CN103687297A - Power resistor on printed circuit board and method for designing resistor - Google Patents

Abstract

The invention discloses a power resistor on a printed circuit board and a method for designing the power resistor. According to the power resistor on the printed circuit board, the power resistor is a circuit section on the printed circuit board and is formed by conductive substances; the power resistor is connected with other components through a bonding pad; length, width, and thickness of the circuit section are determined by parameters of the power resistor, current passing through the power resistor, and parameters of the conductive substances. The adoption of the power resistor on the printed circuit board and the method for designing the power resistor can greatly save structural space of a system; additional heat dissipation treatment is not required; length, width and thickness of the power resistor can be designed flexibly according to different design requirements, so that the design complexity of circuit principle is reduced.

Description

Power resistor on a kind of printed circuit board (PCB) and the method for designing of this resistance

Technical field

The principle design technical field that the present invention relates to Power Electronic Circuit, relates in particular to a kind of resistance little, the power resistor on high-power printed circuit board (PCB) and the method for designing of this power resistor.

Background technology

In the principle design process of existing Power Electronic Circuit, if required power resistance device, conventionally designer can use in type power resistor device or uses moulding device to carry out connection in series-parallel or to producer's customization power resistor device, meet principle design demand.For example: in photovoltaic system, conventionally will adopt three rank LCL filters to carry out filtering, because the resistance value of LCL filter is inversely proportional to the power frequency flowing through, frequency is higher, and impedance is less, can filtering high-frequency harmonic.Yet, the shunting action of filter capacitor, make the current control system of rectifier become three rank from single order, control more complicatedly, and under some higher harmonic current, the total impedance of LCL filter approaches zero, cause resonance effect, affect the steady-state behaviour of system, so under the topology of this Power Electronic Circuit, the power resistor of all need to connecting on electric capacity.Conventionally power resistor device is placed on to the electric capacity side in photovoltaic system rack.And the feature of this power resistor is that resistance is very little, but power is very large, causes the volume of resistance larger, be placed in described rack and need to take certain space, and power resistor can generate heat in circuit; The size of resistance and power also will regulate according to the power grade of photovoltaic system, if resistance and power demand be not in conventional resistance range, also needs carry out connection in series-parallel or customize to producer with conventional resistance.Again for example: in the static switch switch unit of EPS system, switch speed is for cutting soon <4ms, employing controllable silicon switches, because switch speed is fast, the in the situation that at electrical network, abnormal and locking phase potential difference being larger, there will be electric current between civil power and inversion, mutually to pour in down a chimney phenomenon, for preventing pouring in down a chimney, when switching, add buffer circuit.This buffer circuit comprises power resistor, and these power resistors can be placed on the printed circuit board (PCB) of static switch switch unit conventionally.And the feature of power resistor on the printed circuit board (PCB) of described static switch switch unit is also that resistance is very little, but power is very large.Like this, just cause the volume of power resistor larger, be placed in the printed circuit board (PCB) of described static switch switch unit and need to take larger space, and described power resistor in circuit because loss is larger, and heat release is more; And the resistance of described power resistor and the size of power also will regulate according to the power grade of EPS system, if resistance and power demand be not in conventional resistance range, also need carry out connection in series-parallel or customize to producer with conventional resistance.

In realizing the design process of available circuit principle, inventor finds that in prior art, there are the following problems:

The common resistance of power resistor needing is in some applications less, but the power consuming is larger, generate heat more, and it is also larger to take system configuration space, thereby makes system space utilance poor, also needs extra radiating treatment; Because resistance and the choosing of power of power resistor is restricted, thereby make the design of circuit theory comparatively complicated.

Summary of the invention

Embodiments of the invention provide power resistor on a kind of printed circuit board (PCB) and the method for designing of this power resistor.For achieving the above object, embodiments of the invention adopt following technical scheme:

A power resistor on printed circuit board (PCB), comprising: described power resistor is the part of path that on printed circuit board (PCB), conductive materials forms; Described power resistor is connected with other components and parts by pad; The length of described part of path, width and thickness are by described power resistor parameter, definite by electric current and the described conductive materials parameter of described power resistor.

A method for designing for power resistor on printed circuit board (PCB), comprising:

Obtain the resistance parameter of power resistor, by electric current and the described conductive materials parameter of described power resistor;

According to the resistance parameter of described power resistor, by electric current and the described conductive materials parameter of described power resistor, obtain the part of path parameter that on described printed circuit board (PCB), conductive materials forms; The part of path that on described printed circuit board (PCB), conductive materials forms is described power resistor.

Power resistor on a kind of printed circuit board (PCB) provided by the invention and the method for designing of this power resistor, described power resistor is the part of path that on printed circuit board (PCB), conductive materials forms; Described power resistor is connected with other components and parts by pad; The length of described part of path, width and thickness are by described power resistor parameter, definite by electric current and the described conductive materials parameter of described power resistor.Adopt power resistor on printed circuit board (PCB) provided by the invention and the method for designing of this power resistor not only can greatly save the structure space of system, without extra heat dissipation, process, can also, according to the length of design requirement flexible design power resistor, width, thickness, reduce the design complexities of circuit theory.

Accompanying drawing explanation

Power resistor structural representation on a kind of printed circuit board (PCB) that Fig. 1 provides for the embodiment of the present invention;

The method for designing flow chart of power resistor on a kind of printed circuit board (PCB) that Fig. 2 provides for the embodiment of the present invention.

Embodiment

Power resistor on a kind of printed circuit board (PCB) embodiment of the present invention being provided below in conjunction with accompanying drawing and the method for designing of this power resistor are described in detail.

As shown in Figure 1, the power resistor on a kind of printed circuit board (PCB) providing for the embodiment of the present invention; The method comprises: described power resistor is the part of path that on printed circuit board (PCB) 102, conductive materials forms; Described power resistor 101 is connected with other components and parts by pad 103; The length of described part of path, width and thickness are by described power resistor parameter, definite by electric current and the described conductive materials parameter of described power resistor.

Wherein, described power resistor parameter comprises: the resistance value of power resistor; Described conductive materials parameter comprises: the resistivity of conductive materials, temperature coefficient.

It should be noted that, described conductive materials is copper, or the electric conducting material such as gold, silver, alloy.

Also it should be noted that, the length of described part of path, width and thickness are determined by following formula:

wherein, the resistivity that ρ is conductive materials, the Ω m of unit, the length that L is described part of path, the m of unit; H is the thickness of described part of path, the m of unit; D is the width of described part of path, the m of unit;

In formula, the thickness H of part of path, determines according to design requirement;

The width D of part of path, according to by the electric current of power resistor, the thickness H of part of path, the temperature rise of power resistor is determined.

Also it should be noted that, the power resistor shape that the embodiment of the present invention provides can arrange flexibly according to the design requirement of printed circuit board (PCB).

As shown in Figure 2, the method for designing flow chart of power resistor on a kind of printed circuit board (PCB) providing for the embodiment of the present invention;

S201: obtain the resistance parameter of power resistor, by electric current and the described conductive materials parameter of described power resistor;

S202: according to the resistance parameter of described power resistor, by electric current and the described conductive materials parameter of described power resistor, obtain the part of path parameter that on described printed circuit board (PCB), conductive materials forms; The part of path that on described printed circuit board (PCB), conductive materials forms is described power resistor.

Wherein, described power resistor parameter comprises: the resistance value of power resistor; Described conductive materials parameter comprises: the resistivity of conductive materials, temperature coefficient; The part of path parameter that on described printed circuit board (PCB), conductive materials forms, comprising: the length of described part of path, width and thickness, the part of path that on described printed circuit board (PCB), conductive materials forms is described power resistor.

It should be noted that, obtain the part of path parameter that on described printed circuit board (PCB), conductive materials forms; The step that the part of path that on described printed circuit board (PCB), conductive materials forms is described power resistor, comprising:

Obtain the computing formula of the part of path parameter that on described printed circuit board (PCB), conductive materials forms, the part of path that on described printed circuit board (PCB), conductive materials forms is described power resistor; The length of described part of path, width and thickness are determined by following formula:

wherein, the resistivity that ρ is conductive materials, the Ω m of unit, the length that L is described part of path, the m of unit; H is the thickness of described part of path, the m of unit; D is the width of described part of path, the m of unit;

In formula, the thickness H of part of path, determines according to design requirement;

The width D of part of path, according to by the electric current of power resistor, the thickness H of part of path, the temperature rise of power resistor is determined.

According to the described computing formula of obtaining, determine length, width and the thickness of described part of path.

For example: the power resistor in photovoltaic system on LCL filter capacity branch road, described power resistor covers copper by printed circuit board (PCB) to be realized, power resistor resistance: 0.1 Ω, the electric current by resistance is 18A; The resistivity of conductive materials copper: 1.7 * 10 ^-8Ω * m(20 ℃), temperature coefficient: 0.00393/ ℃.According to above parameter, the length of described part of path, width and thickness are determined by following formula:

The thickness H of described part of path: selecting printed circuit board (PCB) copper thickness is 70um;

The width D of described part of path: according to test, copper is thick is 70um, what width was 6mm covers copper for a long time by the electric current of 18A, can meet the temperature rise requirement of system under the natural type of cooling; .

The length L of described part of path: $L=\frac{R\&times;D\&times;H}{\mathrm{\&rho;}}=\frac{0.1\&times;70\&times;{10}^{-6}\&times;6\&times;{10}^{-3}}{1.7\&times;{10}^{-8}}=2.47m;$

For example: the power resistor in static switch switch unit, described power resistor covers copper by printed circuit board (PCB) to be realized, power resistor resistance: 0.8 Ω, the electric current by resistance is 15A; The resistivity of conductive materials copper: 1.7 * 10 ^-8Ω * m(20 ℃), temperature coefficient: 0.00393/ ℃.According to above parameter, the length of described part of path, width and thickness are determined by following formula:

The thickness H of described part of path: selecting printed circuit board (PCB) copper thickness is 35um;

The width D of described part of path: according to test, copper is thick is 35um, what width was 5mm covers copper for a long time by the electric current of 15A, can meet the temperature rise requirement of system under the natural type of cooling;

The length L of described part of path: $L=\frac{R\&times;D\&times;H}{\mathrm{\&rho;}}=\frac{0.8\&times;35\&times;{10}^{-6}\&times;5\&times;{10}^{-3}}{1.7\&times;{10}^{-8}}=8.23m;$

Power resistor on a kind of printed circuit board (PCB) provided by the invention and the method for designing of this power resistor, described power resistor is the part of path that on printed circuit board (PCB), conductive materials forms; Described power resistor is connected with other components and parts by pad; The length of described part of path, width and thickness are by described power resistor parameter, definite by electric current and the described conductive materials parameter of described power resistor.Adopt power resistor on printed circuit board (PCB) provided by the invention and the method for designing of this power resistor not only can greatly save the structure space of system, without extra heat dissipation, process, can also, according to length, width, the thickness of different design requirement flexible design power resistors, reduce the design complexities of circuit theory.

One of ordinary skill in the art will appreciate that all or part of step realizing in above-described embodiment method is to come the hardware that instruction is relevant to complete by program, described program can be stored in a computer read/write memory medium, this program is when carrying out, comprise the steps: (step of method), described storage medium, as: ROM/RAM, magnetic disc, CD etc.

The above; be only the specific embodiment of the present invention, but protection scope of the present invention is not limited to this, is anyly familiar with those skilled in the art in the technical scope that the present invention discloses; can expect easily changing or replacing, within all should being encompassed in protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of described claim.

Claims (7)

1. the power resistor on printed circuit board (PCB), is characterized in that, described power resistor is the part of path that on printed circuit board (PCB), conductive materials forms; Described power resistor is connected with other components and parts by pad; The length of described part of path, width and thickness are by described power resistor parameter, definite by electric current and the described conductive materials parameter of described power resistor.

2. the power resistor on printed circuit board (PCB) according to claim 1, is characterized in that, described power resistor parameter comprises: the resistance value of power resistor; Described conductive materials parameter comprises: the resistivity of conductive materials, temperature coefficient.

3. the power resistor on printed circuit board (PCB) according to claim 2, is characterized in that, described conductive materials is copper, or the electric conducting material such as gold, silver, alloy.

4. according to the power resistor on the printed circuit board (PCB) described in any one in claims 1 to 3, it is characterized in that, the length of described part of path, width and thickness are determined by following formula:

wherein, the resistivity that ρ is conductive materials, the Ω m of unit, the length that L is described part of path, the m of unit; H is the thickness of described part of path, the m of unit; D is the width of described part of path, the m of unit;

In formula, the thickness H of part of path, determines according to design requirement;

The width D of part of path, according to by the electric current of power resistor, the thickness H of part of path, the temperature rise of power resistor is determined.

5. a method for designing for power resistor on printed circuit board (PCB), is characterized in that, comprising:

Obtain the resistance parameter of power resistor, by electric current and the described conductive materials parameter of described power resistor;

According to the resistance parameter of described power resistor, by electric current and the described conductive materials parameter of described power resistor, obtain the part of path parameter that on described printed circuit board (PCB), conductive materials forms, the part of path that on described printed circuit board (PCB), conductive materials forms is described power resistor.

6. the method for designing of power resistor on printed circuit board (PCB) according to claim 5, is characterized in that, described power resistor parameter comprises: the resistance value of power resistor; Described conductive materials parameter comprises: the resistivity of conductive materials, temperature coefficient; The part of path parameter that on described printed circuit board (PCB), conductive materials forms, comprising: the length of described part of path, width and thickness, the part of path that on described printed circuit board (PCB), conductive materials forms is described power resistor.

7. the method for designing of power resistor on printed circuit board (PCB) according to claim 6, is characterized in that, obtains the part of path parameter that on described printed circuit board (PCB), conductive materials forms; The step that the part of path that on described printed circuit board (PCB), conductive materials forms is described power resistor, comprising:

Obtain the computing formula of the part of path parameter that on described printed circuit board (PCB), conductive materials forms, the part of path that on described printed circuit board (PCB), conductive materials forms is described power resistor; The length of described part of path, width and thickness are determined by following formula:

wherein, the resistivity that ρ is conductive materials, the Ω m of unit, the length that L is described part of path, the m of unit; H is the thickness of described part of path, the m of unit; D is the width of described part of path, the m of unit;

In formula, the thickness H of part of path, determines according to design requirement;

The width D of part of path, according to by the electric current of power resistor, the thickness H of part of path, the temperature rise of power resistor is determined;

According to the described computing formula of obtaining, determine length, width and the thickness of described part of path.

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