RU2035109C1 - Self-contained power supply system - Google Patents

Abstract

FIELD: electrical engineering. SUBSTANCE: self-contained power supply system includes N identical power supply subsystems placed in parallel to load buses, bus of emergency switching over of sections of solar batteries and buses of emergency charge-discharge of storage batteries and controlling computer. Power of system is varied by connection of required number of power supply subsystems to load buses, by emergency switching over of sections of solar batteries, by emergency charge-discharge of storage batteries and by change of functioning program of controlling computer. Each subsystem incorporates extreme power controller of section of solar battery. EFFECT: enhanced reliability and efficiency of power supply system. 3 dwg

Description

 The invention relates to electrical engineering, and in particular to power supply systems (SES) of autonomous objects using solar batteries (SB) and energy storage batteries of batteries (AB) as a primary source of energy.

Known parallel structure of an autonomous power supply system containing an arbitrary number of batteries and sections SB [1]
In this system, the control unit and the shunt regulator provide voltage stabilization on the output bus with excess power SB. If the batteries are discharged, the charge-discharge blocks provide their charge with excess power of the batteries. The charge state of the battery is controlled by units that generate signals to turn on and off the charge. With a lack of power SB lacking energy enters the load from the batteries. In this case, the voltage at the output bus of the SES is stabilized by charge-discharge blocks.

 The advantage of such a system is a sufficiently high coefficient of energy transfer from the SB panels to the load. In this mode, the main energy losses occur in diode isolators. With an output voltage of 27–28 V, the energy transfer coefficient reaches 0.97. However, the connection of the output bus power supply of the load with the buses of the sections of the SB through the separation diodes and determines all the disadvantages of such a system.

 Firstly, the shunt regulator must ensure the discharge of excess power SB. Under the traditional requirement, the operation of the SES in idle mode, the installed value of the power of the shunt controller (SR) is almost equal to the total power of the non-degraded SB. The mass of ballast is significant and is determined by the power of the SB.

 Secondly, the connection of the buses eliminates the possibility of regulating the voltage of the SB at the optimum operating point. The voltage of each SB panel is rigidly connected with the stabilized voltage of the load power bus. As a result, the low energy efficiency of SES at objects with changing operating conditions of SB panels (low-orbit spacecraft and objects of study of the planets of the solar system) is low. In addition, the connection of load power buses and sections of the SB does not allow the design of solar panels with an operating voltage greater than the load voltage. Which makes it impossible to reduce the current, and therefore the mass of SB cables.

 Closest to the proposed system in technical essence is a power supply system containing an extreme power regulator SB; Voltage regulator; sections of the SB; charging blocks; bit blocks; charge control devices; rechargeable batteries.

 In such systems, an individual AB charge-discharge is implemented, extreme power control of the SB is provided, and power converting devices are protected from overcurrents (power), and buffer energy sources from overcharge and overdischarge. Such a structure is more universal. Its use is advisable at facilities with changing operating conditions of the SB panels and rapidly changing load schedules (at facilities with a significant share of energy transferred to the load from the SB through the AB energy storage devices).

 Advantages and advantages of the structure are explained by the separation of all power buses SES SB, AB, LOAD. As a result, firstly, the SB can be designed with an operating voltage that exceeds both the voltage of the battery and the load voltage. It is possible to reduce the current SB and the mass of its cables. Secondly, only the required energy value is selected from the SB. There is no need to "reset" the excess power of the SB, therefore, the established calculated values of the power and mass of the thermal control system (STR) of the object will have lower values than the power and mass of the STR of the object with a parallel structure of the SES. The installed power of the series voltage regulator is determined by the energy consumption pattern and can be optimized. Thirdly, there is the possibility of continuous regulation of the operating voltage of the SB at the point of power extreme under changing operating conditions, which allows you to select the maximum possible value of power from the SB. That is, use SB with the highest energy efficiency. Well-known power supply systems are widely used in autonomous facilities with a resource of 2-3 years. With the toughening of the traditional technical requirements for on-board systems (increasing the SES resource to 7-10 years while improving reliability, autonomy of operation and improving energy and overall mass characteristics) and the emergence of a new requirement, the capacity of SES by increasing the number of unified energy subsystems began to appear " weaknesses and the flaws of these systems.

 The disadvantage of the system is the impossibility of extreme power control of individual (discrete) SB panels. The need for individual power control of each discrete SB panel is explained by the fact that when designing and creating long-term facilities (more than 5-7 years) with a total power level of on-board needs of more than 5-10 kW, it is almost impossible to guarantee the identity of the current-voltage characteristics of individual SB panels due to uneven temperature conditions and degradation rates of the characteristics of solar cells. The total volt-watt characteristic in this case has several extrema. The extreme regulator in the search mode can carry out the "capture" and regulation of any extremum on the volt-watt characteristic. As a result, the maximum power value is selected only from that SB panel, the power extremum of which coincides with an adjustable local extremum. Other SB panels are underused for power.

 Other disadvantages of this system are insufficient reliability and resource systems with an output power of more than 3-5 kW. In such SES a number of batteries are used. However, in the event of a failure of any charging or discharge blocks, or any battery, all of the named blocks of a specific energy subsystem are immediately excluded from work. So, for example, in case of failure of the charging unit, the battery will be discharged and shut down. In the future, the discharge block and AB are not used in the operation of the SES. In case of failure of the discharge unit, the charging unit and the battery are simultaneously excluded from operation. In the event of a battery failure, the charging and discharge blocks are excluded from operation, although it is advisable to use them to charge and discharge the battery of those energy subsystems in which similar blocks failed.

 The system has insufficient reliability and resource, since its structure lacks nodes and blocks providing continuous quality control of the device’s operability, analysis of their functioning, as well as identification and exclusion of failed elements from the circuit. It is advisable to implement these functions when creating powerful SESs with a significant number of batteries, SB panels, as well as module or unit converters by using microprocessor control and monitoring systems. When designing and creating new, more powerful SPPs, it is not possible to use only previously developed blocks. A new development of the control system, as well as the voltage regulator, is required, since the installed power and the connection diagram are changing.

 The aim of the invention is to achieve greater efficiency in the use of energy of SB panels, the possibility of increasing the capacity of SES by using standardized energy subsystems, increasing its reliability and increasing resource.

 This is achieved by introducing into the system of the controlling computing device and organizing N the number of identical energy subsystems connected in parallel to the load buses, the emergency switching bus of the SB sections and to the emergency battery-discharge bus of the AB.

 In addition to a rechargeable battery with charge-discharge blocks and charge control devices, an individual extreme power regulator of the SB panel, a load current sensor, a current sensor of the SB, a current sensor AB, a power distribution device, a pulse serial voltage regulator, a control unit and sharing information.

 In FIG. 1 shows an autonomous power supply system.

 It has a solar panel section 1; current sensor section SB (TBS) 2; voltage stabilizer (CH) 3; load current sensor (VT) 4; extreme power regulator section SB (ERM) 5; charging unit (ST) 6; bit block (RB) 7; control unit and information exchange (BUOI) 8; power distribution device (URM) 9; charge-discharge current sensor AB (TAB) 10; rechargeable battery 11; device for monitoring the degree of charge of the battery (UKZB) 12; microprocessor computing device (MPVU) 13; interface device (US) 14; K1.K6 power contacts of remote switches BUOI; UVP control computing device.

 The power supply system of FIG. 1 operates as follows. Energy subsystems are controlled by commands from the central on-board computer complex of the facility, which are transmitted via a communication channel to the microprocessor-based computing device MPVU 13, where they are processed and transmitted to the control and information exchange unit 8 of each subsystem via interface devices 14. The control and information exchange unit 8 receives command and performs the required action, closing the contacts K1.K6 (remote switches are activated), or translates the command to the desired block subsystem voltages, and also issues information to the MPVU 13 through the interface device 14 about the status of the subsystem device (values of charge-discharge currents, load, solar battery, the on state of the device, the operability of converter modules and devices).

 In the event that commands are received to close the contacts K1 and K4, then in each energy subsystem the power supplies of SB and AB are connected to the converting devices of their subsystem. By closing the contacts K2, K3, K5, K6, power sources or converting devices are switched with devices of other subsystems. The need for such switching is determined by the MPVU 13 or the central on-board computer complex of the facility. This achieves greater survivability of the system, and therefore increases the reliability and resource of SES.

 The inclusion of the system in the work is carried out by commands, as a result of which the contacts K1 and K4 in each subsystem are closed. In this mode, the SB section is connected to the inputs of the charging unit 6 and voltage stabilizer 3, and the battery is connected to the connection point of the output of the charging unit 6 and the input of the discharge unit 7. If the batteries are pre-charged and the load power does not exceed the power of the SB, then the system operates in power mode load from SB. In this mode, extreme regulators do not work.

 SN stabilizers, working in parallel on a common load bus, provide a stable voltage at the SES output. As the load increases, the currents from each energy subsystem grow. At a certain value of the load, the voltage at the output of one of the stabilizers decreases to a certain set value. Subsequently, this stabilizer regulates the input voltage (voltage of its section SB). Voltage stabilization on the output bus is carried out by stabilizers of other energy subsystems. With a further increase in the load power, any next stabilizer switches to the mode of regulating the set value of the input voltage (section SB). This happens until the last stabilizer enters the input voltage regulation mode. In this case, all stabilizers regulate the voltage of their sections of the SB at the minimum allowable specified levels (points M1.M2 in Fig. 2). The voltage on the load power bus decreases and reaches the output voltage control sub-ranges by the discharge blocks. The discharge blocks are turned on, which, working in parallel to the total load, make up for the lack of energy on the SES output bus and stabilize the output voltage. At the same time, a uniform distribution of currents between the batteries using the OOS is implemented according to the deviation of the current of the energy subsystem from the highest value. In the block URM 9, the values of the voltages proportional to the discharge current of their subsystem are compared (fed to input 2 from the current sensor 10), with the values of the voltages proportional to the discharge currents of other energy subsystems that are received via communication channels. The discharge block with the highest current is automatically selected, which becomes the leading one and stabilizes the load voltage. The remaining discharge blocks tend to repeat the current of the lead. A signal proportional to the difference between the discharge current of the leading unit and the discharge current of the battery of its energy subsystem, from the output 4 of the URM 9 is fed to input 2 of the discharge unit 7, trying to increase the discharge current of the battery. In the subsystem that stabilizes the voltage on the output bus (leading power subsystem), this signal is equal to zero. When the discharge current of the battery from the first output of the current sensor 10 appears at the first input of the control unit 8 receives a signal. If a command is issued to block 8 that permits the extreme power control mode of the SB section, then control unit 8 generates an ESM enable signal, which, by controlling stabilizer 3 at input 2, makes a step-by-step change in the position of the operating point on VVH (toward the power extreme). If the load power exceeds the total power value of all SB panels during their operation at the maximum power points, then after searching for the power extreme in each subsystem, the position of the operating point will fluctuate around the extremum point (point 0, Fig. 2). If the load power is less than the total power value of all sections of the SB, then after turning on the computer and several step-by-step changes in the position of the operating point, the discharge current will stop to the extreme power of the SB panel. The control unit generates a stop signal for the ERM 5. The control signal at the output 3 of the ERM 5 (and therefore at the input 2 of block 3) will cease to change step by step, which will correspond to the new setpoint value of the operating point voltage (for example, point P on VVH). The system will switch to load power mode from SB. When the load power increases, the system will again begin to function in the discharge mode of the battery. Extreme regulators will turn on again and the search for power extremes will continue.

 As the battery is discharged by block 12, the degree of their charge is monitored. With a certain degree of discharging (usually 10-30% of the nominal capacity of the battery), UKZB 12 generates a signal to turn on the charging unit 6, which comes from output 1 to the fourth input of control unit 8. If a command is issued to control unit 8 from the on-board command complex , allowing the battery to be charged in this energy subsystem, the control unit generates an enable signal, which comes from the output of the 7 control unit to the input 1 of the charging unit 6. Now, in the case of the system described above, in the load power mode from SB and the presence of excess power SB will turn on the charging blocks of those energy subsystems in which signals are formed allowing the battery charge. Some values of the charge currents are set. From the current sensor 10 to the first input of the control unit will receive a signal whose voltage value is proportional to the charge current. When the charge current exceeds a certain minimum value, the control unit will generate an EPM switch-on signal 5 and give a signal to the stabilizer 3 to lower the control sub-range, which must be done so that the SB current in the energy subsystem, where the battery charge is required, is directed specifically for the battery charge, and in energy subsystems, where the battery charge is not required was directed to power the load. If the power of the SB power subsystems, where the batteries are charged, are sufficient to supply the load, then the voltage stabilizing on the output buses and the power of the on-board consumers are stabilized by these subsystems, and the entire SB current of the other subsystems is used to charge the battery. If the power of the SB of those subsystems in which the battery is not charged enough to power the load, the voltage on the output bus is reduced to the voltage control sub-ranges of the subsystems in which the battery is charged. Part of the SB current of these subsystems will go to the load, and the battery charge will be provided by the remaining excess power.

 If the load increases and becomes greater than the total power value of all SB panels, then the battery charge current will stop, the voltage at the SES output will drop to the subrange for regulating the discharge blocks and the battery will start charging as described above. In this case, the regulated voltage on the SB panels will decrease, since the regulation sub-bands of stabilizers 3 are slightly lower than the regulation sub-ranges in charge mode (Fig. 3). The change of the voltage control sub-ranges of the SB panel by the stabilizer 3 and the charging unit 6 is carried out synchronously at each step of the search for the power extreme.

 Thus, if the load power is greater than the total power of the SB or if a battery charge is required in any energy subsystem, then the most effective extreme power control of each SB panel is implemented in the system. This means that the proposed system has the highest possible energy efficiency of SB panels.

 The proposed structure allows to increase the capacity of SES by parallel connection of identical energy subsystems. In this case, identical unified blocks of control and control equipment are used (voltage stabilizers, charge-discharge blocks and others), which allows to reduce the time for designing, manufacturing and testing SES. When developing each new SES on the basis of identical energy subsystems, only the adjustment of the central control device is required, the introduction of additional conversion devices for parameters 14 and the adjustment of the SES functioning program due to changes in the composition of the monitored parameters. In view of the realization of the possibility of the independent functioning of each energy subsystem, the restoration of the battery characteristics, as well as the presence of an emergency functioning scheme, the proposed system has a long resource (determined by the durability of the constituent elements), high reliability and survivability.

Claims (1)

 AUTONOMOUS POWER SUPPLY SYSTEM, containing a sectioned solar battery (SB) and N rechargeable batteries (AB) with individual charge and discharge units, characterized in that, in order to provide discrete increase in power and autonomy of operation, increase its resource, reliability and energy efficiency, in it introduced a control computing device, consisting of a microprocessor computing device and N interface devices, and organized N identical energy subsystems connected in parallel with the load buses, the switch bus of the SB sections and the emergency battery charge-discharge bus, moreover, in each subsystem, in addition to the SB section and the battery with charging and discharging units, sensors for load current, SB section current and battery charge-discharge current sensors are introduced, power distribution device, extreme power regulator of the SB section, a pulse series voltage stabilizer, a device for controlling the degree of charge connected to the battery by the first communication channel a second battery, and the second with an individual pairing device, and a control and information exchange unit, the first four measuring inputs connected respectively to the first measuring outputs of the charge-discharge current sensor, load current, SB section current and charge state control device, and other control outputs to the first control inputs, respectively, of AB, power distribution device, charging unit, discharge unit, extreme regulator and voltage stabilizer, as well as connected to a third communication channel with an individual interface device of the control computing device, all devices of which are connected to each other and to the onboard computer with the fourth communication channel, the power input of the pulse series voltage regulator of each subsystem is connected to the power output of the current section current measuring sensor and the power input of the charging unit, and the output with the power output of the discharge unit and the power input of the sensor for measuring the load current of the subsystem, the power output of which is connected to similar outputs with load current sensors of all other subsystems and a load power terminal, the power input of the current sensor of the SB section current measurement is connected to the closing contacts of the first and second remote control current switches, the second terminals of which are connected respectively to the SB section and the common emergency switching bus of the SB sections, the closing contact of the third a remote switch of the control unit is connected between the emergency switching bus of the SB sections and the connection point of the first make contact with the power output of the SB section, W A swarm terminal of which is connected to the common bus AB, SB and the second load terminal, the first terminals of the normally open contacts of the fourth and fifth remote switches are connected to the battery, and the second, respectively, to the first power terminal of the battery current sensor and the common battery for emergency charge-discharge AB, the closing contact of the sixth switch is connected between the common emergency-discharge bus of the system and the first power terminal of the battery current measuring sensor, the second power terminal of which connected to the connection current of the power output of the charging unit and the power input of the discharge unit, the second measuring output of the current sensor of the SB section in each subsystem is connected to the second control input of the extremal regulator, the third and fourth control outputs of which are connected respectively to the second control inputs of the voltage regulator and the charging unit, the second measuring output of the charge-discharge current sensor is connected to the second measuring input of the power distribution device, the third and fourth controlling e outputs of which are respectively connected to the inputs of the charge and discharge blocks, and the other N 1 power distribution unit outputs N 1 inputs connected channels communicate with devices other energy power distribution subsystems.

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