Relay control circuit and energy storage power supply

Abstract

The invention relates to a relay control circuit and an energy storage power supply. The relay control circuit comprises a control module and a plurality of relays arranged on a power supply circuit from the electric energy input end to the load power supply end, and the control end of each relay is connected with the control module; the control module is used for outputting a pulse width modulation (PWM) voltage signal to each relay, so that a power supply circuit from the electric energy input end to the load power supply end is conducted; the phases of different PWM voltage signals are different. By adopting the relay control circuit, the disconnection speed of the power supply circuit from the electric energy input end to the load power supply end can be improved by improving the disconnection speed of the relay.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a relay control circuit and an energy storage power supply. Background Art

[0002] With the rapid development of lithium battery and power electronics technologies, energy storage power supplies are gaining popularity among an increasing number of users. Energy storage power supplies include multiple relays arranged in the power supply circuit from the power input to the load power supply. When all the relays are on, the power supply circuit from the power input to the load power supply is connected, and the power input transmits power to the load power supply through the multiple relays. When at least one of the multiple relays is off, the power supply circuit from the power input to the load power supply is disconnected, and the power input stops transmitting power to the load power supply.

[0003] However, in the related art, there is a problem that the power supply circuit from the power input end to the load power supply end is disconnected slowly. Summary of the Invention

[0004] Based on this, the present application provides a relay control circuit and an energy storage power supply, which can improve the disconnection speed of the power supply circuit from the power input end to the load power supply end by increasing the disconnection speed of the relay.

[0005] In the first aspect, the present application provides a relay control circuit, which includes a control module and multiple relays arranged on the power supply circuit from the power input end to the load power supply end, and the control end of each relay is connected to the control module; the control module is used to output a pulse width modulation (PWM) voltage signal to each relay to make the power supply circuit from the power input end to the load power supply end conductive; different PWM voltage signals have different phases.

[0006] In some embodiments, in the PWM voltage signal output by the control module to each adjacent relay among the multiple relays, the phase difference between the PWM voltage signal corresponding to the latter relay and the PWM voltage signal corresponding to the previous relay is the target phase difference; wherein the target phase difference is the ratio of 360 degrees to the number of relays in the multiple relays.

[0007] In some embodiments, before the control module outputs the PWM voltage signal to each relay, the control module is further configured to output a first voltage signal of a preset duration to each relay, where the first voltage signal is a voltage signal for driving the relay to conduct.

[0008] In some embodiments, the PWM voltage signal includes a first voltage signal and a second voltage signal that alternate periodically; the first voltage signal is a voltage signal that drives the relay to turn on, and the second voltage signal is a voltage signal that drives the relay to turn off; each time each relay receives the second voltage signal, the current passing through the coil in each relay gradually decreases to a target current; each time each relay receives the first voltage signal, the current passing through the coil in each relay gradually increases from the target current; wherein the target current is greater than the critical current passing through the coil when each relay switches from the on state to the off state.

[0009] In some embodiments, the power supply circuit from the power input end to the load power supply end includes two power supply lines; for any power supply line, if at least two relays are provided on the power supply line, then at least two relays are connected in series, and the first relay is also connected to the power input end, and the last relay is also connected to the load power supply end; if there is a relay provided on the power supply line, the first conductive end of the relay is connected to the power input end, and the second conductive end of the relay is connected to the load power supply end.

[0010] In some embodiments, the control module includes a controller and signal amplification units corresponding to each relay; each signal output end of the controller is connected to the control end of each relay through each signal amplification unit; each signal output end of the controller corresponds to each signal amplification unit.

[0011] In some embodiments, each signal amplification unit includes a transistor, a current limiting resistor and a pull-down resistor; the first end of each current limiting resistor is connected to the signal output end of the controller, the second end of each current limiting resistor is connected to the base of each transistor, the first end of each pull-down resistor is connected to the base of the transistor, the second end of each pull-down resistor is connected to the ground end, the collector of each transistor is connected to the control end of each relay, and the emitter of each transistor is connected to the ground end.

[0012] In some embodiments, the relay control circuit also includes an energy storage module, the output end of the energy storage module is connected to the load power supply end, and the controlled end of the energy storage module is connected to the energy storage control end of the control module; the control module is also used to control the energy storage module to transmit power to the load power supply end, and output a voltage signal to each relay for driving the relay to disconnect, so that the power supply circuit from the power input end to the load power supply end is disconnected.

[0013] In some embodiments, the energy storage module includes a battery unit, a power supply voltage stabilizing unit, and a bidirectional inverter unit; the battery unit is connected to the first conductive end of the bidirectional inverter unit through the power supply voltage stabilizing unit, and the second conductive end of the bidirectional inverter unit is connected to the load power supply end; the control end of the bidirectional inverter unit is also connected to the control module, and the control module controls the conduction of the bidirectional inverter unit to enable the energy storage module to transmit power to the load power supply end.

[0014] In a second aspect, the present application provides an energy storage power supply, which includes any one of the relay control circuits described above.

[0015] In the technical solution provided in the embodiment of the present application, since the controller outputs a PWM voltage signal to each relay, the current passing through the coil in each relay is a current that fluctuates up and down (for example, in the form of a triangular wave), and the current passing through the coil in each relay is greater than the critical current passing through the coil when each relay switches from the on state to the off state, instead of the related art where, in order to make the relay turn on, the voltage input to the relay is a fixed voltage signal (for example, a high voltage signal) that drives the relay to turn on, resulting in the current passing through the coil in each relay in the related art being continuously the maximum current, and further resulting in a longer time for the current in the coil of each relay to drop from the maximum current to the critical current during the shutdown process. In the embodiment of the present application, since the current passing through the coil in each relay is a current that fluctuates up and down (in the form of a triangular wave), when the current passing through the coil in a certain relay is a lower current, the time it takes for the current in the coil of the relay to drop from the lower current to the critical current is shorter. The duration is short, thereby reducing the time delay between the relay receiving the disconnect instruction and the relay disconnecting; and, since the phases of different PWM voltage signals are different, at the same moment, there will always be at least one relay whose coil current is the smallest and less than the maximum current, so that the current difference between the current passing through the coil in the at least one relay and the critical current is the smallest, and then when the control module outputs a voltage signal for driving the relay to disconnect to each relay, the current passing through the coil in the at least one relay reaches the critical current first, and the time between the moment when the at least one relay receives the voltage signal for driving the relay to disconnect and the moment when it disconnects is the shortest, thereby shortening the time delay between the moment when the at least one relay receives the disconnect instruction and the moment when the relay disconnects, and the disconnection of at least one relay will cause the power supply circuit from the power input end to the load power supply end to be disconnected, so that the embodiment of the present application can improve the disconnection speed of the power supply circuit from the power input end of the relay to the load power supply end. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic structural diagram of a relay control circuit provided in the first embodiment;

[0018] Figure 2 A schematic diagram showing the relationship between a PWM voltage signal output to a relay and a current passing through a coil in the relay, provided in some embodiments;

[0019] Figure 3 A schematic structural diagram of a relay control circuit provided in a second embodiment;

[0020] Figure 4 A schematic structural diagram of a relay control circuit provided in a third embodiment;

[0021] Figure 5 A schematic structural diagram of a relay control circuit provided in a fourth embodiment;

[0022] Figure 6 A schematic structural diagram of a relay control circuit provided in a fifth embodiment;

[0023] Figure 7 A schematic diagram of the structure of an energy storage power supply provided in some embodiments. DETAILED DESCRIPTION

[0024] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0026] In the description of the embodiments of the present application, the technical terms "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined. In the description of the embodiments of the present application, "each" means each or each of a plurality, unless otherwise clearly and specifically defined.

[0027] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0028] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two elements or the interaction between two elements. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0030] The design principle of a relay is to use a current flowing through a pull-in coil (referred to as the coil) to generate a magnetic field that attracts a spring, shorting the circuit and thus turning the relay on. Because the pull-in coil of a relay is equivalent to an inductor, the relay is considered disconnected only after the current in the pull-in coil drops to a point where the magnetic field generated by the coil can no longer maintain the pull-in of the spring. However, since the current in the pull-in coil decreases gradually, rather than instantaneously, there is a time delay between the relay receiving a disconnect command (e.g., receiving a voltage signal to drive the relay to disconnect, also known as an invalid voltage signal) and the relay disconnecting. This results in a slow disconnection of the power supply circuit from the relay's power input to the load power supply.

[0031] In order to reduce the time delay between the time when the relay receives the disconnect command and the time when the relay disconnects, higher-performance relays are often used in related technologies. However, the use of higher-performance relays not only leads to higher costs for the relays, thereby also leading to higher costs for the relay control circuits, but also is limited by the design principles of the relays. The degree of reduction in the time delay between the time when the relay receives the disconnect command and the time when the relay disconnects is limited, that is, there is still the problem of slow disconnection speed in the power supply circuit from the power input end of the relay to the load power supply end.

[0032] In order to solve the problem of slow disconnection speed of the power supply circuit from the power input end of the relay to the load power supply end, a technical solution of the embodiment of the present application is proposed.

[0033] Figure 1 A schematic diagram of the structure of the relay control circuit provided in the first embodiment, as shown in FIG. Figure 1As shown, the relay control circuit includes a control module and multiple relays arranged on the power supply circuit from the power input end to the load power supply end, and the control end of each relay is connected to the control module; the control module is used to output a pulse width modulation (PWM) voltage signal to each relay to make the power supply circuit from the power input end to the load power supply end conductive; different PWM voltage signals have different phases.

[0034] exist Figure 1 In the illustrated embodiment, the power supply circuit from the power input end to the load power supply end includes two power supply lines. Two relays (RLY1 and RLY2, respectively) are provided on the first power supply line, and two relays (RLY3 and RLY4, respectively) are provided on the second power supply line. In other embodiments, the first power supply line may have no relays or may have another number of relays, such as one, three, or four relays, and / or the second power supply line may have no relays or may have another number of relays, such as one, three, or four relays, etc., which are not limited in this embodiment of the present application.

[0035] In some embodiments, relays RLY1 to RLY4 have two control terminals, one of which is connected to the control module and the other is connected to the relay power supply voltage VCC (also called RLY_VCC). In other embodiments, the other control terminal is grounded.

[0036] In some embodiments, the control module may include a controller for controlling the switching state of the relay. For example, the controller may include an integration of one or at least two of the following: a microcontroller unit (MCU), a general-purpose processor, an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a central processing unit (CPU), a graphics processing unit (GPU), an embedded neural network processing unit (NPU), a microprocessor, a programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, a data processing logic based on quantum computing, an artificial intelligence (AI) processor, etc.

[0037] In some embodiments, a power input terminal and a load power supply terminal may be included in a relay control circuit. The power input terminal is used to connect to the power grid, and the load power supply terminal is used to connect to a load (illustratively, the load may include one or more electrical devices). For example, the power grid may transmit power to the load via the power input terminal, multiple relays, and the load power supply terminal.

[0038] In some embodiments, the models of the plurality of relays may be the same or different. In some embodiments, the plurality of relays may all be normally open relays, or may all be normally closed relays.

[0039] In some embodiments, each of the plurality of relays includes a first conductive end and a second conductive end, and the first conductive end and the second conductive end of each relay constitute part of a power supply circuit from the power input end to the load power supply end. For example, the plurality of relays are arranged on the power supply circuit from the power input end to the load power supply end, and the first conductive end of each relay is connected to the power input end, and the second conductive end of each relay is connected to the load power supply end. In this way, when each of the plurality of relays is turned on, the power supply circuit from the power input end to the load power supply end is turned on, and the power output from the power input end can reach the load power supply end, that is, the load can receive the power provided by the power grid; when at least one of the plurality of relays is turned off, the power supply circuit from the power input end to the load power supply end is turned off, and the power output from the power input end cannot reach the load power supply end, so that the load cannot obtain the power provided by the power grid.

[0040] In some embodiments, the PWM voltage signal may include a first voltage signal and a second voltage signal that alternate periodically. For example, the first voltage signal and the second voltage signal are two voltage signals of different high and low voltages. Exemplarily, the first voltage signal is a high voltage signal, and the second voltage signal is a low voltage signal. Another exemplary embodiment, the first voltage signal is a low voltage signal, and the second voltage signal is a high voltage signal. In some embodiments, the voltage values corresponding to the first voltage signals in different PWM voltage signals may be the same or different, and the voltage values corresponding to the second voltage signals in different PWM voltage signals may be the same or different. Exemplarily, the voltage value corresponding to the low voltage signal may be 0V. Exemplarily, the voltage value corresponding to the high voltage signal may be the power supply voltage VCC of the relay.

[0041] For example, assuming that the first voltage signal is a high voltage signal and the second voltage signal is a low voltage signal, and that the relay is driven on when it receives the high voltage signal and is driven off when it receives the low voltage signal, the current in the coil of the relay (i.e., the aforementioned pull-in coil) gradually increases each time the relay receives the high voltage signal, and gradually decreases each time the relay receives the low voltage signal. In this embodiment of the present application, when each relay receives the PWM voltage signal, the current in the coil of each relay fluctuates (e.g., in a triangular wave pattern) between a target current and a maximum current. The maximum current is the current flowing through the coil of the relay when the high voltage signal is continuously input to the relay, and the target current is always higher than the critical current flowing through the coil when the relay switches from the on state to the off state.

[0042] Because the current in each relay coil is always higher than the critical current passing through the coil when each relay switches from an on state to an off state, the magnetic field generated by the coil in each relay can still maintain the energized spring, preventing one or more relays from disconnecting while the control module outputs a PWM voltage signal to each relay. This ensures reliable conduction of the power supply circuit between the power input terminal and the load power supply terminal. Furthermore, because the current in each relay coil fluctuates between the target current and the maximum current, and because different PWM voltage signals have different phases, the currents passing through the coils of different relays at the same time are different. This ensures that, at any given moment, the minimum current passing through the coils of multiple relays is always less than the maximum current. Consequently, when each relay receives a low voltage signal, the time it takes for the relay current to drop from the minimum current to the target current is shorter than the time it takes for the relay current to drop from the maximum current to the target current, thereby reducing the relay disconnection time. Furthermore, when the current in each relay coil is less than or equal to the critical current, the magnetic field generated by the coil in that relay cannot maintain the energized spring, causing the relay to disconnect.

[0043] In some embodiments, the duty ratios of different PWM voltage signals may be the same or different. For example, the duty ratio of a PWM voltage signal may be in the range of 0.3 to 0.8. For example, the duty ratio of a PWM voltage signal may be 0.3, 0.5, or 0.8. For example, the duty ratios of multiple PWM voltage signals may all be 0.5. The duty ratio may be the ratio of the duration of the first voltage signal in a cycle to the duration of the cycle.

[0044] In some embodiments, at least one of the period, duty cycle, and amplitude of different PWM voltage signals is the same, and the phases of different PWM voltage signals are different.

[0045] In some embodiments, the control module is further configured to output a voltage signal to each relay for driving the relay to disconnect (or to stop outputting a PWM voltage signal to each relay, or to stop outputting a voltage signal), thereby disconnecting each relay and disconnecting the power supply circuit from the power input terminal to the load power supply terminal. For example, the voltage signal for driving the relay to disconnect can be a low voltage signal, or the voltage signal for driving the relay to disconnect can be a high voltage signal.

[0046] In the technical solution provided in the embodiment of the present application, since the controller outputs a PWM voltage signal to each relay, the current passing through the coil in each relay is a current that fluctuates up and down (for example, in the form of a triangular wave), and the current passing through the coil in each relay is greater than the critical current passing through the coil when each relay switches from the on state to the off state, instead of the related art where, in order to make the relay turn on, the voltage input to the relay is a fixed voltage signal (for example, a high voltage signal) that drives the relay to turn on, resulting in the current passing through the coil in each relay in the related art being continuously the maximum current, and further resulting in a longer time for the current in the coil of each relay to drop from the maximum current to the critical current during the shutdown process. In the embodiment of the present application, since the current passing through the coil in each relay is a current that fluctuates up and down (in the form of a triangular wave), when the current passing through the coil in a certain relay is a lower current, the time it takes for the current in the coil of the relay to drop from the lower current to the critical current is shorter. The duration is short, thereby reducing the time delay between the relay receiving the disconnect instruction and the relay disconnecting; and, since the phases of different PWM voltage signals are different, at the same moment, there will always be at least one relay whose coil current is the smallest and less than the maximum current, so that the current difference between the current passing through the coil in the at least one relay and the critical current is the smallest, and then when the control module outputs a voltage signal for driving the relay to disconnect to each relay, the current passing through the coil in the at least one relay reaches the critical current first, and the time between the moment when the at least one relay receives the voltage signal for driving the relay to disconnect and the moment when it disconnects is the shortest, thereby shortening the time delay between the moment when the at least one relay receives the disconnect instruction and the moment when the relay disconnects, and the disconnection of at least one relay will cause the power supply circuit from the power input end to the load power supply end to be disconnected, so that the embodiment of the present application can improve the disconnection speed of the power supply circuit from the power input end of the relay to the load power supply end.

[0047] In some embodiments, in the PWM voltage signal output by the control module to each adjacent relay among the multiple relays, the phase difference between the PWM voltage signal corresponding to the latter relay and the PWM voltage signal corresponding to the previous relay is the target phase difference; wherein the target phase difference is the ratio of 360 degrees to the number of relays in the multiple relays.

[0048] The embodiment of the present application does not limit the numbering order of the multiple relays, as long as the numbers of the multiple relays are consecutive and the same relay is numbered only once.

[0049] Exemplarily, the plurality of relays include relays 1 to N (N is an integer greater than or equal to 2), and a phase difference between a PWM voltage signal corresponding to relay i+1 and a PWM voltage signal corresponding to relay i is a ratio of 360 degrees to N.

[0050] For example, the multiple relays include two relays, the phase difference between the PWM voltage signal corresponding to the second relay and the PWM voltage signal corresponding to the first relay is 180 degrees, and the phase difference between the PWM voltage signal corresponding to the first relay and the PWM voltage signal corresponding to the second relay is also 180 degrees.

[0051] For another example, the multiple relays include three relays, the phase difference between the PWM voltage signal corresponding to the second relay and the PWM voltage signal corresponding to the first relay is 120 degrees, the phase difference between the PWM voltage signal corresponding to the third relay and the PWM voltage signal corresponding to the second relay is 120 degrees, and the phase difference between the PWM voltage signal corresponding to the first relay and the PWM voltage signal corresponding to the third relay is 120 degrees.

[0052] For another example, the plurality of relays includes four relays, and the phase difference between the PWM voltage signal corresponding to the second relay and the PWM voltage signal corresponding to the first relay is 90 degrees, the phase difference between the PWM voltage signal corresponding to the third relay and the PWM voltage signal corresponding to the second relay is 90 degrees, the phase difference between the PWM voltage signal corresponding to the fourth relay and the PWM voltage signal corresponding to the third relay is 90 degrees, and the phase difference between the PWM voltage signal corresponding to the first relay and the PWM voltage signal corresponding to the fourth relay is 90 degrees. In other words, the four PWM voltage signals are controlled using a four-interleaved PWM wave method.

[0053] The following example uses multiple relays including four relays to illustrate:

[0054] Figure 2 A schematic diagram of the relationship between the PWM voltage signal output to the relay and the current passing through the coil in the relay is provided in some embodiments. Figure 2 The relays shown in the figure are all driven to conduct by high voltage signals and to disconnect by low voltage signals. The four relays are identical. Figure 2 As shown, the period, duty cycle and amplitude of the PWM voltage signals output to the four relays (RLY_PWM1 signal, RLY_PWM2 signal, RLY_PWM3 signal and RLY_PWM4 signal) are the same, and the phase difference between the PWM voltage signal output to the rear relay and the PWM voltage signal output to the front relay of the two adjacent relays in the four relays is 90 degrees. Figure 2 In the embodiment shown, the currents passing through the coils of the four relays are I_RLY1 , I_RLY2 , I_RLY3 , and I_RLY4 , respectively.

[0055] Starting at time T1, the first relay starts to receive the low voltage signal of the RLY_PWM1 signal, and the current passing through the coil of the first relay starts to gradually decrease from the maximum current (for example, the maximum current is the current passing through the coil of the first relay when the high voltage signal is continuously input to the first relay) until at time T2, the current passing through the coil of the first relay reaches the target current, and the target current is still greater than the critical current passing through the coil when the first relay switches from the on state to the off state. Starting at time T2, the first relay starts to receive the high voltage signal, and the current passing through the coil of the first relay starts to gradually increase until at time T3, the current passing through the coil of the first relay reaches the maximum current. Starting at time T3, the first relay starts to receive the low voltage signal again, and the current passing through the coil of the first relay starts to gradually decrease from the maximum current. And so on, when the first relay obtains the RLY_PWM1 signal, the current passing through the coil of the first relay fluctuates back and forth between the target current and the maximum current.

[0056] Similarly, starting from time T4, the current passing through the coil of the second relay fluctuates back and forth between the target current and the maximum current. Starting from time T2, the current passing through the coil of the third relay fluctuates back and forth between the target current and the maximum current. Starting from time T5, the current passing through the coil of the fourth relay fluctuates back and forth between the target current and the maximum current.

[0057] exist Figure 2 The solid line in the figure depicts the lowest current flowing through the relay coil at each moment. This lowest current is always greater than the critical current flowing through the coil when the relay switches from on to off, and is also less than the average current between the maximum current and the target current. When each relay receives a PWM voltage signal, the lowest current represented by the solid line varies in a triangular wave between the target current and the set current (Iset). The set current is the ratio of the difference between the maximum current and the target current divided by 4. That is, when the control module outputs a PWM voltage signal to each relay, at any moment, there will be a relay whose coil current is the lowest and closest to the critical current when the relay switches from on to off. Therefore, when the control module outputs a voltage signal to each relay to drive the relay to open, the current flowing through the coil of the multiple relays closest to the critical current drops to the critical current first, and the relay that drops to the critical current first opens first.

[0058] For example, at time T2, the current passing through the coil of the first relay is the target current, and the current difference between the target current and the critical current is much smaller than the current difference between the maximum current and the critical current. Therefore, at time T2, when each relay receives the voltage signal for driving the relay to disconnect, the current passing through the coil of the first relay is the first to drop from the target current to the critical current, i.e., the first relay is disconnected first. Disconnection of the first relay also disconnects the power supply circuit from the power input terminal to the load power supply terminal. Exemplarily, the time delay between the moment the voltage signal for driving the relay to disconnect is received and the moment the first relay disconnects (i.e., the time delay for the current to drop from the target current to the critical current) is the first time delay. In the related art, when a relay receives the voltage signal for driving the relay to disconnect, the current passing through the coil of the relay needs to drop from the maximum current to the critical current, and the time delay between the moment the voltage signal for driving the relay to disconnect is received and the moment the relay disconnects (i.e., the time delay for the current to drop from the maximum current to the critical current) is the second time delay. The first time delay is much smaller than the second time delay, thereby reducing the relay disconnection speed and thereby improving the disconnection speed of the power supply circuit from the power input terminal of the relay to the load power supply terminal.

[0059] Similarly, if at time T6, the current passing through the coils of the first and fourth relays is the set current (Iset), although the current difference between the set current and the critical current is greater than the current difference between the target current and the critical current, it is still much smaller than the current difference between the maximum current and the critical current. Therefore, the disconnection speed of the relay can still be reduced, thereby improving the disconnection speed of the power supply circuit from the power input end of the relay to the load power supply end.

[0060] When the relay's current is smaller, the magnetic field strength is also smaller. When the relay receives a voltage signal used to drive the relay to disconnect (for example, when the power supply is stopped), the smaller the current flowing through the relay, the faster the time it takes for the relay's current to drop to the critical current can be shortened. In other words, the time it takes for the magnetic field generated by the relay's drive winding to fall below the magnetic field threshold for attraction can be shortened. Traditional high-voltage signal relays drive the operating current at its highest value (i.e., maximum current), and the disconnection time is the time required for the maximum current to reach the critical current, Ta. However, using array PWM wave relay drive, the disconnection time is less than or equal to the time required for the set current to reach the critical current, Tb, and greater than or equal to the time required for the target current to reach the critical current, Tc. This time reduction is very significant, which greatly shortens the relay's disconnection time, thereby achieving the effect of quickly disconnecting the power supply circuit from the power input end to the load power supply end.

[0061] In addition, the average current of the four relays is Iav (i.e., the average of the maximum current and the target current), thereby effectively reducing the overall power consumption of the relay array through the four-interleaved PWM wave control method. In other embodiments, the average current of other numbers of relays is also Iav.

[0062] In the technical solution provided by the embodiments of the present application, in the PWM voltage signals output by the control module to each adjacent relay among the multiple relays, the phase difference between the PWM voltage signal corresponding to the subsequent relay and the PWM voltage signal corresponding to the preceding relay is a target phase difference. The target phase difference is the ratio of 360 degrees to the number of relays in the multiple relays. As a result, the current waveforms of the coils of each relay exhibit a regular interlacing pattern, enabling the current passing through the coil in each relay to fluctuate (in a triangular wave) between the set current and the target current. The current passing through the coil in each relay always remains close to the critical current, thereby avoiding a large difference between the minimum value of the current passing through the coils of the multiple relays and the critical current, which could result in a slow relay disconnection speed. By setting the phase difference of the PWM voltage signals, it is possible to ensure that the relays can be disconnected at a relatively fast speed at every moment, thereby improving the relay disconnection rate and, in turn, improving the disconnection speed of the power supply circuit from the power input terminal of the relay to the load power supply terminal.

[0063] In some embodiments, before the control module outputs the PWM voltage signal to each relay, the control module is further configured to output a first voltage signal of a preset duration to each relay, where the first voltage signal is a voltage signal for driving the relay to conduct.

[0064] Exemplarily, the first voltage signal is a high voltage signal. Another exemplary embodiment is that the first voltage signal is a low voltage signal.

[0065] Taking the first voltage signal as a high voltage signal as an example, please continue to refer to Figure 2 ,exist Figure 2 In the embodiment, before time T1, the control module can output a high voltage signal to each relay so that each relay can be reliably turned on.

[0066] In the technical solution provided in the embodiment of the present application, before the control module outputs the PWM voltage signal to each relay, the control module is also used to output a voltage signal of a preset duration to each relay to drive the relay to conduct, so that each relay can be reliably conducted, avoiding the situation where the PWM voltage signal is output to each relay when each relay is disconnected, which will cause the magnetic field generated by the current passing through the coil in each relay to be unable to reliably maintain the attraction of the spring. Therefore, in the embodiment of the present application, after each relay is reliably conducted, even if the PWM voltage signal is output to each relay, the magnetic field generated by the current passing through the coil in each relay can reliably maintain the attraction of the spring, thereby improving the reliability of the conduction of the power supply circuit from the power input end to the load power supply end.

[0067] In some embodiments, the PWM voltage signal includes a first voltage signal and a second voltage signal that alternate periodically; the first voltage signal is a voltage signal that drives the relay to turn on, and the second voltage signal is a voltage signal that drives the relay to turn off; each time each relay receives the second voltage signal, the current passing through the coil in each relay gradually decreases to a target current; each time each relay receives the first voltage signal, the current passing through the coil in each relay gradually increases from the target current; wherein the target current is greater than the critical current passing through the coil when each relay switches from the on state to the off state.

[0068] In the technical solution provided in the embodiment of the present application, the current passing through the coil in each relay is not a fixed maximum current, but continuously rises and falls between the target current and the maximum current. Combined with the different phases of different PWM voltage signals, at any moment, there will be a relay whose current passing through the coil is the minimum current among the currents passing through the coils in multiple relays, and the minimum current is between the target current and the set current (the ratio of the difference between the maximum current and the target current and the number of relays). The minimum current is much smaller than the maximum current, thereby improving the disconnection rate of the relay corresponding to the minimum current.

[0069] In some embodiments, the power supply circuit from the power input terminal to the load power supply terminal includes two power supply lines. Exemplarily, the two power supply lines are a live wire and a neutral wire. Exemplarily, the power input terminal may include a positive power input terminal and a negative power input terminal, and the load power supply terminal may include a positive load power supply terminal and a negative load power supply terminal. The first power supply line is the line between the positive power input terminal and the positive load power supply terminal, and the second power supply line is the line between the negative power input terminal and the negative load power supply terminal.

[0070] For any power supply circuit, if at least two relays are provided on the power supply circuit, the at least two relays are connected in series, and the first relay is also connected to the power input end, and the last relay is also connected to the load power supply end.

[0071] For example, for the first power supply current, two relays are provided on the first power supply line, the first conducting end of the first relay is connected to the positive power input end, the second conducting end of the first relay is connected to the first conducting end of the second relay, and the second conducting end of the second relay is connected to the positive load power supply end.

[0072] For example, for the second power supply current, two relays are provided on the second power supply line, the first conducting end of the first relay is connected to the negative power input end, the second conducting end of the first relay is connected to the first conducting end of the second relay, and the second conducting end of the second relay is connected to the negative load power supply end.

[0073] For any power supply circuit, if a relay is provided on the power supply circuit, the first conducting end of the relay is connected to the power input end, and the second conducting end of the relay is connected to the load power supply end.

[0074] In the technical solution provided in the embodiment of the present application, two power supply lines are used from the power input end to the load power supply end. The relays on each power supply line are flexibly connected according to the number. Multiple relays are connected in series, and a single relay is directly connected to the power input end and the load power supply end, thereby improving the flexibility of relay setting.

[0075] Figure 3 A schematic diagram of the structure of the relay control circuit provided in the second embodiment, Figure 3 Example compared to Figure 1 The difference between the embodiments is that the control module includes a controller and signal amplification units corresponding to each relay (four relays correspond to four signal amplification units one by one, and the four signal amplification units are signal amplification unit 1, signal amplification unit 2, signal amplification unit 3, and signal amplification unit 4 respectively); each signal output end of the controller is connected to the control end of each relay through each signal amplification unit; each signal output end of the controller corresponds to each signal amplification unit.

[0076] The signal amplification unit is configured to amplify the acquired voltage signal. In some embodiments, different signal amplification units have the same signal amplification factor. For example, the voltage signal acquired by each signal amplification unit is a third voltage signal, the voltage value corresponding to the third voltage signal is less than the voltage value corresponding to the aforementioned high voltage signal and greater than the voltage value corresponding to the aforementioned low voltage signal, and each signal amplification unit is configured to amplify the third voltage signal to the aforementioned high voltage signal.

[0077] In the technical solution provided in the embodiment of the present application, the signal amplification unit can specifically amplify the third voltage signal output by the controller which is lower than the high voltage signal, ensuring that the signal strength input to the control end of the relay meets the action threshold requirement, effectively avoiding the problem of false operation or non-operation of the relay due to signal attenuation or interference. In addition, each signal amplification unit corresponds to each relay respectively, so that the control circuits of each relay are independent of each other, reducing the risk of signal crosstalk between different relays, and improving the stability and reliability of controlling the relay.

[0078] In some embodiments, Figure 3 Example compared to Figure 1 The difference between the embodiments is that each signal amplifying unit includes a transistor (in Figure 3 In the circuit, four relays correspond to four transistors, namely transistor Q1, transistor Q2, transistor Q3, and transistor Q4. The four transistors work in saturation state to amplify the signal), current limiting resistor and pull-down resistor (in Figure 3 In the figure, the four relays correspond to four current-limiting resistors, which are respectively current-limiting resistor R1, current-limiting resistor R2, current-limiting resistor R3, and current-limiting resistor R4; the four relays correspond to four pull-down resistors, which are respectively pull-down resistor R5, pull-down resistor R6, pull-down resistor R7, and pull-down resistor R8); the first end of each current-limiting resistor is connected to the signal output end of the controller, the second end of each current-limiting resistor is connected to the base of each transistor, the first end of each pull-down resistor is connected to the base of the transistor, the second end of each pull-down resistor is connected to the ground end, the collector of each transistor is connected to the control end of each relay, and the emitter of each transistor is connected to the ground end.

[0079] In the technical solution provided in the embodiment of the present application, by setting a current-limiting resistor in each signal amplification unit, it is possible to prevent the current input to the base of each transistor from being too large, causing damage to the transistor; by setting a pull-down resistor in each signal amplification unit, the pull-down resistor can stably ground the base of the transistor when there is no signal input, thereby avoiding false triggering due to interference signals.

[0080] With the rapid development of lithium battery and power electronics technologies, energy storage power supplies are gaining popularity among more and more users. An uninterruptible power supply (UPS) is a key feature of energy storage power supplies. It can promptly respond and provide power when the grid power supply stops, thereby maintaining power supply to the load. This is also a fundamental reason why energy storage power supplies are widely used in areas with unstable power supply: to prevent sudden grid power outages from causing power outages to the load.

[0081] For example, energy storage power supplies can include integrated storage and charging devices or integrated photovoltaic storage and charging devices. For integrated photovoltaic storage and charging devices, the UPS function is a common feature used by users. This allows the integrated photovoltaic storage and charging device to promptly provide power to maintain the power needs of the terminal after the mains power (power supply from the grid) is disconnected. This is also a fundamental reason why integrated photovoltaic storage and charging devices are widely used in areas with unstable power supply, precisely to prevent sudden power outages that could disrupt daily life and work, and prevent the loss of important data.

[0082] In related technologies, the grid side is connected to the load through a relay in the energy storage power supply. When the grid side is powered off, the grid side voltage does not meet the power demand, or there is no voltage on the grid side, the energy storage power supply needs to start the UPS function. At this time, it is often necessary to control the disconnection of the relay so that the energy storage module can continue to supply power to the load.

[0083] However, the related art has the problem of long UPS switching time, which results in the load being unable to obtain power from the energy storage module in time when the power supply on the grid side stops, thereby causing power outage to the load.

[0084] In order to solve the problem of long UPS switching time in the related art, the relay control circuit is further provided below:

[0085] Figure 4 A schematic structural diagram of a relay control circuit provided in the third embodiment. Figure 4 Example compared to Figure 1 The difference between the embodiments is that the relay control circuit also includes an energy storage module, the output end of the energy storage module is connected to the load power supply end, and the controlled end of the energy storage module is connected to the energy storage control end of the control module; the control module is also used to control the energy storage module to transmit power to the load power supply end, and output a voltage signal to each relay for driving the relay to disconnect, so that the power supply circuit from the power input end to the load power supply end is disconnected.

[0086] For example, a target node is provided in the power supply circuit from the power input end to the load power supply end, there is no relay between the target node and the load power supply end, and the target node is connected to the energy storage module. Figure 4 As shown, the target node includes a first node A and a second node B, the first node A is set on the circuit between the positive power input terminal and the positive load power supply terminal, and no relay is set in the circuit between the first node A and the positive load power supply terminal, the second node B is set on the circuit between the negative power input terminal and the negative load power supply terminal, and no relay is set in the circuit between the second node B and the negative load power supply terminal, and an energy storage module is connected between the first node A and the second node B.

[0087] By setting up an energy storage module, the grid side can supply power to the energy storage module through multiple conductive relays, and can also supply power to the load. When the grid side is powered off, the grid side voltage does not meet the power demand, or there is no voltage on the grid side, at least one relay can be disconnected to stop the grid side from supplying power to the load and / or energy storage module.

[0088] In some embodiments, when the voltage provided by the grid side is unstable or when the grid side loses power, it is necessary to disconnect at least one of the multiple relays so that the grid side no longer supplies power to the energy storage module and / or the load. At this time, the energy storage module can be controlled to supply power to the load.

[0089] However, the related art has the problem that if the grid side loses power, at least one relay needs to be disconnected to prevent the power provided by the energy storage module from being absorbed by the grid side and unable to reach the load. That is, the UPS switching (i.e. switching from the grid side to supply power to the load to the energy storage module to supply power to the load) is slow, resulting in the load having no power input for a long time, causing the load to lose power, restart or burn out.

[0090] In some embodiments, the UPS switching process may include: a controller phase-locking the grid side to detect when the grid loses power; outputting a voltage signal to each relay to drive the relay to disconnect; and controlling the output voltage of the energy storage module. While the controller phase-locks the grid side and controls the output voltage of the energy storage module as quickly as possible, relay disconnection time accounts for a significant portion of this time. Conventional relay disconnection times are relatively long, so shortening this time through circuit design is a key technical issue in this case.

[0091] In the technical solution provided in the embodiment of the present application, when the control module outputs a PWM voltage signal to each relay, at least one relay in the relay control circuit can be quickly disconnected, so that the power supply circuit from the power input end to the load power supply end can be quickly disconnected, so that the power provided by the energy storage module can quickly reach the load. The UPS has a fast switching speed and can quickly provide power to the load through the energy storage module when the grid side loses power, thereby avoiding the situation where the load has no power input for a long time and thus causing the load to lose power, thereby improving the reliability of the load power supply.

[0092] Figure 5 This is a schematic structural diagram of a relay control circuit provided in the fourth embodiment. Figure 5 Example compared to Figure 4The difference between the embodiments is that the energy storage module includes a battery unit, a power supply voltage stabilizing unit and a bidirectional inverter unit; the battery unit is connected to the first conductive end of the bidirectional inverter unit through the power supply voltage stabilizing unit, and the second conductive end of the bidirectional inverter unit is connected to the load power supply end (that is, connected to the load power supply end through the first node A and the second node B); the control end of the bidirectional inverter unit is also connected to the control module, and the control module controls the bidirectional inverter unit to conduct, so that the energy storage module transmits power to the load power supply end (for example, Figure 5 The state changes of switches Q5 to Q8 of the bidirectional inverter unit are controlled so that the energy storage module transmits power to the load power supply end. For example, the control module can control the states of switches Q5 to Q8 by outputting G1_H, G2_H, G1_L, and G1_L signals).

[0093] For example, the battery unit may include one battery or a plurality of batteries connected in series and / or in parallel.

[0094] Exemplarily, the power regulated power supply may include a high voltage bus (BUS) capacitor C1 .

[0095] In some embodiments, the bidirectional inverter unit includes an inverter switch subunit and a filter subunit; the inverter switch subunit is connected between the power supply stabilization unit and the filter subunit, and the filter subunit is also connected to the power supply circuit from the power input end to the load power supply end.

[0096] The inverter switch subunit can be used to convert direct current (DC) power into alternating current (AC) power, or vice versa. When the grid is charging the battery cell, the controller can control the switches in the inverter switch subunit accordingly, so that the inverter switch subunit converts the AC power output from the grid into DC power that can be stored by the battery cell. When the battery cell needs to supply power to a load, the controller can control the switches in the inverter switch subunit accordingly and control at least one relay in the power supply circuit from the power input end to the load power supply end to open, so that the inverter switch subunit converts the DC power output from the battery cell into AC power that can be used by the load. When the battery cell needs to discharge to the grid, the controller can control the switches in the inverter switch subunit accordingly and control multiple relays in the power supply circuit from the power input end to the load power supply end to close, so that the inverter switch subunit converts the DC power output from the battery cell into AC power that can be absorbed by the grid.

[0097] exist Figure 5In the illustrated embodiment, the inverter switch subunit includes four bridge arms (illustratively, each bridge arm includes a switch and a resistor connected between the control terminal and the first conduction terminal of the switch. The four switches may be switches Q5 to Q8, and the corresponding four resistors may be R9 to R12). In other embodiments, the inverter switch subunit may also include two or six bridge arms, which is not limited in this embodiment of the present application. Exemplarily, the switches in the bridge arms may include insulated-gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs).

[0098] The filter subunit includes an inductor L1 and a capacitor C2. One conductive end of the switch Q7 is connected to the first end of the capacitor C2 through the inductor L1. The second end of the capacitor C2 is connected to one conductive end of the switch Q6. The second end of the capacitor C2 is also connected to the second node B. The first end of the capacitor C2 is also connected to the first node A, so that the inverter switch subunit is connected to the power supply circuit from the power input end to the load power supply end through the filter subunit.

[0099] In the technical solution provided in the embodiment of the present application, the electric energy output by the battery unit first passes through the power supply voltage stabilizing unit to convert the unstable voltage into a stable voltage, providing a reliable basis for subsequent power supply. The bidirectional inverter unit can flexibly realize the bidirectional flow of electric energy under the instruction of the controller.

[0100] Figure 6 This is a schematic structural diagram of a relay control circuit provided in the fifth embodiment. Figure 6 The embodiment is Figure 3 and Figure 5 The combination of Figure 6 The description of the circuit structure can refer to the description of the above embodiment, and the embodiments of this application will not be repeated.

[0101] Figure 7 A schematic diagram of the structure of an energy storage power supply provided in some embodiments, such as Figure 7 As shown, the energy storage power supply includes the relay control circuit in any of the above embodiments.

[0102] In some embodiments, the energy storage power supply may further include a power management module, wherein the output of the power management module is connected to the power supply of the control module and the power supply of the current acquisition module, and the power management module is configured to supply power to the control module and the current acquisition module. For example, the input of the power management module is connected to the battery cells in the energy storage module.

[0103] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0104] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A relay control circuit, characterized in that: The relay control circuit includes a control module and a plurality of relays arranged on a power supply circuit from an electric energy input end to a load power supply end, wherein the control end of each relay is connected to the control module; The control module is used to output a pulse width modulation (PWM) voltage signal to each of the relays to conduct the power supply circuit from the power input end to the load power supply end; different PWM voltage signals have different phases.

2. The relay control circuit according to claim 1, characterized in that: In the PWM voltage signal output by the control module to each adjacent relay among the multiple relays, the phase difference between the PWM voltage signal corresponding to the latter relay and the PWM voltage signal corresponding to the previous relay is a target phase difference; wherein, the target phase difference is the ratio of 360 degrees to the number of relays in the multiple relays.

3. The relay control circuit according to claim 1 or 2, characterized in that: Before the control module outputs the PWM voltage signal to each of the relays, the control module is further configured to output a first voltage signal of a preset duration to each of the relays, where the first voltage signal is a voltage signal for driving the relay to conduct.

4. The relay control circuit according to claim 1 or 2, characterized in that: The PWM voltage signal includes a first voltage signal and a second voltage signal that alternate periodically; the first voltage signal is a voltage signal for driving the relay to be turned on, and the second voltage signal is a voltage signal for driving the relay to be turned off; Each time each of the relays receives the second voltage signal, the current passing through the coil in each of the relays gradually decreases to a target current; each time each of the relays receives the first voltage signal, the current passing through the coil in each of the relays gradually increases from the target current; The target current is greater than a critical current passing through the coil when each relay switches from an on state to an off state.

5. The relay control circuit according to claim 1 or 2, characterized in that: The power supply circuit from the power input end to the load power supply end includes two power supply lines; For any of the power supply lines, if at least two relays are provided on the power supply line, the at least two relays are connected in series, and the first relay is also connected to the power input end, and the last relay is also connected to the load power supply end; If a relay is provided on the power supply line, the first conducting end of the relay is connected to the power input end, and the second conducting end of the relay is connected to the load power supply end.

6. The relay control circuit according to claim 1 or 2, characterized in that: The control module includes a controller and signal amplifying units corresponding to the relays respectively; Each signal output end of the controller is connected to the control end of each relay through each signal amplifying unit; each signal output end of the controller corresponds to each signal amplifying unit.

7. The relay control circuit according to claim 6, characterized in that: Each of the signal amplifying units includes a transistor, a current limiting resistor and a pull-down resistor; The first end of each current-limiting resistor is connected to the signal output end of the controller, the second end of each current-limiting resistor is connected to the base of each transistor, the first end of each pull-down resistor is connected to the base of the transistor, the second end of each pull-down resistor is connected to the ground end, the collector of each transistor is connected to the control end of each relay, and the emitter of each transistor is connected to the ground end.

8. The relay control circuit according to claim 1 or 2, characterized in that: The relay control circuit further includes an energy storage module, wherein the output end of the energy storage module is connected to the load power supply end, and the controlled end of the energy storage module is connected to the energy storage control end of the control module; The control module is also used to control the energy storage module to transmit power to the load power supply end, and output a voltage signal to each relay for driving the relay to disconnect, so as to disconnect the power supply circuit from the power input end to the load power supply end.

9. The relay control circuit according to claim 8, characterized in that: The energy storage module includes a battery unit, a power supply voltage stabilization unit and a bidirectional inverter unit; The battery unit is connected to the first conductive end of the bidirectional inverter unit through the power supply voltage stabilizing unit, and the second conductive end of the bidirectional inverter unit is connected to the load power supply end; The control end of the bidirectional inverter unit is also connected to the control module. The control module controls the bidirectional inverter unit to be turned on, so that the energy storage module transmits power to the load power supply end.

10. An energy storage power supply, characterized in that: The energy storage power supply includes the relay control circuit according to any one of claims 1 to 9.

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