Bipolar DC voltage intelligent balancing system based on load switching

Abstract

The utility model provides a bipolar direct current voltage intelligent balancing system based on load switching, which is connected between a bipolar direct current bus and a load, two ends of a voltage measuring element are respectively connected with the bipolar direct current bus and an stm32 chip, and the stm32 chip, a current measuring element and a load type judging module are connected in pairs; the other current measuring element is connected with the bipolar direct current bus; the load type judgment module is connected with a plurality of loads, the stm32 chip and the load type judgment module are respectively connected with a logic control signal module, a current measuring element, positive and negative electrodes of the bipolar direct current bus and a neutral line, and the logic control signal module and the plurality of loads are connected with the constant-resistance, constant-current and constant-power switch module. According to the utility model, the optimal load switching strategy is calculated according to the sampling voltage and current, the logic control signal generates high and low levels for controlling the conduction of the switch tube, the switch module completes the on-off according to the high and low levels, the load polarity is correctly switched, and the circuit has the advantages of simple principle, low cost and remarkable effect.

Description

Technical Field

[0001] The utility model relates to the field of electrical and automatic control, in particular to a bipolar direct current voltage intelligent balancing system based on load switching. Background Art

[0002] The DC distribution system has become a new trend in the development of future distribution networks. In comparison, its distributed power supply grid connection can save rectifiers, inverters and other devices. The DC load can directly meet the power supply demand without rectification, which greatly improves the acceptability of new energy and loads.

[0003] The DC power distribution system is divided into unipolar and bipolar DC systems. Bipolar DC can generate a DC voltage with the same voltage and opposite direction through split capacitor voltage stabilization, which is called positive and negative poles. The positive and negative poles are similar to the ABC three-phase AC power distribution system. Each busbar in the system contains positive and negative poles and a neutral line. The positive pole and neutral line, and the neutral line and negative pole of the busbar can be connected to the load at the same time to improve the power supply efficiency. However, when the load size between the positive pole and the neutral line, and the neutral line and the negative pole of each busbar is different, it will cause an unbalanced current on the neutral line. The current flowing through the neutral line resistance will cause a voltage drop, affecting the positive and negative pole voltages of the busbar, making the positive and negative pole voltages tend to be unbalanced, and when the load and line parameters are excessively unbalanced, it will exceed 3% of the range specified by ANSIC84, seriously affecting the power supply quality of the load.

[0004] Therefore, how to take corresponding measures and use some kind of intelligent balancing system to connect each busbar and the corresponding load in the bipolar DC system to reduce the voltage imbalance caused by the different load sizes between the positive pole and the neutral line, and between the neutral line and the negative pole of each busbar is an important issue to be solved in the development of bipolar DC distribution system. Utility Model Content

[0005] The main purpose of the utility model is to provide a bipolar DC voltage intelligent balancing system based on load switching, so as to reduce the problem of unbalanced bus voltage under asymmetric load and line parameters.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is: a bipolar DC voltage intelligent balancing system based on load switching, connected between the bipolar DC bus and the load, including a voltage measuring element located at the entrance of the system, one end of the voltage measuring element is connected to the bipolar DC bus, and the other end is connected to the STM32 chip, the STM32 chip, a current measuring element and a load type judgment module are connected in pairs; another current measuring element is connected to the bipolar DC bus;

[0007] The load type judgment module is connected to multiple loads, the stm32 chip and the load type judgment module are respectively connected to a logic control signal module, the current measurement element, the positive and negative poles and the neutral line of the bipolar DC bus, the logic control signal module and the multiple loads are all connected to the constant resistance switch module, the constant current switch module and the constant power switch module.

[0008] In the preferred solution, the program is written into the stm32 chip, and a data acquisition line is used to connect the voltage measurement element, and a data acquisition line is used to connect the current measurement element and the load type judgment module; a logic signal transmission line is used below to connect the constant resistance switch module, the constant current switch module and the constant power switch module.

[0009] In the preferred solution, the voltage measuring element is connected to the bipolar DC bus using an electrical physical connection line, and the right side is connected to the STM32 chip using a data acquisition line.

[0010] In the preferred embodiment, two current measuring elements are provided, and the load type judgment module, the constant resistance switch module, the constant current switch module and the constant power switch module are connected by electrical and physical connection lines respectively; the other is located at the lower right position of the system, and the neutral line of the bipolar DC bus, the constant resistance switch module, the constant current switch module and the constant power switch module are connected by electrical and physical connection lines.

[0011] In the preferred solution, the load type judgment module uses electrical physical connection lines to connect load 1 to load n, and uses data acquisition lines to connect the stm32 chip.

[0012] In the preferred embodiment, the load type judgment module includes resistance calculation, power calculation and logic result output, and also includes voltage measurement elements, current measurement elements, electrical and physical connection lines, data acquisition lines, and logic signal transmission lines contained in the intelligent balancing system.

[0013] In the preferred solution, the constant resistance switch module, the constant current switch module, and the constant power switch module are located in the middle of the system, and electrical physical connection lines are used to connect multiple loads, the positive and negative poles of the bipolar DC bus and the neutral line with the current measurement element, and a logic signal transmission line is used to connect the two logic control signal modules.

[0014] In a preferred embodiment, the constant resistance switch module includes n +2 fully controlled switching devices first IGBT and electrical physical connection lines, where, n The first IGBT to Connected in series with the load and then in parallel, the remaining two first IGBTs to Connect the positive and negative electrodes respectively and then connect them in reverse parallel with the load; Emitter, The collector is connected to the positive pole and the negative pole of the bipolar DC bus by electrical and physical connection lines.

[0015] In the preferred embodiment, the constant current switch module and the constant power switch module have the same structure, and the constant current switch module includes n +4 fully controlled switch devices second IGBT and electrical physical connection line, constant power switch module includes third IGBT and electrical physical connection line, where n A second IGBT or a third IGBT to Connected in series with the load and then in parallel, the remaining 4 second IGBTs or third IGBTs to Arranged in a bridge-like manner, the midpoints of the upper and lower bridge arms are indirectly loaded, connected , The midpoint of the electrical physical connection line is connected to the neutral line of the bipolar DC bus; collector, The emitter is connected to the positive pole and the negative pole of the bipolar DC bus by electrical and physical connection lines.

[0016] In the preferred embodiment, two logic control signal modules are set, one of which uses logic signal transmission lines to connect the stm32 chip, constant resistance switch module, constant current switch module and constant power switch module, and the other logic control signal module uses logic signal transmission lines to connect the load type judgment module, constant resistance switch module, constant current switch module and constant power switch module.

[0017] The utility model discloses a bipolar DC voltage intelligent balancing system based on load switching, which can dynamically adjust the number of loads connected to the positive pole and the load according to the current bipolar DC bus voltage imbalance. For a multi-bus distribution network, the connection of multiple buses and loads to this system can effectively reduce the bus positive and negative voltage imbalance problem to 3% of the ANSIC84 limit, improve the power supply quality, and ensure the safety and reliability of the power grid operation. The utility model has the advantages of simple principle, low cost, significant effect, etc., and is easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0019] Figure 1 The utility model is a bipolar DC voltage intelligent balancing system based on load switching;

[0020] Figure 2 It is the internal composition of the load type judgment module of the utility model;

[0021] Figure 3 It is the internal composition of the constant resistance switch module of the utility model;

[0022] Figure 4 It is the internal composition of the constant current and constant power switch module of the utility model;

[0023] In the figure: voltage measurement element 1; stm32 chip 2; current measurement element 3; load type judgment 4; resistance calculation 41; power calculation 42; logic result output 43; constant resistance switch 5; first IGBT 51; constant current switch 6; second IGBT 61; constant power switch 7; third IGBT 71; logic control signal 8; electrical and physical connection line 9; data acquisition line 10; logic signal transmission line 11; bipolar DC bus 12. DETAILED DESCRIPTION

[0024] Example 1

[0025] like Figure 1-4 As shown, a bipolar DC voltage intelligent balancing system based on load switching is connected between a bipolar DC bus 12 and a load, and includes a voltage measuring element 1 located at the entrance of the system, one end of the voltage measuring element 1 is connected to the bipolar DC bus 12, and the other end is connected to an STM32 chip 2, and the STM32 chip 2, a current measuring element 3 and a load type judgment module 4 are connected in pairs; another current measuring element 3 is connected to the bipolar DC bus 12;

[0026] The load type judgment module 4 is connected to multiple loads, the stm32 chip 2 and the load type judgment module 4 are respectively connected to a logic control signal 8 module, the current measurement element 3, the positive and negative poles and the neutral line of the bipolar DC bus 12, the logic control signal 8 module and multiple loads are all connected to the constant resistance switch 5 module, the constant current switch 6 module and the constant power switch 7 module.

[0027] When the system is running, the load is normally connected to the positive and negative poles for operation. After a delay of several switching cycles, the program of the stm32 chip 2 is started. The voltage measuring element 1 and the current measuring element 3 are used to collect the positive and negative voltages of the bipolar DC bus 12, the currents of loads 1 to load n, and the total current of the load flowing into the neutral line. The load current and voltage are judged by the load type judgment 4 module to determine which variable of the current, resistance, and power remains unchanged during several switching cycles, and then the load type result is output. According to the collected voltages and currents, the stm32 chip is used to calculate the best access pole of the load, and the corresponding high and low levels are generated by the logic control signal 8 module to control the on and off of each switch module, and the load access pole is redistributed to the load to minimize the current flowing into the neutral line, that is, the positive and negative loads are balanced as much as possible, so that the positive and negative voltages of the bus tend to be consistent.

[0028] In the preferred solution, the stm32 chip 2 is programmed and located at the top of the system. The data acquisition line 10 is used to connect the voltage measurement element 1, and the data acquisition line 10 is used to connect the current measurement element 3 and the load type judgment 4 module; the logic signal transmission line 11 is used below to connect the constant resistance switch 5 module, the constant current switch 6 module and the constant power switch 7 module. The stm32 chip 2 can collect the positive and negative voltages of the bipolar DC bus 12, the total current flowing into the neutral line, and the current of each load.

[0029] The stm32 chip 2 contains a delay function. After the system is put into operation, the load is connected to the positive and negative poles normally for operation, and the program starts after a delay of several switching cycles.

[0030] In the preferred embodiment, the voltage measuring element 1 is located at the entrance of the system, connected to the bipolar DC bus 12 by an electrical physical connection line 9, and connected to the stm32 chip 2 by a data acquisition line 10 on the right. The voltage measuring element 1 measures the positive and negative voltages of the bipolar DC bus 12 and transmits them to the stm32 chip 2.

[0031] In the preferred solution, the current measuring element 3 exists in two places in the system, one is located in the upper position of the system, and uses electrical and physical connection lines to connect the load type judgment 4 module, the constant resistance switch 5 module, the constant current switch 6 module and the constant power switch 7 module; the other is located in the lower right position of the system, and uses electrical and physical connection lines 9 to connect the middle line of the bipolar DC bus 12, the constant resistance switch 5 module, the constant current switch 6 module and the constant power switch 7 module. The current measuring element 3 measures the total current and each load current flowing into the middle line and transmits them to the stm32 chip 2.

[0032] In the preferred solution, the load type judgment module 4 is located at the upper right position of the system, and the load 1-load n , the data acquisition line 10 is used to connect the stm32 chip 2. The load type judgment module is used to judge the type of load and provide the stm32 chip and the logic control signal for sampling.

[0033] In the preferred solution, the load type determination module 4 includes resistance calculation 41, power calculation 42 and logic result output 43, and also includes the voltage measurement element 1, current measurement element 3, electrical physical connection line 9, data acquisition line 10, and logic signal transmission line 11 contained in the intelligent balancing system. In several switching cycles, the voltage measurement element 1 and the current measurement element 3 measure the load voltage and current, and then calculate the load resistance and power through the resistance calculation 41 and power calculation 42 modules, and determine which variable of the current, resistance, and power remains unchanged in several switching cycles, and then output the load type result.

[0034] In the preferred solution, the constant resistance switch 5 module, the constant current switch 6 module, and the constant power switch 7 module are located in the middle of the system, and the electrical physical connection line 9 is used to connect the load 1 to the load n , the positive and negative poles and the neutral line of the bipolar DC bus 12 and the current measuring element 3, and the two logic control signal 8 modules are connected by a logic signal transmission line 11.

[0035] In the preferred embodiment, the constant resistance switch 5 module includes n +2 fully controlled switching devices first IGBT51 and electrical physical connection line 9, wherein, n The first IGBT51 to The other two first IGBT51 are connected in parallel after being connected in series with the load. to Connect the positive and negative electrodes respectively and then connect them in reverse parallel with the load; Emitter, The collector is connected to the positive electrode and the negative electrode of the bipolar DC bus 12 by means of an electrical physical connection line 9 .

[0036] like Figure 3 As shown, the first IGBT51 Emitter, The collector is connected to the positive and negative poles of the bipolar DC bus 12 respectively. , They are connected and disconnected to control the positive and negative poles of the load respectively. The logic signal comes from the stm32 chip 2. to Connected in series with the load and then in parallel, the logic signal comes from the load type judgment.

[0037] In the preferred embodiment, the constant current switch module 6 and the constant power switch module 7 have the same structure, and the constant current switch module 6 includes n +4 fully controlled switch devices second IGBT61 and electrical physical connection line 9, constant power switch 7 module includes third IGBT71 and electrical physical connection line 9, wherein n The second IGBT61 or the third IGBT71 to The other four IGBTs are connected in series with the load and then in parallel. - Arranged in a bridge-like manner, the midpoints of the upper and lower bridge arms are indirectly loaded, connected , The midpoint of the electrical physical connection line 9 is connected to the midline of the bipolar DC bus 12; collector, The emitter is connected to the positive electrode and the negative electrode of the bipolar DC bus 12 by using an electrical physical connection line 9 respectively.

[0038] like Figure 4 As shown, the four second IGBT61 or the third IGBT71 - Arranged in a bridge-like manner, the midpoints of the upper and lower bridge arms are indirectly loaded. , The midpoint of the line is connected to the middle line of the bipolar DC bus 12. collector, The emitter is connected to the positive and negative poles of the bipolar DC bus 12 respectively, and the logic signal comes from the stm32 chip 2. to Connected in series with the load and then in parallel, the logic signal comes from the load type judgment.

[0039] In the preferred solution, the logic control signal 8 module exists in two places in the system, one of which is located in the upper left position of the system, and is connected to the stm32 chip 2, the constant resistance switch 5 module, the constant current switch 6 module and the constant power switch 7 module by a logic signal transmission line 11, and the other is located on the right side of the system, and is connected to the load type judgment 4 module, the constant resistance switch 5 module, the constant current switch 6 module and the constant power switch 7 module by a logic signal transmission line 11. The logic control signal 8 module is used to generate the corresponding high and low levels after the load type is judged and the stm32 chip 2 calculates, and controls the on and off of the IGBT of each switch module.

[0040] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A bipolar DC voltage intelligent balancing system based on load switching, characterized by: Connected between a bipolar DC bus (12) and a load, including a voltage measuring element (1) located at a system entrance, one end of the voltage measuring element (1) is connected to the bipolar DC bus (12), and the other end is connected to an STM32 chip (2), the STM32 chip (2), a current measuring element (3) and a load type determination (4) module are connected in pairs; another current measuring element (3) is connected to the bipolar DC bus (12); The load type judgment (4) module is connected to a plurality of loads, the STM32 chip (2) and the load type judgment (4) module are respectively connected to a logic control signal (8) module, and the current measurement element (3), the positive and negative poles and the neutral line of the bipolar DC bus (12), the logic control signal (8) module and the plurality of loads are all connected to the constant resistance switch (5) module, the constant current switch (6) module and the constant power switch (7) module.

2. The bipolar DC voltage intelligent balancing system based on load switching according to claim 1 is characterized in that: The stm32 chip (2) is programmed, and a data acquisition line (10) is used to connect the voltage measurement element (1), and a data acquisition line (10) is used to connect the current measurement element (3) and the load type judgment (4) module; a logic signal transmission line (11) is used below to connect the constant resistance switch (5) module, the constant current switch (6) module, and the constant power switch (7) module.

3. The bipolar DC voltage intelligent balancing system based on load switching according to claim 1 is characterized in that: The voltage measuring element (1) is connected to a bipolar DC bus (12) using an electrical physical connection line (9), and is connected to an STM32 chip (2) on the right side using a data acquisition line (10).

4. The bipolar DC voltage intelligent balancing system based on load switching according to claim 1 is characterized in that: The current measuring elements (3) are provided with two, one of which is connected to the load type determination (4) module, the constant resistance switch (5) module, the constant current switch (6) module and the constant power switch (7) module by means of electrical and physical connection lines; the other is located at the lower right position of the system, and is connected to the middle line of the bipolar DC bus (12), the constant resistance switch (5) module, the constant current switch (6) module and the constant power switch (7) module by means of electrical and physical connection lines (9).

5. The bipolar DC voltage intelligent balancing system based on load switching according to claim 1 is characterized in that: The load type determination (4) module uses an electrical physical connection line (9) to connect multiple loads, and uses a data acquisition line (10) to connect the STM32 chip (2).

6. The bipolar DC voltage intelligent balancing system based on load switching according to claim 5 is characterized in that: The load type determination (4) module includes resistance calculation (41), power calculation (42) and logic result output (43), and also includes a voltage measurement element (1), a current measurement element (3), an electrical physical connection line (9), a data acquisition line (10), and a logic signal transmission line (11) included in the intelligent balancing system.

7. The bipolar DC voltage intelligent balancing system based on load switching according to claim 1 is characterized in that: The constant resistance switch (5) module, the constant current switch (6) module, and the constant power switch (7) module are located in the middle of the system, and use electrical physical connection lines (9) to connect multiple loads, the positive and negative poles and the neutral line of the bipolar DC bus (12) and the current measurement element (3), and use logic signal transmission lines (11) to connect two logic control signal (8) modules.

8. The bipolar DC voltage intelligent balancing system based on load switching according to claim 1 is characterized in that: The constant resistance switch (5) module comprises n +2 fully controlled switching devices first IGBT (51) and electrical physical connection lines (9), wherein, n First IGBT (51) to Connected in series with the load and then in parallel, the remaining two first IGBTs (51) to Connect the positive and negative electrodes respectively and then connect them in reverse parallel with the load; Emitter, The collector is connected to the positive electrode and the negative electrode of the bipolar DC bus (12) respectively by means of electrical physical connection lines (9).

9. The bipolar DC voltage intelligent balancing system based on load switching according to claim 1 is characterized in that: The constant current switch (6) module has the same structure as the constant power switch (7) module. The constant current switch (6) module includes n +4 fully controlled switch devices, a second IGBT (61) and an electrical physical connection line (9), a constant power switch (7) module including a third IGBT (71) and an electrical physical connection line (9), wherein n A second IGBT (61) or a third IGBT (71) to The remaining four second IGBTs (61) or third IGBTs (71) are connected in series with the load and then in parallel. - Arranged in a bridge-like manner, the midpoints of the upper and lower bridge arms are indirectly loaded, connected , The midpoint of the electrical physical connection line (9) is connected to the midline of the bipolar DC bus (12); collector, The emitter is connected to the positive electrode and the negative electrode of the bipolar DC bus (12) respectively by means of electrical physical connection lines (9).

10. The bipolar DC voltage intelligent balancing system based on load switching according to claim 1 is characterized in that: Two logic control signal (8) modules are provided, wherein one logic control signal (8) module is connected to the STM32 chip (2), the constant resistance switch (5) module, the constant current switch (6) module and the constant power switch (7) module by using logic signal transmission lines (11), and the other logic control signal (8) module is connected to the load type judgment (4) module, the constant resistance switch (5) module, the constant current switch (6) module and the constant power switch (7) module by using logic signal transmission lines (11).

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