Automatic overvoltage protection device for multi-winding series charging power supply

Abstract

The invention belongs to the technical field of charging power supplies, and particularly relates to an automatic overvoltage protection device for a multi-winding series charging power supply. The multi-winding series charging power supply is mainly composed of an inversion unit, a resonance network, a transformer and n diode rectification modules. The automatic overvoltage protection circuit comprises n isolation units and n overvoltage protection units in one-to-one correspondence with the n isolation units, the n isolation circuits are respectively connected in parallel with the two ends of the n diode rectification modules, and the n overvoltage protection units are respectively connected in parallel with the two ends of the overload; the isolation unit comprises a bleeder resistor R and a switch K which are connected in series; the overvoltage protection unit comprises a light-emitting diode Da, a voltage-regulator tube Db, a divider resistor Ra and a divider resistor Rb, the voltage-regulator tube Db, the divider resistor Ra and the divider resistor Rb are sequentially connected in series, and the light-emitting diode is connected to the two ends of the divider resistor Ra in parallel.

Description

Technical Field

[0001] The invention belongs to the technical field of charging power supplies, and in particular relates to an automatic overvoltage protection device for a charging power supply with multiple windings connected in series. Background Art

[0002] The series resonant circuit is a type of soft switching converter. It has the advantages of topological structure, high power density, and high conversion efficiency. It is widely used in switching power supplies. The series resonant circuit has low voltage DC input and high voltage DC output, such as Figure 1 As shown in the figure, it consists of an inverter unit, a resonant network, a charging transformer, and a diode rectifier module. The main role of the charging transformer in the resonant charging circuit is very important, and it is also a difficult component. Due to the high output voltage of the transformer, it is very difficult to implement. Therefore, it is implemented by using a method of rectifying multiple windings separately and then superimposing them in series.

[0003] The main disadvantage of the series resonator is the danger of overvoltage when the load is open-circuited. In order to overcome the disadvantage of overvoltage generated by the series resonant converter when the load is open-circuited, an effective overvoltage protection circuit can be set during the design.

[0004] At present, in engineering applications, overvoltage protection usually adopts the method of quickly reducing the frequency of the inverter drive signal and the number of inverter units to reduce its output voltage; adopting the method of blocking the inverter drive signal to limit the further increase of the output voltage; and adopting the method of cutting off the initial power supply and connecting the high-voltage discharge circuit or crowbar circuit to completely stop the power supply. The above overvoltage protection methods need to be controlled by the power system to achieve protection or will affect the load power supply, and the corresponding speed of the protection is limited by the sampling and control system algorithm, and cannot be applied to occasions with demanding load power supply requirements under overvoltage voltage. Summary of the invention

[0005] The purpose of the present invention is to provide an automatic overvoltage protection device for a multi-winding series charging power supply to solve the shortcomings of the existing overvoltage protection method that the protection needs to be achieved through power system control or affects the load power supply, and the corresponding speed of the protection is limited by the sampling and control system algorithm, and cannot be applied to occasions with strict load power supply requirements under overvoltage.

[0006] The technical solution for implementing the present invention is as follows:

[0007] An automatic overvoltage protection device applied to a multi-winding series charging power supply, the multi-winding series charging power supply mainly consists of an inverter unit, a resonant network, a transformer and n diode rectifier modules; the automatic overvoltage protection circuit includes: n isolation units and n overvoltage protection units corresponding to the isolation units; the n isolation circuits are respectively connected in parallel to the two ends of the n diode rectifier modules, and the n overvoltage protection units are respectively connected in parallel to the two ends of the overload;

[0008] The isolation unit includes a discharge resistor R and a switch K connected in series;

[0009] The overvoltage protection unit includes: a light emitting diode Da, a voltage stabilizing tube Db, a voltage dividing resistor Ra and a voltage dividing resistor Rb, wherein the voltage stabilizing tube Db, the voltage dividing resistor Ra and the voltage dividing resistor Rb are connected in series in sequence, and the light emitting diode is connected in parallel to both ends of the voltage dividing resistor Ra.

[0010] Furthermore, the voltage-dividing resistors of the n overvoltage protection units described in the present invention are respectively recorded as Ra1-Ran and Rb1-Rbn, and the resistance values ​​of the voltage-dividing resistors satisfy Ra1 / (Ra1+Rb1)>Ra2 / (Ra2+Rb2)>…>Ran / (Ran+Rbn).

[0011] Furthermore, the conduction voltage of the voltage regulator tube of the present invention satisfies Ran (V 0 -Vd) / (Ran+Rbn)>VD.

[0012] Furthermore, the voltage regulator tube and the light emitting diode of the present invention can withstand a transient voltage shock greater than V 0 , R and K withstand voltage greater than V 0 / n.

[0013] Furthermore, the withstand voltage of Ra and Rb in the present invention is greater than V 0 .

[0014] Beneficial Effects

[0015] The method adds an automatic overvoltage protection circuit to the secondary side of the charging transformer of the multi-winding series charging power supply, which can automatically detect overvoltage and quickly isolate the output voltage of the charging power supply in sections to avoid adverse effects on the load. The above method can automatically and quickly respond to power supply overvoltage and perform segmented output protection, and has good engineering applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a structural diagram of a charging power supply with multiple windings connected in series;

[0018] Figure 2 The structure diagram of the automatic overvoltage protection circuit for a multi-winding series charging power supply; DETAILED DESCRIPTION

[0019] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0020] It should be noted that the following embodiments and features in the embodiments may be combined with each other in the absence of conflict; and, based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making any creative work are within the scope of protection of the present disclosure.

[0021] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein may be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein may be implemented independently of any other aspect, and two or more of these aspects may be combined in various ways. For example, any number of aspects described herein may be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein may be used to implement this device and / or practice this method.

[0022] like Figure 1-2 As shown, the present invention provides an automatic overvoltage protection circuit for a multi-winding series charging power supply.

[0023] like Figure 1 As shown, the multi-winding series charging power supply is a DC input, and the multiple windings are rectified separately and then superimposed in series for output, including: an inverter unit (for DC to AC conversion), a resonant network (working in a resonant state to achieve zero voltage switching), a transformer (secondary multi-winding output to achieve low voltage to high voltage conversion), and a diode rectifier module (corresponding to n secondary windings, including a total of n modules for AC to DC conversion).

[0024] The automatic overvoltage protection circuit comprises two parts: the first part is the isolation unit of the diode rectifier module, and the second part is the overvoltage protection unit; n isolation units and n overvoltage protection units; the n isolation circuits are respectively connected in parallel to the two ends of the n diode rectifier modules, and the n overvoltage protection units are respectively connected in parallel to the two ends of the overload.

[0025] The isolation unit includes a discharge resistor R and a switch K connected in series; the overvoltage protection unit includes: a light-emitting diode Da, a voltage-stabilizing diode Db, a voltage-dividing resistor Ra and a voltage-dividing resistor Rb, the voltage-stabilizing diode Db, the voltage-dividing resistor Ra and the voltage-dividing resistor Rb are connected in series in sequence, and the light-emitting diode is connected in parallel to both ends of the voltage-dividing resistor Ra.

[0026] In the embodiments of the present application, the resistance values of the voltage-dividing resistors satisfy Ra1 / (Ra1 + Rb1) > Ra2 / (Ra2 + Rb2) >... > Ran / (Ran + Rbn).

[0027] The working principle of the present invention is as follows:

[0028] Assume the load voltage is V 0 , the rated load voltage is V, and the voltage of the voltage-regulating diode Db is VD:

[0029] When the load overvoltage V(1 + 2 / n) > V 0 > V(1 + 1 / n), Ra1(V 0 - VD) / (Ra1 + Rb1) > VD, then the voltage-regulating diode Db1 conducts, the output voltage is clamped, and at the same time the light-emitting diode Da1 conducts, the output voltage is clamped, and at the same time the light-emitting diode Da1 conducts, the light signal reaches the switch K1, K1 closes, and the diode rectification module 1 is isolated from the main circuit through R1 and K1 and discharges the energy in the discharge resistor R1;

[0030] When the load overvoltage V(1 + 3 / n) > V 0 > V(1 + 2 / n), Ra1(V 0 - VD) / (Ra1 + Rb1) > VD, and at the same time Ra2(V 0 - VD) / (Ra2 + Rb2) > VD, then the voltage-regulating diodes Db1 and Db2 conduct, the output voltage is clamped, and at the same time the light-emitting diodes Da1 and Da2 conduct, the light signal reaches the switches K1 and K2, K1 and K2 close, and the diode rectification modules 1 and 2 are isolated from the main circuit through R1 and R2 and discharge the energy in the discharge resistors R1 and R2;

[0031] When the load overvoltage (1 + (k + 1) / n) > V 0 > V(1 + k / n), Rai(V 0 - VD) / (Rai + Rbi) > VD (i = 1, 2..k, k < n), then the voltage-regulating diodes Dbi (i = 1, 2..k) are isolated from the main circuit through Ri (i = 1, 2..k) and Ki (i = 1, 2..k) and discharge the energy in the discharge resistor Ri (i = 1, 2..k);

[0032] When the load V 0 > 2V, Rai(V0 - VD) / (Rai + Rbi) > VD (i = 1, 2..k, k < n), then the voltage-regulating diodes Dbi (i = 1, 2..n) conduct, the output voltage is clamped, and at the same time the light-emitting diodes Dai (i = 1, 2..n) conduct, send a light signal to the switches Ki (i = 1, 2..n) and Ki (i = 1, 2..n) are isolated from the main circuit and discharge the energy in the discharge resistor Ri (i = 1, 2..n).

[0033] According to the working principle of the automatic overvoltage protection circuit applied to the multi-winding series charging power supply, it can automatically isolate the diode rectifier module in sections according to the load overvoltage condition. When the load overvoltage is small, V(1+2 / n)>V 0 >V(1+1 / n), only diode rectifier module 1 is isolated. When the load overvoltage is small, V(1+3 / n)>V 0 >V(1+2 / n), diode rectifier modules 1 and 2 are isolated; when load V 0 When the voltage is >2V, the diode rectifier modules are completely isolated and the load has no output.

[0034] The conduction voltage of the voltage regulator tube of the present invention satisfies Ran(Vo-Vd) / (Ran+Rbn)>VD, and the voltage regulator tube and the light emitting diode withstand an instantaneous voltage shock greater than V 0 , R and K withstand voltage greater than V 0 / n, Ra and Rb withstand voltage is greater than V 0 The load rated voltage V and the load allowable maximum voltage V0 are designed according to equipment requirements.

[0035] The present invention can automatically and quickly respond to power supply overvoltage and perform segmented output protection, and has good engineering applicability.

[0036] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An automatic overvoltage protection device for a multi-winding series charging power supply, wherein the multi-winding series charging power supply is mainly composed of an inverter unit, a resonant network, a transformer and n diode rectifier modules; characterized in that: The automatic overvoltage protection circuit comprises: n isolation units and n overvoltage protection units corresponding thereto one by one; the n isolation circuits are respectively connected in parallel to the two ends of the n diode rectifier modules, and the n overvoltage protection units are respectively connected in parallel to the two ends of the overload; The isolation unit includes a discharge resistor R and a switch K connected in series; The overvoltage protection unit includes: a light emitting diode Da, a voltage stabilizing tube Db, a voltage dividing resistor Ra and a voltage dividing resistor Rb, wherein the voltage stabilizing tube Db, the voltage dividing resistor Ra and the voltage dividing resistor Rb are connected in series in sequence, and the light emitting diode is connected in parallel to both ends of the voltage dividing resistor Ra.

2. The automatic overvoltage protection device for a multi-winding series charging power supply according to claim 1, characterized in that: The voltage-dividing resistors of the n overvoltage protection units are respectively denoted as Ra1-Ran and Rb1-Rbn, and the resistance values ​​of the voltage-dividing resistors satisfy Ra1 / (Ra1+Rb1)>Ra2 / (Ra2+Rb2)>…>Ran / (Ran+Rbn).

3. The automatic overvoltage protection device for a multi-winding series charging power supply according to claim 1, characterized in that: The on-state voltage of the voltage regulator tube satisfies Ran(V0-Vd) / (Ran+Rbn)>VD.

4. The automatic overvoltage protection device for a multi-winding series charging power supply according to claim 1, characterized in that: The voltage regulator tube and the light emitting diode withstand an instantaneous voltage impact greater than V0, and the withstand voltage of R and K is greater than V0 / n.

5. The automatic overvoltage protection device for a multi-winding series charging power supply according to claim 1, characterized in that: The withstand voltage of Ra and Rb is greater than V0.

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