Electric machinery and personnel of design of inverter of electric source control can encounter same question, how will be controlled namely and user interface circuit and segregation of dangerous power line voltage. Keeping apart the mainest demand is circuit of control of damage of voltage of means power line, more important is, protective user is harmed by dangerous tension. The system must accord with the safe requirement that corresponding international standard sets, cover the IEC 61800 of electric machinery drive and solar energy inverter and IEC 62109 for example. These standards basically pay attention to accordance test. How can accordance test of the standard gift is engineer freedom spent? The standard can provide guidance for the engineer in security aspect, but how to gift engineer freedom is spent, where is the corresponding framework that so that can you choose,accords with target system norms and standard, circuit and component? These are satisfy in efficiency, bandwidth and precision respect to offer systematic place to require performance by circuit, satisfy safe segregation to ask to decide again at the same time.

 

The difficult problem that designs innovation system is, the design regulation that drafts to have framework, circuit and element is possible no longer applicable. Accordingly, the engineer needs to spend time to evaluate new circuit or component to accord with the ability of EMC and security standard seriously. The liability of certain zone engineer is bigger, once what design safe function invalidation of the system to cause harm, the engineer may need to assume individual responsibility. The article discussed systematic framework to choose the influence of pair of power source and control circuit design and systematic performance. How is the function promotion that the article still will show cell of newest and usable segregation helped replace a framework to promote a system property below the premise that does not affect security.

 

 

The problem that we care is the order that you need to be offerred according to the user, control surely flow to laden energy from alternating current source. The system of drive of tall n electric machinery that this problem shows 1 times in the graph is aimed at in the graph the following region of 3 power source undertook elaborating: Give, control and power. Security demand is, the user gives circuit to must undertake with the dangerous tension on power circuit potential is kept apart. The framework is decision-making depend on give and segregation bar is placed still is control and power circuit between control circuit between.

 

Segregation introduces to bar can affect signal integrality and raise cost between circuit. The segregation of imitate feedback signal especially difficult, because traditional transformer method can restrain dc signal heft,introduce nonlinear. The digital signal segregation when low speed is quite simple, but special when low defer of high speed or need difficulty, and power consumption is tremendous. The power source in the system that takes 3 photographs inverter is kept apart particularly difficult, because have region of many power source,join comes power source circuit. Power source circuit has 4 different region, these region need need function sex is kept apart between each other; So sex of function of high-end grid drive and need of signal of winding electric current and control circuit is kept apart, although both likelihood and power ground in all.

 

Graph 1. Electric machinery controls the segregation framework in the system

 

Framework of control of blame segregation type is being controlled and collective ground connection exists to join between power source circuit. Such electric machinery control ADC to be able to get all signal in power source circuit. Electric current of electric machinery winding flows into low side inverter when the arm, ADC undertakes sampling in the midpoint place of the PWM signal that is based on a center. The driver of grid of low side IGBT can be simple blame segregation type, but by of PWM signal beard has functional sex to keep apart or implementation of n shift changeover and grid of IGBT of 3 high side are kept apart.

 

Command and the complexity that control the segregation between circuit to cause depend on final application, but involve use only system and communication processor normally. Interface of the face plate before simple processor can manage is in slow fast speed jussive framework is sent to be in on serial interface family expenses equipment or low end can be accepted in industrial application. Because command the tall bandwidth of interface asks, in the high-powered driver that framework of blame segregation type is using at robot and automation application scarcer.

 

Framework of segregation type control is being controlled and collective ground connection exists to join between command circuit. This makes control and very close together coupling can come true between command interface, and can use single processor. Segregation problem turns to signal of power source inverter to come up, bring a series of different challenges thereby. Grid drive signal needs to satisfy the sequential requirement of inverter relative to high-speed number segregation.

 

Because be put in very tall voltage, the driver of magnetism or optical coupling asks in segregation the performance in extremely tall inverter application is good. The requirement of circuit of segregation of dc generatrix voltage criterion moderate, because the dynamic limits of its need and bandwidth are inferior,this is. Feedback of electric machinery electric current is the biggest difficult problem in high-powered driver, because its need tall bandwidth and linear segregation.

 

Voltaic transformer (CT) is very good choice, the segregation signal that provides because of them can be measured easily. CT is had when small electric current nonlinear, won’t transmit dc n, but use extensively at low end in inverter. CT still is used at taking blame segregation type to control the high-power inverter of the framework, because minute of galvanic block sampling is used below these circumstances,can cause loss too big.

 

Open loop and sensor of electric current of effect of closed circuit suddenly Er are measurable communicate signal, because this suits high-end driver more, but suffer maladjusted effect. Block sex spreader can provide tall bandwidth, linear signal, and deflection is low, but amplifier of segregation of need and tall bandwidth, low deflection matchs. Normally, electric machinery controls ADC but signal of electric current of direct sampling segregation, but the substitution measurement framework of a description can change segregation problem digital region, and can promote property considerably.

 

 

Improving a kind of when keep apart systematic degree of linearity common method is move ADC to keep apart digital signal to the another side that keeps apart bar. Below a lot of circumstances, this need combines series connection ADC and digital signal isolator use. Because spread the special demand with feedback high frequency existence to electric machinery report, and need undertakes be responsed quickly to drive protection, because this can choose Σ-Δ ADC. Σ-Δ ADC deserves to one can change imitate signal the linear modulator that flows for a code, deploy ever since can reframe signal the digital filter that is word of high resolution number.

 

The advantage of this method is the digital filter that can use two kinds to be the same as: Slower use at high fidelity feedback, another low protect really fast filter to be used at protecting inverter. In the graph 2 in, winding spreader is used at measuring electric current of electric machinery winding, segregation type ADC is used at 10 MHz data is being transmitted to flow on segregation bar. Sinc filter can submit data of high resolution electric current electric machinery to control algorithm, this algorithmic meeting computation brings to bear on the inverter that wants inverter voltage need occupies sky comparing. Filter of another low resolution can detect voltaic overload, will jump when occurrence breakdown change signal is sent to PWM modulator. The parameter that Sinc filter frequency answers curvilinear explanation to say palpability is appropriate chooses how to can make filter restrains the PWM switch ripple in voltaic sampling.

 

Graph 2. Segregation type electric current feedbacks
 

 

Graph 3. Sinc filter frequency is answered
 

 

Two kinds of common problems that control a framework are to need to support region of many segregation power source. If every region needs many slant buy course, more come true hard. Graph the circuit of 4 can arise + 15 V and –7.5 V voltage are used at grid drive, + 5 V voltage is used at be ADC power supply, all be in inside the country, at the same time every region uses a transformer only winding cites a base with two. Use core of a transformer magnetism and framework to differ for 4 power source region creates double power source or 3 power source.

 

Graph 4. The circuit of segregation power source of grid drive and voltaic feedback converter