CN106100026B - A kind of satellite power supply nickel-cadmium storage battery charging regulator - Google Patents

Abstract

The utility model relates to a nickel-cadmium accumulator charging regulator for a satellite power supply, which relates to the field of charging a battery pack by a satellite power supply. The invention aims to solve the existing problem of lack of an adjusting device for ensuring the stable charging of the storage battery pack by the satellite power supply and the stable charging termination. The boost topology circuit boosts the input bus voltage; the current and voltage sampling feedback control unit samples the charging output current and voltage and synthesizes the signal to complete the acquisition and output of the feedback signal; the PWM control unit outputs the corresponding signal through the feedback signal. The pulse width signal of the boost circuit drives the NMOS tube of the boost circuit; the control unit receives the charging enable signal obtained by the error amplification of the bus voltage of the satellite power supply. When the battery pack voltage reaches the charging termination voltage corresponding to the temperature monitoring signal, the charging is stopped, and the charging process is completed. It is used for busbar to charge battery pack.

Description

A nickel-cadmium storage battery charge regulator for satellite power supply

technical field

The invention relates to a nickel-cadmium accumulator charging regulator for a satellite power supply. The utility model belongs to the field of charging a battery pack by a satellite power supply.

Background technique

With the rapid development of aerospace technology, artificial earth satellites are widely used in military, civilian and scientific research fields. The satellite power supply system is an important subsystem of the satellite platform. It is responsible for the important function of power supply for other satellite subsystems and payloads. Its basic function is to convert light energy, nuclear energy or chemical energy into The electric energy is stored, adjusted and transformed according to the needs, and then supplies power to the subsystems of the spacecraft. The battery is an important part of the satellite power system, providing stable power for the normal work of the spacecraft during the Earth shadow period. Therefore, it is particularly important to charge it effectively during the light period, and directly affects the mission quality of the aircraft during the shadow period. The charge regulator is an important functional unit to realize the power regulation function of the satellite power system. During the light period of the orbit cycle, when the output power of the solar cell array is greater than the load demand, the power system enters the charging domain, and the excess power is charged to the battery pack through the charging regulator, so as to stabilize the bus voltage of the satellite power supply and charge the battery pack function.

Contents of the invention

The invention aims to solve the existing problem of lack of an adjusting device for ensuring the stable charging of the storage battery pack by the satellite power supply and the stable charging termination. A charging regulator for a nickel-cadmium storage battery for a satellite power supply is now provided.

A nickel-cadmium storage battery charging regulator for satellite power supply, which includes a storage battery pack and a satellite power supply bus, and also includes a boost topology circuit, a voltage and current sampling feedback control unit, a PWM control unit, a drive circuit, a control unit and a switch S,

The boost topology circuit is used to perform corresponding step-up conversion on the output voltage of the satellite power bus, realize the transmission of charging power from the satellite power bus voltage to the battery pack, and then output the charging output voltage and current to the voltage and current sampling feedback control unit;

The voltage and current sampling feedback control unit is used to sample the voltage and current of the charging output, synthesize the voltage and current sampling signals to obtain a unified sampling feedback control signal, and then feed the signal back to the PWM control unit;

The PWM control unit is used to compare the received sampling feedback control signal with its internal reference voltage through the internal error amplifier, adjust the duty cycle of the switching signal to achieve a stable output of the charging voltage, and finally output the pulse width signal. The pulse width signal drives the NMOS tube of the boost topology circuit through the driving circuit;

The control unit is used to receive the charging enable signal obtained by amplifying the error of the bus voltage of the satellite power supply. When the enabling signal is valid, the switch S is closed to turn on the boost topology circuit, so that the entire charging circuit is turned on to form a battery pack. Charging, at the same time obtain the temperature monitoring signal T _battery and the voltage monitoring signal V _battery of the battery pack during the charging process, and obtain the corresponding charging termination voltage V _stop according to the temperature monitoring signal T _battery , when the voltage monitoring signal V _battery reaches the charging termination voltage V _stop , outputs a charging termination signal, cuts off the switch S, thereby disconnecting the boost topology circuit, so that the entire charging circuit stops charging the battery.

The beneficial effect of the present invention is: the present invention adopts the switching power supply circuit based on the boost circuit principle, which is composed of a boost topology circuit, a voltage and current sampling feedback control unit, a PWM control unit, and a control unit. The boost topology circuit realizes the power transmission and level conversion functions of charging regulation, and performs corresponding boost conversion on the input voltage. The voltage and current sampling feedback control unit implements sampling and signal synthesis of the charging output current and voltage, and completes the acquisition and output of the feedback signal. The PWM control unit outputs a corresponding pulse width signal through the feedback signal and drives the switching tube of the boost circuit. The control unit receives the charging enable signal obtained by amplifying the error of the satellite power bus voltage, and controls the switch S to turn on when the enabling signal is valid, so that the boost topology circuit is turned on and the entire charging circuit is turned on. And by obtaining the working temperature and voltage of the battery pack, the charging is stopped when the voltage of the battery pack reaches the charging termination voltage corresponding to the temperature monitoring signal, and the charging process is completed.

On the one hand, according to the electrochemical characteristics of the nickel-cadmium storage battery, the constant current and constant voltage charging function of the nickel-cadmium battery pack is realized during the light period; on the other hand, according to the temperature characteristics of the nickel-cadmium storage battery, the temperature monitoring signal The corresponding V-T charge termination curve obtains the charge termination voltage corresponding to the corresponding temperature, so as to complete the charge termination function at an appropriate charge termination voltage. To sum up the above two aspects, the satellite power supply can realize stable charging and stable termination charging of the battery pack during the light period. Discharge regulator is the key unit of power regulation in satellite power system. The result of this design will become an important component unit of satellite power system. Its development has great practical significance and practical value.

The advantage that the present invention has is:

1. Realize charging circuit based on boost circuit to realize charging power transmission and level conversion;

2. Realize charging current and charging voltage sampling and realize the combination of circuit sampling signal and voltage sampling signal;

3. Realize the PWM feedback control loop function to stabilize the output voltage and current;

4. Realize the processing of the temperature signal and voltage signal of the battery pack and output the charging termination signal to complete the entire charging process.

Description of drawings

Fig. 1 is the schematic diagram of a kind of satellite power nickel-cadmium accumulator charging regulator described in specific embodiment one;

Fig. 2 is a schematic diagram of a boost topology circuit in a satellite power supply nickel-cadmium storage battery charge regulator;

Figure 3 is the working waveform diagram of the boost topology circuit, where u _g represents the gate voltage of the switch tube, u _VT represents the anode voltage of the diode, u _L represents the inductor voltage, i _L represents the inductor current, i _VT represents the diode current, and i _C Indicates the capacitive current I ₁ indicates the minimum value of the inductor current change, I ₂ indicates the maximum value of the inductor current change, t ₁ indicates the conduction time of the switch in one cycle, t ₂ indicates the end time of the switching cycle, U _d indicates the steady state of the input voltage Value, U _o represents the change of the inductor L current;

FIG. 4 is a conduction state diagram of an NMOS transistor in a boost topology circuit;

Fig. 5 is a closed state diagram of an NMOS transistor in a boost topology circuit;

Fig. 6 is a schematic diagram of a voltage and current sampling feedback control unit in a nickel-cadmium storage battery charging regulator of a satellite power supply;

Fig. 7 is a schematic diagram of a PWM control unit in a nickel-cadmium storage battery charging regulator for a satellite power supply;

Fig. 8 is a schematic diagram of a control unit in a satellite power nickel-cadmium storage battery charge regulator;

Fig. 9 is a flowchart of the control unit.

Detailed ways

Specific embodiment one: with reference to Fig. 1 specific description present embodiment, a kind of satellite power nickel-cadmium accumulator charge regulator described in the present embodiment, it comprises storage battery pack and satellite power bus bar, and it also comprises boost topological structure circuit 1, voltage With the current sampling feedback control unit 2, the PWM control unit 3, the driving circuit 4, the control unit 5 and the switch S,

The boost topology circuit 1 is used to perform corresponding step-up conversion on the voltage output by the satellite power bus and realize charging regulation, and then output the voltage and current output by charging to the voltage and current sampling feedback control unit 2;

The voltage and current sampling feedback control unit 2 is used to sample the voltage and current of the charging output, synthesize the voltage and current sampling signals to obtain a unified sampling feedback control signal, and then feed the signal back to the PWM control unit 3;

The PWM control unit 3 is used to pass the received sampling feedback control signal through the internal error amplifier, adjust the duty ratio of the switching signal to achieve a stable output of the charging voltage, and finally output a pulse width signal, which is driven by Circuit 4 drives the NMOS tube of boost topology circuit 1;

The control unit 5 is used to receive the charging enabling signal obtained by amplifying the error of the bus voltage of the satellite power supply, and control the switch S to close when the enabling signal is valid, so that the boost topology circuit 1 is turned on, so that the entire charging circuit is turned on as The battery pack is charged, and the temperature monitoring signal T _battery and the voltage monitoring signal V _battery of the battery pack during the charging process are obtained at the same time, and the corresponding charging termination voltage V _stop is obtained according to the temperature monitoring signal T _battery . When the voltage monitoring signal V _battery reaches the charging V _stop of the termination voltage outputs a charging termination signal to cut off the switch S, thereby disconnecting the boost topology circuit 1, so that the entire charging circuit stops charging the battery.

In this embodiment, the control unit receives the charging enabling signal obtained by amplifying the error of the bus voltage of the satellite power supply, and controls the switch S to turn on the boost topology circuit 1 when the enabling signal is valid, so that the entire charging circuit is turned on. And by acquiring the working temperature and voltage of the battery pack, the charging is stopped when the voltage of the battery pack reaches the charging termination voltage corresponding to the temperature monitoring signal, and the charging process is completed.

In this embodiment, the design of the control unit is shown in FIG. 8 . The control unit receives the temperature monitoring signal T _battery and the voltage monitoring signal V _battery of the battery pack during the charging process, and obtains the corresponding charging termination voltage V _stop according to the temperature monitoring signal T _battery . When the voltage monitoring signal reaches the charging termination voltage V _stop , is to output the charging termination signal, cut off the charging circuit, and realize the charging termination operation. The software design is shown in Figure 9. .

In this embodiment, the input terminal of the charging regulator according to the present invention is connected to the satellite bus to obtain input electric energy; the output terminal of the charging regulator according to the present invention is connected to the battery pack nickel-cadmium battery pack to output charging electric energy; The control unit is connected to the charging enable signal, and the charging circuit is turned on under the control of the charging enabling signal so that the power input of the charging regulator outputs a stable charging voltage through the boost circuit; the control unit is connected to the temperature signal and voltage signal of the battery pack to During the charging process, it is judged whether the charging termination voltage at the temperature is reached, and when the charging termination voltage is reached, the charging circuit is disconnected to complete the charging process.

Specific embodiment 2: This embodiment will be described in detail with reference to Fig. 2 to Fig. 5. This embodiment is a further description of a satellite power nickel-cadmium storage battery charging regulator described in specific embodiment 1. In this embodiment, the boost topology The structural circuit 1 includes an inductor L, an NMOS transistor VT, a diode D, a capacitor C and a resistor R,

One end of the inductor L is connected to the anode of the diode D and the drain of the NMOS transistor VT at the same time.

The cathode of the diode D is connected to one end of the capacitor C and one end of the resistor R at the same time, and the other end of the capacitor C is connected to the other end of the resistor R, the source of the NMOS transistor VT and one end of the satellite power bus.

The other end of the inductor L is connected to one end of the switch S, the other end of the switch S is connected to the other end of the satellite power bus, and the gate of the NMOS transistor VT is connected to the drive output end of the drive circuit 4,

One end of the resistor R is connected to the positive pole of the battery pack, and the other end of the resistor R is connected to the negative pole of the battery pack.

The positive pole of the battery pack and the negative pole of the diode D serve as the voltage and current output terminals of the boost topology circuit 1 .

In this embodiment, the step-up conversion circuit, namely the boost circuit, is a non-isolated PWM DC/DC converter whose output voltage is higher than the input voltage, and its basic topology is shown in FIG. 2 .

According to the switching state of the NMOS tube, the waveforms of each state during the working process are shown in Figure 3.

Its working process is as follows:

1. NMOS tube conduction state t ₀ ≤ t ≤ t ₁ = K T where, t ₀ represents the start time of the switching cycle, t represents the working time of the NMOS tube, K represents the duty cycle of the NMOS tube, and T represents the switching cycle express.

The diode D is turned off, and the equivalent circuit topology is shown in Figure 4. Under ideal conditions, u _d and u _o remain unchanged and are constant values. Have:

In the formula, u _L represents the voltage of the inductor L, u _d represents the input voltage, u _o represents the output voltage,

In the formula, △I represents the change of the inductor L current, U _d represents the steady-state value of the input voltage,

2. NMOS tube off state t ₁ ≤t≤T

At this time, the diode D is in the conduction mode, and the inductor continues to flow. Its equivalent circuit topology is shown in Figure 5, which is:

In the formula, U _o represents the change of the inductor L current, and t ₂ represents the end time of the switching cycle.

Considering the periodicity of the steady-state operation of the circuit, the open state of the NMOS transistor is equal to the △I of the closed state, that is:

Where: t ₂ =T, get:

According to the above working process, the charging electric energy transmission and level conversion from the bus voltage to the battery pack are realized.

Specific embodiment three: this embodiment is described in detail with reference to Fig. 1, and this embodiment is a kind of satellite power nickel-cadmium accumulator charging regulator described in specific embodiment one or two to make further explanation, in this embodiment, it also includes resistance R _s ,

One end of the resistor R _s is connected to the negative pole of the diode D, and the other end of the resistor R _s is connected to the positive pole of the battery pack.

In this embodiment, the resistor R _s is isolated.

Specific Embodiment 4: This embodiment will be described in detail with reference to FIG. 6. This embodiment is a further description of a satellite power nickel-cadmium storage battery charging regulator described in Embodiment 3. In this embodiment, the voltage and current sampling feedback The control unit ₂ includes a current shunt monitor, a resistor R1 and _a resistor R2,

The positive input of the current shunt monitor is connected to one end of the resistor R _s ,

_The negative input terminal of the current shunt monitor is connected to the other end of the resistor R _s and _one end of the resistor R1 at the same time, and the other end of the resistor R1 is connected to _one end of the resistor _R2 , the other end of the resistor R2 and the negative pole of the battery pack, power supply ground and the ground terminal of the current shunt monitor,

_The other end of the resistor R1 is used as the output terminal of the voltage sampling signal _IF of the current sampling feedback control unit 2,

The output end of the current shunt monitor is used as the output end of the current sampling signal I _F of the voltage and current sampling feedback control unit 2 .

In this embodiment, the specific design of the voltage and current sampling feedback control unit 2 is shown in Figure 6. The current sampling signal I _F is obtained through current sampling, the voltage sampling signal V _F is obtained through voltage sampling, and finally the current sampling signal and current sampling The signals are synthesized to obtain a unified sampling feedback control signal, and _SF realizes the current sampling feedback and voltage sampling feedback of the charging output.

1. Current sampling:

The charging output current is sampled, and the voltage drop generated by the sampling resistor is converted into a corresponding voltage signal by a certain multiple through the current shunt monitor.

2. Voltage sampling:

The realization of voltage sampling is achieved by dividing the charging output voltage output through high-precision voltage dividing resistors.

3. Synthesis of current sampling and voltage sampling signals

In the process of charging the battery, because the battery pack needs to be charged with a constant current at the initial stage of charging, the current sampling feedback signal I _F is greater than the voltage sampling feedback control signal V _F at this time, and the voltage of the battery pack gradually rises as the charging progresses. , the charging voltage for maintaining constant current charging continues to rise correspondingly, so that the voltage feedback control signal V _F gradually increases until the voltage feedback signal V _F is greater than the current feedback control signal I _F , and the charging enters the constant voltage charging mode. The current sampling feedback signal I _F and the voltage sampling feedback control signal V _F are output in parallel through diodes to synthesize them into a unified sampling feedback signal S _F . Through the above process, the constant current-constant voltage charging process for the battery pack is realized.

Specific embodiment five: this embodiment is specifically described with reference to Fig. 7, and this embodiment is a kind of satellite power nickel-cadmium accumulator charge regulator described in specific embodiment one to be further described, and in this embodiment, PWM control unit 3 includes Resistor R, capacitor C, resistor R _T , capacitor C _T and a current-mode PWM controller model UC3843,

Pin 1 of the current-mode PWM controller model UC3843 is connected to one end of the resistor R and one end of the capacitor C at the same time, and the other end of the resistor R is connected to the other end of the capacitor C and 2 pins of the current-mode PWM controller model UC3843. Pin No. 2, the No. 2 pin of the UC3843 current-mode PWM controller is used as the sampling feedback control signal input terminal of the PWM control unit 3,

The No. 5 pin of the current-mode PWM controller whose model is UC3843 is connected to one end of the resistor RT, and the other end of the resistor R _T is connected to one end of the capacitor C _T and the No. 4 pin of the current-mode PWM controller whose model is UC3843 _. The other end of the capacitor C _T is connected to pin 8 of the current-mode PWM controller model UC3843 and the power ground at the same time.

The No. 6 pin of the current-mode PWM controller whose model is UC3843 is connected to the power supply,

The No. 7 pin of the current mode PWM controller whose model is UC3843 is used as the pulse width signal output end of the PWM control unit 3 .

In this embodiment, the PWM control unit uses the above-mentioned feedback signal S _F as an input signal of the PWM controller, and after the feedback voltage passes through the error amplifier inside the PWM controller, the duty ratio of the switching signal is adjusted to realize a stable output of the charging voltage. This design uses TI's UC3843 current-mode PWM controller, the hardware design is shown in Figure 7, and the specific working process is as follows:

The input signal S _F is input to the feedback input terminal VFB of the PWM controller, and is compared with its internal reference voltage through its internal error amplifier. The output terminal COMP of the amplifier is connected to the input terminal VBF of the feedback signal as shown in Figure 7. , adjust the dynamic characteristics of the controller through the resistor R and the capacitor C.

The maximum duty cycle and frequency of the output pulse width signal can be set correspondingly through different values of resistor R _T and capacitor C _T , and the maximum output duty cycle corresponding to different values can be calculated according to formula 1-7.

where V _{RT/CT(valley)} =1.2V, V _RT/CT(peak) =2.8V, V _ref =5V, I _dischg =8.3mA

The output signal frequency is derived from Equation 1-8.

When the feedback signal S _F increases, the duty cycle of the output signal of the PWM controller decreases accordingly; conversely, when the feedback signal S _F decreases, the duty cycle of the output signal of the PWM controller increases accordingly. Through the above process, the dynamic adjustment of the output voltage and output current is realized, so that it can work stably.

Claims (5)

1. A nickel-cadmium accumulator charge regulator for a satellite power supply, which comprises a storage battery pack and a satellite power bus, is characterized in that it also includes a boost topology circuit (1), a voltage and current sampling feedback control unit (2), a PWM control unit (3), drive circuit (4), control unit (5) and switch S, The boost topology circuit (1) is used for corresponding step-up conversion of the voltage output by the satellite power bus, so as to realize the transmission of charging power from the satellite power bus voltage to the battery pack, and then output the charging output voltage and current to the voltage and A current sampling feedback control unit (2); A voltage and current sampling feedback control unit (2), used for sampling the voltage and current output by charging, synthesizing the voltage and current sampling signals to obtain a unified sampling feedback control signal, and then feeding the signal back to the PWM control unit (3 ); The PWM control unit (3) is used to compare the received sampling feedback control signal with its internal reference voltage through the internal error amplifier, and realize the stable output of the charging voltage by adjusting the duty cycle of the switching signal, and finally output the pulse width signal, the pulse width signal drives the NMOS transistor of the boost topology circuit (1) through the driving circuit (4); The control unit (5) is used to receive the charging enable signal obtained by amplifying the error of the bus voltage of the satellite power supply, and control the switch S to close when the enabling signal is valid, so that the boost topology circuit (1) is turned on, so that the entire charging The circuit is connected to charge the battery pack, and at the same time, the temperature monitoring signal T _battery and the voltage monitoring signal V _battery of the battery pack during the charging process are obtained, and the corresponding charge termination voltage V _stop is obtained according to the temperature monitoring signal T _battery . When the voltage monitoring signal When V _battery reaches the V _stop of the charging termination voltage, a charging termination signal is output, and the switch S is cut off, thereby disconnecting the boost topology circuit (1), so that the entire charging circuit stops charging the battery; By when the feedback signal S _F increases, the duty cycle of the output signal of the PWM control unit (3) decreases accordingly; otherwise, when the feedback signal S _F decreases, the duty cycle of the output signal of the PWM control unit (3) increases accordingly Large, through this process, the dynamic adjustment of the output voltage and output current is realized to make it work stably. 2. a kind of satellite power supply nickel-cadmium accumulator charging regulator according to claim 1 is characterized in that, boost topological structure circuit (1) comprises inductance L, NMOS tube VT, diode D, electric capacity C and resistance R, One end of the inductor L is connected to the anode of the diode D and the drain of the NMOS transistor VT at the same time. The cathode of the diode D is connected to one end of the capacitor C and one end of the resistor R at the same time, and the other end of the capacitor C is connected to the other end of the resistor R, the source of the NMOS transistor VT and one end of the satellite power bus. The other end of the inductor L is connected to one end of the switch S, the other end of the switch S is connected to the other end of the satellite power bus, and the gate of the NMOS transistor VT is connected to the drive output end of the drive circuit (4). One end of the resistor R is connected to the positive pole of the battery pack, and the other end of the resistor R is connected to the negative pole of the battery pack. The positive pole of the battery pack and the negative pole of the diode D serve as the voltage and current output terminals of the boost topology circuit (1). 3. a kind of satellite power supply nickel-cadmium accumulator charging regulator according to claim 1 or 2 is characterized in that, it also comprises resistance R _s , One end of the resistor R _s is connected to the negative pole of the diode D, and the other end of the resistor R _s is connected to the positive pole of the battery pack. 4. a kind of satellite power supply nickel-cadmium accumulator charging regulator according to claim 3 is characterized in that, voltage and current sampling feedback control unit (2) comprises current shunt monitor, resistance R ₁ and resistance R ₂ , The positive input of the current shunt monitor is connected to one end of the resistor R _s , _The negative input terminal of the current shunt monitor is connected to the other end of the resistor R _s and _one end of the resistor R1 at the same time, and the other end of the resistor R1 is connected to _one end of the resistor _R2 , the other end of the resistor R2 and the negative pole of the battery pack, power supply ground and the ground terminal of the current shunt monitor, _The other end of the resistance R1 is used as the output terminal of the voltage sampling signal I _F of the current sampling feedback control unit (2), The output end of the current shunt monitor is used as the output end of the current sampling signal I _F of the voltage and current sampling feedback control unit (2). 5. a kind of satellite power supply nickel-cadmium accumulator charging regulator according to claim 1 is characterized in that, PWM control unit (3) comprises resistance R, electric capacity C, resistance R _T , electric capacity C _T and the electric current that the model is UC3843 type PWM controller, Pin 1 of the current-mode PWM controller model UC3843 is connected to one end of the resistor R and one end of the capacitor C at the same time, and the other end of the resistor R is connected to the other end of the capacitor C and 2 pins of the current-mode PWM controller model UC3843. The No. 2 pin of the UC3843 current-mode PWM controller is used as the sampling feedback control signal input terminal of the PWM control unit (3), The No. 5 pin of the current-mode PWM controller whose model is UC3843 is connected to one end of the resistor RT, and the other end of the resistor R _T is connected to one end of the capacitor C _T and the No. 4 pin of the current-mode PWM controller whose model is UC3843 _. The other end of the capacitor C _T is connected to pin 8 of the current-mode PWM controller model UC3843 and the power ground at the same time. The No. 6 pin of the current-mode PWM controller whose model is UC3843 is connected to the power supply, The No. 7 pin of the current-mode PWM controller whose model is UC3843 is used as the pulse width signal output terminal of the PWM control unit (3).