Automatic switching device of direct current power supply

Abstract

The utility model discloses an automatic switching device for a DC power supply, and the device comprises a main control module which is used for obtaining the potential difference of two DC buses at different sampling moments through a voltage detection module, and obtaining a target voltage according to the potential difference; and if it is monitored that the bus battery pack voltage of one section of direct-current bus is abnormal based on the target voltage, controlling a contactor to pull in so as to make the two sections of direct-current buses parallel, thereby using a normal power supply to supply power to the abnormal direct-current bus. According to the invention, a normal power supply is automatically and quickly used to replace an abnormal power supply to supply power to the DC bus with abnormal power supply, the current situation of passive and hysteresis operation of personnel is changed, uninterrupted power supply is realized, the power failure time is reduced, loss caused by power failure is avoided, the user experience is improved, and the application prospect is wide. According to the invention, automatic switching of the dual power supplies during fault, maintenance and operation mode adjustment is realized, the operation of operation and maintenance personnel on equipment is reduced, and the safety coefficient of operation is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the power supply technology field especially relates to a kind of automatic switching device of direct current power supply. BACKGROUND

[0002] In prior art, most of the double configuration direct current system substation is in unattended state, under the condition of unattended, when the direct current system one-way direct current power supply is abnormal, it is difficult for operating personnel and professional personnel to arrive in time to repair, if the abnormal direct current power supply is abnormal for a long time, it affects the stable operation of power grid. SUMMARY

[0003] Therefore, it is necessary to propose an automatic switching device of direct current power supply to solve the technical problem that direct current power supply cannot be repaired in time in prior art.

[0004] The application provides an automatic switching device of direct current power supply, which is applied to a double configuration direct current system substation, the double configuration direct current system substation includes two-way direct current power supply, each of the two-way direct current power supply includes a first direct current bus and a second direct current bus powered by different power supplies, the first direct current bus and the second direct current bus can be connected or disconnected through a contactor, the first direct current bus and the second direct current bus each include a positive potential, a negative potential and a zero potential, the automatic switching device of direct current power supply includes a master control module, a voltage detection module and a contactor control module electrically connected to the master control module.

[0005] The voltage detection module is connected to the first direct current bus and the second direct current bus respectively.

[0006] The contactor control module is connected to the contactor.

[0007] The master control module is used to obtain a first potential difference of the first direct current bus and a second potential difference of the second direct current bus at different sampling times by using the voltage detection module, and obtain a target voltage at different sampling times according to the first potential difference and the second potential difference, wherein the target voltage includes bus battery pack voltages of the two direct current buses, and the bus battery pack voltage is the potential difference between the positive potential and the negative potential of the same direct current bus.

[0008] The master control module is also used to control the contactor to attract and connect the first direct current bus and the second direct current bus in parallel if the bus battery pack voltage of any direct current bus is abnormal based on the target voltage at different sampling times, so as to supply power to the direct current bus with abnormal bus battery pack voltage by using the normal power supply, wherein the normal power supply is the power supply corresponding to the direct current bus with normal bus battery pack voltage.

[0009] The application determines whether the power supply of the DC bus is normal by monitoring the target voltage of two DC buses in the double configuration DC system substation, and when determining that the power supply of one of the DC buses is abnormal, the normal power supply is used to replace the abnormal power supply to automatically switch the power supply of the abnormal DC bus, so that the power supply of the voltage abnormal DC bus is quickly restored, and the normal operation of the power grid is restored. The automatic switching of the DC power supply changes the current situation of passive and lagging operation of personnel, realizes uninterrupted power supply, reduces the power outage time, avoids the loss caused by power outage, and improves the efficiency of operation and maintenance. The application can realize automatic switching of double power supply in fault, maintenance and operation mode adjustment, reduces the operation of the equipment by the operation and maintenance personnel, and improves the safety coefficient of operation. The application improves the power supply reliability, reduces complaints caused by frequent power outages, improves user experience, and has wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiment or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0011] Among them:

[0012] Figure 1 It is a structure block diagram of the automatic switching device of the DC power supply in one embodiment of the application.

[0013] Figure 2 It is a circuit diagram of the contactor control module in one embodiment of the application.

[0014] Figure 3 It is a circuit diagram of the contactor manual control module in one embodiment of the application,

[0015] Figure 4 It is a circuit diagram of the voltage detection unit in one embodiment of the application.

[0016] Figure 5 It is a circuit diagram of the main control module in one embodiment of the application.

[0017] Figure 6 It is a circuit diagram of the power supply module in one embodiment of the application.

[0018] Figure 7 It is a structure block diagram of the automatic switching device of the DC power supply in another embodiment of the application.

[0019] Among them, the drawing symbol is:

[0020] Automatic switching device 00, master control module 10, voltage detection module 20, contactor control module 30, relay module 31, relay control module 32. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] In the prior art, most of the double-configuration DC system substations are in an unattended state. In the unattended state, when one-way DC power supply of the DC system is abnormal, it is difficult for the operating personnel and professional personnel to arrive in time for repair. If the abnormal DC power supply is abnormal for a long time, the stable operation of the power grid is affected.

[0023] In addition, the charging device is faulty or set incorrectly, and in the unattended state, the power supply cannot be normally charged for a long time, and even the capacity is completely lost, which affects the safe and stable operation of the power grid.

[0024] The DC bus voltage difference and other conditions do not meet the requirements, and when the bus tie switch is operated, a great impact current may be caused to threaten the life safety of the operating personnel and cause damage to the storage battery.

[0025] Based on this, the present application provides an automatic switching device of a DC power supply.

[0026] Figure 1 For a structural block diagram of the automatic switching device of the DC power supply in an embodiment, as shown in Figure 1 The present application provides an automatic switching device of a DC power supply, which is applied to a double-configuration DC system substation. The double-configuration DC system substation includes two-way DC power supply, and each of the two-way DC power supply includes a first DC bus and a second DC bus supplied by different power supplies. The first DC bus and the second DC bus can be connected or disconnected through a contactor. The first DC bus and the second DC bus each include a positive potential, a negative potential and a zero potential. The automatic switching device of the DC power supply 00 includes a master control module 10, and a voltage detection module 20 and a contactor control module 30 electrically connected with the master control module 10.

[0027] The voltage detection module 20 is connected with the first DC bus and the second DC bus respectively.

[0028] The contactor control module 30 is connected with the contactor.

[0029] The master module 10 is configured to acquire, by using the voltage detection module 20, a first potential difference of the first DC bus and a second potential difference of the second DC bus at different sampling moments, and obtain a target voltage at the different sampling moments according to the first potential difference and the second potential difference, wherein the target voltage includes a bus battery voltage of each of the two DC buses, and the bus battery voltage is a potential difference between a positive potential and a negative potential of the same DC bus.

[0030] The master module 10 is further configured to, if it is monitored that the bus battery voltage of any one of the DC buses is abnormal based on the target voltage at the different sampling moments, control the contactor to attract to parallel the first DC bus and the second DC bus by using the contactor control module 30, so as to supply power to the DC bus with the abnormal bus battery voltage by using a normal power supply, wherein the normal power supply is a power supply corresponding to the DC bus with the normal bus battery voltage.

[0031] Specifically, the dual DC system substation includes two DC power supplies, and each of the two DC power supplies includes one DC bus, that is, the first DC power supply includes the first DC bus (i.e., the I DC bus), and the second DC power supply includes the second DC bus (i.e., the II DC bus). In a normal case, the first DC bus and the second DC bus are respectively supplied with power by different power supplies, and the two DC buses are independent of each other. The power supply supplies power to the DC bus, and the AC charger charges the power supply. If the AC charger or the power supply is abnormal, the voltage of the corresponding DC bus is abnormal.

[0032] The power supply is a DC power supply, for example, a battery pack.

[0033] The first DC bus and the second DC bus can be connected or disconnected by using the contactor. If the first DC bus and the second DC bus are connected by using the contactor, they share the same power supply. If the first DC bus and the second DC bus are disconnected by using the contactor, they correspond to different power supplies respectively and are supplied with power by the different power supplies.

[0034] The on-off of the contactor is controlled by the automatic switching device 00 of the DC power supply.

[0035] The contactor can be part of the automatic switching device 00 of the DC power supply or can be independent of the automatic switching device 00 of the DC power supply.

[0036] The automatic switching device of the direct current power supply 00 comprises a master control module 10, a voltage detection module 20 connected with the master control module 10, and a contactor control module 30 connected with the contactor. The voltage detection module 20 is connected with the detection points corresponding to the positive potential, the negative potential and the zero potential of the first section direct current bus and the second section direct current bus respectively, and is used for detecting the first potential difference of the first section direct current bus and the second potential difference of the second section direct current bus.

[0037] The first potential difference is the difference between any two potentials of the positive potential, the negative potential and the zero potential of the first section direct current bus. The second potential difference is the difference between any two potentials of the positive potential, the negative potential and the zero potential of the second section direct current bus. The positive potential, the negative potential and the zero potential correspond to three voltage detection points of the direct current bus, for example, under normal circumstances, the positive potential is +110v, the negative potential is -110v, and the zero potential is 0v.

[0038] The master control module 10 can obtain the first potential difference and the second potential difference by using the voltage detection module 20, and calculate or obtain the target voltage according to the first potential difference and the second potential difference. The voltage detection module 20 is connected with the first section direct current bus and the second section direct current bus respectively, and is used for detecting the first potential difference of the first section direct current bus and the second potential difference of the first section direct current bus, converting the first potential difference into a first analog amplification signal, converting the second potential difference into a second analog amplification signal, and outputting the first analog amplification signal and the second analog amplification signal to the master control module 10.

[0039] The master control module 10 is specifically used for converting the first analog amplification signal into the corresponding first potential difference, and converting the second analog amplification signal into the corresponding second potential difference.

[0040] More specifically, the first potential difference includes the difference between any two potentials of the positive potential, the negative potential and the zero potential of the first section direct current bus; the voltage difference or difference value between the positive potential and the negative potential of the first section direct current bus, which is called the I section bus battery pack voltage (i.e. the bus battery pack voltage of the first section direct current bus). The second potential difference includes the difference between any two potentials of the positive potential, the negative potential and the zero potential of the second section direct current bus; the voltage difference or difference value between the positive potential and the negative potential of the second section direct current bus, which is called the II section bus battery pack voltage (i.e. the bus battery pack voltage of the second section direct current bus). The bus battery pack voltage belongs to the potential difference or voltage difference.

[0041] The target voltage includes the bus battery pack voltage of the first section direct current bus and the bus battery pack voltage of the second section direct current bus.

[0042] The target voltage at different sampling moments can be obtained by the main control module 10 through the voltage detection module 20. According to the target voltage at different sampling moments, the main control module 10 can determine whether the bus battery voltage of the first and second DC bus is abnormal. The bus battery voltage abnormality includes, for example, continuous decrease of the bus battery voltage.

[0043] If the bus battery voltage of one of the two DC buses is abnormal, and the bus battery voltage of the other DC bus is normal, it indicates that the power supply of one of the two DC buses is abnormal. The main control module 10 can control the contactor to be attracted by the contactor control module 30, thereby controlling the two DC buses to be parallel. Specifically, the two DC buses are parallel, which means that the two DC buses share the same power supply.

[0044] More specifically, if the DC bus with abnormal bus battery voltage is the first DC bus, the DC bus with normal bus battery voltage is the second DC bus; if the DC bus with abnormal bus battery voltage is the second DC bus, the DC bus with normal bus battery voltage is the first DC bus.

[0045] Under normal circumstances, the first power supply supplies power to the first DC bus, and the second power supply supplies power to the second DC bus. If the first power supply is abnormal, it will cause the bus battery voltage of the first DC bus to be abnormal. Therefore, the first DC bus and the second DC bus need to be parallel by the contactor, so that the second power supply replaces the first power supply to supply power to the first DC bus, and the second power supply also supplies power to the second DC bus.

[0046] Similarly, if the second power supply is abnormal, it will cause the bus battery voltage of the second DC bus to be abnormal. Therefore, the first DC bus and the second DC bus need to be parallel by the contactor, so that the first power supply replaces the second power supply to supply power to the second DC bus, and the first power supply also supplies power to the first DC bus.

[0047] Of course, in addition to the contactor, a first switch (tie-in switch) can also be arranged between the first DC bus and the second DC bus. The first switch is, for example, an air switch.

[0048] When the operating personnel maintain the DC bus, the air switch needs to be opened. After maintenance, the air switch is closed, the main control module 10 is powered on and reset, the contactor returns to the open state, for example, the normal open state, and the two DC buses are independent of each other and supplied by different power supplies.

[0049] In one specific embodiment, when the main control module 10 switches the power supply, the DC bus with abnormal bus battery voltage can also be disconnected from the original connected power supply.

[0050] For example, each DC bus is connected to its original power supply through a circuit breaker.

[0051] Normally, the circuit breaker is in the closed position, and the DC bus is powered by its original power supply. If the original power supply cannot supply power normally, it will cause the bus battery voltage of the DC bus to be abnormal. At this time, the main control module 10 will disconnect the circuit breaker and make it in the open position, so that the original power supply no longer continues to supply power to the DC bus.

[0052] The main control module 10 connects another power supply to the DC bus with power supply failure by controlling the contactor to be attracted, so that the switching of the power supply is realized.

[0053] The contactor can be a circuit breaker, a relay, or other elements that can be used as a switch.

[0054] For example:

[0055] Normally, the A circuit breaker and the A tie switch are in the closed position, and the C circuit breaker is in the open position. The A route DC power supply system is powered by the A route DC power supply. When the A route DC power supply fails, the main control module 10 detects that the bus battery voltage of the A route DC power supply system is abnormal, disconnects the A circuit breaker, and closes the C circuit breaker. The A tie switch is not actuated (in the closed position). The power supply of the A route DC power supply system is switched from the A route DC power supply to the B route DC power supply, and the automatic switching of the charging DC power supply is completed.

[0056] Among them, the B route DC power supply is the original power supply of the B route DC power supply system. Normally, the B circuit breaker and the B tie switch are in the closed position, and the C circuit breaker is in the open position. The B route DC power supply system is powered by the B route DC power supply.

[0057] The embodiment can accurately and quickly identify faults: the automatic switching device 00 of the DC power supply in the dual configuration DC system can quickly and accurately identify power supply failure, so as to timely switch the power supply and ensure stable operation of the system.

[0058] The embodiment can automatically switch control: in the case of unattended, the automatic switching device 00 of the DC power supply has automatic control function, which can automatically switch the power supply according to the state of the system, avoiding problems caused by untimely manual operation.

[0059] The embodiment can be intelligent and automated: the automatic switching device 00 of the DC power supply has high intelligence and automation, so as to reduce the need for manual intervention, improve work efficiency and system reliability.

[0060] The embodiment determines whether the power supply of the DC bus is normal by monitoring the target voltage of two DC buses in the double configuration DC system substation, and when determining that the power supply of one of the DC buses is abnormal, the normal power supply is used to replace the abnormal power supply to automatically switch the power supply of the abnormal DC bus, so that the power supply of the voltage abnormal DC bus is quickly restored, and the normal operation of the power grid is restored. The automatic switching of the DC power supply changes the current situation of passive and lagging operation of personnel, realizes uninterrupted power supply, reduces the power outage time, avoids the loss caused by power outage, and improves the efficiency of operation and maintenance. The embodiment can realize automatic switching of the dual power supply in fault, maintenance and operation mode adjustment, reduce the operation of the equipment by the operation and maintenance personnel, and improve the safety factor of operation. The embodiment improves the power supply reliability, reduces complaints caused by frequent power outages, improves user experience, and has wide application prospect.

[0061] In one embodiment, the target voltage further includes a bus imbalance voltage of each of the two DC buses, wherein the bus imbalance voltage is a difference between a high-end voltage and a low-end voltage of the same DC bus, the high-end voltage is a potential difference between a positive potential and a zero potential of the same DC bus, and the low-end voltage is a potential difference between the zero potential and a negative potential of the same DC bus.

[0062] The master control module 10 is also used to determine that the target DC bus is not high resistance grounded if the DC bus imbalance voltage of the target DC bus is greater than the corresponding DC bus imbalance voltage threshold, and control the contactor to be in the open and prohibited attraction state through the contactor control module 30 to prohibit the parallel connection of the first DC bus and the second DC bus, wherein the target DC bus includes at least one of the first DC bus and the second DC bus.

[0063] Specifically, the first potential difference includes a difference between each two of the positive potential, the negative potential and the zero potential of the first DC bus;

[0064] The second potential difference includes a difference between each two of the positive potential, the negative potential and the zero potential of the second DC bus;

[0065] The bus imbalance voltage of the first DC bus is a difference between the high-end voltage and the low-end voltage of the first DC bus;

[0066] The bus imbalance voltage of the second DC bus is a difference between the high-end voltage and the low-end voltage of the second DC bus;

[0067] The high-end voltage is a potential difference between the positive potential and the zero potential of the same DC bus;

[0068] The low-end voltage is a potential difference between the zero potential and the negative potential of the same DC bus.

[0069] The high-end voltage and the low-end voltage both belong to potential difference or voltage difference.

[0070] For example, the voltage difference between the positive potential of the first DC bus and the 0 potential is called the high-end voltage of the I bus;

[0071] The voltage difference between the 0 potential and the negative potential of the first DC bus is called the low-end voltage of the I bus.

[0072] The voltage difference between the positive potential of the second DC bus and the 0 potential is called the high-end voltage of the II bus;

[0073] The voltage difference between the 0 potential and the negative potential of the second DC bus is called the low-end voltage of the II bus.

[0074] The difference between the high-end voltage of the I bus and the low-end voltage of the I bus is called the unbalance voltage of the I bus;

[0075] The difference between the high-end voltage of the II bus and the low-end voltage of the II bus is called the unbalance voltage of the II bus.

[0076] If the unbalance voltage of the first DC bus is greater than the unbalance voltage threshold of the first DC bus, it is determined that the first DC bus is not high-resistance grounded, and the contactor is controlled to be in the open and prohibited closing state, so as to prohibit the parallel of the first DC bus and the second DC bus, that is, to prohibit the parallel of the two DC buses.

[0077] If the unbalance voltage of the second DC bus is greater than the unbalance voltage threshold of the second DC bus, it is determined that the second DC bus is not high-resistance grounded, and the contactor is controlled to be in the open and prohibited closing state, so as to prohibit the parallel of the second DC bus and the second DC bus, that is, to prohibit the parallel of the two DC buses.

[0078] The first DC bus and the second DC bus may occur ground fault at the same time, that is, one of them may occur ground fault.

[0079] The control of the contactor in the open and prohibited closing state is to lock the contactor.

[0080] In this embodiment, the unbalance voltage of each DC bus is calculated, and then the unbalance voltage is compared with the unbalance voltage threshold of each DC bus, so as to determine whether each DC bus occurs ground fault. When at least one DC bus occurs ground fault, the contactor is controlled to be in the open and prohibited closing state, thereby prohibiting the parallel of the two DC buses, which can effectively prevent the interference of the DC bus with ground fault to the normal operation of the DC bus, effectively avoid the safety problem caused by the misoperation of the contactor due to the non-compliance, and ensure the safety of the partial power grid.

[0081] In one embodiment, the target voltage further comprises a two-section bus voltage difference, wherein the two-section bus voltage difference is a difference between the bus battery pack voltage of the first section DC bus and the bus battery pack voltage of the second section DC bus.

[0082] The master control module 10 is further configured to control the contactor to be in the open and prohibited attraction state by the contactor control module 30 if the two-section bus voltage difference is greater than the parallelable voltage difference threshold, so as to prohibit the parallel of the second section DC bus and the second section DC bus.

[0083] Specifically, the difference between the I-section bus battery pack voltage and the II-section bus battery pack voltage is referred to as the two-section bus voltage difference.

[0084] If the two-section bus voltage difference is greater than the parallelable voltage difference threshold, an impact current will be generated if the two section DC buses are parallel, and therefore, the contactor needs to be locked (controlled to be in the open and prohibited attraction state) to prohibit the parallel of the two section DC buses.

[0085] In the embodiment, the two-section bus voltage difference between the two section DC buses is calculated, and the two-section bus voltage difference is compared with the parallelable voltage difference threshold, so as to control the contactor to be in the open and prohibited attraction state if necessary, to prohibit the parallel of the two section DC buses, which can effectively avoid the impact current generated by the parallel of the two section DC buses, thereby avoiding the threat to the personal safety of the operator and avoiding the damage to the power supply such as the battery, and effectively protecting the personal safety and the operation safety of the power grid.

[0086] In one embodiment, the master control module 10 is further configured to control the contactor to be in the open and prohibited attraction state by the contactor control module 30 if the target DC bus battery pack voltage intermittently drops, so as to prohibit the parallel of the second section DC bus and the second section DC bus.

[0087] The master control module 10 is specifically configured to control the contactor to be attracted to parallel the first section DC bus and the second section DC bus if the target voltage based on different sampling time points shows that the bus battery pack voltage of any section DC bus continuously decreases and the condition of controlling the contactor to be in the open and prohibited attraction state is not met.

[0088] Specifically, if the battery pack voltage of a certain DC bus is detected to intermittently drop, it indicates that the power supply of the DC bus may be unstable, and at this time, it is impossible to determine whether the power supply is really unable to normally supply power. In order to prevent blind switching of the power supply in the case of unstable power supply, the contactor is locked (controlled to be in the open and prohibited attraction state) when the battery pack voltage intermittently drops (non-continuous decrease), so as to prohibit the parallel of the two section DC buses. In addition, the master control module can also control the device to issue a DC bus battery pack abnormality alarm.

[0089] The embodiment allows parallel connection of two DC bus bars only when the voltage of the bus battery of any one of the DC bus bars continuously decreases and the condition for controlling the contactor to be in the open and prohibited attraction state is not met.

[0090] The condition for controlling the contactor to be in the open and prohibited attraction state is not met means that the condition is not met or the following situations are excluded:

[0091] The DC bus imbalance voltage of the target DC bus is greater than the corresponding DC bus imbalance voltage threshold, the target DC bus is not high-resistance grounded,

[0092] The voltage difference between the two bus bars is greater than the parallelable voltage difference threshold,

[0093] The bus battery voltage of the target DC bus intermittently decreases.

[0094] Or,

[0095] The condition for controlling the contactor to be in the open and prohibited attraction state is not met means that the following conditions are met:

[0096] The DC bus imbalance voltage of the target DC bus is not greater than the corresponding DC bus imbalance voltage threshold, or no DC bus is high-resistance grounded;

[0097] And,

[0098] The voltage difference between the two bus bars is not greater than the parallelable voltage difference threshold;

[0099] And,

[0100] No bus battery voltage of the DC bus intermittently decreases.

[0101] Excluding the above situations, if it is detected that the DC bus battery voltage of a certain path continuously decreases, the contactor is attracted, and two DC bus bars are connected in parallel. In addition, the main control module can also control the device to issue a DC bus battery abnormal alarm.

[0102] For example, the continuous decrease can be that the bus battery voltage decreases successively at a plurality of sampling time points (for example, 3 or 4 or 6 sampling time points).

[0103] It should also be noted that controlling the contactor to be in the open and prohibited from engaging state can prevent manual engagement of the contactor. That is, it can prevent manual control of the contactor to engage. This can prevent operators from accidentally operating the contactor without knowing that a ground fault has occurred on the DC bus or that two parallel DC bus sections may generate inrush current, thereby avoiding potential safety hazards to the power grid, the personal safety of operators, and the safety of the power supply.

[0104] This embodiment allows for the rapid switching of available power supplies to the DC bus when a continuous decrease in the voltage of a DC bus battery pack is detected and there is no need to control the contactor to be in an open or prohibited state. It also prevents operators from accidentally operating the contactor without knowing that a ground fault has occurred on the DC bus or that the parallel connection of the two DC bus sections may generate inrush current, thereby avoiding potential safety hazards to the power grid, the personal safety of the operators, and the safety of the power supply.

[0105] In one embodiment, the automatic switching device 00 for DC power supply further includes an alarm module connected to the main control module 10;

[0106] The main control module 10 is also used to control the alarm module to issue corresponding abnormal alarms if the control contactor is in the open and prohibited from engaging state. The abnormal alarms include at least one of the following: first DC bus grounding alarm, second DC bus grounding alarm, and DC bus battery pack abnormal alarm.

[0107] Specifically, the main control module is connected to the alarm module. When parallel operation of two DC bus sections is prohibited, or when the control contactor is in an open and prohibited-from-engaging state, the main control module can also control the alarm module to issue corresponding alarms. For example, if the unbalanced voltage of the first DC bus section is detected to be greater than the unbalanced voltage threshold of the first DC bus section, a DC bus section I ground fault alarm is issued. If the unbalanced voltage of the second DC bus section is detected to be greater than the unbalanced voltage threshold of the second DC bus section, a DC bus section II ground fault alarm is issued. If the voltage difference between the two bus sections is detected to be greater than the parallel operation voltage difference threshold, the alarm module issues a first abnormality alarm for the DC bus battery pack. If an intermittent sudden drop in voltage of a DC bus battery pack is detected, the alarm module issues a second abnormality alarm for the DC bus battery pack.

[0108] To differentiate between different types of alarms, the aforementioned abnormal alarms can be presented in different forms. For example, different abnormal alarms can be indicated with different sounds, different alarm texts, or different alarm lights of different colors, etc. This application does not impose any limitations on this. When alarms are indicated by alarm text, the alarm text can be displayed on the local device's screen and / or sent to the screen of a remote device for display.

[0109] The abnormal voltage of the bus battery pack is caused by the original power supply to the DC bus failing to provide power. This failure may be due to a malfunction in the charger of the power supply unit, causing it to discharge without charging, thus gradually reducing its capacity. If this issue is left unaddressed for an extended period, the original power supply unit may become undercapacitated due to the inability to charge properly, and may even lose all its capacity.

[0110] This embodiment enables operators to promptly detect and address power supply failures by providing timely alarms. This avoids situations where power supplies, such as battery packs, cannot be charged properly for extended periods due to lack of supervision or delayed alarm handling, resulting in capacity loss or even complete loss of capacity.

[0111] This embodiment can promptly notify operators of abnormal conditions through abnormal alarms, assisting them in timely repairs and preventing the power supply from becoming depleted or even losing its full capacity due to prolonged inability to charge normally, thus ensuring the safe and stable operation of the power grid.

[0112] In one embodiment, the contactor control module 30 includes a relay module 31 and a relay control module 32 that are electrically connected.

[0113] Relay module 31 is connected to the contactor;

[0114] The relay control module 32 is connected to the main control module 10 and is used to control the relay in the relay module 31 to activate the contactor and make it engage if it receives the activation signal from the main control module 10.

[0115] The relay control module 32 is also used to de-energize and disconnect the contactor by controlling the relay in the relay module 31 to disconnect if it receives a disconnect signal from the main control module 10.

[0116] The relay control module 32 is also used to continuously control the relay in the relay module 31 to disconnect if it continuously receives the disconnect signal from the main control module 10, so that the contactor is de-energized and in an open and prohibited state.

[0117] Specifically, in this embodiment, the contactor control module 30 controls the energization or de-energization of the contactor by controlling the engagement or disengagement of the relay. The contactor engages when energized and disengages when de-energized, thereby controlling whether the first DC bus and the second DC bus are connected in parallel.

[0118] Furthermore, in this embodiment, the engagement and disengagement signals are generated autonomously by the main control module 10 based on logical judgment.

[0119] If the main control module 10 detects an abnormality in the bus battery pack voltage of any segment of the DC bus based on the target voltage at different sampling times, it generates a pull-in signal.

[0120] If the main control module 10 detects that the DC bus unbalanced voltage of the target DC bus is greater than the corresponding DC bus unbalanced voltage threshold, it determines that the target DC bus is not grounded with high resistance and generates a disconnection signal.

[0121] If the main control module 10 detects that the voltage difference between the two bus sections is greater than the voltage difference threshold for parallel operation, it generates a disconnection signal.

[0122] If the main control module 10 detects an intermittent sudden drop in the voltage of the bus battery pack of the target DC bus, it generates a disconnection signal.

[0123] If the main control module 10 detects that the voltage of the bus battery pack of any DC bus segment continuously decreases based on the target voltage at different sampling times, and the conditions for controlling the contactor to be in the open and prohibited from engaging state are not met, then an engaging signal is generated.

[0124] In this embodiment, the contactor is energized or de-energized by controlling the activation or deactivation of the relay. The contactor will activate when energized and de-energize when de-energized, thereby enabling rapid control over whether the first DC bus and the second DC bus are connected in parallel.

[0125] In one embodiment, the relay control module 32 includes a first resistor, an optocoupler, a second resistor, a third resistor, a first switching transistor, and a first diode;

[0126] Relay module 31 includes a first relay and a first terminal block;

[0127] The first end of the first resistor is connected to the main control module 10, the second end is connected to the second end of the optocoupler, the first end of the optocoupler is connected to the first voltage, the third end is grounded, the fourth end is connected to the second voltage through the second resistor, the fourth end is also connected to the first end of the first switching transistor through the third resistor, the second end of the first switching transistor is connected to the second voltage, the third end is connected to the cathode of the first diode, the third end is also connected to the first contact of the first relay, and the anode of the first diode is grounded.

[0128] The fourth contact of the first relay is grounded. An iron core is connected between the first and fourth contacts of the first relay. The fifth contact of the first relay is connected to the third voltage. The second contact is connected to the contactor through the first terminal. When energized, the fifth contact of the first relay is connected to the second contact. When de-energized, the fifth contact of the first relay is connected to the third contact.

[0129] Specifically, such as Figure 2 The diagram shown is a circuit diagram of the contactor control module 30 in one embodiment; see reference. Figure 2 The relay control module 32 includes a first resistor R27, an optocoupler U5, a second resistor R28, a third resistor R26, a first switching transistor Q2, and a first diode D2;

[0130] Relay module 31 includes a first relay RLY2 and a first terminal U37;

[0131] The first end of the first resistor R27 is connected to the main control module 10 to obtain a pull-in signal or a pull-out signal; the second end is connected to the second end of the optocoupler U5; the first end of the optocoupler U5 is connected to a first voltage (e.g., 3.3V); the third end is grounded (GND); the fourth end is connected to a second voltage (e.g., +5V) through the second resistor R28; the fourth end is also connected to the first end of the first switching transistor Q2 through the third resistor R26; the second end of the first switching transistor Q2 is connected to the second voltage (e.g., +5V); the third end is connected to the cathode of the first diode D2; the third end is also connected to the first contact of the first relay RLY2; the anode of the first diode D2 is grounded (GND).

[0132] The fourth contact of the first relay RLY2 is grounded to GND. An iron core is connected between the first and fourth contacts of the first relay RLY2. The fifth contact of the first relay RLY2 is connected to a third voltage (e.g., 24V). The second contact is connected to the contactor through the first terminal U37. When the first relay RLY2 is energized, the fifth contact of the first relay RLY2 is connected to the second contact. When the first relay RLY2 is not energized, the fifth contact of the first relay RLY2 is connected to the third contact.

[0133] The first terminal of the first terminal U37 is connected to the second contact of the first relay RLY2, and the second terminal is grounded. The first and second terminals of the first terminal U37 are connected to a contactor.

[0134] The first switching transistor Q2 can be either a transistor or a MOSFET. If the first switching transistor Q2 is a transistor, then the first terminal of the first switching transistor Q2 is the base, the second terminal is the emitter, and the third terminal is the collector.

[0135] Among them, signal OUT2 is the control signal output by the main control module 10. When signal OUT2 is high, it is a disconnect signal, and when signal OUT2 is low, it is a energizing signal.

[0136] More specifically, taking the first switching transistor Q2 as an example, when the signal OUT2 output of the main control module 10 is low, the optocoupler U5 is turned on, pulling down the base of the NPN transistor Q2. The emitter and collector of the transistor are turned on, and the first relay RLY2 is energized. At this time, the contactor coil is energized, and the contactor is energized.

[0137] When the main control module 10 outputs a high-level signal OUT2, optocoupler U5 is not conducting, the base of transistor Q2 is pulled high, transistor Q2 is cut off, and the first relay RLY2 is disconnected. At this time, the contactor coil is not energized, and the contactor is disconnected. When the contactor is locked, the prohibition signal OUT2 outputs a low-level signal, and the contactor remains normally open.

[0138] When the contactor coil is energized, the coil current generates a magnetic field. This magnetic field causes an electromagnetic attraction in the stationary iron core, drawing in the moving iron core and actuating the contactor contacts. The normally closed contacts open, and the normally open contacts close; these actions are linked. When the coil is de-energized, the electromagnetic attraction disappears, and the armature is released by the release spring, causing the contacts to return to their original position. The normally open contacts open, and the normally closed contacts close. In this design, a relay is used to control the energization and de-energization of the contactor coil.

[0139] In one embodiment, the contactor control module 30 further includes an indicator module connected to the relay control module 32.

[0140] The indicator module includes a fourth resistor R24 ​​and a light-emitting diode LED3;

[0141] The third terminal of the first switching transistor Q2 is also grounded to GND through the fourth resistor R24 ​​and the light-emitting diode LED3.

[0142] Specifically, when the signal OUT2 output of the main control module 10 is low, the optocoupler U5 is turned on, pulling down the base of the NPN transistor Q2. The emitter and collector of the transistor are turned on, and the light-emitting diode LED3 lights up, representing that the two DC bus sections are connected in parallel.

[0143] If signal OUT2 is high, LED3 will not light up, indicating that the two DC bus sections are not connected in parallel.

[0144] In this embodiment, the indicator module can clearly indicate to the user whether two DC bus sections are connected in parallel.

[0145] In one embodiment, the automatic switching device 00 for DC power supply further includes a contactor manual control module connected to the main control module 10.

[0146] The contactor manual control module is used to receive manual operations from users, generate engagement or disengagement commands based on the manual operations, and output the engagement or disengagement commands to the main control module 10.

[0147] The main control module 10 is used to generate an engagement signal according to the engagement command and output the engagement signal to the relay control module 32;

[0148] The main control module 10 is also used to generate a disconnect signal according to the disconnect command and output the disconnect signal to the relay control module 32.

[0149] Specifically, the automatic switching device 00 for DC power supply in this embodiment is also equipped with a contactor manual control module. Through this contactor manual control module, the operator can manually connect two DC bus sections in parallel or manually disconnect two parallel DC bus sections. This achieves more convenient and flexible human-machine interaction control.

[0150] Figure 3 Here is a circuit diagram of the contactor manual control module in one embodiment, with reference to... Figure 3 The contactor manual control module includes a first button circuit and a second button circuit.

[0151] The first terminal of resistor R156 in the first button circuit is connected to a first voltage (e.g., 3.3V), and the second terminal is grounded to GND through capacitor C76. The second terminal of resistor R156 is connected to the main control module 10 through terminal U97. The first terminal of terminal U97 is grounded, and the second terminal is connected to the second terminal of resistor R156 and the main control module 10.

[0152] The first terminal of resistor R155 in the second button circuit is connected to a first voltage (e.g., 3.3V), and the second terminal is grounded to GND through capacitor C75. The second terminal of resistor R155 is connected to the main control module 10 through terminal U98. The first terminal of terminal U98 is grounded, and the second terminal is connected to the second terminal of resistor R155 and the main control module 10.

[0153] The first and second button circuits each have one button, designated Button 1 and Button 2, which control the on and off states of the contactor, respectively. The main control module 10 uses an external interrupt to detect whether a button is pressed. When Button 1 of the first button circuit is pressed, the OUT2 output of the main control module 10 is low, causing the contactor to engage. When Button 2 of the second button circuit is pressed, the OUT2 output of the main control module 10 is high, causing the contactor to disengage.

[0154] This embodiment includes a contactor manual control module, allowing operators to manually control the contactor's on / off state according to actual needs.

[0155] In one embodiment, the voltage detection module 20 includes at least one voltage detection unit, each voltage detection unit comprising an isolated operational amplifier unit and a voltage divider unit electrically connected to each other.

[0156] The two ends of the voltage divider unit are connected to two different detection points on the same DC bus. The two different detection points correspond to two different target potentials on the DC bus. The voltage divider unit is used to divide the potential difference obtained from the two target potentials through a series resistor and input the resulting voltage divider to the isolation operational amplifier unit.

[0157] The isolation operational amplifier unit is used to isolate and amplify the voltage divider, and input the resulting analog amplified signal to the main control module 10.

[0158] The main control module 10 is used to convert the analog amplified signal into a potential difference between two target potentials according to the amplification factor and the voltage division ratio. The two target potentials are any two of the positive potential, negative potential and zero potential.

[0159] Specifically, Figure 4 Here is a circuit diagram of the voltage detection unit in one embodiment; see reference. Figure 4 The voltage detection unit is connected to two different detection points on the same DC bus. These two different detection points can be any two potentials among positive, negative, and zero potentials. Figure 4 This example uses detection points corresponding to the positive and negative potentials of the same DC bus at both ends. The voltage difference between the two ends of the voltage detection unit is divided by a voltage divider unit, and the resulting voltage is input to the second and third pins (differential voltage input terminals) of the isolation operational amplifier U2. The voltage divider unit includes resistors R1, R2, R3, R5, R7, R8, and R9. The two ends of resistor R5 are connected to the second and third pins of the isolation operational amplifier U2, respectively. The first pin of the isolation operational amplifier U2 is connected to voltage GL1_3.3V, and the fourth pin is grounded to GL1_GND. The first pin of the isolation operational amplifier U2 is also grounded to GL1_GND through capacitor C1. The eighth pin of the isolation operational amplifier U2 is connected to a voltage of 3.3V. The eighth pin of the isolation operational amplifier U2 is also grounded to GND through capacitor C2. The sixth pin of the isolation operational amplifier U2 is grounded to GND. The seventh pin of the isolation operational amplifier U2 is grounded to GND through resistor R6 and capacitor C3. The common node of resistor R6 and capacitor C3 is connected to the main control module 10, which is used to output the analog amplified signal ACD1 to the main control module 10.

[0160] The isolation operational amplifier U2 can be an AMC1200BDWVR.

[0161] The voltage detection unit can be connected to two potentials through wiring terminals.

[0162] The voltage detection unit can be connected to the voltage GL1_3.3V through the fourth pin of the isolation power supply U99. The voltage detection unit can be grounded to GL1_GND through the third pin of the isolation power supply U99. The fourth pin of the isolation power supply U99 is also grounded to GL1_GND through capacitor C54.

[0163] The second pin of the isolation power supply U99 is connected to +5V, and it is also grounded to GND through capacitor C53. The first pin of the isolation power supply U99 is also grounded to GND. The isolation power supply U99 converts the +5V voltage to GL1_3.3V.

[0164] The model number of the isolation power supply U99 can be B0503S-1W.

[0165] The AMC1200 is an isolation operational amplifier. The voltage being detected is divided by a series of resistors and then input to the differential voltage input of the isolation operational amplifier. After internal isolation, it is amplified and output to the ADC interface of the main control chip. The main control chip then calculates the measured voltage value based on the amplification factor and the voltage division ratio. The main purpose of using an isolation operational amplifier is to separate high-voltage and low-voltage regions, preventing high-voltage damage to the low-voltage circuit. Therefore, the isolation operational amplifier also requires a DC-DC isolated power supply module to provide power. The B0503S is a DC 5V to DC 3.3V isolated power supply with isolated input and output.

[0166] Figure 4 This is a circuit diagram of one voltage detection unit in voltage detection module 20. The circuit diagrams of other voltage detection units are similar. Figure 4 resemblance.

[0167] For example, the first DC bus has three potential difference detection points:

[0168] (1) The voltage difference between the positive and negative potentials (potential difference) is called the voltage of the I-section bus battery pack;

[0169] (2) The voltage difference (potential difference) between the positive potential and the 0 potential is called the high-end voltage of the I section bus;

[0170] (3) The voltage difference between 0 potential and negative potential (potential difference) is called the low-end voltage of bus section I.

[0171] The second DC bus has three potential difference detection points:

[0172] (4) The voltage difference between the positive and negative potentials (potential difference) is called the voltage of the II section bus battery pack;

[0173] (5) The voltage difference between the positive potential and the 0 potential (potential difference) is called the high-end voltage of the II section bus;

[0174] (6) The voltage difference between 0 potential and negative potential (potential difference) is called the low-end voltage of section II bus.

[0175] Therefore, the voltage detection module 20 has at least six voltage detection units. Different voltage detection units are responsible for detecting different potential differences. The six voltage detection units output analog amplified signals ACD1, ACD2, ACD3, ACD4, ACD5 and ADC6 to the main control module 10, respectively.

[0176] Figure 5 Here is a circuit diagram of the main control module 10 in one embodiment of this application, with reference to... Figure 5 U1 is the main control chip, model STM32F103c8t6. Pins 20 and 44 are for power-on boot, connected to the negative power supply via resistors R4 and R11. Pins 5 and 6 are external clock input pins, connected to the two ends of crystal oscillator X1, and connected to the negative power supply via capacitors C8 and C9. H1 is the programming interface, connected to the main control's debug pins SWCLK and SWDIO. The main control has three power supply pins, which need to be connected to the positive power supply, with capacitors C10, C11, and C13 in parallel for filtering. ADC1 and ADC2 interfaces are used for voltage detection, and CN1 is the LCD screen interface. SW1 is the reset circuit; when button SW1 is pressed, RST goes low, and the MCU restarts. See the circuit schematic. Figure 5 .

[0177] Pins 5 and 6 of the main control chip U1 are connected to the two ends of crystal oscillator X1 to acquire signals OS_8M_IN and OS_8M_OUT. One end of crystal oscillator X1 is grounded through capacitor C8, and the other end is grounded through capacitor C9. Pin 7 of the main control chip U1 is connected to the reset signal RST. The first end of resistor R23 in the reset module is connected to a voltage of 3.3V, and the second end is grounded to GND through capacitor C7. The two ends of capacitor C7 are connected to the two ends of switch SW1, and the second end of resistor R23 is also connected to pin 7 of the main control chip U1. Pin 8 of the main control chip U1 is grounded to GND, pin 9 of the main control chip U1 is connected to a voltage of 3.3V, and pins 10, 11, and 16-19 of the main control chip U1 are connected to six different voltage detection units to acquire analog amplified signals ACD1, ACD2, ACD3, ACD4, ACD5, and ADC6, respectively.

[0178] Pins 12 and 13 of the main control chip U1 are connected to serial port 2 (USART2_RX, USART2_TX) of the wireless communication module. Pins 14 and 15 of the main control chip U1 are connected to the two setting terminals M0 and M1 of the wireless communication module, which are used to configure the working mode of the wireless module.

[0179] Pin 20 of the main control chip U1 is grounded to GND through resistor R11. Pins 21 and 22 of the main control chip U1 are extension pins. Pins 23, 47, and 35 of the main control chip U1 are grounded. Pins 24, 48, and 36 of the main control chip U1 are connected to a voltage of 3.3V. Pin 44 of the main control chip U1 is grounded through resistor R4. Pin 42 of the main control chip U1 is the output terminal for the pull-in or pull-out signal, i.e., the output terminal of signal OUT2. Pin 46 of the main control chip U1 is connected to the cathode of LED2, and the anode of LED2 is connected to a voltage of 3.3V through resistor R25. Pins 37 and 34 of the main control chip U1 are connected to pins 3 and 2 of terminal H1. Pin 1 of terminal H1 is connected to a voltage of 3.3V, pin 3 of terminal H1 is grounded, and pin 5 of terminal H1 is connected to the second end of resistor R23 and pin 7 of chip U1.

[0180] The ADC module of the main control chip U1 is typically based on the Successive Approximation Register (SAR) architecture, and its working principle is as follows:

[0181] Sampling Phase: During the sampling phase, the ADC holds the analog input signal across the sampling capacitor via a sampling switch to stabilize the input voltage. The sampling time determines the duration of the input signal sampling, affecting the conversion accuracy and speed. A longer sampling time helps improve accuracy but reduces the sampling rate.

[0182] Conversion Phase: In the conversion phase, the ADC compares the analog voltage with the reference voltage using a successive approximation algorithm to generate the corresponding digital value. During this process, the ADC gradually approximates the voltage value of the analog input signal until it finds a digital code that matches the analog voltage.

[0183] In one embodiment, the automatic switching device 00 for DC power supply may further include a wireless communication module connected to the main control module 10.

[0184] The wireless communication module, for example, is a LoRa wireless module. It includes a chip U13 and a header U14, which is used to configure the module. M0 and M1 configure the module's operating mode; when both pins are low, serial data transmission is supported, allowing communication between wireless modules with the same configuration within range. A receiver can be designed to communicate with it. The wireless communication module connects to the main control module 10 via serial port 2 (USART2_RX, USART2_TX) to transmit and receive serial data.

[0185] In one embodiment, the automatic switching device 00 for DC power supply may further include a power module. Figure 6This is a circuit diagram of a power module in one embodiment of this application; see reference. Figure 6 The power module includes a first power unit, a second power unit, and a third power unit. Figure 6 The first circuit diagram above is the first power supply unit, which is the first-stage step-down circuit. The input range of this power supply is 85V~275VAC or 100V~370VDC, and the output is DC24V. F25 is a fuse.

[0186] Pins 6 and 5 of U32 are connected to the first terminals of capacitors C43, C46, ​​C47, and C44, respectively. Pins 3 and 4 of U32 are connected to the second terminals of capacitors C43 and C46, ​​respectively. The second terminal of capacitor C43 is connected to the second terminals of capacitors C47 and C44 through inductor L7. Pins 6 and 5 of U32 are also connected to the first terminal of U31. The second terminals of capacitors C47 and C44 are also connected to the second terminal of U31. The third terminal of U31 is grounded. The fourth terminal of U31 outputs a voltage of 24V. The fourth terminal of U31 is also grounded through capacitor C45 and capacitor C48. Pin 2 of U32 is connected to the first terminal of U30. Pin 2 of U32 is also connected to the PE line (Protective Earth) through capacitor C41. Pin 1 of U32 is connected to the second terminal of U30. Pin 1 of U32 is also connected to the PE line through capacitor C42. The third terminal of U30 is connected to the L / DC+ line (Live Line) through resistors R93 and F25. The third terminal of U30 is also connected to the first terminals of capacitor C40, resistor R94, and resistor R95 respectively. The fourth terminal of U30 is also connected to the second terminals of capacitor C40, resistor R94, and resistor R95, as well as the N / DC- line (Neutral Line).

[0187] U32 can convert AC power to 24V.

[0188] Figure 6 The second circuit diagram in the middle is the second power supply unit, which is the second-stage step-down circuit. Pin 1 of U10 is connected to the output terminal through capacitor C17 and inductor L1, with an output voltage of +5V. Pin 2 of U10 is connected to a voltage of 24V. Pin 2 of U10 is also grounded to GND through parallel capacitors C20 and C21. Pin 3 of U10 is connected to a voltage of 24V through resistor R34. Pin 4 of U10 is grounded through resistor R39. Pin 3 of U10 is also grounded through resistor R41. Pin 8 of U10 is connected to the output terminal through inductor L1. Pin 8 of U10 is also grounded through D6. Pins 7 and 9 of U10 are grounded. Pin 6 of U10 is grounded through capacitor C22. Pin 5 of U10 is grounded through resistor R40. The two ends of capacitor C19 are connected to the output terminal and ground respectively. The two ends of capacitor C18 are connected to the output terminal and ground respectively. The output terminal is grounded through resistors R31 and R40.

[0189] U10 can convert 24V voltage to +5V to power other modules.

[0190] U32 is an isolated step-down power supply module with an input range of 85V to 275VAC or 100V to 370VDC and an output of DC 24V. F25 is a fuse. U10 is an LMR14050 device, a 40V, 5A step-down regulator with an integrated high-side MOSFET. This device has a wide input voltage range of 4V to 40V, a wide adjustable switching frequency range, and incorporates multiple protection features: cycle-by-cycle current limiting protection, thermal sensing and thermal shutdown protection to handle excessive power consumption, and output overvoltage protection.

[0191] Figure 6 The third circuit diagram above is the third power supply unit, which is the third-stage step-down circuit. Pin 1 of U9 is connected to the cathode of D3, and the anode of D3 is connected to +5V. Pin 1 of U9 is connected to pin 3. Pin 2 of U9 is grounded. Pin 5 of U9 is the output terminal with an output voltage of 3.3V. Pin 5 of U9 is grounded through parallel capacitors C15 and C16.

[0192] This part of the circuit takes a DC 24V input and outputs a DC 3.3V output, achieved in two steps. First, the DC 24V is stepped down to DC 5V, and the output voltage is adjusted by R31 and R40. Then, a linear regulator is used to step down the 5V voltage to DC 3.3V.

[0193] DC5V=Vout=(1+R31 / R40)*0.75.

[0194] In this embodiment, the power module can obtain at least one target voltage through multi-stage step-down to power other modules of the device.

[0195] Figure 7 This is a structural block diagram of an automatic switching device 00 for DC power supply according to another embodiment of this application. (See reference...) Figure 7 The automatic switching device 00 for DC power supply includes a main control module 10, and a power module, a voltage detection module 20, a contactor control module 30, a button module, a wireless module, and an LCD screen connected to the main control module 10.

[0196] The power module can convert AC85-275 input and DC110-DC385 input to DC24V, and can further convert the DC24V input voltage to DC3.3C output voltage.

[0197] Figure 7The DC busbars in sections I and II can be connected via air switches and contactors. The air switches are closed by default, and the contactors are open by default. Both sections I and II of the DC busbar contain a positive potential of +110V, a negative potential of -110V, and a zero potential of 0V.

[0198] The LCD screen can display data such as target voltage and potential difference in real time, and can also show whether two DC bus sections are currently connected in parallel, for users to view conveniently.

[0199] It should be noted that the resistance values, capacitance values, voltages, chip models, terminal block models, inductance values, etc. in the various circuit diagrams of this application are merely illustrative examples. The actual values ​​are determined according to the actual application scenario, and this application does not impose any restrictions on them.

[0200] This application enables accurate and rapid fault identification: the automatic switching device 00 for DC power supply in a dual-configuration DC system needs to be able to quickly and accurately identify power supply faults so as to switch the battery charging power supply in a timely manner and ensure the stable operation of the system.

[0201] This application enables automatic switching control: In unattended situations, the device needs to have automatic control functions, which can automatically switch the power supply according to the system status to avoid problems caused by untimely manual operation.

[0202] This application enables intelligence and automation: the device should be highly intelligent and automated to reduce the need for manual intervention and improve work efficiency and system reliability.

[0203] This application enables the determination of conditions for bus tie switch operation: When performing bus tie switch operation, the device should be able to determine whether conditions such as DC bus voltage difference meet the requirements, so as to avoid inrush current and damage to the battery caused by failure to meet the conditions.

[0204] Automatic switching device: The device can quickly and accurately identify faults and automatically switch faults, reducing the need for manual intervention.

[0205] Intelligent and automated design: The device adopts intelligent and automated design concepts, which greatly improves the reliability and efficiency of the system.

[0206] Condition judgment function: The device has the function of judging the operating conditions of the bus tie switch, which effectively avoids safety problems caused by failure to meet the conditions.

[0207] This application has time benefits: the successful application of the automatic switching device 00 for DC power supply will change the current situation of passive and delayed operation by personnel, realize uninterrupted power supply, reduce power outage time, avoid losses caused by power outages, and improve the efficiency of operation and maintenance.

[0208] This application offers safety benefits: by installing an automatic switching device 00 for DC power supply, automatic switching between dual power supplies can be achieved during faults, maintenance, and operational mode adjustments, reducing the need for maintenance personnel to operate the equipment and improving operational safety.

[0209] This application has social benefits: the automatic switching device for DC power supply improves power supply reliability, reduces complaints and work orders caused by frequent power outages, wins unanimous praise from customers, and maintains the company's good social image. This project has broad application prospects.

[0210] Those skilled in the art will understand that any references to memory, storage, databases, or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0211] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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 specification.

[0212] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An automatic switching device of a direct current power supply, the automatic switching device of the direct current power supply being applied to a dual configuration direct current system substation, the dual configuration direct current system substation comprising two direct current powers, each of the two direct current powers comprising a first section of direct current bus and a second section of direct current bus respectively powered by different power supplies, the first section of direct current bus and the second section of direct current bus being connectable or disconnectable through a contactor, the first section of direct current bus and the second section of direct current bus each comprising a positive potential, a negative potential and a zero potential, characterized in that, The automatic switching device of the direct current power supply comprises a master control module, a voltage detection module and a contactor control module electrically connected with the master control module; The voltage detection module is connected with the first section of direct current bus and the second section of direct current bus respectively; The contactor control module is connected with the contactor; The master control module is used for obtaining a first potential difference of the first section of direct current bus and a second potential difference of the second section of direct current bus at different sampling time points by the voltage detection module, and obtaining a target voltage at different sampling time points according to the first potential difference and the second potential difference, wherein the target voltage comprises bus battery voltage of each of the two sections of direct current bus, and the bus battery voltage is a potential difference between positive potential and negative potential of the same section of direct current bus; The master control module is further used for controlling the contactor to attract to parallel the first section of direct current bus and the second section of direct current bus if the bus battery voltage of any section of direct current bus is abnormal based on the target voltage at different sampling time points, so as to supply power to the direct current bus with abnormal bus battery voltage by the normal power supply, wherein the normal power supply is a power supply corresponding to the direct current bus with normal bus battery voltage.

2. The apparatus according to claim 1, wherein The target voltage further comprises bus unbalance voltage of each of the two sections of direct current bus, wherein the bus unbalance voltage is a difference between high end voltage and low end voltage of the same section of direct current bus, the high end voltage is a potential difference between positive potential and zero potential of the same section of direct current bus, and the low end voltage is a potential difference between zero potential and negative potential of the same section of direct current bus; The master control module is further used for determining that the target direct current bus is not high resistance grounding if the direct current bus unbalance voltage of the target direct current bus is greater than the corresponding direct current bus unbalance voltage threshold, and controlling the contactor to be in a disconnected and forbidden attraction state by the contactor control module, so as to prohibit the first section of direct current bus and the second section of direct current bus from being parallel, wherein the target direct current bus comprises at least one of the first section of direct current bus and the second section of direct current bus.

3. The apparatus according to claim 1, wherein The target voltage further comprises two-section bus voltage difference, wherein the two-section bus voltage difference is a difference between bus battery voltage of the first section of direct current bus and bus battery voltage of the second section of direct current bus; The master control module is further used for controlling the contactor to be in a disconnected and forbidden attraction state by the contactor control module if the two-section bus voltage difference is greater than a parallelable voltage difference threshold, so as to prohibit the second section of direct current bus and the second section of direct current bus from being parallel.

4. The automatic switching device of the direct current power supply according to claim 1, wherein The master control module is further used for controlling the contactor to be in a disconnected and forbidden attraction state by the contactor control module if the bus battery voltage of the target direct current bus is intermittently dropped, so as to prohibit the second section of direct current bus and the second section of direct current bus from being parallel. The master module is specifically configured to, if the target voltage based on different sampling time points is monitored to continuously decrease the bus battery voltage of any one section of DC bus, and the condition of controlling the contactor to be in the open and forbidden attraction state is not met, control the contactor to attract to parallel the first section of DC bus and the second section of DC bus.

5. The automatic switchover apparatus of a DC power supply according to any one of claims 2 to 4, characterized by The automatic switching device of the DC power supply further comprises an alarm module connected with the master module. The master module is further configured to, if the contactor is controlled to be in the open and forbidden attraction state, control the alarm module to perform corresponding abnormal alarm, wherein the abnormal alarm comprises at least one of first section of DC bus grounding alarm, second section of DC bus grounding alarm and DC bus battery abnormal alarm.

6. The apparatus according to any one of claims 1 to 4, wherein The contactor control module comprises a relay module and a relay control module connected electrically; The relay module is connected with the contactor; The relay control module is connected with the master module, and is configured to, if an attraction signal of the master module is received, control a relay in the relay module to attract so that the contactor is powered and attracted; The relay control module is further configured to, if an open signal of the master module is received, control the relay in the relay module to open so that the contactor is powered off and opened; The relay control module is further configured to, if the open signal of the master module is continuously received, continuously control the relay in the relay module to open so that the contactor is powered off and in the open and forbidden attraction state.

7. The automatic transfer device of a DC power supply as claimed in claim 6, wherein The relay control module comprises a first resistor, an optocoupler, a second resistor, a third resistor, a first switch tube and a first diode; The relay module comprises a first relay and a first terminal; A first end of the first resistor is connected with the master module, and a second end thereof is connected with a second end of the optocoupler, a first end of the optocoupler is connected with a first voltage, a third end thereof is grounded, a fourth end thereof is connected with a second voltage through a second resistor, and the fourth end is further connected with a first end of the first switch tube through a third resistor, a second end of the first switch tube is connected with the second voltage, a third end thereof is connected with a cathode of the first diode, and the third end is further connected with a first contact of the first relay, and an anode of the first diode is grounded; A fourth contact of the first relay is grounded, an iron core is connected between the first contact and the fourth contact of the first relay, a fifth contact of the first relay is connected with a third voltage, and a second contact thereof is connected with the contactor through the first terminal, the fifth contact of the first relay is connected with the second contact in the powered condition, and the fifth contact of the first relay is connected with a third contact in the unpowered condition.

8. The automatic transfer device of a DC power supply as claimed in claim 7, wherein The contactor control module further comprises an indication module connected with the relay control module, The indication module comprises a fourth resistor and a light emitting diode; The third end of the first switch tube is further connected with the fourth resistor and the light emitting diode to ground.

9. The apparatus of claim 6 wherein, The automatic switching device of the DC power supply further comprises a contactor manual control module connected with the master module. The contactor manual control module is configured to receive a manual operation of a user, generate a closing instruction or an opening instruction according to the manual operation, and output the closing instruction or the opening instruction to the main control module; The main control module is configured to generate a closing signal according to the closing instruction, and output the closing signal to the relay control module; The main control module is further configured to generate an opening signal according to the opening instruction, and output the opening signal to the relay control module.

10. The automatic switching device of the direct current power supply according to claim 1, wherein the voltage detection module comprises at least one voltage detection unit, each voltage detection unit comprising an electrically connected isolation operational amplifier unit and a voltage division unit; The two ends of the voltage division unit are respectively connected to two different detection points of the same DC bus, wherein Two different detection points correspond to two different target potentials on the direct current bus, and are configured to divide a potential difference obtained from the two target potentials through a series-connected resistor, and input the obtained divided voltage to the isolation operational amplifier unit; The isolation operational amplifier unit is configured to isolate and amplify the divided voltage, and input an obtained analog amplified signal to the main control module; The main control module is configured to convert the analog amplified signal into a potential difference between two target potentials according to an amplification factor and a voltage division ratio, wherein the two target potentials are any two of a positive potential, a negative potential and a zero potential.

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