation, the temperature of RT1 rises and the resistance value decreases, reducing the voltage drop and loss on the resistor. Because of the need to support a higher input voltage, electrolytic capacitors C1 / C2 are connected in series, and resistors R1 / R2 are used for voltage balancing;

[0038] (4) The above three steps can realize the function of AC / battery / busbar jointly supplying power to the auxiliary power supply, and the auxiliary power supply can work when any circuit voltage is established. The power supply of the auxiliary power supply under this circuit depends entirely on the high-voltage circuit. In energy storage products, even if the battery SOC drops to 0%, the battery voltage is higher than the DC voltage after the AC voltage is rectified. Therefore, all auxiliary power supply losses come from the battery. Therefore, it is necessary to design a DC side switch control circuit. When there is no AC voltage, the DC side circuit switch is closed, and the auxiliary power supply is powered by the DC side battery and bus voltage. After the AC voltage is established and reaches the required replication, the DC side circuit switch needs to be disconnected so that the auxiliary power supply is completely powered by AC to avoid continuous loss of the battery. The specific circuit design is as follows:

[0039] The circuit consists of anti-reverse diode D7, fuse Fu4, current limiting voltage divider resistor R3, voltage stabilizing diode Z1, filter capacitor C3,

[0040] It consists of voltage-dividing and stabilizing resistors R4 / R5, TL431 voltage stabilizing chip U1 and DC power supply circuit switch K1;

[0041] Switch K1 uses a normally closed contact relay to keep the switch closed when the AC voltage is not established, and the auxiliary power supply is supplied by the DC side;

[0042] The diode D7 mainly plays the role of anti-reverse, preventing the DC side voltage from affecting the control circuit of switch K1;

[0043] The fuse Fu4 protects the auxiliary power supply circuit. When the switch K1 control circuit is abnormal, the fuse is disconnected and the auxiliary power supply can still operate normally without being affected.

[0044] The resistor R3 and the voltage regulator Z1 form a voltage-stabilizing and current-limiting circuit, which provide the operating voltage for the switch K1 control coil. The voltage regulator Z1 plays a voltage-stabilizing role, clamping the coil voltage of the switch K1 to prevent the K1 coil from being damaged by excessive voltage. The voltage regulator voltage of the voltage regulator is selected according to the coil operating voltage range to ensure the reliable operation of the switch K1 while the voltage does not damage the coil;

[0045] Resistors R4 / R5 and TL431 voltage reference chip U1 form a voltage stabilization circuit for the control coil of switch K1. By using the voltage stabilization characteristics of U1 and the voltage division of R4 / R5, the voltage of the action coil of switch K1 can be effectively controlled to ensure the reliable operation of switch K1.

[0046] Working principle description:

[0047] ①After the battery voltage and bus voltage are established, switch K1 is often closed to supply power to the auxiliary power supply;

[0048] ② The AC voltage is established, and the voltage after rectification by diodes D1 / D2 / D3 / D4 / D5 / D6 is used to power the switch K1 control circuit. When the voltage-divided amplitude of R5 and R4 reaches the regulated voltage of the TL431 voltage reference chip U1, U1 is turned on, the switch K1 coil is energized and the DC power supply circuit is disconnected, and the auxiliary power supply is powered by a separate AC side rectification;

[0049] ③ When the AC circuit is disconnected, the voltage is reduced to a certain value after rectification by diodes D1 / D2 / D3 / D4 / D5 / D6, and the voltage divided by R5 and R4 is less than the regulated voltage of the TL431 voltage reference chip U1, the coil circuit of switch K1 is disconnected, K1 turns to a closed state, and the auxiliary power supply is switched to the DC circuit.

[0050] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. An auxiliary power supply multi-channel power supply active selection circuit, characterized in that: Includes the following circuit modules: AC rectifier power circuit: rectifies AC power into DC power through diodes to supply auxiliary power; Battery rectifier power supply circuit: converts the positive and negative battery DC power into positive DC power through diode rectification to supply auxiliary power; Bus power supply circuit: The bus DC power passes through the diode and the battery rectifier power supply circuit to supply power to the subsequent auxiliary power supply. The diode plays an anti-reverse role to prevent the AC and battery rectified energy from flowing into the bus through this circuit; RTC buffer circuit: uses resistors as buffer circuits for power supply voltage; Support capacitor circuit: The electrolytic capacitor serves as a support for the input voltage of the auxiliary power supply system to ensure the stability of the auxiliary system power supply voltage during the switching process of the DC power supply circuit.

2. The auxiliary power supply multi-channel active selection circuit according to claim 1, characterized in that: The resistor used in the RTC buffer circuit is a negative temperature coefficient thermistor.

3. The auxiliary power supply multi-channel active selection circuit according to claim 1, characterized in that: It includes a DC power switch control circuit: a DC power loop switch control circuit, which is passively controlled by the AC side voltage. After the rectified AC side voltage reaches the required amplitude, the DC power loop switch is controlled to disconnect. This control circuit does not need to occupy system control port resources.

4. The auxiliary power supply multi-channel active selection circuit according to claim 1, characterized in that: Including a DC power supply circuit switch: using a normally closed relay, it remains closed before the AC voltage reaches the corresponding amplitude, and the DC power supply circuit is connected. After the AC voltage is established and reaches the required amplitude, the switch is disconnected, cutting off the DC power supply circuit, and the power is supplied solely by the AC circuit.

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