Power supply module and power supply system

Abstract

The utility model discloses a power supply module and a power supply system. The power supply module comprises a power supply unit and a current sharing device. The current sharing device comprises a sampling signal output unit, a difference signal output unit, a control signal output unit and an isolation unit. The sampling signal output unit is connected with the power supply unit; the isolation unit is connected with the current sharing bus BUS +; the difference signal output unit is connected with the sampling signal output unit and the output end of the isolation unit; the control signal output unit is respectively connected with the output ends of the difference signal output unit and the power supply unit; and the power supply unit is connected with the control signal output unit. According to the power supply module and the power supply system disclosed by the utility model, current sharing of a plurality of power supply modules is realized through master-slave-free current sharing control, the expandability of the power supply system is improved, and the power supply module and the power supply system have great practical significance.

Description

Technical Field

[0001] The utility model relates to the technical field of power management, in particular to a power module and a power system. Background Art

[0002] In the existing railway signal power supply system, in order to improve the reliability and safety of signal power supply and realize the scalability of different power combinations, an N+M redundant power supply mode (N and M are both natural numbers greater than 1, where N is the basic power supply module and M is the redundant power supply module) in which multiple power modules (specifically DC power supply modules) are connected in parallel is often used.

[0003] When one or more of the 1 to N power modules fail, the M redundant power modules can still ensure reliable power supply for the signal system. This leads to the problem of evenly distributing the load current among the N+M power modules. If current flows between the power modules (i.e., a circulating current is formed), the power system will be unstable and irreversible damage will be caused to the power modules. Therefore, multiple power modules need to be connected in parallel for current balancing.

[0004] The existing current sharing methods include external control method and master-slave unit current sharing method:

[0005] External control method: In addition to the multiple power modules connected in parallel, a separate controller is set up to compare the current signals of each power module. According to the different sizes of the current signals, the voltage feedback sampling or the reference level of the amplifier of each power module is adjusted to adjust the output voltage of each power module, thereby achieving current sharing. However, this method increases the cost due to the addition of an external controller.

[0006] Master-slave unit current sharing method: set one power module as the master power module among multiple power modules, and the other power modules as slave power modules. When multiple power modules are working, the master power module is responsible for the output voltage control of the power system as a whole. The output of the voltage comparator of the master power module is sent to the output end of the voltage error amplifier of each slave power module, and the master power module performs PWM (pulse width modulation) control to achieve current sharing. However, this method loses the power supply reliability of the N+M redundancy mode, that is, when the master power module fails, the slave power module will also shut down.

[0007] Therefore, there is an urgent need to develop a technology that can overcome the above-mentioned defects. Utility Model Content

[0008] The purpose of the utility model is to provide a power module and a power system in view of the technical defects in the prior art.

[0009] To this end, the utility model provides a power supply module, characterized by comprising: a power supply unit and a current balancing device;

[0010] A current balancing device, comprising a sampling signal output unit, a difference signal output unit, a control signal output unit and an isolation unit;

[0011] A sampling signal output unit is connected to the power supply unit and is used to collect the output current signal of the power supply unit and then output it to the difference signal output unit;

[0012] An isolation unit is connected to the current sharing bus BUS+, and is used to isolate the current sharing bus BUS+ from the difference signal output unit in the current sharing device, and output the current sharing line voltage signal V_JLBUS+ to the difference signal output unit after isolating the voltage on the current sharing bus BUS+;

[0013] The difference signal output unit is connected to the output ends of the sampling signal output unit and the isolation unit, and is used to receive the output current signal of the power supply unit sent by the sampling signal output unit, and then compare the output current signal with the current-sharing line voltage V_JLBUS+ signal output by the isolation unit through the operational amplifier U1 therein, and then output the current difference signal ERR to the control signal output unit;

[0014] A control signal output unit, connected to the output ends of the difference signal output unit and the power supply unit, respectively, for obtaining a corresponding control signal according to the current difference signal ERR output by the difference signal output unit and the voltage signal output by the output end of the power supply unit, and then outputting the corresponding control signal to the power supply unit;

[0015] The power supply unit is connected to the control signal output unit, and is used to receive the control signal output by the control signal output unit, and adjust the voltage of its output terminal V_out+ accordingly according to the change of the duty cycle of the control signal, thereby adjusting the output current.

[0016] In addition, the utility model also provides a power supply system, comprising a plurality of power supply modules as described above;

[0017] Multiple power modules are DC power modules with parallel output.

[0018] It can be seen from the technical solution provided by the above utility model that, compared with the prior art, the utility model provides a power supply module and a power supply system, which are scientifically designed and can achieve current sharing of multiple power supply modules through non-master-slave current sharing control, thereby improving the scalability of the power supply system and having great practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A connection circuit diagram of a power module provided by the utility model;

[0020] Figure 2 A structural block diagram of a current balancing device in a power module provided by the utility model;

[0021] Figure 3 This is a structural schematic diagram of a power supply system provided by the utility model, in which each power supply module in the power supply system is equipped with a current balancing device;

[0022] In the figure, the power supply unit is 110; the sampling signal output unit is 111; the current transformer is TA; the difference signal output unit is 112; the operational amplifier is U1; the control signal output unit is 113; the PWM controller is U3; the isolation unit is 114; and the photoelectric coupler is U2. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0026] See also Figure 1 , Figure 2 , Figure 3 As shown, the utility model provides a power supply module, including: a power supply unit 110 and a current balancing device;

[0027] The current balancing device comprises a sampling signal output unit 111, a difference signal output unit 112, a control signal output unit 113 and an isolation unit 114;

[0028] The sampling signal output unit 111 is connected to the power supply unit 110 and is used to collect the output current signal of the power supply unit 110 and then output it to the difference signal output unit 112;

[0029] The isolation unit 114 is connected to the current sharing bus BUS+, and is used to isolate the current sharing bus BUS+ from the difference signal output unit 112 in the current sharing device, and output the current sharing line voltage signal V_JLBUS+ to the difference signal output unit 112 after isolating the voltage on the current sharing bus BUS+;

[0030] It should be noted that the current sharing bus BUS+ is used to connect the isolation unit 114 in the power module with the isolation units of other power modules in the power system where the power module is located;

[0031] The difference signal output unit 112 is connected (e.g., electrically connected) to the output ends of the sampling signal output unit 111 and the isolation unit 114, and is used to receive the output current signal of the power supply unit 110 sent by the sampling signal output unit 111, and then compare the output current signal with the current-sharing line voltage V_JLBUS+ signal output by the isolation unit 114 through the operational amplifier U1 therein, and then output a current difference signal (ERR) to the control signal output unit 113;

[0032] The control signal output unit 113 is connected to the output end of the difference signal output unit 112 and the power supply unit 110, respectively, and is used to obtain a corresponding control signal (i.e., a PWM pulse width modulation signal) according to the current difference signal (ERR) output by the difference signal output unit 112 and the voltage signal output by the output end of the power supply unit 110, and then output it to the power supply unit 110 (specifically the switch tube S therein);

[0033] The power supply unit 110 (specifically the switch tube S therein) is connected to the control signal output unit 113, and is used to receive the control signal output by the control signal output unit 113, and adjust the voltage of its output terminal V_out+ accordingly according to the change of the duty cycle of the control signal, thereby adjusting the output current.

[0034] Based on the power module provided by the utility model, see Figure 3 As shown, the utility model also provides a power supply system, including multiple power supply modules (which are DC power supply modules);

[0035] In specific implementation, the isolation units 114 in the multiple power modules are respectively connected to the current sharing bus BUS+;

[0036] The sampling signal output units 111 in the multiple power modules are respectively connected to the current sharing ground line JL-.

[0037] It should be noted that multiple power modules, specifically DC power modules with parallel output

[0038] In the present utility model, it should be noted that the current-sharing bus BUS+ is a common current-sharing line in a power system composed of multiple power modules, and the current-sharing line of each power module is connected to this common current-sharing line. The voltage on the current-sharing bus BUS+ reflects the average value of the output current of each power module. The current-sharing BUS+ is introduced into the inverting terminal of the error operational amplifier inside the module through the isolation unit 114, and the difference is amplified with the output current sampling value of the power module.

[0039] In specific implementation, the current-sharing ground line corresponds to the current-sharing bus line. It can be understood that the current-sharing line is composed of two lines, where the current-sharing line at the positive end is marked as the current-sharing bus line BUS+, and the current-sharing line at the negative end is marked as the current-sharing ground line JL-.

[0040] In the present utility model, in specific implementation, the power supply unit 110 includes a switch tube S, a transformer T1, diodes D5, D6 and an electrolytic capacitor CD1;

[0041] The input terminal 1 of the primary side of the transformer T1 is connected to the positive terminal of the input power supply Vin;

[0042] The negative terminal of the input power supply Vin is connected to the input terminal 2 of the primary side of the transformer T1 through the switch tube S;

[0043] The output terminal 6 of the secondary side of the transformer T1 is connected to the anode of the diode D5;

[0044] The output terminal 3 of the secondary side of the transformer T1 is connected to the anode of the diode D6;

[0045] The cathodes of diodes D5 and D6 are connected to the positive output terminal V_out+ after the currents converge and intersect;

[0046] The positive output terminal V_out+ is connected to the negative output terminal V_out- through the electrolytic capacitor CD1;

[0047] The connecting wire between the output terminal 5 and the output terminal 4 of the secondary side of the transformer T1 (i.e., the secondary side lead wire) is connected to the primary side of the current transformer TA in the sampling signal output unit 111;

[0048] The output terminal 4 of the secondary side of the transformer T1 is also connected to the negative electrode of the electrolytic capacitor CD1;

[0049] In specific implementation, the power module is connected to the load LOAD;

[0050] The positive terminal of the load LOAD is connected to the positive output terminal V_out+;

[0051] The negative terminal of the load LOAD is connected to the negative output terminal V_out--.

[0052] It should be noted that the switch tube S is a mature and universal N-channel enhancement MOSFET power tube with existing technology. For example, the N-channel enhancement MOSFET power tube products of Infineon's CoolMOS series, such as SPW47N60C3 and other models, can be used. The switch tube S is used as a power device in the switching power supply to realize energy conversion.

[0053] In the present utility model, the specific implementation is as follows: Figure 2 As shown, the sampling signal output unit 111 includes: a resistor R1, a current transformer TA and diodes D1-D4;

[0054] The primary side of the current transformer TA, as a signal acquisition end, is connected to the secondary side lead wire (i.e., the secondary side high-frequency rectification circuit) of the high-frequency transformer T1 of the power supply unit 110 in the power module, and is used to collect the output current signal of the power supply unit 110 in the power module.

[0055] The secondary side of the current transformer TA is connected to the input end of the bridge rectifier circuit composed of diodes D1, D2, D3 and D4;

[0056] The output end of the bridge rectifier circuit is connected in parallel to both ends of the resistor R1;

[0057] One end of the resistor R1 is used as the current sampling signal output end of the sampling signal output unit 111 and is connected to the common end of the resistors R4 and R2 in the difference signal output unit 112;

[0058] The other end of the resistor R1 is connected to the current sharing ground line V_JL of the power system where the power module is located.

[0059] It should be noted that the utility model uses a current transformer TA to perform isolated sampling on the output current of the power module, thereby improving the reliability of the power module.

[0060] In the present utility model, in specific implementation, the difference signal output unit 112 includes resistors R2 to R6 and an operational amplifier U1;

[0061] One end of the resistor R2, as a sampling signal receiving end of the difference signal output unit 112, is respectively connected to one end of the resistor R1 and one end of the resistor R4 in the sampling signal output unit 111;

[0062] The other end of the resistor R2 is connected to the current sharing bus BUS+ through the photoelectric coupler U2 in the isolation unit 114;

[0063] The other end of the resistor R2 is also connected to one end of the resistor R5;

[0064] The other end of the resistor R4 is connected to the inverting input end of the operational amplifier U1 and one end of the resistor R6 respectively;

[0065] The other end of the resistor R6 is connected to the output end of the operational amplifier U1;

[0066] The output end (i.e., the first pin) of the operational amplifier U1 is connected to one end of the resistor R8 in the control signal output unit 113;

[0067] The other end of the resistor R5 is connected to the non-inverting input end of the operational amplifier U1 and one end of the resistor R3 respectively;

[0068] The other end of resistor R3 is the reference ground;

[0069] In a specific implementation, one end of the resistor R5 intersecting with the second resistor R2 is connected to the third pin of the photoelectric coupler U2 in the isolation unit 114 .

[0070] It should be noted that, for the difference signal output unit 112 of the present invention, the difference signal between the sampling signal (i.e., the current sampling signal of the power module) and the current sharing bus signal is obtained through resistors R2, R3, R4, R5, R6 and operational amplifier U1, but the present invention is not limited to this.

[0071] In the present utility model, in specific implementation, the control signal output unit 113 includes: resistors R8 to R11 and a PWM controller U3;

[0072] One end of the resistor R8, as a receiving end of the control signal output unit 113, is connected to the output end of the operational amplifier U1 inside the difference signal output unit 112;

[0073] The other end of the resistor R8 is connected to one end of the resistor R9 and the non-inverting input end of the PWM controller U3 (specifically, the operational amplifier inside it);

[0074] The other end of the resistor R9 is connected to the reference voltage 2.5V;

[0075] One end of the resistor R10 is connected to the positive output terminal V_out+ of the power supply unit 110 in the power module;

[0076] The other end of the resistor R10 is connected to one end of the resistor R11 and the inverting input end of the PWM controller U3 (specifically, the operational amplifier inside it);

[0077] The other end of the resistor R11 is connected to the negative output terminal V_out- of the power supply unit 110 in the power module;

[0078] The output end of the PWM controller U3 is connected to the control end of the switch tube S of the power supply unit 110 in the power module;

[0079] In the present utility model, the specific implementation is as follows: Figure 2 As shown, the isolation unit 114 includes a photocoupler U2 and a seventh resistor R7;

[0080] The fourth pin of the photocoupler U2 is connected to the current sharing bus BUS+;

[0081] The third pin of the photocoupler U2 is connected to the common end of the resistors R2 and R5 in the difference signal output unit 112;

[0082] The first pin of the photocoupler U2 is connected to a DC power supply (eg, a 12V DC power supply);

[0083] The second pin (CON1 pin) of the photocoupler U2 is used as an input terminal for controlling the on and off of the photocoupler U2, and is used to be connected to an external control signal output terminal, so as to receive an external input control signal. When a high-level external input control signal (such as a high-level fault signal) is received, the photocoupler U2 is disconnected;

[0084] In specific implementation, the power supply unit 110 of the utility model can be a component unit of some existing finished power modules, specifically the power supply unit included in the MW1-Z24 / 60, MW-Z48 / 30 and other model power modules produced by Tianjin Railway Signal Co., Ltd. The power supply unit 110 is a circuit structure design included in these existing power modules.

[0085] For the utility model, the second pin of the photocoupler U2 is connected to the external control signal output terminal capable of outputting a high-level control signal. For example, the second pin of the photocoupler U2 can be connected to the operating status output signal terminal of the existing power modules (specifically the single-chip microcomputer therein) of the MW1-Z24 / 60, MW-Z48 / 30 and other models of Tianjin Railway Signal Co., Ltd. Among them, the power supply unit 110 is specifically the power supply unit structure of these models of power modules. When the power supply unit 110 in these models of power modules is in an abnormal state (for example, the input voltage is too high or too low), the single-chip microcomputer in these models of power modules can output a high-level signal, and the high-level signal connects the 2nd pin of the optocoupler U2, so that the photocoupler U2 is disconnected. At this time, the current-sharing device in the power module of the utility model will be disconnected from the current-sharing line (specifically the current-sharing bus BUS+) of the power system, and the failed power module will no longer participate in the current-sharing of the power system. When the power supply unit in the power module works normally, the operating status output signal is at a low level, so that the photocoupler U2 is turned on, and the power module participates in the current sharing of the power system.

[0086] It should be noted that the existing power supply modules of models such as MW1-Z24 / 60 and MW-Z48 / 30 produced by Tianjin Railway Signal Co., Ltd. include a power supply unit and a single-chip microcomputer, wherein the structure of the power supply unit is as follows: Figure 1 The structure of the power supply unit 110 shown in the figure is an existing single-chip microcomputer which is built into these models of power modules and is used to detect the input voltage status of the power supply unit in the power module. These original single-chip microcomputers are connected to the power supply unit in these models of power modules and can detect the input voltage status of the power supply unit in the power module. This is a function of these single-chip microcomputers themselves and will not be repeated here.

[0087] In specific implementation, the photoelectric coupler can also be replaced by a relay or the like to achieve this function.

[0088] It should be noted that, for the present invention, by sending a high-level signal to the second pin (CON1 pin) of the photocoupler U2, the photocoupler U2 can be controlled through the second pin (CON1 pin) to cut off the connection between the current equalizing device in the power module and the current equalizing bus BUS+.

[0089] In the present utility model, it should be noted that, for the present utility model, the two input terminals of the operational amplifier U1 in the difference signal output unit 112 are connected to the two ends of the second resistor R2 through resistors R4 and R5 respectively, and the operational amplifier U1 amplifies the difference signal and outputs the amplified difference signal ERR to the control signal output unit 113. The control signal output unit 113 adjusts the duty cycle of the output PWM signal according to the reference voltage Vref, and adjusts the output current of each module.

[0090] It should be noted that for the present utility model, see Figure 2 As shown, the control signal output unit 113 includes resistors R8, R9, R10, R11 and a PWM controller U3. The voltage signal of the current difference signal ERR after being superimposed by the resistors R8 and R9 and the 2.5V bias voltage is Vref. Vref is used as the reference voltage of the PWM controller U3 and input to the in-phase control terminal of the PWM controller U3. The output voltage V_out+ of the power module is divided by the voltage-dividing resistors R10 and R11 to generate a feedback voltage Vfb and send it to the inverting control terminal of the PWM controller U3. Vref and Vfb are used as the input of the PWM controller together to form a negative feedback regulation output PWM (pulse width modulation) signal to the power module (specifically, the signal control terminal of the switch tube S in the power module).

[0091] Among them, if the current output current of the current power module is larger than the current of other modules in the parallel system, that is, the voltage value V_JL generated by the current of this module is greater than the voltage V_JLBUS+ introduced by the current-sharing bus to the power module, then the difference voltage ERR output by the operational amplifier U1 in the difference signal output unit 112 is less than 0. The more negative the ERR value is, the lower the reference voltage of the in-phase input terminal of the PWM controller is. The PWM controller U3 adjusts the duty cycle to reduce the output voltage of the power module, and the current output current of the power module will also decrease until the voltage value V_JL corresponding to the current output current of the power module is the same as the current-sharing line voltage (that is, the voltage V_JLBUS+ introduced by the current bus to the power module) and no longer adjusts it.

[0092] Among them, the voltage signal Vref affects the non-inverting input terminal of the PWM controller U3, and the feedback signal of the output voltage of the power module (that is, the voltage signal of the output terminal V_out+) is connected to the inverting input terminal of the PWM controller U3 to form a negative feedback system, which works together to adjust the output voltage of the module.

[0093] In the present invention, the feedback control unit of the power module is formed by the PWM controller U3 to generate a PWM driving signal to control the switch tube S in the power module.

[0094] In the utility model, the control signal output unit 113 in the current balancing device in the power module is respectively connected to the switch tube S in the power supply unit 100 (such as electrically connected), and the control signal output unit 113 outputs a pulse width modulation drive signal, that is, a PWM signal. The change of the PWM signal adjusts the output terminal voltage of the power module where it is located, and accordingly changes the output current of the power module.

[0095] In specific implementation, the PWM controller in the control signal output unit 113 may be a PWM controller chip provided in the power module, or may be a digital signal processor DSP or a single-chip microcomputer MCU.

[0096] In the present utility model, in specific implementation, as Figure 3 As shown, the power supply system includes multiple power supply modules, for example, power supply module 1, power supply module 2...power supply module N, where N is a positive integer.

[0097] It should be noted that the power supply system can adopt an N+M redundant power supply mode in which multiple power supply modules (DC power supply modules) 1, 2, N are connected in parallel to supply power, but the present invention is not limited thereto.

[0098] It should be noted that, for the present invention, each power module includes: a current balancing device; the switch tube S in each power module adjusts the output current of the power module connected thereto according to the control signal output by the current balancing device (specifically, the control signal output unit 113 therein), thereby achieving current balancing of multiple power modules (e.g., power module 1, power module 2 ... power module N). Therefore, the present invention achieves current balancing of multiple power modules by adopting a non-master-slave current balancing method, thereby improving the scalability of the power system.

[0099] See also Figure 3 The power supply system of the utility model includes multiple power supply modules (which are DC power supply modules); the multiple power supply modules are specifically DC power supply modules with parallel output.

[0100] It should be noted that in Figure 2 In the illustrated embodiment, the current balancing device is integrated into the power module, but the present invention is not limited thereto. In other embodiments, the current balancing device may also be provided independently of the power module.

[0101] In the present invention, it should be noted that the difference signal output unit 112 is electrically connected to the current sharing bus BUS+ of the power system through the photoelectric coupler U2 in the isolation unit 114 .

[0102] It should be noted that the power supply system includes a current-sharing bus BUS+; one end of the difference signal output unit 112 is electrically connected to the sampling signal output unit 111; the other end of the difference signal output unit 112 is electrically connected to the current-sharing bus BUS through the optocoupler U2 in the isolation unit 114.

[0103] It should be noted that in the present utility model, see Figure 2 As shown, for the current sharing bus BUS+, it is connected to the fourth pin of the photoelectric coupler U2 in the isolation unit 114;

[0104] The current sharing bus BUS+ is a current sharing control line of a power system including multiple power modules;

[0105] In the present invention, the connection relationship of the current sharing bus BUS+ refers to Figure 2 , connected to R2 and R5 in the difference signal output unit 112 through the 3rd and 4th pins of the photocoupler U2 in the isolation unit 114, as the in-phase input of the subtractor, and participating in the difference amplification of the subtractor.

[0106] In specific implementation, the voltage of the current-sharing bus BUS+ is related to the output current of each module. The currents output by the N modules are I1, I2...IN respectively. The voltages output by the sampling signal output unit 111 inside each module are V_JL1, V_JL2...V_JLN respectively. The N voltages are connected to the current-sharing bus through the resistor R2 with the same resistance value inside the N modules. According to the principle of voltage superposition, the voltage value of the voltage V_JLBUS+ connected to the current-sharing line through the isolation unit is (V_JL1+V_JL2+...+V_JLN) / N, that is, the voltage on the current-sharing bus BUS+ is the average value of the voltages corresponding to the output current values ​​of the N modules.

[0107] The negative end (negative end, ie, the current sharing ground line) of the output current sharing line is the negative end of the sampling signal output unit 111 of the output current of each module.

[0108] In specific implementation, the current-sharing bus BUS+ is used to provide a current-sharing bus signal. Given that the current level signal on the current-sharing bus BUS+ represents (i.e. is equal to) the average value of the load currents of all multiple power modules, the current-sharing bus signal adopted by the present invention is: the voltage level signal corresponding to the current value after the output current of multiple power modules together is averaged to each module.

[0109] It should be noted that the output ends of multiple power modules (including the positive output end V_out+ and the negative output end V_out-) are connected in parallel to supply power to the load LOAD (DC load). The current sharing bus BUS+ is not connected to the output ends of the power modules (including the positive output end V_out+ and the negative output end V_out-).

[0110] In the present utility model, it should be noted that pin 3 of the photoelectric coupler U2 in the isolation unit 114 is electrically connected to the second resistor R2, and pin 4 of the photoelectric coupler U2 in the isolation unit 114 is electrically connected to the current equalizing bus BUS+. The photoelectric coupler U2 inside the isolation unit 114 can be disconnected by controlling the connection between the current equalizing device of the faulty power module itself and the current equalizing bus.

[0111] In the utility model, in a specific implementation, the resistance value of resistor R1 is determined according to the rated current and the turns ratio of the current transformer TA. For example, when the rated current is 60A and the turns ratio of the current transformer TA is 1:300, the resistance value of R1 can be selected as 10Ω, that is, when the rated current is output, the voltage value of the current sharing bus V_JLBUS+ is 60 / 300x10=2V.

[0112] In the present invention, the resistor R2 is a resistor connecting each module to the current sharing bus. The resistor values ​​are required to be the same, and the resistor values ​​can be 10kΩ or 15kΩ, or any other values.

[0113] In the utility model, in specific implementation, the current transformer TA is an electrical component with mature prior art, which is a magnetic component. It is necessary to determine the turns ratio according to the rated current in the actual circuit and select suitable soft magnetic materials so that the current transformer can sample current signals varying in the frequency range of 10kHz-100kHz. The current transformer TA can, for example, adopt the T-24-CT02 current transformer produced by Tianjin Railway Signal Co., Ltd.

[0114] In the present utility model, if Figure 2 The circuit connection diagram of the sampling signal output unit 111 is an embodiment of the sampling signal output unit. The current transformer TA used can pass through the secondary side lead wire of the high-frequency transformer T1 in a through-hole manner and be fixed to the secondary side lead wire. A Hall current sensor or other method can also be used to sample and output the current sampling signal.

[0115] In the present utility model, the specific implementation is as follows: Figure 2As shown, by using an operational amplifier U1 to form a subtractor circuit, the error signal of the voltage value between this module and the current sharing bus V_JLBUS+ is amplified. For example, R4=R5=5.1kΩ, R3=R6=5.1MΩ, then the difference is amplified by 1000 times, that is, the output voltage V_ERR of the operational amplifier U1 is V_ERR=1000X(V_JLBUS+-V_JL-). The operational amplifier U1 can be a general model, such as the LM358 operational amplifier of TI Texas Instruments or STMicroelectronics, or it can be replaced by an instrument amplifier.

[0116] In the present invention, the photocoupler U2 in the isolation unit 114 is used to realize the isolation function of the current sharing bus of the power supply system and the current sharing circuit (i.e., the current sharing device) inside the voltage module. When the module is working normally, the photocoupler U2 needs to be in a closed state, and when the module is in an abnormal state, the photocoupler U2 needs to be in a disconnected state. The photocoupler U2 used in the isolation unit 114 is a universal signal, which can be a PC817C model, which is produced by Guangdong Youtai Semiconductor Co., Ltd., Shenzhen Sacco Micro Semiconductor Co., Ltd. and other companies, or a universal model photocoupler of other companies.

[0117] In order to more clearly understand the technical solution of the utility model, the working principle of the utility model is explained below.

[0118] According to the utility model, the output current is sampled by the current transformer TA, so that each current balancing device is isolated from the main circuit of the power module to which it is connected, and the failure of the current balancing device will not affect the operation of the main circuit of the power module;

[0119] At the same time, the utility model also uses the isolation unit 114 to enable each power module to be controllably connected to the current-sharing bus BUS+ of the power system. If one of the power modules fails, the isolation unit 114 is controlled by a fault signal to cut off the connection between the failed power module and the current-sharing bus BUS+ of the power system, and automatically exit current sharing, thereby not affecting the current-sharing work of the current-sharing bus BUS+ of the power system and the remaining power modules, thereby improving the reliability of the power module.

[0120] The following combination Figure 1 , Figure 2 And a specific embodiment is used to specifically illustrate the working process of the utility model:

[0121] For a power supply system, first, the output current signal of each power supply module is collected and sampled through the sampling signal output unit 111 in each power supply module, and then the voltage signal V_JL converted from the output current signal of the power supply unit 110 in each power supply module is output to the difference signal output unit 112;

[0122] Then, the difference signal between the sampling signal (ie, the voltage signal V_JL) and the current sharing bus signal is obtained through the difference signal output unit 112 in each power module;

[0123] Then, the difference signal is amplified by the difference signal output unit 112 in each power module, and the amplified difference signal ERR is output to the control signal output unit 113 in each power module;

[0124] It should be noted that see Figure 2 As shown, the operational amplifier U1 can be used to amplify the difference signal ERR, and the resistors R3, R4, R5, R6 and U1 together form a subtractor to amplify the input difference, thereby obtaining the difference signal ERR output by the difference signal output unit 112. The difference signal ERR is input to the control signal output unit 113, connected to the resistor R8 of the control signal output unit 113, and the bias voltage connected through the resistor R9 is superimposed to output a Vref voltage signal as a reference voltage of the operational amplifier inside the PWM controller U3.

[0125] In the present utility model, the realization of current sharing of multiple power modules refers to: N power modules are connected in parallel to provide current to the load together, the total current is I, the output current of each module is one Nth of the total current, and the output current of the actual module should provide a current equal to I / N±a%, and it is generally required to control a≤5.

[0126] Finally, the control signal output unit 113 in each power module adjusts the current PWM waveform (pulse width modulation waveform) output by the power supply unit 110 in the power module according to the reference level Vref of the PWM controller U3, and then adjusts the output voltage of each power module, ultimately achieving the effect of current sharing.

[0127] It should be noted that see Figure 2 As shown, the op amp reference level Vref is the voltage of the non-inverting input terminal of the PWM controller U3, which is the reference voltage of the voltage negative feedback control loop. Together with the output voltage feedback signal Vfb as the inverting input terminal of the PWM controller U3, it controls the output drive signal pulse width to keep the output voltage stable. Specifically, when the module output is stable, the voltage of the non-inverting input terminal of the PWM controller is the same as the voltage of the inverting terminal, that is, Vref=Vfb=V_out+*(R11 / (R11+R10)). When Vref is adjusted to be smaller, the module output voltage V_out+=Vref*(R10+R11) / R11 will also decrease proportionally.

[0128] The PWM controller is a dedicated integrated circuit that generates a PWM drive signal. The PWM pulse width can be changed by adjusting the reference voltage at the non-inverting input terminal of the PWM controller.

[0129] See also Figure 2 As shown, for the Vref voltage adjustment circuit composed of resistors R8 and R9, one end of resistor R9 is 2.5V. When the difference signal ERR is positive, the voltage of Vref will be raised, and when the difference signal ERR is negative, the voltage of Vref will be lowered. The change of the ERR difference signal will change the voltage of Vref.

[0130] In the present invention, a PWM waveform is generated by a PWM controller U3 to control the on and off of the switch tube S of the power supply unit 110 in the power module. The PWM waveform is adjusted, that is, the pulse width is adjusted, and the on and off time of the power tube (i.e., the switch tube S) is changed, thereby adjusting the output voltage of the power module.

[0131] For example, when the output current of a power module increases and exceeds the average level on the current sharing bus BUS+, the power module Figure 2 The voltage at the inverting input terminal of the operational amplifier U1 is greater than the voltage at the non-inverting input terminal. After being amplified by the error amplifier E, the output difference signal ERR is negative. In this embodiment, the negative value ERR pulls down the reference level signal Vref. The reference level signal reduces the output voltage of the power module through the voltage feedback loop control, thereby reducing the output current of the power module and completing the current sharing regulation.

[0132] In this utility model, see Figure 2 As shown, when the current-sharing bus voltage V_JLBUS+ is higher than the voltage value V_JL corresponding to the output current of the power supply unit 110 in the power module, the difference amplification signal ERR is negative, that is, Vref will decrease. When ERR is 0, Vref = 2.5V, when ERR = -xV, Vref is a voltage value between -x and 2.5, and the resistance value is determined by the voltage-dividing resistors R8 and R9, that is, Vref = 2.5-R9*(2.5+x) / (R8+R9).

[0133] See also Figure 2 As shown, the voltage feedback loop includes resistors R10, R11 and a PWM controller U3; the voltage divider resistors in the voltage feedback loop are composed of R10 and R11, and the voltage Vfb obtained by dividing the voltage at the output terminal V_out+ of the power supply unit 110 in the voltage module by resistors is the feedback voltage, and the size of Vfb directly reflects the size of the output voltage. The feedback voltage is input to the inverting input terminal of the PWM controller U3, and together with the PWM controller U3, the voltage feedback control is completed.

[0134] In this utility model, see Figure 2 As shown, after the module output voltage is adjusted, when the output current corresponding voltage V_JL of the power supply unit 110 in this voltage module is equal to the current sharing bus voltage V_JLBUS+, the ERR voltage value is 0, and the PWM controller stably outputs the drive signal. When the output current corresponding voltage V_JL of this module is greater than the current sharing bus voltage V_JLBUS+, the output voltage of the power module will be reduced. Resistors R3, R4, R5, and R6 determine the size of the ERR output by the subtractor, and thus determine the variation range of Vref. Each module is compared with the current sharing bus, and no adjustment is made when the output current is adjusted to be the same as the current sharing bus.

[0135] In the utility model, the PWM controller U3 is a mature controller in the prior art, for example, it can be a TL494 series chip of Texas Instruments TI or an EG7500 model controller of Yijing Microelectronics, or other control chips of the same type, which can be used as a PWM controller to realize output voltage feedback control.

[0136] In addition, when the output current of a power module decreases and is lower than the average level of the current sharing bus BUS+, a potential difference of negative at the top and positive at the bottom appears on the second resistor R2 of the power module. After amplification by the operational amplifier U1, the difference amplification signal ERR is positive. In this embodiment, the difference amplification signal ERR is greater than 0V at this time, and the reference level signal Vref superimposed with the bias voltage 2.5V increases. The PWM controller in the control signal output unit 113 adjusts the output PWM control signal according to the change of the reference level signal, controls the switch tube S of the power supply unit 110 in the power module, and increases the module output voltage, thereby increasing the output current of the power module and completing the current sharing regulation.

[0137] See also Figure 2 As shown, when the output current of the power module decreases, it is lower than the average level of the current sharing bus BUS+, that is, the voltage at the non-inverting input terminal of the operational amplifier U1 represents the current sharing bus, the non-inverting terminal is greater than the inverting terminal, and the error amplifier outputs a positive signal, that is, ERR is greater than 0V, which will raise Vref, and the increased reference level signal Vref. The control signal output unit 113 increases the output voltage of the power module through the voltage feedback loop control according to the reference level signal, thereby increasing the output current of the power module and completing the current sharing regulation.

[0138] Thus, it can be seen that the current balancing scheme adopted by the utility model is relatively stable and does not have serious interference problems because the current balancing bus BUS+ is an average level. Each power module controls its own output current waveform (i.e., pulse width modulation PWM waveform) by comparing its own output current with the current balancing bus signal provided by the current balancing bus. There is no mutual interference between the power modules and between the current balancing device and the main circuit of the power module.

[0139] Compared with the prior art, the current balancing module and power supply system provided by the utility model have the following beneficial effects:

[0140] 1. The utility model can realize current sharing of multiple power modules through non-master-slave current sharing control, thereby improving the scalability of the power supply system;

[0141] 2. In the present invention, the current sharing control of a single power module is isolated from its own main circuit, and a current transformer is used to isolate and sample the output current. At the same time, the feedback part is also isolated through an isolation unit, thereby improving the reliability of the power module;

[0142] 3. In the present invention, each power module independently controls its output current. When a power module fails, it can be disconnected from the current sharing bus. Therefore, the current sharing control between each power module does not interfere with each other, thereby improving the reliability of the power supply system.

[0143] 4. After testing, the utility model has achieved a load imbalance of less than 2% through a non-master-slave current sharing control method.

[0144] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A power module, characterized in that: include: A power supply unit (110) and a current balancing device; A current balancing device, comprising a sampling signal output unit (111), a difference signal output unit (112), a control signal output unit (113) and an isolation unit (114); A sampling signal output unit (111), connected to the power supply unit (110), used for collecting an output current signal of the power supply unit (110), and then outputting the signal to the difference signal output unit (112); An isolation unit (114) is connected to the current sharing bus BUS+ and is used to isolate the current sharing bus BUS+ from the difference signal output unit (112) in the current sharing device, and output a current sharing line voltage signal V_JLBUS+ to the difference signal output unit (112) after isolating the voltage on the current sharing bus BUS+; A difference signal output unit (112) is connected to the output ends of the sampling signal output unit (111) and the isolation unit (114), and is used to receive an output current signal of the power supply unit (110) sent by the sampling signal output unit (111), and then compare the output current signal with the current-sharing line voltage V_JLBUS+ signal output by the isolation unit (114) through an operational amplifier U1 therein, and then output a current difference signal ERR to the control signal output unit (113); A control signal output unit (113) connected to the output ends of the difference signal output unit (112) and the power supply unit (110), respectively, and configured to obtain a corresponding control signal based on the current difference signal ERR output by the difference signal output unit (112) and the voltage signal output by the output end of the power supply unit (110), and then output the corresponding control signal to the power supply unit (110); The power supply unit (110) is connected to the control signal output unit (113) and is used to receive the control signal output by the control signal output unit (113), and adjust the voltage of its output terminal V_out+ accordingly according to the change of the duty cycle of the control signal, thereby adjusting the output current.

2. The power module according to claim 1, characterized in that: The power supply unit (110) includes a switch tube S, a transformer T1, diodes D5, D6 and an electrolytic capacitor CD1; The input terminal 1 of the primary side of the transformer T1 is connected to the positive terminal of the input power supply Vin; The negative terminal of the input power supply Vin is connected to the input terminal 2 of the primary side of the transformer T1 through the switch tube S; The output terminal 6 of the secondary side of the transformer T1 is connected to the anode of the diode D5; The output terminal 3 of the secondary side of the transformer T1 is connected to the anode of the diode D6; The cathodes of diodes D5 and D6 are connected to the positive output terminal V_out+ after the currents converge and intersect; The positive output terminal V_out+ is connected to the negative output terminal V_out- through the electrolytic capacitor CD1; A connecting wire between the output terminal 5 and the output terminal 4 of the secondary side of the transformer T1 is connected to the primary side of the current transformer TA in the sampling signal output unit (111); The output terminal 4 on the secondary side of the transformer T1 is also connected to the negative electrode of the electrolytic capacitor CD1.

3. The power module according to claim 2, characterized in that: The power module is connected to the load LOAD; The positive terminal of the load LOAD is connected to the positive output terminal V_out+; The negative terminal of the load LOAD is connected to the negative output terminal V_out--.

4. The power module according to claim 1, characterized in that: The sampling signal output unit (111) comprises: a resistor R1, a current transformer TA and diodes D1~D4; The primary side of the current transformer TA is connected to the secondary side lead wire of the high-frequency transformer T1 of the power supply unit (110) in the power module, and is used to collect the output current signal of the power supply unit (110) in the power module; The secondary side of the current transformer TA is connected to the input end of the bridge rectifier circuit composed of diodes D1, D2, D3 and D4; The output end of the bridge rectifier circuit is connected in parallel to both ends of the resistor R1; One end of the resistor R1, as the current sampling signal output end of the sampling signal output unit (111), is connected to the common end of the resistors R4 and R2 in the difference signal output unit (112); The other end of the resistor R1 is connected to the current sharing ground line V_JL.

5. The power module according to claim 1, characterized in that: A difference signal output unit (112), comprising resistors R2-R6 and an operational amplifier U1; One end of the resistor R2 is connected to one end of the resistor R1 and one end of the resistor R4 in the sampling signal output unit (111) respectively; The other end of the resistor R2 is connected to the current sharing bus BUS+ via the photoelectric coupler U2 in the isolation unit (114); The other end of the resistor R2 is also connected to one end of the resistor R5; The other end of the resistor R4 is connected to the inverting input end of the operational amplifier U1 and one end of the resistor R6 respectively; The other end of the resistor R6 is connected to the output end of the operational amplifier U1; The output end of the operational amplifier U1 is connected to one end of the resistor R8 in the control signal output unit (113); The other end of the resistor R5 is connected to the non-inverting input end of the operational amplifier U1 and one end of the resistor R3 respectively; The other end of the resistor R3 is the reference ground.

6. The power module according to claim 5, characterized in that: One end of the resistor R5 that intersects with the second resistor R2 is connected to the third pin of the photoelectric coupler U2 in the isolation unit (114).

7. The power module according to claim 1, characterized in that: A control signal output unit (113) comprises: resistors R8-R11 and a PWM controller U3; One end of the resistor R8, serving as a receiving end of the control signal output unit (113), is connected to the output end of the operational amplifier U1 inside the difference signal output unit (112); The other end of the resistor R8 is connected to one end of the resistor R9 and the non-inverting input end of the PWM controller U3 respectively; The other end of the resistor R9 is connected to the reference voltage 2.5V; One end of the resistor R10 is connected to the positive output terminal V_out+ of the power supply unit (110) in the power module; The other end of the resistor R10 is connected to one end of the resistor R11 and the inverting input end of the PWM controller U3 respectively; The other end of the resistor R11 is connected to the negative output terminal V_out- of the power supply unit (110) in the power module; The output end of the PWM controller U3 is connected to the control end of the switch tube S of the power supply unit (110) in the power module.

8. The power module according to any one of claims 1 to 7, characterized in that: An isolation unit (114), comprising a photoelectric coupler U2 and a seventh resistor R7; The fourth pin of the photocoupler U2 is connected to the current sharing bus BUS+; The third pin of the photoelectric coupler U2 is connected to the common end of the resistors R2 and R5 in the difference signal output unit (112); The first pin of the photocoupler U2 is connected to the DC power supply; The second pin of the photocoupler U2 is used to connect to the external control signal output terminal.

9. A power supply system, characterized in that: comprising a plurality of power modules according to any one of claims 1 to 8; Multiple power modules are DC power modules with parallel output.

10. The power supply system according to claim 9, characterized in that: The isolation units (114) in the plurality of power modules are respectively connected to the current sharing bus BUS+; The sampling signal output units (111) in the plurality of power modules are respectively connected to the current-sharing ground line JL-.

Images