Redundant hot backup power supply and current sharing control method thereof

Abstract

The application discloses a redundant hot backup power supply, comprising a front-stage conversion circuit, a plurality of rear-stage conversion circuits and a control circuit, the front-stage conversion circuit outputs constant voltage, and the output end of the front-stage conversion circuit is connected with an intermediate DC bus in parallel; the rear-stage conversion circuits are connected with the intermediate DC bus in parallel; the control circuit is used for controlling the rear-stage conversion circuits, and comprises a current control outer ring, a current control inner ring and a control circuit; the current control outer ring samples output current of the front-stage conversion circuit, adjusts the output current with a first reference value and then outputs a second reference value; the current control inner ring samples input current of the rear-stage conversion circuits, adjusts the input current with the second reference value and then outputs a first signal; and the first signal is used for controlling power switches in the rear-stage conversion circuits. The application realizes input constant power control of the input parallel rear-stage conversion circuits, and realizes input current sharing control and redundant hot backup functions of the plurality of input parallel circuits.

Description

Technical Field

[0001] This invention relates to power supply technology with multiple modules connected in parallel, and more particularly to current sharing control methods. Background Technology

[0002] To meet power requirements and reliability needs, redundancy is often necessary when connecting multiple circuits in series or parallel. For power systems with multiple circuits operating in parallel (e.g., input parallel, output parallel, or input-output parallel), current sharing control is required to distribute thermal stress evenly and reduce the current stress on individual circuit modules. Furthermore, if one or more circuit modules fail, the remaining functional modules should continue to operate stably to maintain system power requirements, thus meeting the power system's reliability requirements. Summary of the Invention

[0003] This invention provides a redundant hot backup power supply and its current sharing control method, which performs inner current loop and outer current loop control to achieve redundant hot backup.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A redundant hot backup power supply, including

[0006] The pre-conversion circuit has a constant voltage output, and its output terminal is connected in parallel to the intermediate DC bus.

[0007] Multiple downstream conversion circuits, wherein the downstream conversion circuits are connected in parallel with the intermediate DC bus.

[0008] A control circuit, used to control the subsequent conversion circuit, includes,

[0009] The current-controlled outer loop samples the output current of the preceding conversion circuit and adjusts it with a first reference value before outputting a second reference value.

[0010] The current control inner loop samples the input current of the subsequent conversion circuit and adjusts it with a second reference value before outputting a first signal. The first signal is used to control the power switch in the subsequent conversion circuit.

[0011] The aforementioned current control outer loop includes a first adder and a first regulator. The first adder calculates the difference between the output current of the preceding conversion circuit and the first reference value, and then adjusts the result through the first regulator to output the second reference value.

[0012] The aforementioned control circuit includes multiple current control inner loops, each controlling a power switch in a subsequent conversion circuit. Each current control inner loop includes a second adder, a second regulator, and a drive signal generator. The second adder takes the difference between the input current of the subsequent conversion circuit and a second reference value, adjusts the result through the second regulator, and outputs a first signal to the drive signal generator. The drive signal generator generates a drive signal for the power switch based on the first signal.

[0013] The aforementioned current control inner loop includes a third adder, which adds the first signal and the second reference value and outputs a second signal to the drive signal generator. The drive signal generator generates the drive signal for the power switch based on the second signal.

[0014] The output terminals of the aforementioned subsequent conversion circuits are connected in parallel with loads.

[0015] The output terminals of the aforementioned multiple subsequent conversion circuits are connected in parallel, and then a load is connected in parallel.

[0016] The aforementioned redundant hot backup power supply also includes an electrical load, which is connected in parallel with the DC bus.

[0017] The present invention also provides a current sharing control method for controlling the aforementioned redundant hot backup power supply, comprising,

[0018] Step S1: Sample the output current of the pre-conversion circuit;

[0019] Step S2: The output current of the pre-conversion circuit is subtracted from the first reference value and then adjusted and controlled to output the second reference value.

[0020] Step S3 samples the input current of the subsequent conversion circuit;

[0021] After step S4, the input current of the subsequent conversion circuit is subtracted from the second reference value and then adjusted to generate the first signal.

[0022] In step S5, the first signal is calculated to generate a drive signal that controls the power switch in the subsequent conversion circuit to turn on and off.

[0023] After the first signal and the second reference value are added together in step S5 above, a drive signal is generated to control the power switch in the subsequent conversion circuit to turn on and off.

[0024] This invention realizes constant power control of input parallel-connected subsequent conversion circuits, and realizes input current sharing control and redundant hot backup functions of multiple input parallel circuits.

[0025] To make the above-mentioned features and advantages of the invention more apparent and understandable, specific embodiments are described below, and detailed descriptions are provided in conjunction with the accompanying drawings. Attached Figure Description

[0026] Figure 1 This is the first specific embodiment of the redundant hot backup power supply of the present invention.

[0027] Figure 2 This is a second specific embodiment of the redundant hot backup power supply of the present invention.

[0028] Figure 3 This is the first specific embodiment of the control circuit of the present invention.

[0029] Figure 4 This is a second specific embodiment of the control circuit of the present invention.

[0030] Figure 5 for Figure 1 One specific embodiment.

[0031] Figure 6 This is a flowchart of the flow sharing control method of the present invention. Detailed Implementation

[0032] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] The terms "first," "second," "third," etc., as used in this invention (if applicable), are used to distinguish similar elements and do not necessarily describe a specific order or chronological sequence. It should be understood that these terms are interchangeable in appropriate contexts, allowing implementations of the subject matter described herein to be performed, for example, in an order different from those described or in an order otherwise described herein. Furthermore, wherever possible, components / members / steps using the same reference numerals in the figures and embodiments represent the same or similar parts.

[0034] Figure 1 As shown, a redundant hot backup power supply includes a front-end conversion circuit 1 and an intermediate DC bus BUS. The output of the front-end conversion circuit 1 is connected in parallel to the intermediate DC bus BUS, and the front-end conversion circuit provides a constant voltage output. Multiple back-end conversion circuits 2n and electrical loads 3 are connected in parallel to the intermediate DC bus BUS. The outputs of the back-end conversion circuits 2n are connected in parallel to the loads respectively. R n And output voltage V on The intermediate DC bus BUS is also connected in parallel with electrical load 3.

[0035] Please refer to this again. Figure 2 ,and Figure 1 The difference in the illustrated embodiment is that the output of the subsequent conversion circuit 2n is connected in parallel with a load. R And output voltage V o .

[0036] exist Figure 1 and Figure 2 In the redundant hot backup power supply shown, the front-end conversion circuit 1 provides power as the power supply terminal, and the back-end conversion circuit 2n and the electrical load 3 absorb power as the load of the front-end conversion circuit 1. The front-end conversion circuit 1 outputs constant voltage, and the power flow can be expressed by equation (1).

[0037]

[0038] Among them, current I bus The total current output from the pre-conversion circuit 1 to the DC bus BUS. I in_n These are the input currents of the subsequent converter circuit 2n, and the currents are respectively... I L This is the input current for electrical load 3. Maintaining current. I bus remain unchanged. I L As the independent variable, I in_n As the dependent variable, redundant design is implemented for the 2n-stage power conversion circuit.

[0039] Figure 3 The control circuit 4 of this invention is used to control the subsequent conversion circuit 2n. The control circuit 4 includes a current control outer loop 40 and a current control inner loop 4n. The current control outer loop 40 samples the output current of the preceding conversion circuit 1. I bus Current I bus Compared with the first reference value I bus_ref After the difference is calculated by adder 401, the second reference value is output through PID closed-loop control by regulator 402. I _ref The input current of the sampling stage converter circuit 2n. I in_n , the second reference value I _ref As a reference value for the inner loop 4n of the 2n current control in the subsequent conversion circuit, it is related to the input current. I in_nAfter the difference is calculated by adder 4n1, the output signal is then processed by regulator 4n2 for PID closed-loop control. V pn ,Signal V pn The PWM signal is generated by the drive signal generator 4n3. V gn Control the on and off of the power switch in the subsequent conversion circuit 2n.

[0040] This invention first samples the output current of the pre-conversion circuit and the input current of the post-conversion circuit, and then samples the output current of the pre-conversion circuit. I bus Compared with the first reference value I bus_ref After calculating the difference, PID closed-loop control is performed to complete the outer loop control of the total input current; then, the closed-loop output of the outer loop control of the total input current is set to the second reference value. I _ref As a reference value for the inner loop of the input current of the subsequent conversion circuit, the difference between the sampled actual value of the input current of the subsequent conversion circuit is used for PID closed-loop control to complete the inner loop control of the input current. Finally, the output of the inner loop control of the input current is used by the PWM module to generate a PWM signal to control the on and off of the power switch, thereby realizing constant power control and current sharing control of the input of the subsequent conversion circuit.

[0041] Since all subsequent conversion circuits have the same input current reference value, input current sharing control of multiple subsequent conversion circuits can be achieved through current inner loop control; and when a certain subsequent conversion circuit is not working, the remaining subsequent conversion circuits automatically share the total input current, realizing the redundancy hot backup function.

[0042] exist Figure 3 In the control circuit 4 shown, the output of the outer current control loop 40 is used entirely as a reference value for the inner current control loop 4n. Therefore, the control bandwidth of the inner current control loop 4n needs to be greater than the control bandwidth of the outer current control loop 40. That is, the cutoff frequency of the inner current control loop 4n is greater than the cutoff frequency of the outer current control loop 40. Thus, when a large signal disturbance (such as the switching of the subsequent conversion circuit or the switching of the power load) occurs, the current sharing transient response of the subsequent conversion circuit is faster than the constant power transient response of the total input current. However, under a large signal disturbance, it is necessary to first ensure the total DC bus current. I bus The stability can be determined by Figure 3 The proposed control is derived to Figure 4 A constant power redundant current sharing control circuit with current feedforward input.

[0043] Figure 4 and Figure 3The difference lies in the output second reference value of the current control outer loop 40. I _ref In addition to serving as a reference value for the current control inner loop 4n, it also interacts with the output signal of the current control inner loop 4n. V pn The superimposed values ​​are used as the input level of the PWM module 4n3. By introducing total input current feedforward, the stability of the total input current can be maintained first when disturbances occur. Furthermore... Figure 4 In the dual current loop with current feedforward shown, if the bandwidth of the inner current loop is still greater than the bandwidth of the outer current loop, the control effect is the same as... Figure 3 The same applies to the outer loop. Conversely, when the bandwidth of the inner current loop is less than that of the outer current loop, it can quickly stabilize the total input current, such as when a large disturbance occurs.

[0044] Figure 5 As shown Figure 1 The illustrated redundant hot backup power supply is a specific embodiment in which the circuit topology of the subsequent conversion circuit 21 and subsequent conversion circuit 22 is a step-down circuit. The subsequent conversion circuit 21 includes a switch. Q 1 ,diode D 1 ,inductance L 1 and capacitor C 1 The switch Q 1 ,diode D 1 ,inductance L 1 and capacitor C 1 The connection method is a BUCK buck topology. The subsequent conversion circuit 22 includes switches. Q 2 ,diode D 2 ,inductance L 2 and capacitor C 2 The switch Q 2 ,diode D 2 ,inductance L 2 and capacitor C 2 The connection method is a BUCK step-down topology.

[0045] like Figure 6 As shown, the present invention also provides a current sharing control method for controlling the aforementioned redundant hot backup power supply. It includes the following steps:

[0046] Step S1: Sample the output current of the pre-conversion circuit. I bus .

[0047] Step S2 current I bus Compared with the first reference value I bus_ref After differential calculation, the output is adjusted and controlled to produce a second reference value. I _ref .

[0048] Step S3: Sample the input current of the subsequent conversion circuit. I in_n .

[0049] Step S4 Current I in_n Compared with the second reference value I _ref After differential calculation, the output signal is adjusted and controlled. VPN .

[0050] Step S5 signal VPN The calculation generates a PWM signal to control the power switch in the subsequent conversion circuit to turn on and off.

[0051] Step S5 can also be a signal. VPN Compared with the second reference value I _ref The superimposed signals are then calculated to generate a PWM signal that controls the power switching transistors in the subsequent conversion circuit to turn on and off.

[0052] This invention enables constant power control of input for multiple parallel-connected downstream converter circuits, and also implements input current sharing control and redundant hot backup functions.

[0053] Although the invention has been disclosed above with reference to embodiments, it is not intended to limit the invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the invention shall be determined by the appended claims.

Claims

1. A redundant hot backup power supply, characterized in that, include The pre-conversion circuit has a constant voltage output, and its output terminal is connected in parallel to the intermediate DC bus. Multiple downstream conversion circuits, wherein the downstream conversion circuits are connected in parallel with the intermediate DC bus. A control circuit, used to control the subsequent conversion circuit, includes, The current-controlled outer loop samples the output current of the preceding conversion circuit and adjusts it with a first reference value before outputting a second reference value. The current control inner loop samples the input current of the subsequent conversion circuit and adjusts it with a second reference value to output a first signal. The first signal and the second reference value are added together to output a second signal, which is used to control the power switch in the subsequent conversion circuit.

2. The redundant hot backup power supply as described in claim 1, characterized in that, The current control outer loop includes a first adder and a first regulator. The first adder calculates the difference between the output current of the preceding conversion circuit and the first reference value, and then adjusts the result through the first regulator to output a second reference value.

3. The redundant hot backup power supply as described in claim 2, characterized in that, The control circuit includes multiple current control inner loops, each controlling a power switch in a subsequent conversion circuit. Each current control inner loop includes a second adder, a second regulator, and a drive signal generator. The second adder takes the difference between the input current of the subsequent conversion circuit and a second reference value, adjusts it through the second regulator, and outputs a first signal to the drive signal generator. The drive signal generator generates a drive signal for the power switch based on the first signal.

4. The redundant hot backup power supply as described in claim 3, characterized in that, The current control inner loop includes a third adder, which adds the first signal and the second reference value and outputs a second signal to the drive signal generator. The drive signal generator generates the drive signal for the power switch based on the second signal.

5. A redundant hot backup power supply as described in claim 1, characterized in that, The output terminals of the subsequent conversion circuits are connected to loads in parallel.

6. A redundant hot backup power supply as described in claim 1, characterized in that, The outputs of multiple subsequent conversion circuits are connected in parallel, and then a load is connected in parallel.

7. A redundant hot backup power supply as described in claim 1, characterized in that, It also includes electrical loads, which are connected in parallel with the DC bus.

8. A current sharing control method for controlling a redundant hot backup power supply as described in any one of claims 1-7, characterized in that, include, Step S1: Sample the output current of the pre-conversion circuit; Step S2: The output current of the pre-conversion circuit is subtracted from the first reference value and then adjusted and controlled to output the second reference value. Step S3 samples the input current of the subsequent conversion circuit; After step S4, the input current of the subsequent conversion circuit is subtracted from the second reference value and then adjusted and controlled to generate the first signal. In step S5, the first signal is added to the second reference value and then calculated to generate a drive signal to control the power switch in the subsequent conversion circuit to turn on and off.

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